Thank you for going into the details of what you found, and how you fixed it. Given the early manufacture of this amp, it may well have been designed to NEVER overdrive the tubes. Just plug in your Gretsch or Gibson hollow body and play backing chords.
You're too kind. I need to take more time to focus on practicing and learning new tricks. Just don't seem to have a ton of time to play these days. More focused on getting better on drums right now.
Sounds really great. 100 year from now though, some Amp Tech is going to say "What is this white stuff? Why didn't he paint everything with rattle reducing red paint like everyone else?"
Thank you, Dan. Unfortunately, not enough to matter yet. I have a few projects in line I've already promised people I'd do; after that, we'll have to see. At current levels, it's completely unsustainable. TBH, the past 2 years has driven home the fact that I'm just a man who is not welcome in the guitar community, such as it is. I've read some really disparaging and defamatory things about me on forums and in comments of late, and NO ONE seems to be coming to my defense on these threads. It's just a long train of abuse and piling on about how terrible I am as a human being, as a tech, as a guitarist, etc. I lack the energy to try and change these perceptions.
@@TheGuitologist Brad who cares about what some dweebs say about you.keep doing what you're doing man.Speak your mind and stand proud the world needs a lot more people just like you. Because this cuntry is run by commie dickheads that want us to obey without question and that aint gonna happen and I think these assholes need a good swift kick in their baby berries to wake them up.NO we aint gonna take it anymore ! Keep on Keeping on my Brutha from Anutha Mutha !
There are some diminishing returns on it. If the gain is pretty high, it's probably worth doing, but on a lot of vintage amps, the results won't be as noticeable, if at all. Always good to experiment though and have these tricks up one's sleeve.
Man.your playing always blows me away,a true God given talent..Im missing my work already,though I might take a small of course,number of a couple of home jobs a month...Yeah for reals,two maximum and NO Mesas.ever again!Good to see you ;ooking a bit happier again.You have inspired me to go get rid of my protest hair and beard,shave and a buzzcut on the cards tomorrow/.Cheers brother,
Brave standing barefoot on tile using a tube amp. I once got a mike screen pattern burned into my lips when I had my Bassman switched to a different phase setting as the Peavy P.A. It was funny after it quit stinging! But then again I guess this new-fangled grounding stuff took all that away. Great work as always, Brad!
It may not have a shit ton of head room but that never stopped anyone from throwing a stage mic on it and pumping it into the board.. Lot's of guys do that anyway. Sounds great. I'd probably set that on a folding chair like everyone else does.. LOL
Maybe I'm just an old dude, but I think I actually prefer the amount of overdrive this amp gets in NORMAL just simply cranked up. If I ever got ahold of one of these amps, that underpowered output transformer would have to go. Might even add a choke to it as well. Good work/engineering Brad. You never disappoint. :)
Dude. You've got such amazing technical skills playing . You are humble musician and I respect the hell out of that!!!! Top that with true passion for the electrical side of our music output and all , this is a great video again. Thank You.
Changing the plate resistors from 1/2 watt carbon comp to 1 watt carbon film will get rid of a lot of white noise. Capacitor/s in the bias supply can also introduce hum. Exchanging a 25uf 50v to 2 10uf 100/150v in parallel will make a significant difference.
I seem to remember that pretty much all the 12AX7, 12AT7, 12AU7, ECC83, ECC82, ECC81 twin triode tubes, and their equivalents, have a Heater to Cathode voltage-rating of something like 100V DC maximum, so, raising/elevating the Heaters above ground is actually a good thing to do to prevent Heater-Cathode leakage.
The transformer is the most expensive part in a tube amp and many manufacturers would scrimp on the VA of the transformers figuring the customer would not care or even notice. Lower the VA cheaper the transformer. They got to make a buck somehow. Regardless, that amp sounds terrific!
Seriously though, this amp was at about 5W RMS with PP 6V6s. This should have also allowed them to cheap out on the speaker...BUT this amp originally came with a Jensen P12Q! So that theory doesn't hold. Just weird. I think it's really down to a guitar company trying to sell amps and really didn't know what they were doing and weren't cohesive about their vision for the line.
@@TheGuitologist With all the tube gear I've worked on often I wonder what was on their minds by designing things like they did. Some stuff was golden and other stuff was... crap! It may very well be down to what was in stock at the time, anyway Brad, you'll set them straight, you did wonders with this one.
@@TheGuitologist back then supply and demand was the rule and dictated economies, specially the USA.. it could be the trans they wanted to use was either too expensive to justify cost or that Jensens and other components were dirt cheap also due to supply, really hard to say but 59' was an odd year for sure specifically economic wise... revolving credit was introduced and anyone with a job could buy almost anything, I suspect someone could research copper demands in 59 maybe they were upside down? I did look at a chart form macrotrends and indeed in early to mid 59 copper prices soared over the norm then dropped in 60', maybe that had something to do with it? maybe a suitable tranny wasn't available aside from bespoke or in house? things were weird in 59 for sure it really was a hallmark year in terms of economy, unemployment and finance private consumption, does seem odd in any event as loud loud loud was in and bigger is better was fashionable, maybe its a design flaw in the engineering? lol
Some of these ancient amps can really wail if done up right. Imagine the kind of tones these 50s cats had at their fingertips with just a couple mods...
Amazing video. That's like an amp with teeth. The guts of that amp look so cool. Suggestions: 1. Something I've always wanted to see you do is amp BUILDING videos. Mojo tone builds, other kit builds, or even maybe an amp of your own making, would be cool. That's a rabbit hole I've always wanted to go down, and would love to see a pro amp repair guy do it on a video before I try it myself. haha. I bet a lot of companies that sell those kits would send you product just to have a complete build video on youtube. I've seen others do it, but it not as in depth as what you do on your channel with your repair stuff. It would be really cool to see someone explain things as it's being built, in depth. Could be an entire series of videos, if you could get enough sponsors behind it. The DIY culture is really through the roof right now. I bet videos like that would do well. 2. Maybe do a video about the top five guitars in your collection, going through why you like them. Also, a top five amps would be cool, too, if you have five amps in your collection. I assume you have a truckload of amps around, but in my time in watching you, I haven't seen them; but I know you have a billion guitars. 3. Maybe rebrand 'Guitologist 2' to 'Guitologist After Hours' and do SPF and talking head stuff over there; stuff you want to do that isn't amp/guitar related. Separation would be great for people who aren't interested in the political stuff, and it would allow people to opt-in if they wanted. Random: I know you hate this type of amp, and in fact so do I, but: I hope someday you do a video on a garbage digital Marshall MG250DFX. I have one that turns on fine, plays fine, and then seemingly randomly, has volume go to zero. Blows my mind how weird and dumb digital Marshall amps are. I've been trying to get the thing to work for more than 15 minutes at a time, for months. SIGH.
A lot of companies back in the day especially the off-brand companies often underpowered their amps for the simple reasons of (A): the longevity of the amp figuring that most people could not afford big amps and would try to get the most out of their little and it wouldn't blow up.. (B): that the amp under long continuous play would have a melt down and burn down the local VFW Hall or the school gymnasium wherever they were playing... A lot of companies back in the day got sued due to malfunctions of the amp so in order to keep that from happening they underpowered them... My high school electronics teacher used to work for Gibson back in the early years of his career.. and in the 80s when I brought in my 1962 Gibson GA300 RVT. amp to get rebuilt we had lots of discussions over amplifiers and which were better and which were worse and this is one of the conversations that had come up he remembered at one time (in the early to mid 60s when he worked for Gibson) that Fender (the competition)... Had gotten sued due to an amp at some high school venue had caught fire while it was in standby and nine kids or something like that had died as a result of the fire that it had caused... Of course none of this was released to the public and was contained as to not ruin the reputation of the company... Obviously they compensated and swept it under the rug.. The conversation that that created was because I wanted the hot rod up that amplifier and how we could go about it safely he was extremely knowledgeable and yes we did Hot rod up that 300 amp. So the moral of the story is that most amplifiers were never put up to their optimum capacity I guess you'd call it due to these varying reasons.... Anyway enjoyed the video and keep up the good work Brad looking forward to more
Great video. Appreciate your description of everything and your playing. Came across a weird Danelectro Amp yesterday. The Phase Inverter output connects to two pairs of 6L6 tubes with two tubes driving one output transformer and another pair driving a second output transformer. Each output transformer connects to a single 12 inch field coil speaker to make a 2x12 combo. Certainly unique! Not sure of why Danelectro did that.
More power. Having two amps is better than one in terms of volume. Lots of older amps did that. I showed one Gretsch recently on the channel that had stereo output.
Never tried to ground at the PI. I have used the power tubes cathode. If ive got an anemic PT i like to use SS rectifier. Saves some stress on the power section and gives the amp a little more umph
I'm more into hi-gain amps with 4-5 gain stages but man... THIS IS SICK AS FOOK. Currently i'm playing in punk/Oi band and tone like this should fit as hell. Time to warm up solder gun...
I love the crunch tone on this thing. It's dirty and mean. I'm not a fan of oversaturated gain tones. I think it sucks all the life and honesty out of the music, but this has balls.
you had mentioned a drop in viewership a bit back. let me explain my drop in viewership. i had bilateral carpal tunnel surgery a while back. i had hope that i would be able to play guitar again, but no such luck. i had a washburn, and an ibanez, and was not a great player, but enjoyed noodling around. sometimes the simplest of manual duties makes my fingers violently cramp...i have to pry them apart, and it is VERY painful. i am beside myself with anger and sadness that i can no longer play guitar without intense pain. i have been running away from all things guitar cuz im just too fucking sad to even think about it. i will try to support you more, as i LOVE your content, and try to get over this, your internet bud and admirer, andy
I am truly sorry to hear that about your hands. I have carpel tunnel in BOTH wrists from years of IT work. Get a lap steel and a slide and learn Hawaiian and Delta Blues styles. There is a whole world of music on the guitar that very few people explore because they don't have enough heroes who do it.
@@TheGuitologist im actually getting a drum kit from a friend,and we are going to see how that goes...ive done some drumming years ago. your advice is great, i have just been too angry to think of reasonable solutions. if the drums dont work out, im for sure looking into what you advised!
That is pretty epic! Great sound and you even managed to demo the return input in normal mode a little by mistake at 16:25! Very good information throughout, well done in both videos Brad! Greetings from Hungary ;)
Prayer that amplifier does sound killer! When I heard you playing I heard you hit a few chords I instantly recognize the sound. Because I too have a 1968 guild thunderstar. And it has the same throtty low mids and thundurus Bass. Although mine has 7591 power tubes which really sound cool and a little more detailed perhaps.
Hi Brad, do you think "Curly " Guitar leads can make a difference to the signal compared to a straight lead? I have a 30ft coiled cable that is very well made but compared to a 30ft straight lead it makes the Guitar sound brighter(I know 30ft is too long and we should reallt be using 18ft 6") ?
Cool mod job! The thing sounds like it's ready to blow at any moment. It's got that controlled chaos thing going on in spades. No good excuse for being boring, right?
I’ve long been interested in this stuff. But for some reason I kind of half tune out during any electronic stuff. I think I’m gonna learn this craft now.
In the case of the Harvard, I can only theorize, but it would be true to Leo as we know him to design an amp around a low voltage transformer to utilize a bargain he picked up. We get used to thinking in terms of maximum potential in wattage for an amp design where Leo was thinking maximum clean all the time, and for cheap. Noticing the distinction of the cathode bias, which would normally raise our wattage potential, yet other Fenders are not cathode biased. It just feels like analyzing it backwards, but in his case, he was able to squeeze a bit more out of that cheap transformer this way without adding cost to the build. It does make me wonder though, how this design would perform at say 400+ volts. Feel free to clone that Harvard with a Hotter transformer and see how it holds up. Sharing that with the rest of us, of course.
Wouldn't the lower plate voltage give it less headroom and the ability to overdrive easier, albeit at a lower power level? Especially when hitting the output tubes with an extra gain stage.
You're right. I think I misspoke on that. It'll break up at lower volumes but won't have full headroom. The load line slope will be way off. That's what I meant to say.
Great vid, learned a lot. Amp really sounds amazing, keep the vids coming! The "black dot" reminded me of a question I had. How is adding an internal gain stage via the mod different to putting a booster pedal in front of the amp, assuming you had a similar amount of gain in the pedal?
The internal mod is adding another TUBE gain stage. A pedal would not be a tube gain, or if it was, it would be running in a starved plate configuration that would not be the same. I prefer all-tube saturation where possible.
DAYUMMMMM BRAD! You're playing was on another level here! Not to say that it was bad in other videos, but wowww, you were ripping it up!! That amp sounds amazing too!! Hehe.
🤘🤘🤘sup Brad! I’ve got an orange Rocker 15 terror on backorder that will arrive in several weeks, and I plan on modding it once I do a little homework. Your in-depth stuff is always appreciated.
You could also substitute other members of the 12a?7 family in for the preamp tube to tweak the gain but not raise the noise floor so much. Maybe also make the beast switch go from Blues to Rock instead of Rock to Metal depending on what the owner plays.
There is european equivalent to the 6v6 that doesnt handle as much voltage. So to use it you have to cool the bias down. Im wondering if that tube would be better in an amp like this than the actual 6v6. I cant remember what its called, its related to the 6p3s. Might be something to try next time you repair an amp with a transformer like this. Very interesting video, thanks.
The strange way that can cap was acting really makes me wonder if people like Ken Fischer are/were really able to hear/feel the minute differences between components that are supposedly identical.
Nope didn't get anything.. of course I'm sure they already know I'm a supporter and agree with you on most all subjects. Love the content, stay tough dude!!
Hey Brad, how come you do not use a toroid with a few windings for a choke on the ground and on the the AC input. That might have solved the issue(s) without doing all that extra work. Your work is very clean and tidy. Thanks for sharing. I alway learn something when I watch you solve a problem like this. I do have a concerned about the wire loom passing though the hole in the chassis(where you signed your name) with no grommet. Ricky from IBM, Ret
That's a very interesting problem, Brad. I haven't seen the previous video yet, but did you measure the high voltage AC from the Power Transformer? If that was OK, I assume the B+ must have been low. What rectifier was it? If its a 5Y3, try a 5V4 or even 5AR4. That may give you enough B+ to run your cathode resistors again. :-)
The way they run the 6V6s on there sounds kinda like my old Silvertone 1483. It's only 22 watts or so out of a pair of 6L6s, nowhere near the 50 watts they typically run at. It's supposed to be a bass amp, but at 22 watts....
I'm workiong on the same amp and have almost 430V B+. I had to increase the cathode resistor to 500 ohms. They must have started using a different transformer at some point.
hey Brad , do you think in this situations with under spec transformers could it be possible to use maybe low power tubes, such as 6g6 or 6k6, less power output but less current needed too...maybe if the ot has the same load ? ah and Btw great job the amp sounds great and super playing too 🤟
I found that really interesting how many options you tried to increase the power. Is component longevity a factor in your final decision? Meaning do your alterations affect tube life, or maybe increase heat in any way? Regardless, the sound of that little growler is fantastic. Nice job.
I'm not sure why putting the tubes heaters 6vdc or 6avdc to a virtual ground using the phase inverters cathode DC voltage as the virtual ground would reduce the noises. Any reasons why tubes heaters are inducing noises in general that you have to put the heater grounds at a different DC offset virtual ground?
I am desperately looking for info on my FGenterprises ga445 amp. Its a solid state dual input combo with a 15 inch speaker and i believe FG stands for Fred Gretsch. Is there any way to get more gain out of late 60s, early 70s Gretsch/Kay/Multi-vox amps?
I wonder if an undersized transformer would increase the attack. Full voltage at the start of a note, but compresses down as the power supply drains due to the transformer. Either that, or a clean attack but a overdriven sustain.
Brad, I think you are one of those guitarists who can make any amp sound great! Your guitar chops are stellar!
Not so sure about that, but it's kind of you to say, nonetheless.
Thank you for going into the details of what you found, and how you fixed it. Given the early manufacture of this amp, it may well have been designed to NEVER overdrive the tubes. Just plug in your Gretsch or Gibson hollow body and play backing chords.
Sounds great Brad. As always the greatest results with someone who knows what they are doing.
Jesus, dude. Your guitar skills and musicality is phenomenal. I really don't think you get enough credit for your chops!
You're too kind. I need to take more time to focus on practicing and learning new tricks. Just don't seem to have a ton of time to play these days. More focused on getting better on drums right now.
Sounds really great. 100 year from now though, some Amp Tech is going to say "What is this white stuff? Why didn't he paint everything with rattle reducing red paint like everyone else?"
Beastmaster Brad. I never tire of watching amp issues getting diagnosed and solutions applied. I hope the stats are looking better.
Thank you, Dan. Unfortunately, not enough to matter yet. I have a few projects in line I've already promised people I'd do; after that, we'll have to see. At current levels, it's completely unsustainable. TBH, the past 2 years has driven home the fact that I'm just a man who is not welcome in the guitar community, such as it is. I've read some really disparaging and defamatory things about me on forums and in comments of late, and NO ONE seems to be coming to my defense on these threads. It's just a long train of abuse and piling on about how terrible I am as a human being, as a tech, as a guitarist, etc. I lack the energy to try and change these perceptions.
@@TheGuitologist Brad who cares about what some dweebs say about you.keep doing what you're doing man.Speak your mind and stand proud the world needs a lot more people just like you. Because this cuntry is run by commie dickheads that want us to obey without question and that aint gonna happen and I think these assholes need a good swift kick in their baby berries to wake them up.NO we aint gonna take it anymore ! Keep on Keeping on my Brutha from Anutha Mutha !
I don't know about the technical stuff but I like to hear you talk and play!
Ok Brad, you have won my loyal admiration now.
Great content. Thanks for sharing ….
Love the video and the perfect timing. I am fixing up my GUILD F-212 from 1975 to list in REVERB. I will be listening to Leo Kotke while I work!!!!!!
I saw Leo live a few years back. He was a shadow of his former self on the instrument, but still way better than me.
Leo had, n has, some great licks! Brad ain’t too bad, either!
I always raise the filament virtual CT to about 50V with a voltage divider and filter cap from the B+. It gets rid of virtually all filament hum.
There are some diminishing returns on it. If the gain is pretty high, it's probably worth doing, but on a lot of vintage amps, the results won't be as noticeable, if at all. Always good to experiment though and have these tricks up one's sleeve.
Man.your playing always blows me away,a true God given talent..Im missing my work already,though I might take a small of course,number of a couple of home jobs a month...Yeah for reals,two maximum and NO Mesas.ever again!Good to see you ;ooking a bit happier again.You have inspired me to go get rid of my protest hair and beard,shave and a buzzcut on the cards tomorrow/.Cheers brother,
I was going to go full shaved - like a warrior monk - but that wouldn't have been any better for my image I'm told.
Brave standing barefoot on tile using a tube amp. I once got a mike screen pattern burned into my lips when I had my Bassman switched to a different phase setting as the Peavy P.A. It was funny after it quit stinging! But then again I guess this new-fangled grounding stuff took all that away. Great work as always, Brad!
It may not have a shit ton of head room but that never stopped anyone from throwing a stage mic on it and pumping it into the board.. Lot's of guys do that anyway. Sounds great. I'd probably set that on a folding chair like everyone else does.. LOL
Maybe I'm just an old dude, but I think I actually prefer the amount of overdrive this amp gets in NORMAL just simply cranked up. If I ever got ahold of one of these amps, that underpowered output transformer would have to go. Might even add a choke to it as well. Good work/engineering Brad. You never disappoint. :)
Brad, nadie como tu haciendo actualizaciones a esos viejos amps, grandioso trabajo!!! saludos desde CCS Venezuela
Gracias! Estoy feliz de que disfrutes de los videos.
Dude. You've got such amazing technical skills playing . You are humble musician and I respect the hell out of that!!!! Top that with true passion for the electrical side of our music output and all , this is a great video again. Thank You.
That thing sounds killer! You should start building amps. I'd buy one in a heartbeat.
And now... Brand name ideas!
Great to know about putting the virtual centre tap at the phase inverter stage!
BRRRAAAAAADDDD!!! Hey dude, your video was first on my feed when I opened TH-cam. Thought ya might wanna know.
I guess that's a positive.
Mine too!
Changing the plate resistors from 1/2 watt carbon comp to 1 watt carbon film will get rid of a lot of white noise. Capacitor/s in the bias supply can also introduce hum. Exchanging a 25uf 50v to 2 10uf 100/150v in parallel will make a significant difference.
Sounds incredible!!! Great work!!
I seem to remember that pretty much all the 12AX7, 12AT7, 12AU7, ECC83, ECC82, ECC81 twin triode tubes, and their equivalents, have a Heater to Cathode voltage-rating of something like 100V DC maximum, so, raising/elevating the Heaters above ground is actually a good thing to do to prevent Heater-Cathode leakage.
The transformer is the most expensive part in a tube amp and many manufacturers would scrimp on the VA of the transformers figuring the customer would not care or even notice. Lower the VA cheaper the transformer. They got to make a buck somehow. Regardless, that amp sounds terrific!
Seriously though, this amp was at about 5W RMS with PP 6V6s. This should have also allowed them to cheap out on the speaker...BUT this amp originally came with a Jensen P12Q! So that theory doesn't hold. Just weird. I think it's really down to a guitar company trying to sell amps and really didn't know what they were doing and weren't cohesive about their vision for the line.
@@TheGuitologist With all the tube gear I've worked on often I wonder what was on their minds by designing things like they did. Some stuff was golden and other stuff was... crap! It may very well be down to what was in stock at the time, anyway Brad, you'll set them straight, you did wonders with this one.
I recall V1 being the priciest component for my express build. LOL!!!!
@@TheGuitologist back then supply and demand was the rule and dictated economies, specially the USA.. it could be the trans they wanted to use was either too expensive to justify cost or that Jensens and other components were dirt cheap also due to supply, really hard to say but 59' was an odd year for sure specifically economic wise...
revolving credit was introduced and anyone with a job could buy almost anything, I suspect someone could research copper demands in 59 maybe they were upside down? I did look at a chart form macrotrends and indeed in early to mid 59 copper prices soared over the norm then dropped in 60', maybe that had something to do with it? maybe a suitable tranny wasn't available aside from bespoke or in house?
things were weird in 59 for sure it really was a hallmark year in terms of economy, unemployment and finance private consumption, does seem odd in any event as loud loud loud was in and bigger is better was fashionable, maybe its a design flaw in the engineering? lol
If you put in a heftier power transformer to maximise the PP 6V6 output, then the output transformer might also be under powered?
Brad... I Love your guitar playing.....DAMN
Great to see and hear are you back with the amps.... right on Brad!
Killer Job on this one Guitologist man you make these old amps sound sweet great video.
Some of these ancient amps can really wail if done up right. Imagine the kind of tones these 50s cats had at their fingertips with just a couple mods...
Amazing video. That's like an amp with teeth. The guts of that amp look so cool.
Suggestions:
1. Something I've always wanted to see you do is amp BUILDING videos. Mojo tone builds, other kit builds, or even maybe an amp of your own making, would be cool. That's a rabbit hole I've always wanted to go down, and would love to see a pro amp repair guy do it on a video before I try it myself. haha. I bet a lot of companies that sell those kits would send you product just to have a complete build video on youtube. I've seen others do it, but it not as in depth as what you do on your channel with your repair stuff. It would be really cool to see someone explain things as it's being built, in depth. Could be an entire series of videos, if you could get enough sponsors behind it. The DIY culture is really through the roof right now. I bet videos like that would do well.
2. Maybe do a video about the top five guitars in your collection, going through why you like them. Also, a top five amps would be cool, too, if you have five amps in your collection. I assume you have a truckload of amps around, but in my time in watching you, I haven't seen them; but I know you have a billion guitars.
3. Maybe rebrand 'Guitologist 2' to 'Guitologist After Hours' and do SPF and talking head stuff over there; stuff you want to do that isn't amp/guitar related. Separation would be great for people who aren't interested in the political stuff, and it would allow people to opt-in if they wanted.
Random: I know you hate this type of amp, and in fact so do I, but: I hope someday you do a video on a garbage digital Marshall MG250DFX. I have one that turns on fine, plays fine, and then seemingly randomly, has volume go to zero. Blows my mind how weird and dumb digital Marshall amps are. I've been trying to get the thing to work for more than 15 minutes at a time, for months. SIGH.
That's one killer sounding amp, regardless of the low output. It sounds just great.
A lot of companies back in the day especially the off-brand companies often underpowered their amps for the simple reasons of
(A): the longevity of the amp figuring that most people could not afford big amps and would try to get the most out of their little and it wouldn't blow up..
(B): that the amp under long continuous play would have a melt down and burn down the local VFW Hall or the school gymnasium wherever they were playing...
A lot of companies back in the day got sued due to malfunctions of the amp so in order to keep that from happening they underpowered them...
My high school electronics teacher used to work for Gibson back in the early years of his career.. and in the 80s when I brought in my 1962 Gibson GA300 RVT. amp to get rebuilt we had lots of discussions over amplifiers and which were better and which were worse and this is one of the conversations that had come up he remembered at one time (in the early to mid 60s when he worked for Gibson) that Fender (the competition)... Had gotten sued due to an amp at some high school venue had caught fire while it was in standby and nine kids or something like that had died as a result of the fire that it had caused...
Of course none of this was released to the public and was contained as to not ruin the reputation of the company... Obviously they compensated and swept it under the rug..
The conversation that that created was because I wanted the hot rod up that amplifier and how we could go about it safely he was extremely knowledgeable and yes we did Hot rod up that 300 amp. So the moral of the story is that most amplifiers were never put up to their optimum capacity I guess you'd call it due to these varying reasons.... Anyway enjoyed the video and keep up the good work Brad looking forward to more
Lol. Brad’s ALWAYS in beast mode.
Love it!
Great video. Appreciate your description of everything and your playing. Came across a weird Danelectro Amp yesterday. The Phase Inverter output connects to two pairs of 6L6 tubes with two tubes driving one output transformer and another pair driving a second output transformer. Each output transformer connects to a single 12 inch field coil speaker to make a 2x12 combo. Certainly unique! Not sure of why Danelectro did that.
More power. Having two amps is better than one in terms of volume. Lots of older amps did that. I showed one Gretsch recently on the channel that had stereo output.
Never tried to ground at the PI. I have used the power tubes cathode. If ive got an anemic PT i like to use SS rectifier. Saves some stress on the power section and gives the amp a little more umph
Tre-MO-lo. Gets me every time.
I'm more into hi-gain amps with 4-5 gain stages but man... THIS IS SICK AS FOOK. Currently i'm playing in punk/Oi band and tone like this should fit as hell. Time to warm up solder gun...
I love the crunch tone on this thing. It's dirty and mean. I'm not a fan of oversaturated gain tones. I think it sucks all the life and honesty out of the music, but this has balls.
you had mentioned a drop in viewership a bit back. let me explain my drop in viewership. i had bilateral carpal tunnel surgery a while back. i had hope that i would be able to play guitar again, but no such luck. i had a washburn, and an ibanez, and was not a great player, but enjoyed noodling around. sometimes the simplest of manual duties makes my fingers violently cramp...i have to pry them apart, and it is VERY painful. i am beside myself with anger and sadness that i can no longer play guitar without intense pain. i have been running away from all things guitar cuz im just too fucking sad to even think about it.
i will try to support you more, as i LOVE your content, and try to get over this,
your internet bud and admirer,
andy
I am truly sorry to hear that about your hands. I have carpel tunnel in BOTH wrists from years of IT work. Get a lap steel and a slide and learn Hawaiian and Delta Blues styles. There is a whole world of music on the guitar that very few people explore because they don't have enough heroes who do it.
@@TheGuitologist im actually getting a drum kit from a friend,and we are going to see how that goes...ive done some drumming years ago.
your advice is great, i have just been too angry to think of reasonable solutions. if the drums dont work out, im for sure looking into what you advised!
My first Amp that I learned on from my music teacher. I had a pig nose and a couple of pedals at home to practice on.
Brad, that's a nice sounding amp and you did a great job on it.
Thank you, Jeff.
That is pretty epic! Great sound and you even managed to demo the return input in normal mode a little by mistake at 16:25! Very good information throughout, well done in both videos Brad! Greetings from Hungary ;)
It'll pass signal in that mode on that channel, but best to use an outboard preamp of some kind if doing that.
@@TheGuitologist Yes I was wondering if it was just the powerstage without the pre-amp circuitry. Even more versatile as I thought! Great job!
Cool amp and mighty fine pickin’, too!
Brad, The amp is beautiful inside and out. Very nice clean work as always! Thanks as I enjoyed the video.
I was just thinking about UD’s Harvard video when you mentioned it! Lol! Sounds great!
Prayer that amplifier does sound killer! When I heard you playing I heard you hit a few chords I instantly recognize the sound. Because I too have a 1968 guild thunderstar. And it has the same throtty low mids and thundurus Bass. Although mine has 7591 power tubes which really sound cool and a little more detailed perhaps.
The wimpy txr makes this the perfect candidate for metal tubes! Once you go black ya never go back
Ah, the glorious tone of overdriven 6v6s
Good to see you doing what you do best, your friend in tone, Norman Mozley
Hi Brad, do you think "Curly " Guitar leads can make a difference to the signal compared to a straight lead? I have a 30ft coiled cable that is very well made but compared to a 30ft straight lead it makes the Guitar sound brighter(I know 30ft is too long and we should reallt be using 18ft 6") ?
Cool mod job! The thing sounds like it's ready to blow at any moment. It's got that controlled chaos thing going on in spades. No good excuse for being boring, right?
Aw man missed it again - I had the notification but was just not physically here when it went live. Sounds great, Brad, nice one.
I’ve long been interested in this stuff. But for some reason I kind of half tune out during any electronic stuff. I think I’m gonna learn this craft now.
Did you try a GZ34 recto tube or a SS diode replacement? That should provide less v drop and give a bit more to work with.
In the case of the Harvard, I can only theorize, but it would be true to Leo as we know him to design an amp around a low voltage transformer to utilize a bargain he picked up. We get used to thinking in terms of maximum potential in wattage for an amp design where Leo was thinking maximum clean all the time, and for cheap.
Noticing the distinction of the cathode bias, which would normally raise our wattage potential, yet other Fenders are not cathode biased. It just feels like analyzing it backwards, but in his case, he was able to squeeze a bit more out of that cheap transformer this way without adding cost to the build. It does make me wonder though, how this design would perform at say 400+ volts. Feel free to clone that Harvard with a Hotter transformer and see how it holds up. Sharing that with the rest of us, of course.
Your playing is superb!
Hi David. Thanks man. Nice of you to say.
I've got a 62 Guild 100j amp. Great sound!
Love the amp videos bro they're what got me into the channel in the 1st place a couple of years ago now.
Loving all the amp videos lately
Mate Kentucky has just been slammed by mother nature. Brad i hope you and our famly are safe and unaffected. God bless brother.
Wouldn't the lower plate voltage give it less headroom and the ability to overdrive easier, albeit at a lower power level? Especially when hitting the output tubes with an extra gain stage.
Or are you just referring to the fact that they can't deliver their full power? Maybe I fell asleep. LOL
Sounds great regardless!
You're right. I think I misspoke on that. It'll break up at lower volumes but won't have full headroom. The load line slope will be way off. That's what I meant to say.
@@TheGuitologist there's the solution I was looking for.
Love beast mode! Your playing is awesome as always
Thanks Mike. I appreciate that, my friend.
Brad is a real guitar hero :) Very sweet sounding amp. Thanks man!
Great vid, learned a lot. Amp really sounds amazing, keep the vids coming! The "black dot" reminded me of a question I had. How is adding an internal gain stage via the mod different to putting a booster pedal in front of the amp, assuming you had a similar amount of gain in the pedal?
The internal mod is adding another TUBE gain stage. A pedal would not be a tube gain, or if it was, it would be running in a starved plate configuration that would not be the same. I prefer all-tube saturation where possible.
@@TheGuitologist Thanks!
DAYUMMMMM BRAD! You're playing was on another level here! Not to say that it was bad in other videos, but wowww, you were ripping it up!! That amp sounds amazing too!! Hehe.
That is one great sounding amp.
Look (and sounded like) you were having way too much fun :-)
Brad ,i think its time to combine all the best tube amp recipe and come up with your own Boutique amp or pedals.
No one could afford to buy one at what I'd have to charge.
@@TheGuitologist Lol....thats what Mr Dumble said.
@@TheGuitologist 🙌🏻🙌🏻🙌🏻🙌🏻
🤘🤘🤘sup Brad! I’ve got an orange Rocker 15 terror on backorder that will arrive in several weeks, and I plan on modding it once I do a little homework. Your in-depth stuff is always appreciated.
Imagine Chuck Berry if he had got hold of one of these ;-0
Brad, you are the man
Perfect recording amp
Genius.
I wonder if swapping out the 5y3 for a 5v4 or maybe even a 5ar4 would get the voltage and current up to what might be "more normal"?
Or even silicon diodes. Anyway, if he can't drive the power amp to distortion, it also indicates a preamp / PI problem: Not enough voltage gain.
You could also substitute other members of the 12a?7 family in for the preamp tube to tweak the gain but not raise the noise floor so much. Maybe also make the beast switch go from Blues to Rock instead of Rock to Metal depending on what the owner plays.
There is european equivalent to the 6v6 that doesnt handle as much voltage. So to use it you have to cool the bias down. Im wondering if that tube would be better in an amp like this than the actual 6v6. I cant remember what its called, its related to the 6p3s. Might be something to try next time you repair an amp with a transformer like this. Very interesting video, thanks.
The strange way that can cap was acting really makes me wonder if people like Ken Fischer are/were really able to hear/feel the minute differences between components that are supposedly identical.
Nope didn't get anything.. of course I'm sure they already know I'm a supporter and agree with you on most all subjects. Love the content, stay tough dude!!
Sounds great. I'd love to use that amp for some recordings.
Shout out to tío Doug! One love
UD is the best. Period.
Shaka brah 🤙🏼
Hey Brad, Where did you learn to work on electronics and amplifiers?
Hey Brad, how come you do not use a toroid with a few windings for a choke on the ground and on the the AC input.
That might have solved the issue(s) without doing all that extra work. Your work is very clean and tidy.
Thanks for sharing. I alway learn something when I watch you solve a problem like this.
I do have a concerned about the wire loom passing though the hole in the chassis(where you signed your name) with no grommet.
Ricky from IBM, Ret
Sounds awesome , top notch work Brad
That's a very interesting problem, Brad. I haven't seen the previous video yet, but did you measure the high voltage AC from the Power Transformer? If that was OK, I assume the B+ must have been low. What rectifier was it? If its a 5Y3, try a 5V4 or even 5AR4. That may give you enough B+ to run your cathode resistors again. :-)
What a sweet little amp! Great job Brad
Try a pair of 6K6’s? That might give you some interesting results 🎸
I agree.
This lesson was nifty you balanced the noise out
Does the lack in the transformer contribute to that great break up sound - kind of like EVH starving brown sound?
It’s possible.
Sounds Bodacious
I always found it interesting that Princetons and Deluxes both have 2 6V6's, yet the Princeton has essentially half the power.
The way they run the 6V6s on there sounds kinda like my old Silvertone 1483. It's only 22 watts or so out of a pair of 6L6s, nowhere near the 50 watts they typically run at. It's supposed to be a bass amp, but at 22 watts....
That's some very tasty legato you got there Brad! Killer bro
I'm workiong on the same amp and have almost 430V B+. I had to increase the cathode resistor to 500 ohms. They must have started using a different transformer at some point.
that thing honks !
No notification for this on... Saw it by luck!
Thank you Brad!!
hey Brad , do you think in this situations with under spec transformers could it be possible to use maybe low power tubes, such as 6g6 or 6k6, less power output but less current needed too...maybe if the ot has the same load ?
ah and Btw great job the amp sounds great and super playing too 🤟
I think that could be a way to make the amp perform differently, yes. It’s a cool suggestion.
@@TheGuitologist cheers man👍🏻
So cool!!! You got one of those vanta black holes from Acme... Did Wile E Coyote recommend it to you?
Be careful, don't fall in!!
I didn't see any solder on the folding mount tabs to the cap can. Usually soldered to the chasis to eliminate vibration.
I found that really interesting how many options you tried to increase the power. Is component longevity a factor in your final decision? Meaning do your alterations affect tube life, or maybe increase heat in any way?
Regardless, the sound of that little growler is fantastic. Nice job.
I'm not sure why putting the tubes heaters 6vdc or 6avdc to a virtual ground using the phase inverters cathode DC voltage as the virtual ground would reduce the noises. Any reasons why tubes heaters are inducing noises in general that you have to put the heater grounds at a different DC offset virtual ground?
So it's a power-scaled amp! What is the plate voltage on the 6V6's ?
I am desperately looking for info on my FGenterprises ga445 amp. Its a solid state dual input combo with a 15 inch speaker and i believe FG stands for Fred Gretsch. Is there any way to get more gain out of late 60s, early 70s Gretsch/Kay/Multi-vox amps?
I wonder if an undersized transformer would increase the attack. Full voltage at the start of a note, but compresses down as the power supply drains due to the transformer. Either that, or a clean attack but a overdriven sustain.