I clicked on this link, thinking you were crazy for making an hour long video for OHMS, yet I stayed RIVETED on every word. You sir, are a man who knows his shit....
Thank you my friend! I have total respect for you for actually sticking around and absorbing all of the information. Some folks just don't CARE enough to learn about what they love. lol I truly appreciate you putting in the time and dedication! Cheers
You know, I have been looking on the internet for something that really explained ohms in a way I could understand. This was an hour very well spent. You are a great teacher.
Listening to you is very easy You seem so at ease in front of your cam. I've taken in two really long segments one on amp controls this one on the Ohms and Watts. Both were very instructional and neither was in the least bit preachy, or conceited. You have an innate natural talent.
Hey man, I am an electrician and have had many guitar players ask me questions about ohm ratings and wattage of amps. I think you described it in the easiest put terms I have ever heard. Great video. Very informative. By the way, my favorite head ever was the first series of the Marshall 8100 valve state head. I primarily played death metal in my younger days and that solid state head was a beast! I think it did have AX7 pre amp tubed though. Other than that, when I first started I inherited my older brothers Kramer(silver and black Eddie Van Halen looking thing, bought a single hum buckler Peavey Predator(loved it), and my Peavey Bandit amp. I could have ruled the world(in my room)!
I also are an electrician and started studying electronics and radio stuff in 1975, thanks to a family member. The reason a person can have a 4 speaker cab driven by a 4 ohm head is if you have 4 of the 16 ohm speakers in parallel, the equivalent is 4 ohms. In series, resistance is directly additive. In parallel, it is inverse. So, in parallel, 1/Rt = 1/R1 + 1/R2 + 1/R3 + 1/R4. Well, those add up to .25. And 1/.24 = 4 ohms. So, the real trick is impedance matching and if you have a set of speakers not equal to the output of the amp head, you need an impedance matcher to translate, as it were;
I'm glad that it helped out, if only a little. There is a lot of "Poindexter" stuff that could be explained, but it takes away from playing time. Most want to know what they NEED to know and then get back to playing. So, general conversations and trying to hit on the key points and time to actually plug back in and have some fun! Glad you enjoyed it!
Spot on, about the sound and dependability of tubes vs solid state. Crazy to get tubes today, unless you’re building a museum. I beg to differ on the watts issue, however. 100 watts RMS, perfectly matched to its speakers, will produce the same kick, tubes or solid state. The key is, that it’s RMS (Root Mean Square). If it only says 100 watts, then it’s probably based on “Peak Power Output” which means in a small band width, it could surge to peak at 100 watts, but under continuous usage across the full audio spectrum, it’s likely only 20 watts RMS. Bear in mind, however, 100 watts RMS paired with the wrong speakers (mismatched impedance) can sound like 20 watts as well. The correct impedance assures the highest efficiency. I have compared a 100 watt RMS vintage Silvertone tube amp (four 6L6) matched to six 10 inch speakers, to a Hartke solid state 100 watt RMS matched to two 12 inch speakers, and the solid state Hartke is actually louder than the tube amp (probably because the tubes are old). But of course the issue is mute, since today it makes no sense for a professional musician to go on the road with a tube amp, unless you’re independently wealthy, or as I say, starting a museum collection.
Hey scott, im only 15 and i understood the things you were saying. I really enjoy all your videos, especially ones like this that are really useful and teach you something. your videos have saved me alot of time and money by not falling into the webs that many other people do because the so called experts at guitar center told them to lol. i also pass along this info with my friends and help them out too. again i cant thank you enough for all the help you have given me, keep on rockin!
I knew nothing about anything about half stacks and ohms and watts and i owned one back in the day. Now that i bought my old amp back, Crate GT3500H Shockwave 350 Watt Head, I know what the 220W@4ohm and 350W@2ohm means. I walked into guitar center out here in vegas and told a guy what setup for cabs i want. i want a 4x12 4ohm cab with any celest/sheff speaker and i want a 2x12 for my topper at 4 ohms as well. and i told him why he was very impressed. thats because of this video giving me the knowledge. thanks brother.
solid state for life lol. and i literally just found my baby. Crate GT412SL with celst!!!!!!! 16, 8, 4ohm switch. thanks for the explenation. i have the knowledge. and knowledge is power, in ohms and RMS of course! lol
I learned most of this stuff back when I was putting together the Heathkit stereo amps. back in the mid 60s. My dad bought me two of these kits to teach me about electronics.I made one into a mono 100 watt tube amp for my guitar (a 64 casino I found in the garbage) with one 8 ohm 12" mid range speaker hooked to it. I made the other into a tubed 50 watt per channel stereo with a built in preamp that I hooked up a Heathkit FM tuner my dad built and two 16 ohm 12" full range speakers to it.
As I got older, I bought a 4-12 cabinet with vintage 30 Celestions in it and a Marshall JCM900 SLX Superled Head. Traded it less than 6 months later for a Sovetek 100 Watt Tube head. Still,loved my valve state!
Thanks for all your Utubes. All very informative and very welcome. im 75 and only took up guitar 4 yrs back. I have fun but love your broad knowledge and talent. i must admit to getting lost a little on this one but perhaps watching it a couple of times more will help. even though most is not going to be used by me i just love the knowledge and techniques and your no frills approach. thank you so much. I do have your 200 lessons great deal thanks again.
100%. Of course bass rigs will sometimes use 2 different sized speakers in different cabinets since they are basically using a PA system (as they should) for an amp. So, you have the great amps that have built in crossovers, a couple of power amps, a sub (Usually a 15" or 2 in a cabinet) then their mids and highs in the form of a 4X10 and horn cabinet on top. So, since you are using 2 totally separate amps in the head, they bottom cabinet can be 4 Ohms and Tops be 4 ohms, since separate amps.
I wish it was that easy. You can take a Fender Twin Reverb with 85 watts of massively loud tube power, turn it on 10 and it will remain crystal clear and 100% clean with zero breakup. It's designed to be the cleanest amp around at full power and ear shattering volume. So, that is out the window.
Hi my friend. Nope, the Johnson sounds the same on 1 as it does on 9. It's a beautiful thing. Another MAJOR reason I love it. It fits the bill for all gigs big and small. The sound is always the same. A true blessing for sure.
It's always good to hear someone else's point of view, even if you disagree and in this case I do. Like it or not a tube amp has a different sound quality than a solid state. Solid state amps produce some harmonics that sound harsh to the ear of someone who is used to tube amps. I f you can't hear that a Marshall amp has a unique and identifiable tone that's too bad. For me it's one of the sweetest sounds in music, almost an acoustic tone like a cello as ridiculous as that sounds. It's all subjective and I have heard great sounds come from solid state amps but there is a real reason some people prefer tube amps.
Thanks my friend. Yep, exactly the same for everything including bass rigs, car audio, sound systems and everything relating to amps and speakers all the way across the board.
nice to have it spelled out. most of it is common sense, and you filled in the blanks with the important stuff. Still enjoy learning the mechanics of what I've been doing forever.
Thanks so much. I'm so glad that you stay tuned. Your word of mouth will help plenty and gives me hope for the future and I know that you all won't blow up your stuff. lol Happy playing and I'll always be happy to make any videos that I can to help you with any questions you may have.
I've always loved solid state but had to go with a tube amp when I joined a band because the other guy had a tube amp and it ate up my solid state amp as far as cutting through. Now I'm back in love with tube amps but I still love solid state. Just doesn't seem to cut through the drums, bass, other guitar, etc. as much as my tube amp but they are making them incredibly better these days
I've always understood this subject well just from going to a vocational/trade school, but back when I was first learning about this and the whole guitar amp subject this video would have helped a lot. Very well done Scott.
I learn so much from your videos...the best tjing about them, they are long and elaborate. You take your time and it feels good listening to stuff you say. Nowadays its rare to find people having opinions, you people sort of consider everything as this is good that is also good and blah.. I mean there is a good and a bad and bad doesnt mean it sucks it just means its not in your taste. You are someone I look up to and learn from. Just wanted to thank u man. Keep rocking!\m/
Many thanks my friend! I'm glad that you appreciate the LONG TIME that I put into these instead of yelling at me that it's TOO LONG. lol All my best to you. Scott
groovydjs Me, I like it that way. You could go into ohms law (calculations are actually easy on a calculator) but if you explained it in the way I learned in college (the complicated detailed technical picking nits way) it'd be a 20 hour video.
The exact way to calculate equivalent resistance in parallel is as follows: 1/Req=1/R1+1/R2+1/R3+1/R4+.... ohms.1/Rn. So four 16 ohm speakers in parallel would be and equivalent resistance of 1/16 + 1/16 + 1/16 +1/16 =.0625 +.0625 + .0626 +.0625 = 0.25. Now we have 1/Req=0.25. So Req = 1/.025 =4. For just two in parallel the formula reduces to {(R1) (R2)}/R1 +R2. So two 16 ohm speakers in parallel 16x16 would be an equivalent resistance of {(16)(16)}/16+16 = 256/32=8 ohms.
Wow great info, Solid State amps interesting, I own all tube amps and when I plug into a solid state amp I always say why am I not playing a solid state amp. Its great to hear you say that what a breath of fresh air.
Yet another great and informative video. I'm slowly making my way through your whole channel. Some of this I already knew, some not, so it's always good to keep learning. Especially from someone who actually cares about what they're teaching.
Hi Scott, Thankyou so much for that lamens terms of understanding Ohms. Really gave me a logical non bullshit way of understanding it all. Definitely learnt something new as well.
Thank you so much once again, Scott. You're really a fount of knowledge and I appreciate your generosity with your time. I'm becomming sort of addicted to watching Scott Grove vids now. No matter the subject, you're an interesting speaker (yeah, that was a pun, sorry). So... is there anyone making new solid state amps today that you could get behind and endorse, so to speak? Btw, your vid about your health problems was very touching - wishing you all the best in that battle!!!
Miking will always sound best on a guitar amp. For bass guitar, the direct box is usually the best way to go and should be from the instrument to the D.I. and not from the amp to the PA. I use a direct box at most of my gigs with my guitar since I rarely bring an amp anymore. So, if you are using some sort of a rig that doesn't use an amp at all, then of course, the Direct Box is a must since you'll almost always need to lift the ground on the box or it will be a Buzz Fest! lol
Yeah, it's a great tune. It sounds like the good, old stuff! I got to hear them do it live on the 11th of August. They did it very well. It wasn't over produced on the album, so they could cover it with no problems live. It's always great with a classic band like them, to have them go back to what it was that attracted everybody to them in the first place. Sure, it's not going to make any big waves on the radio, but it sure does sit well with the die hard fans!
Finally someone explained this and made it easy to understand. I agree the SS is very reliable and sound very good but tubes seem to be the standard. Even the new and boutique makers are going tubes. Lets just be thankful audio/video equipment evolved beyond the tube, those flat screens wouldn't be so flat...lol
I learned about all this stuff not in my music but, when I started fooling with car stereos. You did a decent job explaining this. It's hard to explain it to most people. Mostly because they just don't want to hear it. Even the RMS ratings are bullshit with some manufacturers these days. Thanks for taking the time to try and explain this. If there is ONE THING I know about its this stuff. You did a good job here. If they listen.....
Thanks... a wealth of information for me. Just picked up my first head/cabinet and was confused by the ohm info on the back. Not that I fully absorbed all that you explained, but I am getting it. Going to watch it again lol
The problem with the advertised power numbers isn't that they are actually incorrect or lies. The problem is that most power amps these days advertise output based on a 2 ohm load which very few setups actually use. If people pay attention, as you have recommended, they should usually list the outputs at 4 8 and sometimes 16 ohms in the manuals. I wish it was easier to find 4 ohm guitar cabs so you can really take advantage of a rack preamp into a reference power amp setup.
I didn't even know he had his own Strat to tell you the truth. If it has the Texas Special pickups in it, I wouldn't go near it though. I really hate those things. I don't mind waiting for an amp to warm up, I just don't like them to break down. lol That seems to be the biggest thing with all of the tube amps I've owned. They are always broke down. It HONESTLY seems that the more that a HUMAN has done during the building process, the more that it will have a chance to screw up.
Scott I love your show. I am not into what every JOE BLOW is using, I use what works for me.{ I dont bother feeding the trolls.} My rig is so easy now and sounds great. modeling amps work if you have a good ear. Oh Scott, your Ibanez axes look huge against the little marshalls..lol. thanks again for the lesson my guitar slinging friend!!
Thanks again, Scott! I know you're a KISS fan like me, so in case you haven't heard it yet, you can hear a new song on youtube from their upcoming album by typing in: KISS - Hell or Halleluja [Single] 2012 LYCRIS. I personally think it rocks! Have a good one!
Scott I'm sure you are technically insane which is cool because it's what makes you special. As much as you go against the grain, you somehow make things make sense to someone who's been a audiophile for 30 years. This tutorial answered all my questions about mixing cabs/speakers that no one else I've seen or read could properly explain. I done learnt somethn
that's hard to tell for any amp. The problem is that the human ear itself perceives a certain sound differently when it is played at different volumes.
Scottie- have a fun conversation about how impedance, m DCR ohms are inner-related, and don't forget damping factors and back EMF of loudspeaker coils, and all of the variables there... Love your videos Scott...
You called out that 800 watt trickster hype!! Good going! You also Schooled up some peeps me for one with the amp fluctuating when the ohms drop way to go that's what people need to know is how shit works!! A+ KEEP ON TRUCKIN!
So many amps are quoting x number of watts, but it should be rated in RMS only. Peak power is RMS x 2 as a rule of thumb to get your speaker ratings on the safe side. That is always how i have done things and then you rate your speakers for peak output. Just a suggestion. Make sure your cables are heavy too as the currents can get quite high and you don't want to loose power in them. Tube amps should be phased out, as modeling amps are now so good you simply cant tell the difference anymore. My Vampire LX 112 sounds better than my old Marshall head (which went up to '11' by the way), and 4 x12.
Scott might chime in, but are you running a valve/tube amp? If so, perhaps check that you have a fresh valve/tube in place to see if the loop will stay quiet/quieter???
wattage = V x A, If the volume placement is before the preamp it will cause distortion or what I call gain. If the volume is placed after the preamp (master volume) it should only increase the decibel of the preamp without distortion until the speaker starts to break up.
I've never found a need for an effects loop, but is it noisy when you simply connect a guitar cable from the out to the in, but without any effects in the effects loop chain?
I think that if you ran your rig through a 1965 twin reverb you would love the sound better than your line 6 , but you may be as stubborn as us tube snobs. nothing wrong with that. As far as explaining the ohms and watts thing, this was a great explanation for those who dont understand electronics. I dig all your videos alot, im still watching all the old ones tryin to catch up
Hey there Gary. I'm glad you are still watching my "antics" on here. lol I don't have any Line 6 stuff at all. I've had a few Twins and a couple of the reissues and they are just so nasty. They just don't trip my trigger at all. I think the worst thing about most amps (especially tube amps) is the crazy amount of noise. My rig is dead quiet. Not even an audible hiss when it's wide open. The Twin also never did break up at all. I had to put so many pedals in front of it to make it do what I like that it was always right back to these Johnson things. I really can't imagine finding an amp that suits my needs better. Keep on watching and I hope you find a nugget here and there that you can use. Cheers.
Ohm boy! Nice job Scott! Yes, I must admit I've found tube amps to be a bit messy. They've got that mad scientist vibe about them; always having to be tweaked and dialed, and managing fluctuations in temperature. The tone is rarely consistent. Sure, they have a romantic quality about them that people love, but they can be a pain for everyday use. A good solid state setup is a wonderful alternative.
Scott, Ive watched this video twice and i feel i have comprehended every word you've said. I would love to pick your brain on a few subjects. I have a Boss Katana Artist MK2. Im trying to learn what this amp is truly putting out, and at what ohms, and how they're divided between taps.
Howdy, your amp is already at its max with the 8 ohm speaker in it. You COULD run 2 16 ohm cabinets together, that would bring you back to 8 ohms (the amp's lowest recommended resistance), but you would have to unplug the internal speaker...or 1 8 ohm cabinet and again, disconnect the internal speaker. They do make the Katana powered 1X12" extension speaker cabinet that you can run so that the rig is in stereo mode. There is a special jack made to do just that. That is the way to get the most that it is capable of.
May I suggest an alternative to Watts could be 'Decibels' and maybe Signal to Noise ratio? That should indicate not just how loud it is but whether is't good-quality loud?
This is exactly what I needed. Thanks, Now the questions... I want a low wattage amp, 40 watt or around there. I just don't need the volume. I like the idea of mic'ing a smaller amp. makes sense to me. I'm looking into a few carvins (any good?) Fender hot rod Deluxe 3 or just going for a Peavey nashville solid state. Tubes, I like the sound but I don't like the thought of biasing or the warm up time to play. I am also a plug and play type of guy. And I don't need the wall of sound.
Scott, what are your thoughts on the PRS Amps? I just picked one up with a 12" Celestion Super Lead Speaker. I think it sounds great for club settings.
Thank you so much Scott, this opened my eyes and ears too. I' m so sorry that I couldn't understand every word of this or how on earth can those 8ohms comes back as a 4ohms because I´m Finnish and I don't understand electricity so much about those not even basics. And same thing with that PA-system when your amp is 8 ohms and you bring them to PA by 4 ohms, you get more power. There´s beeen so much misleading information about watts and peak power that doesn't mean a thing on continuing playing. It looks good if you have 800watts but actually you might have 100 or 200 watts maximum, right? It´s just the power that your amp takes from your house electricity line? Same thing with vacuum cleaners, they might have 1200watts but actual suction power is about 100watts and here they are not allowed to advertise with those arguments.
Hi my friend. Yes, you are correct. I want ALL PEOPLE who REALLY want to understand this to be able to. So, yes...many companies are advertising the PEAK watts (it's a horrible thing to do to people). The RMS power rating is the one and only power rating to go by. You understand it perfectly! You'll also see that people (who simply don't know any better) will advertise used gear as the wattage being what it says next to the power cord. So, a 100 watt RMS little PA head.....they will advertise it as 480 watts because that's how much power it draws from the electrical outlet on the wall. lol But, that's listed on the back.....so, they print it because they simply don't know where to find the correct answer. Feel free to ask questions at any time and I'll do my best to help you out. Cheers, Scott
What do you get when you use a bass head and a 50 watt amp? This was suggested to me, but I don't know enough about it. This is why I turned to you and tuned in on this tutorial. Thanks.
OK so, can I plug my Audix OM2 into a 8 ohm output jack ov my Carvin V3?....lol just kidding Scott. I learned this lesson years ago when I fried a few heads. we had no internet. i love this stuff...I am also not into the volume tweeking on a guitar. I have my HD100 set to sounds and effects that I use. I got sick of lugging my racks and 4 cabs to gigs..im getting older and its a little tougher to do that. I love this head, like the johnson maliniam. it does not loose anything when turned down!
I like the way all this was explained So people without knowkedge of electronics get some basics. There are reasons why wattage of tube amps is lower than solid state wattage. Watts is measured by voltage times current. Tube amps run on very high voltage (over 500 volts) and very little currant. Solid state amps operate at at lower voltages (like 24-48) and higher amps (current). All this gets changed on tube amps going thru the output transformers. Another factor is tube amps reach near peak power they dont break up with that nasty sounding distortion, but they just kind of stop or compress. So a lit of peaks or spikes in the the sound hit a ceiling. They do distort when the ceiling is reached. Buts its an even order harmonic distortion that isnt so painful, and actually is kind of pleasing. Some solid state amps (those using BI-FET transistor circuits) act similar to tubes. In todays world, digital electronics can reproduce tube sounds so well its hard or even impossible to tell the differece. In the digital world, your amp hasnt hit its overload threshold , but the digital process has recreated that tube overdrive sound. I have a small tube amp that the preamp and piwer amp are 100% tubes, but in the middle is a digital proceessor that blows me away. With the turn of a knob I go from a marshall tube amp with closed cabinets to a fender open back twin reverb. This new digital age is amazing. And yes, when emulating a marshal in overdrvive, and then pushing my amp into saturation too, the sound is so lush and fat it nearly gives me goosebumps. I run this into the board direct.
Inside a tube amp the signal is high voltage but low current. The output transformer converts this to low voltage high current, which is what you get from a solid state amp. To get 25W from an 8 ohm speaker requires 14.14V at 1.77A from a tube or solid state amp.
I have a Tonetubby Cabinet(2x12) with 1 8ohm input and another input for stereo use. My Hiwatt can be switched to 4,8,16 ohms. if i wanna run the cab stereo with lets say a micro terror(8ohm), how do I set the Ohm-selector on the Hiwatt? Awesome channel, you bring a lot of info and clarity to the people, thanks for that
I totally agree about what you are talking about, Yes it can be very complex at times. Me being deaf and playing the bass i rather stick to stock standard and let the PA or the MIXERS do the rest.. I love your vids...
No way I found you again! I used to watch your videos when I was in Highschool I forgot the name of your channel after all that time! Having trouble running my boogie into a 16 ohm cab. The manual says it should work through the 8 ohm Jack as a safe miss match but I’m getting no signal
Thanks man! And don't worry about length...I listen to Dream Theater on a regular basis, I can listen to songs that are over 10 minutes no problem (even up to 42 minutes!) so an hour long video is no problem :) ...but this is helpful...my buddy just got a new amp and we're trying to figure out how we can run his cabs with it.
Someone may have asked before and I'm too lazy to look... but what is your opinion on hybrid amps? I am considering this option and they have a VOX VT120 in a local pawnshop for $200. I would buy a small 15 or 20 watt tube amp head too, for variety. Just bought a MIM Strat.. just starting - old fart here. I know about guitars because I'm a percussionist who's played with many Latin Rock groups - most my friends and my son are guitarists. So I'm familiar.
Hey Scott, nice vid! So, quick question, I have a Marshall JCM DSL 2000 100 watt head that I just got and I want to hook it up to my Peavey 4x12 cab which is rated @ 16 ohms. I'm assuming that I set the switch on the back of the head to 8 and run the speaker cable from the 16 ohm input on the head to the cab. The switch on the back can be set to 4 or 8. The inputs are 16, 4 and 8 on the back of the head.Please let me know. Thanks!
This is a great video with lot's of good info but one thing that's not mentioned is that in order to make your amp twice as loud you need to increase the power by 10, a 200 watt amp is not twice as loud as a 100 watt amp kids!
No shit, this video is about OHMS! My WATTS video mentions it 37 times for those who feel that such things should be included in videos that have nothing to about that.
I run a dual amp set-up and I always wondered why the amp that I switch on first always sounds louder after I switch on my second amp and now it's all starting to come to me. See, the less resistance there is in a signalchain, the easier it gets for power to transport through it. When you are unaware of this simple fact, the logic that is applied is that the sound from the first amp should really become less loud when the second one is turned on, because the output level is now shared. But in reality, the amp will just deliver extra wattage which is easier to transport to the speakers. Which eventually will create more vibrations thus moving more air which creates a louder sound. Am I understanding you correctly?
my understanding is solid state amps are easier to match cabs to... because of impedence differences tube amps have to be matched to speakers or you can have some drive tube problems... I always liked how my digitec processor sounded through my garnet minibass tube amp... funny how our ears work... again, lots of very useful info... really enjoy your vids... i watch them at work.
Many thanks my friend! The info on this video is 100% the same for tube amps as well. Bass, guitar amps, PA systems, the whole 9 yards. So, feel VERY safe to apply it to ALL amplifiers. Cheers.
I read in a google search that you can mismatch different impedance configurations. Any truth to that? Here's a snippet of the section that discussed this in the blog: Case 1: running a 16 ohm speaker with an 8 ohm amp output With this combination, the voltage at the speaker output will rise, while the current will almost halve. The power will drop, although you probably won’t notice it too much, as this combination will likely increase the mids in your tone. So long as you don’t overdo it - make it a rule of thumb not to connect a speaker with more than double the output impedance of that of the amp - this method can be quite useful, as you can effectively boost the mids in a cab that might otherwise be lacking in this department. Case 2: running a 4 ohm speaker with a 16 ohm amp output Here, the complete opposite to Case 1 occurs: while the speaker output voltage significantly falls, the flowing current only marginally increases. This will alter your tone too, but in the exact opposite way from before - you’ll get a drop in your mids! If you’ve got a cab that is way too mids-heavy, then, this can be the perfect method to better balance your overall tone. Because this combination can help lessen the self-induction effect that might occur in your tubes, it is generally safer to use than the example in Case 1. In terms of the amount of mismatching you can get away with here, we’d go with the 25% rule: so, for instance, don’t connect a speaker with less than a 4 ohm output to a 16 ohm amp output! Case 3: the exotic combination of 16 and 8 ohms together, and how to hook them up together… Almost every gigging guitarist will have experienced this before: you’ve got one cab with 8 ohms, and one with 16 - and you want to connect them both to a speaker output at the same time. Is that even possible? To put it simply, yes. You just need to know the total impedance you’ll have if you’re running the two speakers in parallel. This can be surprisingly easy to calculate. Another ground rule here: if you’re connecting resistors in parallel, then the total resistance is always going to be smaller than the smallest partial resistance. In this case, that would mean we will end up with a total resistance somewhere south of 8 ohms. To be more exact, we can calculate the precise figure using the following formula (which, by the way, only works in cases where you have two parallel resistors!): Use this handy formula to calculate impedances when you're hooking your amp up to more than one speaker. Use this handy formula to calculate impedances when you’re hooking your amp up to more than one speaker. Or, in our case, that’s (8×16) / (8+16) = 128/24 = 5.333 Ω Simple, right? Well, you’ll get used to it! Based on these variables and peculiarities, you can start to think about whether you would prefer to use this combination with a tube amp output of 4 or 8 ohms. It’s certainly technically feasible, and the difference in volume between the two speakers will also be less than most people would think. And by the way, you should avoid combining 4 ohm cabs if you can, because you’ll end up in a red zone of under four ohms in total (for example if you go for the following ohm combinations: 4+4, 4+8, 4+16). Most amps aren’t designed to go this low, and you could cause serious damage.
Nice one Scott I have never understood why they measured output in watts as its the amperage draw that burns the amplifier out of course measured by the minimum resistance applied across the output. as far as I have always been concerned it was the decibel output that every amp and speaker should be rated by. you don't buy for example horn by its wattage you buy it for its decibel rating. But what do I know as an Electrician lol. regards Clive P.s ill keep taking the tablets
I just listened to this post, and i know NOTHING about oms/watts,ect but i have an old "40 plus years" CRATE G10Xl amp 1 8" speaker, with a Max of 30 watts, and an OLM rating of 3.2... you said here that they NEVER go below a 4.0 rating, so now i don't know if i can safely hook up another amp to this one or not.
What's your opinion regarding mixing speaker sizes. I'm a bassist and I run an 8 Ohm 2x10 into a Genz-Benz head that's 375 watt at 8 Ohms, and 600 watts at 4 Ohms. I want to run another cab, more for air movement than outright power but I'm not sure if I should get another 2x10 or a 1x15.
Very informative mate, Ive been playing for over 30 years and only switched over to valve a few years back, i must say that except for valve being far louder than solid state I dont realy see much differents in sound qaulity.. I fell for the old valve is better saying lol..anyway I now have a Bogner alchemist 2x12 combo "40 watt" which Ive had for a few years ,plus Ive recently got a Blackstar series1,, 100 watt half stack, the Bogner is far louder than the Blackstar any ideas why this is???
Hey Scott! Just watched your whole vid. You're our down-to-earth kind of guy, thanks for your own personal insight! I just picked up my amp, the Fender MH-500 and found it's spec PDF online (you're right, this stuff is so easily accessible these days.) At the end of your video you were talking about the RMS rating. Mine reads: 500w + RMS into 2 OHMS @ 1%thd 400w + RMS into 4 OHMS @ 5%thd I know it's differentiating between if I'm using two speakers or not. There's a little switch on the back that you hit to tell the head whether it's running into 2 or 1 4x12 cabinet. Long story short, I heard you say they don't make speakers at 2 OHMS and I read 2 OHMS in my manual. I was just curious, wanted to pick your brain and hear your thoughts? Thanks again for your videos, they're great.
OK! I understand every thing you said but what if you have an speaker that does not have an RMS rating any where it's just rated at lets say Full Range 800w continuous /1600w program /3200w peak at 4 ohms for a speaker cab how would you determine what power amp you should use? or Vice Versa?
I clicked on this link, thinking you were crazy for making an hour long video for OHMS, yet I stayed RIVETED on every word. You sir, are a man who knows his shit....
Thank you my friend! I have total respect for you for actually sticking around and absorbing all of the information. Some folks just don't CARE enough to learn about what they love. lol I truly appreciate you putting in the time and dedication!
Cheers
I ma 27, and I love to learn from people who now more than me. It helps that I do not assume I know everything.
You know, I have been looking on the internet for something that really explained ohms in a way I could understand. This was an hour very well spent. You are a great teacher.
Listening to you is very easy You seem so at ease in front of your cam. I've taken in two really long segments one on amp controls this one on the Ohms and Watts. Both were very instructional and neither was in the least bit preachy, or conceited. You have an innate natural talent.
Hey man, I am an electrician and have had many guitar players ask me questions about ohm ratings and wattage of amps. I think you described it in the easiest put terms I have ever heard. Great video. Very informative. By the way, my favorite head ever was the first series of the Marshall 8100 valve state head. I primarily played death metal in my younger days and that solid state head was a beast! I think it did have AX7 pre amp tubed though. Other than that, when I first started I inherited my older brothers Kramer(silver and black Eddie Van Halen looking thing, bought a single hum buckler Peavey Predator(loved it), and my Peavey Bandit amp. I could have ruled the world(in my room)!
I also are an electrician and started studying electronics and radio stuff in 1975, thanks to a family member. The reason a person can have a 4 speaker cab driven by a 4 ohm head is if you have 4 of the 16 ohm speakers in parallel, the equivalent is 4 ohms. In series, resistance is directly additive. In parallel, it is inverse.
So, in parallel, 1/Rt = 1/R1 + 1/R2 + 1/R3 + 1/R4. Well, those add up to .25. And 1/.24 = 4 ohms. So, the real trick is impedance matching and if you have a set of speakers not equal to the output of the amp head, you need an impedance matcher to translate, as it were;
I'm glad that it helped out, if only a little. There is a lot of "Poindexter" stuff that could be explained, but it takes away from playing time. Most want to know what they NEED to know and then get back to playing. So, general conversations and trying to hit on the key points and time to actually plug back in and have some fun! Glad you enjoyed it!
Spot on, about the sound and dependability of tubes vs solid state. Crazy to get tubes today, unless you’re building a museum. I beg to differ on the watts issue, however. 100 watts RMS, perfectly matched to its speakers, will produce the same kick, tubes or solid state.
The key is, that it’s RMS (Root Mean Square). If it only says 100 watts, then it’s probably based on “Peak Power Output” which means in a small band width, it could surge to peak at 100 watts, but under continuous usage across the full audio spectrum, it’s likely only 20 watts RMS.
Bear in mind, however, 100 watts RMS paired with the wrong speakers (mismatched impedance) can sound like 20 watts as well. The correct impedance assures the highest efficiency.
I have compared a 100 watt RMS vintage Silvertone tube amp (four 6L6) matched to six 10 inch speakers, to a Hartke solid state 100 watt RMS matched to two 12 inch speakers, and the solid state Hartke is actually louder than the tube amp (probably because the tubes are old).
But of course the issue is mute, since today it makes no sense for a professional musician to go on the road with a tube amp, unless you’re independently wealthy, or as I say, starting a museum collection.
Hey scott, im only 15 and i understood the things you were saying. I really enjoy all your videos, especially ones like this that are really useful and teach you something. your videos have saved me alot of time and money by not falling into the webs that many other people do because the so called experts at guitar center told them to lol. i also pass along this info with my friends and help them out too. again i cant thank you enough for all the help you have given me, keep on rockin!
I enjoy your talks. When my son is old enough, he, too, will listen to you, and learn from you. I will make him. Thanks so much!!!!
Thanks so much my friend!
Well, he's not Jesus...
I knew nothing about anything about half stacks and ohms and watts and i owned one back in the day. Now that i bought my old amp back, Crate GT3500H Shockwave 350 Watt Head, I know what the 220W@4ohm and 350W@2ohm means. I walked into guitar center out here in vegas and told a guy what setup for cabs i want. i want a 4x12 4ohm cab with any celest/sheff speaker and i want a 2x12 for my topper at 4 ohms as well. and i told him why he was very impressed. thats because of this video giving me the knowledge. thanks brother.
solid state for life lol. and i literally just found my baby. Crate GT412SL with celst!!!!!!! 16, 8, 4ohm switch. thanks for the explenation. i have the knowledge. and knowledge is power, in ohms and RMS of course! lol
You are way too kind. Many thanks. I'm glad you are enjoying the stuff I toss out there!
I learned most of this stuff back when I was putting together the Heathkit stereo amps. back in the mid 60s. My dad bought me two of these kits to teach me about electronics.I made one into a mono 100 watt tube amp for my guitar (a 64 casino I found in the garbage) with one 8 ohm 12" mid range speaker hooked to it. I made the other into a tubed 50 watt per channel stereo with a built in preamp that I hooked up a Heathkit FM tuner my dad built and two 16 ohm 12" full range speakers to it.
As I got older, I bought a 4-12 cabinet with vintage 30 Celestions in it and a Marshall JCM900 SLX Superled Head. Traded it less than 6 months later for a Sovetek 100 Watt Tube head. Still,loved my valve state!
Scott, I appreciate ypur honesty. Even when one has a difference of opinion, your information is appreciated and worth a listen. Thank you.
Thank you so much for making life easier with these videos, your time and effort is appreciated.
Thanks for all your Utubes. All very informative and very welcome. im 75 and only took up guitar 4 yrs back. I have fun but love your broad knowledge and talent. i must admit to getting lost a little on this one but perhaps watching it a couple of times more will help. even though most is not going to be used by me i just love the knowledge and techniques and your no frills approach. thank you so much. I do have your 200 lessons great deal thanks again.
100%. Of course bass rigs will sometimes use 2 different sized speakers in different cabinets since they are basically using a PA system (as they should) for an amp. So, you have the great amps that have built in crossovers, a couple of power amps, a sub (Usually a 15" or 2 in a cabinet) then their mids and highs in the form of a 4X10 and horn cabinet on top. So, since you are using 2 totally separate amps in the head, they bottom cabinet can be 4 Ohms and Tops be 4 ohms, since separate amps.
I wish it was that easy. You can take a Fender Twin Reverb with 85 watts of massively loud tube power, turn it on 10 and it will remain crystal clear and 100% clean with zero breakup. It's designed to be the cleanest amp around at full power and ear shattering volume. So, that is out the window.
Hi my friend. Nope, the Johnson sounds the same on 1 as it does on 9. It's a beautiful thing. Another MAJOR reason I love it. It fits the bill for all gigs big and small. The sound is always the same. A true blessing for sure.
It's always good to hear someone else's point of view, even if you disagree and in this case I do. Like it or not a tube amp has a different sound quality than a solid state. Solid state amps produce some harmonics that sound harsh to the ear of someone who is used to tube amps. I f you can't hear that a Marshall amp has a unique and identifiable tone that's too bad. For me it's one of the sweetest sounds in music, almost an acoustic tone like a cello as ridiculous as that sounds. It's all subjective and I have heard great sounds come from solid state amps but there is a real reason some people prefer tube amps.
Prescriptivist claptrap.
Are you one of those guys who tries to belittle pedal users with your ¡gnorant dogma and misconceptions?
Thanks my friend. Yep, exactly the same for everything including bass rigs, car audio, sound systems and everything relating to amps and speakers all the way across the board.
So correct! As a kid back in the day building stereo systems in cars and we do look at watts but it's the rms that matters.
I REALLY dig these old videos you used to do. They are so very informative.
You are the best guitar player and informational giving guy I have ever seen. . . you sir are a genius.
You're one of the most informative people I've ever come across on the Internet when it comes to guitars. Good stuff man!
nice to have it spelled out. most of it is common sense, and you filled in the blanks with the important stuff. Still enjoy learning the mechanics of what I've been doing forever.
Thanks so much. I'm so glad that you stay tuned. Your word of mouth will help plenty and gives me hope for the future and I know that you all won't blow up your stuff. lol Happy playing and I'll always be happy to make any videos that I can to help you with any questions you may have.
I've always loved solid state but had to go with a tube amp when I joined a band because the other guy had a tube amp and it ate up my solid state amp as far as cutting through. Now I'm back in love with tube amps but I still love solid state. Just doesn't seem to cut through the drums, bass, other guitar, etc. as much as my tube amp but they are making them incredibly better these days
I've always understood this subject well just from going to a vocational/trade school, but back when I was first learning about this and the whole guitar amp subject this video would have helped a lot. Very well done Scott.
I learn so much from your videos...the best tjing about them, they are long and elaborate. You take your time and it feels good listening to stuff you say. Nowadays its rare to find people having opinions, you people sort of consider everything as this is good that is also good and blah.. I mean there is a good and a bad and bad doesnt mean it sucks it just means its not in your taste. You are someone I look up to and learn from. Just wanted to thank u man. Keep rocking!\m/
Many thanks my friend! I'm glad that you appreciate the LONG TIME that I put into these instead of yelling at me that it's TOO LONG. lol
All my best to you.
Scott
groovydjs
Me, I like it that way. You could go into ohms law (calculations are actually easy on a calculator) but if you explained it in the way I learned in college (the complicated detailed technical picking nits way) it'd be a 20 hour video.
I wish I could have seen a video like this in the 70's. It took me years to learn this
The exact way to calculate equivalent resistance in parallel is as follows: 1/Req=1/R1+1/R2+1/R3+1/R4+.... ohms.1/Rn. So four 16 ohm speakers in parallel would be and equivalent resistance of 1/16 + 1/16 + 1/16 +1/16 =.0625 +.0625 + .0626 +.0625 = 0.25. Now we have 1/Req=0.25. So Req = 1/.025 =4. For just two in parallel the formula reduces to {(R1) (R2)}/R1 +R2. So two 16 ohm speakers in parallel 16x16 would be an equivalent resistance of {(16)(16)}/16+16 = 256/32=8 ohms.
Wow great info, Solid State amps interesting, I own all tube amps and when I plug into a solid state amp I always say why am I not playing a solid state amp. Its great to hear you say that what a breath of fresh air.
Yet another great and informative video. I'm slowly making my way through your whole channel. Some of this I already knew, some not, so it's always good to keep learning. Especially from someone who actually cares about what they're teaching.
Hi Scott, Thankyou so much for that lamens terms of understanding Ohms. Really gave me a logical non bullshit way of understanding it all. Definitely learnt something new as well.
Thank you so much once again, Scott. You're really a fount of knowledge and I appreciate your generosity with your time. I'm becomming sort of addicted to watching Scott Grove vids now. No matter the subject, you're an interesting speaker (yeah, that was a pun, sorry).
So... is there anyone making new solid state amps today that you could get behind and endorse, so to speak?
Btw, your vid about your health problems was very touching - wishing you all the best in that battle!!!
Miking will always sound best on a guitar amp. For bass guitar, the direct box is usually the best way to go and should be from the instrument to the D.I. and not from the amp to the PA. I use a direct box at most of my gigs with my guitar since I rarely bring an amp anymore. So, if you are using some sort of a rig that doesn't use an amp at all, then of course, the Direct Box is a must since you'll almost always need to lift the ground on the box or it will be a Buzz Fest! lol
Yeah, it's a great tune. It sounds like the good, old stuff! I got to hear them do it live on the 11th of August. They did it very well. It wasn't over produced on the album, so they could cover it with no problems live. It's always great with a classic band like them, to have them go back to what it was that attracted everybody to them in the first place. Sure, it's not going to make any big waves on the radio, but it sure does sit well with the die hard fans!
Great explanation of a complex topic! It definitely cleared up a lot of confusion I had concerning Wattage & Ohms.
Only if you play amazingly and are at a worthwhile and prominent venue.
Finally someone explained this and made it easy to understand. I agree the SS is very reliable and sound very good but tubes seem to be the standard. Even the new and boutique makers are going tubes. Lets just be thankful audio/video equipment evolved beyond the tube, those flat screens wouldn't be so flat...lol
Mr. Scott Grove, thank you!! I learned a lot! All the best!
As always: funny remarks, a lot of controversy and great info (from experience)! Thanks again man!
My pleasure and I'm glad that you "get it" when it comes to my "humor". lol
I learned about all this stuff not in my music but, when I started fooling with car stereos. You did a decent job explaining this. It's hard to explain it to most people. Mostly because they just don't want to hear it. Even the RMS ratings are bullshit with some manufacturers these days. Thanks for taking the time to try and explain this. If there is ONE THING I know about its this stuff. You did a good job here. If they listen.....
Thanks... a wealth of information for me. Just picked up my first head/cabinet and was confused by the ohm info on the back. Not that I fully absorbed all that you explained, but I am getting it. Going to watch it again lol
The problem with the advertised power numbers isn't that they are actually incorrect or lies. The problem is that most power amps these days advertise output based on a 2 ohm load which very few setups actually use. If people pay attention, as you have recommended, they should usually list the outputs at 4 8 and sometimes 16 ohms in the manuals. I wish it was easier to find 4 ohm guitar cabs so you can really take advantage of a rack preamp into a reference power amp setup.
I didn't even know he had his own Strat to tell you the truth. If it has the Texas Special pickups in it, I wouldn't go near it though. I really hate those things. I don't mind waiting for an amp to warm up, I just don't like them to break down. lol That seems to be the biggest thing with all of the tube amps I've owned. They are always broke down. It HONESTLY seems that the more that a HUMAN has done during the building process, the more that it will have a chance to screw up.
Scott , thanks so much...I truly learned a lot from you my friend , really appreciated.
Scott I love your show. I am not into what every JOE BLOW is using, I use what works for me.{ I dont bother feeding the trolls.}
My rig is so easy now and sounds great. modeling amps work if you have a good ear. Oh Scott, your Ibanez axes look huge against the little marshalls..lol. thanks again for the lesson my guitar slinging friend!!
Makes sense. The first amp I ever owned was an old (80's) Solid State Randall Amp at 300 watts. …Great video!
Thanks again, Scott! I know you're a KISS fan like me, so in case you haven't heard it yet, you can hear a new song on youtube from their upcoming album by typing in: KISS - Hell or Halleluja [Single] 2012 LYCRIS. I personally think it rocks! Have a good one!
Scott I'm sure you are technically insane which is cool because it's what makes you special. As much as you go against the grain, you somehow make things make sense to someone who's been a audiophile for 30 years. This tutorial answered all my questions about mixing cabs/speakers that no one else I've seen or read could properly explain. I done learnt somethn
You're videos always help me out. Thanks Scott. :D
I watch your videos all day man. keep it going !!!!!
that's hard to tell for any amp. The problem is that the human ear itself perceives a certain sound differently when it is played at different volumes.
Scottie- have a fun conversation about how impedance, m DCR ohms are inner-related, and don't forget damping factors and back EMF of loudspeaker coils, and all of the variables there...
Love your videos Scott...
You called out that 800 watt trickster hype!! Good going! You also Schooled up some peeps me for one with the amp fluctuating when the ohms drop way to go that's what people need to know is how shit works!! A+ KEEP ON TRUCKIN!
So many amps are quoting x number of watts, but it should be rated in RMS only. Peak power is RMS x 2 as a rule of thumb to get your speaker ratings on the safe side. That is always how i have done things and then you rate your speakers for peak output. Just a suggestion. Make sure your cables are heavy too as the currents can get quite high and you don't want to loose power in them.
Tube amps should be phased out, as modeling amps are now so good you simply cant tell the difference anymore. My Vampire LX 112 sounds better than my old Marshall head (which went up to '11' by the way), and 4 x12.
Very well said and dead on for sure! I agree 10000%
Yea, sisters aren't usually rated in RMS, they are usually rated in PMS or PMT
Superb info as usual, Scott. I vote the title of this vid should be: "Show me the way to go Ohm"
;)
ppps running the wrong speakers on an amp can cause it to overheat so severely it causes a fire....so this is pretty seriously useful help here :)
Scott might chime in, but are you running a valve/tube amp? If so, perhaps check that you have a fresh valve/tube in place to see if the loop will stay quiet/quieter???
wattage = V x A, If the volume placement is before the preamp it will cause distortion or what I call gain. If the volume is placed after the preamp (master volume) it should only increase the decibel of the preamp without distortion until the speaker starts to break up.
Very cool my friend. I'm a bag of wind for sure. lol I hope it got you guys all situated.
Cheers,
Scott
I've never found a need for an effects loop, but is it noisy when you simply connect a guitar cable from the out to the in, but without any effects in the effects loop chain?
I think that if you ran your rig through a 1965 twin reverb you would love the sound better than your line 6 , but you may be as stubborn as us tube snobs. nothing wrong with that. As far as explaining the ohms and watts thing, this was a great explanation for those who dont understand electronics. I dig all your videos alot, im still watching all the old ones tryin to catch up
Hey there Gary. I'm glad you are still watching my "antics" on here. lol I don't have any Line 6 stuff at all. I've had a few Twins and a couple of the reissues and they are just so nasty. They just don't trip my trigger at all. I think the worst thing about most amps (especially tube amps) is the crazy amount of noise. My rig is dead quiet. Not even an audible hiss when it's wide open. The Twin also never did break up at all. I had to put so many pedals in front of it to make it do what I like that it was always right back to these Johnson things. I really can't imagine finding an amp that suits my needs better. Keep on watching and I hope you find a nugget here and there that you can use. Cheers.
Thank you for the good information and have a nice day .
Many thanks to you!!!
As usual, you are correct,informative,and a very funny man.
Cheers
I really learned something from this video, thanks scott.
Ohm boy! Nice job Scott! Yes, I must admit I've found tube amps to be a bit messy. They've got that mad scientist vibe about them; always having to be tweaked and dialed, and managing fluctuations in temperature. The tone is rarely consistent. Sure, they have a romantic quality about them that people love, but they can be a pain for everyday use. A good solid state setup is a wonderful alternative.
Scott, Ive watched this video twice and i feel i have comprehended every word you've said. I would love to pick your brain on a few subjects. I have a Boss Katana Artist MK2. Im trying to learn what this amp is truly putting out, and at what ohms, and how they're divided between taps.
Howdy, your amp is already at its max with the 8 ohm speaker in it. You COULD run 2 16 ohm cabinets together, that would bring you back to 8 ohms (the amp's lowest recommended resistance), but you would have to unplug the internal speaker...or 1 8 ohm cabinet and again, disconnect the internal speaker. They do make the Katana powered 1X12" extension speaker cabinet that you can run so that the rig is in stereo mode. There is a special jack made to do just that. That is the way to get the most that it is capable of.
May I suggest an alternative to Watts could be 'Decibels' and maybe Signal to Noise ratio? That should indicate not just how loud it is but whether is't good-quality loud?
This is exactly what I needed. Thanks, Now the questions...
I want a low wattage amp, 40 watt or around there. I just don't need the volume. I like the idea of mic'ing a smaller amp. makes sense to me.
I'm looking into a few carvins (any good?) Fender hot rod Deluxe 3 or just going for a Peavey nashville solid state. Tubes, I like the sound but I don't like the thought of biasing or the warm up time to play. I am also a plug and play type of guy. And I don't need the wall of sound.
Scott, what are your thoughts on the PRS Amps? I just picked one up with a 12" Celestion Super Lead Speaker. I think it sounds great for club settings.
Thank you so much Scott, this opened my eyes and ears too. I' m so sorry that I couldn't understand every word of this or how on earth can those 8ohms comes back as a 4ohms because I´m Finnish and I don't understand electricity so much about those not even basics. And same thing with that PA-system when your amp is 8 ohms and you bring them to PA by 4 ohms, you get more power. There´s beeen so much misleading information about watts and peak power that doesn't mean a thing on continuing playing. It looks good if you have 800watts but actually you might have 100 or 200 watts maximum, right? It´s just the power that your amp takes from your house electricity line? Same thing with vacuum cleaners, they might have 1200watts but actual suction power is about 100watts and here they are not allowed to advertise with those arguments.
Hi my friend. Yes, you are correct. I want ALL PEOPLE who REALLY want to understand this to be able to. So, yes...many companies are advertising the PEAK watts (it's a horrible thing to do to people). The RMS power rating is the one and only power rating to go by. You understand it perfectly! You'll also see that people (who simply don't know any better) will advertise used gear as the wattage being what it says next to the power cord. So, a 100 watt RMS little PA head.....they will advertise it as 480 watts because that's how much power it draws from the electrical outlet on the wall. lol But, that's listed on the back.....so, they print it because they simply don't know where to find the correct answer. Feel free to ask questions at any time and I'll do my best to help you out.
Cheers,
Scott
What do you get when you use a bass head and a 50 watt amp? This was suggested to me, but I don't know enough about it. This is why I turned to you and tuned in on this tutorial. Thanks.
OK so, can I plug my Audix OM2 into a 8 ohm output jack ov my Carvin V3?....lol just kidding Scott. I learned this lesson years ago when I fried a few heads. we had no internet. i love this stuff...I am also not into the volume tweeking on a guitar. I have my HD100 set to sounds and effects that I use. I got sick of lugging my racks and 4 cabs to gigs..im getting older and its a little tougher to do that. I love this head, like the johnson maliniam. it does not loose anything when turned down!
Always educational. . I have one question if you had to pick a Brand new guitar amp what would you pick?
Groovy,,,, as allways !!!! TY Scott,,, digging the new cave !!!! 😁🖒✌🇺🇸
I like the way all this was explained
So people without knowkedge of electronics get some basics. There are reasons why wattage of tube amps is lower than solid state wattage. Watts is measured by voltage times current. Tube amps run on very high voltage (over 500 volts) and very little currant. Solid state amps operate at at lower voltages (like 24-48) and higher amps (current). All this gets changed on tube amps going thru the output transformers. Another factor is tube amps reach near peak power they dont break up with that nasty sounding distortion, but they just kind of stop or compress. So a lit of peaks or spikes in the the sound hit a ceiling. They do distort when the ceiling is reached. Buts its an even order harmonic distortion that isnt so painful, and actually is kind of pleasing. Some solid state amps (those using BI-FET transistor circuits) act similar to tubes. In todays world, digital electronics can reproduce tube sounds so well its hard or even impossible to tell the differece. In the digital world, your amp hasnt hit its overload threshold , but the digital process has recreated that tube overdrive sound. I have a small tube amp that the preamp and piwer amp are 100% tubes, but in the middle is a digital proceessor that blows me away. With the turn of a knob I go from a marshall tube amp with closed cabinets to a fender open back twin reverb. This new digital age is amazing. And yes, when emulating a marshal in overdrvive, and then pushing my amp into saturation too, the sound is so lush and fat it nearly gives me goosebumps. I run this into the board direct.
Inside a tube amp the signal is high voltage but low current. The output transformer converts this to low voltage high current, which is what you get from a solid state amp. To get 25W from an 8 ohm speaker requires 14.14V at 1.77A from a tube or solid state amp.
All this solid state praise...Any experience with Lab Series amps.......stands up to my super reverb and can pass it in volume...
I have a Tonetubby Cabinet(2x12) with 1 8ohm input and another input for stereo use. My Hiwatt can be switched to 4,8,16 ohms. if i wanna run the cab stereo with lets say a micro terror(8ohm), how do I set the Ohm-selector on the Hiwatt?
Awesome channel, you bring a lot of info and clarity to the people, thanks for that
I totally agree about what you are talking about, Yes it can be very complex at times. Me being deaf and playing the bass i rather stick to stock standard and let the PA or the MIXERS do the rest.. I love your vids...
Scott! If you are wearing earphones are youn listening to the mix of all instruments?
No way I found you again! I used to watch your videos when I was in Highschool I forgot the name of your channel after all that time! Having trouble running my boogie into a 16 ohm cab. The manual says it should work through the 8 ohm Jack as a safe miss match but I’m getting no signal
Great upload mr groovy.Helped me a lot,I stayed with you until the end,thanks dude.
You are the Best Scott. and always right!
Thanks man! And don't worry about length...I listen to Dream Theater on a regular basis, I can listen to songs that are over 10 minutes no problem (even up to 42 minutes!) so an hour long video is no problem :) ...but this is helpful...my buddy just got a new amp and we're trying to figure out how we can run his cabs with it.
Someone may have asked before and I'm too lazy to look... but what is your opinion on hybrid amps? I am considering this option and they have a VOX VT120 in a local pawnshop for $200. I would buy a small 15 or 20 watt tube amp head too, for variety. Just bought a MIM Strat.. just starting - old fart here. I know about guitars because I'm a percussionist who's played with many Latin Rock groups - most my friends and my son are guitarists. So I'm familiar.
Hey Scott, nice vid! So, quick question, I have a Marshall JCM DSL 2000 100 watt head that I just got and I want to hook it up to my Peavey 4x12 cab which is rated @ 16 ohms. I'm assuming that I set the switch on the back of the head to 8 and run the speaker cable from the 16 ohm input on the head to the cab. The switch on the back can be set to 4 or 8. The inputs are 16, 4 and 8 on the back of the head.Please let me know. Thanks!
This is a great video with lot's of good info but one thing that's not mentioned is that in order to make your amp twice as loud you need to increase the power by 10, a 200 watt amp is not twice as loud as a 100 watt amp kids!
No shit, this video is about OHMS! My WATTS video mentions it 37 times for those who feel that such things should be included in videos that have nothing to about that.
I run a dual amp set-up and I always wondered why the amp that I switch on first always sounds louder after I switch on my second amp and now it's all starting to come to me.
See, the less resistance there is in a signalchain, the easier it gets for power to transport through it. When you are unaware of this simple fact, the logic that is applied is that the sound from the first amp should really become less loud when the second one is turned on, because the output level is now shared. But in reality, the amp will just deliver extra wattage which is easier to transport to the speakers. Which eventually will create more vibrations thus moving more air which creates a louder sound.
Am I understanding you correctly?
my understanding is solid state amps are easier to match cabs to... because of impedence differences tube amps have to be matched to speakers or you can have some drive tube problems... I always liked how my digitec processor sounded through my garnet minibass tube amp... funny how our ears work... again, lots of very useful info... really enjoy your vids... i watch them at work.
Many thanks my friend! The info on this video is 100% the same for tube amps as well. Bass, guitar amps, PA systems, the whole 9 yards. So, feel VERY safe to apply it to ALL amplifiers.
Cheers.
I read in a google search that you can mismatch different impedance configurations. Any truth to that?
Here's a snippet of the section that discussed this in the blog:
Case 1: running a 16 ohm speaker with an 8 ohm amp output
With this combination, the voltage at the speaker output will rise, while the current will almost halve. The power will drop, although you probably won’t notice it too much, as this combination will likely increase the mids in your tone. So long as you don’t overdo it - make it a rule of thumb not to connect a speaker with more than double the output impedance of that of the amp - this method can be quite useful, as you can effectively boost the mids in a cab that might otherwise be lacking in this department.
Case 2: running a 4 ohm speaker with a 16 ohm amp output
Here, the complete opposite to Case 1 occurs: while the speaker output voltage significantly falls, the flowing current only marginally increases. This will alter your tone too, but in the exact opposite way from before - you’ll get a drop in your mids! If you’ve got a cab that is way too mids-heavy, then, this can be the perfect method to better balance your overall tone. Because this combination can help lessen the self-induction effect that might occur in your tubes, it is generally safer to use than the example in Case 1. In terms of the amount of mismatching you can get away with here, we’d go with the 25% rule: so, for instance, don’t connect a speaker with less than a 4 ohm output to a 16 ohm amp output!
Case 3: the exotic combination of 16 and 8 ohms together, and how to hook them up together…
Almost every gigging guitarist will have experienced this before: you’ve got one cab with 8 ohms, and one with 16 - and you want to connect them both to a speaker output at the same time. Is that even possible?
To put it simply, yes. You just need to know the total impedance you’ll have if you’re running the two speakers in parallel. This can be surprisingly easy to calculate. Another ground rule here: if you’re connecting resistors in parallel, then the total resistance is always going to be smaller than the smallest partial resistance. In this case, that would mean we will end up with a total resistance somewhere south of 8 ohms. To be more exact, we can calculate the precise figure using the following formula (which, by the way, only works in cases where you have two parallel resistors!):
Use this handy formula to calculate impedances when you're hooking your amp up to more than one speaker.
Use this handy formula to calculate impedances when you’re hooking your amp up to more than one speaker.
Or, in our case, that’s (8×16) / (8+16) = 128/24 = 5.333 Ω
Simple, right? Well, you’ll get used to it!
Based on these variables and peculiarities, you can start to think about whether you would prefer to use this combination with a tube amp output of 4 or 8 ohms. It’s certainly technically feasible, and the difference in volume between the two speakers will also be less than most people would think. And by the way, you should avoid combining 4 ohm cabs if you can, because you’ll end up in a red zone of under four ohms in total (for example if you go for the following ohm combinations: 4+4, 4+8, 4+16). Most amps aren’t designed to go this low, and you could cause serious damage.
Nice one Scott I have never understood why they measured output in watts as its the amperage draw that burns the amplifier out of course measured by the minimum resistance applied across the output. as far as I have always been concerned it was the decibel output that every amp and speaker should be rated by.
you don't buy for example horn by its wattage you buy it for its decibel rating.
But what do I know as an Electrician lol.
regards
Clive
P.s ill keep taking the tablets
I just listened to this post, and i know NOTHING about oms/watts,ect but i have an old "40 plus years" CRATE G10Xl amp 1 8" speaker, with a Max of 30 watts, and an OLM rating of 3.2... you said here that they NEVER go below a 4.0 rating, so now i don't know if i can safely hook up another amp to this one or not.
What's your opinion regarding mixing speaker sizes. I'm a bassist and I run an 8 Ohm 2x10 into a Genz-Benz head that's 375 watt at 8 Ohms, and 600 watts at 4 Ohms. I want to run another cab, more for air movement than outright power but I'm not sure if I should get another 2x10 or a 1x15.
Very informative mate, Ive been playing for over 30 years and only switched over to valve a few years back, i must say that except for valve being far louder than solid state I dont realy see much differents in sound qaulity.. I fell for the old valve is better saying lol..anyway I now have a Bogner alchemist 2x12 combo "40 watt" which Ive had for a few years ,plus Ive recently got a Blackstar series1,, 100 watt half stack, the Bogner is far louder than the Blackstar any ideas why this is???
Hey Scott! Just watched your whole vid. You're our down-to-earth kind of guy, thanks for your own personal insight! I just picked up my amp, the Fender MH-500 and found it's spec PDF online (you're right, this stuff is so easily accessible these days.)
At the end of your video you were talking about the RMS rating.
Mine reads:
500w + RMS into 2 OHMS @ 1%thd
400w + RMS into 4 OHMS @ 5%thd
I know it's differentiating between if I'm using two speakers or not. There's a little switch on the back that you hit to tell the head whether it's running into 2 or 1 4x12 cabinet. Long story short, I heard you say they don't make speakers at 2 OHMS and I read 2 OHMS in my manual. I was just curious, wanted to pick your brain and hear your thoughts? Thanks again for your videos, they're great.
OK! I understand every thing you said but what if you have an speaker that does not have an RMS rating any where it's just rated at lets say Full Range 800w continuous /1600w program /3200w peak at 4 ohms for a speaker cab how would you determine what power amp you should use? or Vice Versa?