You know, there are secret knobs that greatly affect tone. Right there on the front panel. Seriously, as a gigging musician for 45+ years I find it interesting as I have repaired, modded and switched components myself on my 65 super reverb and many other amps, but honestly, nobody can tell or notice any difference that listens to your music. I’m still waiting for someone to come up to me after a gig and say “Man, did you switch out the carbon comp plate resistors since I last heard you?” It’s all good folks if it inspires you to play better go for whatever works. Rock on. 😅
It’s my understanding that the idea of metal oxide vs carbon comp was primarily reducing background “hiss”. With the hiss problem reduced with metal film or metal oxide, over carbon comp. The secondary affect being a loss of tonal character with the metal oxide. That stated, I’ve built them with both. And I can definitely hear a difference in noise present in idle, with said noise disappearing upon my contact with any metallic part of the guitar. Including the strings. Like some of the others here, through your recording, the internet affects plus my own sound reproduction on my end, I hear no appreciable tonal difference when playing. And you’re pretty good on that guitar, by the way.
the difference is so tiny as to not even matter. With a cranked amp, and in a full band mix, it really would not matter one iota. Fwiw, I heard the metal oxides as having just a hair more brilliance/clarity.
@@ryansequeira7938 True, with a live band. But there's often also studio work and golden eared recording engineers to mix into this carbon-comps VS The Rest tonal sitch.
@@oldasrocks9121 even so - adjusting a mic changing a mic type, or using a different speaker or cab could EASILY make up the difference. I say if the metal oxides (or dare i say metal films) provide more stable and reliable operation of the amp then that's what should be in there.
Somehow, it matters in a passive tone circuit. Like in a guitar. I've wired in a 3PDT switch in a guitar temporarily to test it and the high frequency roll off for film caps is very noticeable. I prefer the inner foil to ground, backwards from the typical wiring.
To my ear on an Ipad Pro with Bang & Olufson headphones, really good ones, expensive anyway, the metal was way richer, thick, compressed, just lovely, and the carbon was way thin. Awesome scientific method. I dig it.❤
IMHO, if no signal passes through the cap/resistor it doesn't matter, thats what was available at time of production. Visually, yes it makes the appearance seem more original if a replaced cap/resistor is the same type. Steady reliable voltages are more important than appearance to me personally. Nice work and playing as usual!
Nice. could be my imagination, but i think the Metal oxides have a more open, articulate sound. Very nice on the arpeggiated and chords. CArbons are a little more midrangey, recessed. But if i walked out of the room and came back in later i doubt i would ever know
I think this is close to my thought. The carbon comps aren’t necessarily less harsh they are just blocking some clarity, IMO. My ears aren’t great and I didn’t listen on the best audio platform either, though.
Absolutely can hear the difference... I first was listening without looking at could hear it every time. Carbon Comb was more pleasing to me. Which jives with my 61 Vibrolux which I just did the same thing, and commented to you that it sounded better and even louder.
The only advantage of carbon comp resistors is in applications with high pulse energy. Otherwise, they're noisy and less reliable. For plate resistors, I use 2-watt carbon films, rated for 700V operation. Quiet and reliable, well suited for this application.
Less reliable in that they develop shot or popcorn noise over decades. I replace with Ohmite 1w carbon film rated at 500v from Mouser. 2w and 700v seems really overkill, like why not go metal oxide at that point. The originals were all 1/2w. 1w is already overkill. The voltage drop across the preamp plate resistors will never begin to approach even 500v, much less 700v. All the old 1/2w carbon comp resistors used in Fender amps are generally rated at 350v.
There's a slight softening effect, and the more you use in the signal chain the more noticeable it is. Why carbon comps do that? My guess is because of how they're made and how noisy they can be. Film type resistors all sound the same to me, some with a little less hiss.
I’m new to tube amps just found your video. Please explain why you would remove a center tap and add an artificial tap. What is the benefit or advantage to that?
What are some other things you'd like to see tested like this? So far we've done affect on tone by changing bias, affect on tone changing cathode bias resistor for preamp tubes (type and value), and now plate resistor make.
Thermal stabilization of the operating point please: 1 minute after power on, 2, 5, 10, 30, 1hr. Which could have a very pronounced effect on the tone, esp. with worn tubes, and might well be the actual reason behind perceived differences in different caps or resistors if the amp was not given sufficient time for thermal stabilization before each test.
(Edit) also it would be great to not give the listeners any clue as to what sample they are hearing at any given moment, let people decide and put their guesses in the comments first, with a separate reveal video later. :)
Tested as good examples of the big drop type caps, the blue ones are usually in Fenders, the ones I recall seeing most often elsewhere we called chocolate drops. Compared to the yellow modern MPT types.
I think it was Aussie Brad that described the carbon comp "magic": their resistance changes as the voltage applied changes. And its not a predictable curve, the relation of a particular voltage to the resulting changed resistance isn't logarithmic, its more like a piss shiver. If you will... Lets say a squiggle. So whatever one hears with comps will only be heard in class AB, of course, no need to bother with Class A, I've been happiest with metal oxides in Class A, quiet enough.
I just finished a build using almost all Allen Bradley carbon comps. The amp is dead quite, with only some minor hiss at higher volumes. They're are ways to, avoid/ reduce hiss.
After the treatment by youtube and your own recording gears it is difficult to ear a difference. And directly in front of the amp, do you notice anything ?
Honestly I dont hear any difference between the TH-cam uploads and the original files, I think the TH-cam compression thing is kind of overblown. Especially if you upload in high res where the bitrate is higher. When I recorded the tests I thought the oxide sounded a little brighter and the CC a bit fuller. But sliiiight
Listening through with Studio Monitoring Headphones, I couldn't hear anything noticeable. The best thing to do to determine if there was any difference is to do a "Null Test" running a Loop through the Amp. Inconsequential differences, if there were actually any.
Well I can confirm there is a difference, at some level, as the waveforms are not identical... but ultimately if you can't hear that difference it effectively doesn't exist imo 🙂
I'm not hearing any difference, and I have some decent speakers hooked up to my computer. You would need to have a full frequency spectrum analyzer and look at the even order harmonics to "see" if there was any difference. Chris at Rift Amps used a spectrum analyzer on one of his recent videos.
Why switching to an virtual ground? BTW I am at the vacation. My current setup is not that great to be sure what I hear. With this setup some switching sounded as expected and the other sounded almost the same depending on type of picking and tone of the notes being played. As mentioned already, I use carbon comp resistors only in clones and reparation of old original amplifiers. That speaking of the plate and other non nodal resistors. I tend to go with metal oxide for nodal resistors only.
@YeatzeeGuitar thanks for answering that quickly. Though, I am not sure what's the logic behind it is. You are just introducing two new points of future failure and removing the thing that just works and is as good as never an issue. Virtual ground is a cheap solution when the transformer comes without center tapped filament winding. It is traditionally used in cheaper amplifiers. But if you have native, God-given tap, that's working, I do not see any reason not to use it. Preamp tubes last long time, right? Most often, they get changed when they become noisy or feedback sensitive, right? Sometimes you see very old ones get weak too. Most tubes that fail are power tubes, right? They fail as their cathode get depleted, so it loses its conductance , power, or good sound. Power tubes are bigger and heavier, and by rough handling, they can develop short circuits. Most often, they develop short between screens and ground or some other control element and ground. Most dangerous are those high positive voltage short circuits to ground or cathode. Power transformers can't handle any prolonged shirts on high voltage. On the other side, filament shorts are high current shorts and not that often. Fillament winding is done with very thick wire and is meant to last a long time with that high load. Sure, high voltage winding has always the bias current load but with volume current increases. Music signal has pauses, and that's helping out. Fillament is on as soon as you switch the power on. It is always at its maximum current draw (practically speaking). Those filament windings are way more robust. The mains fuse should and almost always does protect the PT from the filament shirt circuit. On the other hand, high voltage winding dies way more often. Screen resistors can save PT and sometimes HV fuse saves the PT as well. Though you will see dead high voltage winding with HV fuse still in tact. Most of the time, issues with the filament winding are that PT was not capable of delivering enough power, especially when models add one more Preamp tube. Or replacement PT was weak or very cheaply made. Sometimes tap dies as well, and then virtual tap does make sense. Sometimes, transformers just get cooked and develop internal shorts. Sometimes, those internal shorts aren't even to the ground, but between the layers. Lacquer isolation melts and develops shorts, lowering the output voltage on that tap and dangerously heating up the PT as well. Namely, that shorted part of the coil looks inactive at first look, but actually, it is in short with itself and loads, additionally, the PT. It gets even hotter, inviting even further demise and new short circuits. PT i ternal shorts to ground are not that often but can happen. One can see them when hook up wires and their connection to the windings fails and touches grounded noise protection foil if the PT has one. Or touches metal parts of the PT. Shorted filament winding can make issues but even kill its center tap hookup wire, but that can happen even without a bad tube. So I really do not see why doing that.
These are great comparison videos brother, unfortunately for me I don't hear a difference at all.. Maybe just my ears though How about your thoughts now that you've edited the video? 😃
I hear a slight bit of difference with the gainy example, oxide a bit brighter carbon comp a hair fatter. The waveforms are different so there is a difference, but it's subtle enough to not be super noticeable. At times I hear the carbon comp having a bit more low end depending on when I cut the audio next to the oxide but where it ended up in the edit they seem pretty dang close. Certainly not enough of a difference to worry about it. The only caveat is change under heat, I can see there being more of a difference when an amps been on for an hour or two. That'd be hard to test though
If there was a difference, it's not discernable enough to make a difference to my ears. Only reason I'd bother switching back to carbon comps is for originality.
Why fix something thats not broken. Yes carbon drifts but everthing in the amp will drift too when given time. Carbon gives a warmer tone.... thanks for the video........
![[DRIP] ‘BILLIONAIRE’ PREVIEW](http://i.ytimg.com/vi/m0eXQD0gIeE/mqdefault.jpg)
You know, there are secret knobs that greatly affect tone. Right there on the front panel. Seriously, as a gigging musician for 45+ years I find it interesting as I have repaired, modded and switched components myself on my 65 super reverb and many other amps, but honestly, nobody can tell or notice any difference that listens to your music. I’m still waiting for someone to come up to me after a gig and say “Man, did you switch out the carbon comp plate resistors since I last heard you?” It’s all good folks if it inspires you to play better go for whatever works. Rock on. 😅
No thats a bad argument. It would be defined as an informal fallicy argument and you would get an F or possibly tossed from class.😮
It’s my understanding that the idea of metal oxide vs carbon comp was primarily reducing background “hiss”. With the hiss problem reduced with metal film or metal oxide, over carbon comp.
The secondary affect being a loss of tonal character with the metal oxide.
That stated, I’ve built them with both. And I can definitely hear a difference in noise present in idle, with said noise disappearing upon my contact with any metallic part of the guitar. Including the strings.
Like some of the others here, through your recording, the internet affects plus my own sound reproduction on my end, I hear no appreciable tonal difference when playing. And you’re pretty good on that guitar, by the way.
I hear a difference substantial enough to use carbon comps on a higher end build. I wouldn't be concerned on a budget build.
the difference is so tiny as to not even matter. With a cranked amp, and in a full band mix, it really would not matter one iota. Fwiw, I heard the metal oxides as having just a hair more brilliance/clarity.
@@ryansequeira7938 True, with a live band. But there's often also studio work and golden eared recording engineers to mix into this carbon-comps VS The Rest tonal sitch.
@@oldasrocks9121 even so - adjusting a mic changing a mic type, or using a different speaker or cab could EASILY make up the difference. I say if the metal oxides (or dare i say metal films) provide more stable and reliable operation of the amp then that's what should be in there.
That was a cool test . I'm feeling the metal has a little more clarity and Sparkle
I’d love to see you try an outside foil orientation vid like this! Thank you for great stuff as always.
Somehow, it matters in a passive tone circuit. Like in a guitar. I've wired in a 3PDT switch in a guitar temporarily to test it and the high frequency roll off for film caps is very noticeable. I prefer the inner foil to ground, backwards from the typical wiring.
To my ear on an Ipad Pro with Bang & Olufson headphones, really good ones, expensive anyway, the metal was way richer, thick, compressed, just lovely, and the carbon was way thin. Awesome scientific method. I dig it.❤
IMHO, if no signal passes through the cap/resistor it doesn't matter, thats what was available at time of production. Visually, yes it makes the appearance seem more original if a replaced cap/resistor is the same type. Steady reliable voltages are more important than appearance to me personally. Nice work and playing as usual!
Nice. could be my imagination, but i think the Metal oxides have a more open, articulate sound. Very nice on the arpeggiated and chords. CArbons are a little more midrangey, recessed. But if i walked out of the room and came back in later i doubt i would ever know
I think this is close to my thought. The carbon comps aren’t necessarily less harsh they are just blocking some clarity, IMO. My ears aren’t great and I didn’t listen on the best audio platform either, though.
I love the sound of the Tele on the SRV amp 😎👍 . . .
Absolutely can hear the difference... I first was listening without looking at could hear it every time. Carbon Comb was more pleasing to me. Which jives with my 61 Vibrolux which I just did the same thing, and commented to you that it sounded better and even louder.
Never gave that a thought. I can’t tell. Maybe a better ear can, but I can’t.
The only advantage of carbon comp resistors is in applications with high pulse energy. Otherwise, they're noisy and less reliable. For plate resistors, I use 2-watt carbon films, rated for 700V operation. Quiet and reliable, well suited for this application.
Less reliable in that they develop shot or popcorn noise over decades. I replace with Ohmite 1w carbon film rated at 500v from Mouser. 2w and 700v seems really overkill, like why not go metal oxide at that point. The originals were all 1/2w. 1w is already overkill. The voltage drop across the preamp plate resistors will never begin to approach even 500v, much less 700v. All the old 1/2w carbon comp resistors used in Fender amps are generally rated at 350v.
There's a slight softening effect, and the more you use in the signal chain the more noticeable it is.
Why carbon comps do that? My guess is because of how they're made and how noisy they can be. Film type resistors all sound the same to me, some with a little less hiss.
I’m new to tube amps just found your video. Please explain why you would remove a center tap and add an artificial tap. What is the benefit or advantage to that?
@@buzzedalldrink9131 lower noise and safety. If there's a catastrophic problem the resistors will burn up and the transformer will be saved.
@@YeatzeeGuitar thank you
On my own builds I use 1w MF routinely. I find CC hissy and sometimes with pops. I think over time they absorb some humidity.
Tasty tones! I thought the Metal sounded a lil more brilliant then the carbon’s
What are some other things you'd like to see tested like this? So far we've done affect on tone by changing bias, affect on tone changing cathode bias resistor for preamp tubes (type and value), and now plate resistor make.
Oh and also ceramic caps vs non ceramic in a few positions of ab763 amps
Thermal stabilization of the operating point please: 1 minute after power on, 2, 5, 10, 30, 1hr. Which could have a very pronounced effect on the tone, esp. with worn tubes, and might well be the actual reason behind perceived differences in different caps or resistors if the amp was not given sufficient time for thermal stabilization before each test.
(Edit) also it would be great to not give the listeners any clue as to what sample they are hearing at any given moment, let people decide and put their guesses in the comments first, with a separate reveal video later. :)
Tested as good examples of the big drop type caps, the blue ones are usually in Fenders, the ones I recall seeing most often elsewhere we called chocolate drops. Compared to the yellow modern MPT types.
I don't think anyone has the attention span for that type of "hidden then reveal" video series any more haha
I think it was Aussie Brad that described the carbon comp "magic": their resistance changes as the voltage applied changes. And its not a predictable curve, the relation of a particular voltage to the resulting changed resistance isn't logarithmic, its more like a piss shiver. If you will... Lets say a squiggle.
So whatever one hears with comps will only be heard in class AB, of course, no need to bother with Class A, I've been happiest with metal oxides in Class A, quiet enough.
Love to hear the comparative noise floor with the M.O.'s vs CC too. I am guessing the difference there is much more apparent?
Metal oxide definitely a bit quieter, but that doesn't come across when recording with the ox box
I just finished a build using almost all Allen Bradley carbon comps. The amp is dead quite, with only some minor hiss at higher volumes. They're are ways to, avoid/ reduce hiss.
I'm not going to worry with mine. Did you check the tolerances on all those resistors?
@@raedwulfone yes all within 5% of eachother
After the treatment by youtube and your own recording gears it is difficult to ear a difference. And directly in front of the amp, do you notice anything ?
Honestly I dont hear any difference between the TH-cam uploads and the original files, I think the TH-cam compression thing is kind of overblown. Especially if you upload in high res where the bitrate is higher. When I recorded the tests I thought the oxide sounded a little brighter and the CC a bit fuller. But sliiiight
Listening through with Studio Monitoring Headphones, I couldn't hear anything noticeable. The best thing to do to determine if there was any difference is to do a "Null Test" running a Loop through the Amp. Inconsequential differences, if there were actually any.
Well I can confirm there is a difference, at some level, as the waveforms are not identical... but ultimately if you can't hear that difference it effectively doesn't exist imo 🙂
For clean nd edge MEtAL, but man the carbone sounded sweeter in full drive!!
I'm not hearing any difference, and I have some decent speakers hooked up to my computer. You would need to have a full frequency spectrum analyzer and look at the even order harmonics to "see" if there was any difference. Chris at Rift Amps used a spectrum analyzer on one of his recent videos.
Why switching to an virtual ground? BTW I am at the vacation. My current setup is not that great to be sure what I hear. With this setup some switching sounded as expected and the other sounded almost the same depending on type of picking and tone of the notes being played. As mentioned already, I use carbon comp resistors only in clones and reparation of old original amplifiers. That speaking of the plate and other non nodal resistors. I tend to go with metal oxide for nodal resistors only.
Just a bit of protection for the PT against a tube shorting
@YeatzeeGuitar thanks for answering that quickly. Though, I am not sure what's the logic behind it is. You are just introducing two new points of future failure and removing the thing that just works and is as good as never an issue. Virtual ground is a cheap solution when the transformer comes without center tapped filament winding. It is traditionally used in cheaper amplifiers. But if you have native, God-given tap, that's working, I do not see any reason not to use it. Preamp tubes last long time, right? Most often, they get changed when they become noisy or feedback sensitive, right? Sometimes you see very old ones get weak too. Most tubes that fail are power tubes, right? They fail as their cathode get depleted, so it loses its conductance , power, or good sound. Power tubes are bigger and heavier, and by rough handling, they can develop short circuits. Most often, they develop short between screens and ground or some other control element and ground. Most dangerous are those high positive voltage short circuits to ground or cathode.
Power transformers can't handle any prolonged shirts on high voltage.
On the other side, filament shorts are high current shorts and not that often. Fillament winding is done with very thick wire and is meant to last a long time with that high load. Sure, high voltage winding has always the bias current load but with volume current increases. Music signal has pauses, and that's helping out.
Fillament is on as soon as you switch the power on. It is always at its maximum current draw (practically speaking). Those filament windings are way more robust. The mains fuse should and almost always does protect the PT from the filament shirt circuit. On the other hand, high voltage winding dies way more often. Screen resistors can save PT and sometimes HV fuse saves the PT as well. Though you will see dead high voltage winding with HV fuse still in tact.
Most of the time, issues with the filament winding are that PT was not capable of delivering enough power, especially when models add one more Preamp tube. Or replacement PT was weak or very cheaply made. Sometimes tap dies as well, and then virtual tap does make sense.
Sometimes, transformers just get cooked and develop internal shorts. Sometimes, those internal shorts aren't even to the ground, but between the layers. Lacquer isolation melts and develops shorts, lowering the output voltage on that tap and dangerously heating up the PT as well. Namely, that shorted part of the coil looks inactive at first look, but actually, it is in short with itself and loads, additionally, the PT. It gets even hotter, inviting even further demise and new short circuits. PT i ternal shorts to ground are not that often but can happen. One can see them when hook up wires and their connection to the windings fails and touches grounded noise protection foil if the PT has one. Or touches metal parts of the PT. Shorted filament winding can make issues but even kill its center tap hookup wire, but that can happen even without a bad tube.
So I really do not see why doing that.
Carbon Comp just a bit warmer and fatter , less harsh .
These are great comparison videos brother, unfortunately for me I don't hear a difference at all.. Maybe just my ears though
How about your thoughts now that you've edited the video? 😃
I hear a slight bit of difference with the gainy example, oxide a bit brighter carbon comp a hair fatter. The waveforms are different so there is a difference, but it's subtle enough to not be super noticeable. At times I hear the carbon comp having a bit more low end depending on when I cut the audio next to the oxide but where it ended up in the edit they seem pretty dang close. Certainly not enough of a difference to worry about it. The only caveat is change under heat, I can see there being more of a difference when an amps been on for an hour or two. That'd be hard to test though
@@YeatzeeGuitar Interesting, thanks! I've heard that carbon comps are supposed to be warmer and richer. Sounds like you're definitely hearing that!
If there was a difference, it's not discernable enough to make a difference to my ears. Only reason I'd bother switching back to carbon comps is for originality.
Why fix something thats not broken. Yes carbon drifts but everthing in the amp will drift too when given time. Carbon gives a warmer tone.... thanks for the video........
@@jimcastillo8950? They were already replaced with metal oxides when I got it.
@@YeatzeeGuitar understood, I subscribed to your channel. I like your troubleshooting techniques and how you explain.......
I couldn't hear a difference.🤷♂
There is a difference
I hear no appreciable difference. I'd say go with whatever's cheaper or more reliable.
We heard differently.
Silver ones sounded a little more defined, perhaps.