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Thread: Cathode follower without elevated heater voltage

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    Cathode follower without elevated heater voltage

    I have an amp that's always had a problem. I noticed that it has a cathode follower stage, but the filaments are straight 6.3v directly out of the tranny. People talk about how cathode follower stages absolutely require elevated filament voltage, but they never say what the consequence of exceeding the heater-cathode voltage would be in terms of how the amp would sound/perform. Does anyone know? If it matches the way my amp behaves, then I think I'll have found the problem.

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    Quote Originally Posted by Dark Mavis View Post
    I have an amp that's always had a problem. I noticed that it has a cathode follower stage, but the filaments are straight 6.3v directly out of the tranny. People talk about how cathode follower stages absolutely require elevated filament voltage, but they never say what the consequence of exceeding the heater-cathode voltage would be in terms of how the amp would sound/perform. Does anyone know? If it matches the way my amp behaves, then I think I'll have found the problem.
    Please state your problem. You are asking us to pretty much guess. Here's some info on elevation. People here are like dogged reporters of old. They follow the facts, we follow the data you provide. We need problem, amp type and what your voltages for tubes are. Then you will most likely get better answers in a shorter time than if people have to ask for everything.

    Welcome to the board and stay a while.
    nosaj
    from http://www.valvewizard.co.uk/heater.html
    Heater Elevation
    Elevation means referencing the heater supply to a DC voltage other than ground or zero volts. The heaters still operate at 6.3V or whatever, but this floats on top of the elevation voltage. Some valve stages such as cathode followers require the heater supply to be elevated to avoid exceeding the valve's Vhk(max) rating. But even when not explicitly needed, elevation can reduce hum in AC-heated circuits by reducing or saturating the leakage current between heater and cathode.*

    The DC voltage is applied to a transformer centre tap, artificial centre tap, humdinger, or whatever reference connection the heater supply would normally have.

    The elevation voltage can be taken from a potential divider across the HT (it doesn't matter where you position the divider), and an elevation voltage around 30 to 60V is typical. The divider should have a fairly high resistance so as not to waste current, although the lower arm (R2) should not be excessively large or Rhk(max) may be grossly exceeded, so it is advisable not to make it greater than 100k. The elevation voltage should be decoupled/smoothed with an arbitrarily large capacitor (C1), say 10uF or more.

    Another convenient source of elevation voltage is the cathode of a cathode-biased power valve. No current flows ‘into’ the heater supply from here, so the power valve bias is not affected.

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    Bent Member Chuck H's Avatar
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    And to follow Jason's excellent briefing on the matter...

    I'm not aware of any specific sonic consequences to filament/cathode over voltage conditions. Unless a failed tube and a busted amp is included So whatever problem you're having may be from a different cause (ergo Jason't request for more specifics on the actual problem).

    Many classic amp designs exceed the heater to cathode maximum in one or more preamp stages. It was never a problem for over half a century. Problems with certain Rusky tubes have been noted over the years since. This problem is mostly worked out now and you don't hear about it much anymore with current production tubes. But no promises on that. The typical fix is to just use a Chinese (Shuguang) tube in the socket with the cathode follower.

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    Quote Originally Posted by nosaj View Post
    Please state your problem. You are asking us to pretty much guess. Here's some info on elevation. People here are like dogged reporters of old. They follow the facts, we follow the data you provide. We need problem, amp type and what your voltages for tubes are. Then you will most likely get better answers in a shorter time than if people have to ask for everything.

    Welcome to the board and stay a while.
    nosaj
    from http://www.valvewizard.co.uk/heater.html
    Heater Elevation
    Elevation means referencing the heater supply to a DC voltage other than ground or zero volts. The heaters still operate at 6.3V or whatever, but this floats on top of the elevation voltage. Some valve stages such as cathode followers require the heater supply to be elevated to avoid exceeding the valve's Vhk(max) rating. But even when not explicitly needed, elevation can reduce hum in AC-heated circuits by reducing or saturating the leakage current between heater and cathode.*

    The DC voltage is applied to a transformer centre tap, artificial centre tap, humdinger, or whatever reference connection the heater supply would normally have.

    The elevation voltage can be taken from a potential divider across the HT (it doesn't matter where you position the divider), and an elevation voltage around 30 to 60V is typical. The divider should have a fairly high resistance so as not to waste current, although the lower arm (R2) should not be excessively large or Rhk(max) may be grossly exceeded, so it is advisable not to make it greater than 100k. The elevation voltage should be decoupled/smoothed with an arbitrarily large capacitor (C1), say 10uF or more.

    Another convenient source of elevation voltage is the cathode of a cathode-biased power valve. No current flows ‘into’ the heater supply from here, so the power valve bias is not affected.
    I don't know what amp it is. It has no identifying marks or anything that suggests a manufacturer. The problem is that, beyond a certain (pretty low) volume, the amp sputters like a machine gun whenever notes are played. If I set the volume just on the threshold where things get weird, soft notes are fine, but hitting the strings a little harder, causes this crazy machine-gunning sound. The problem exists on both channels, and at around the same volume, regardless of whether the preamp is maxed and the master is low, or vice-versa. I tried playing in the dark, looking for signs of arcing in the tubes or on the sockets. I've tried swapping out the power tubes and preamp tubes. I've swapped out the output transformer. A guy who tried to fix it, said the signal is clean at the effects send, but I haven't confirmed this. The heaters are definitely not elevated. The preamp tubes have their own dedicated transformer, so I'll probably change that after the problem is sorted. Tubes are: 4XEL34s and 6 12AX7 (Actually, I think the driver tube was a 12AT7, but I haven't looked in this amp for a long time)
    It's been suggested that it may be a lead dress problem. I don't have an oscilliscope, but I do have a multimeter. I did measure the plate voltages at one point, but I'd have to do it again, cus I don't remember. Like I said, it's been a while since I last had a crack at this amp. Last time I looked, I noticed a grid wire that never had the shielding grounded at either end, so I'll also need to sort that out to rule it out. I dunno if it would cause this problem though, but no harm in doing it.

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    Master Destroyer nosaj's Avatar
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    Quote Originally Posted by Dark Mavis View Post
    I don't know what amp it is. It has no identifying marks or anything that suggests a manufacturer. The problem is that, beyond a certain (pretty low) volume, the amp sputters like a machine gun whenever notes are played. If I set the volume just on the threshold where things get weird, soft notes are fine, but hitting the strings a little harder, causes this crazy machine-gunning sound. The problem exists on both channels, and at around the same volume, regardless of whether the preamp is maxed and the master is low, or vice-versa. I tried playing in the dark, looking for signs of arcing in the tubes or on the sockets. I've tried swapping out the power tubes and preamp tubes. I've swapped out the output transformer. A guy who tried to fix it, said the signal is clean at the effects send, but I haven't confirmed this. The heaters are definitely not elevated. The preamp tubes have their own dedicated transformer, so I guess the power trans can't provide enough current for all the tube's filaments (4XEL34s and 6 12AX7 (Actually, I think the driver tube was a 12AT7, but I haven't looked in this amp for a long time)
    It's been suggested that it may be a lead dress problem. I don't have an oscilliscope, but I do have a multimeter. I did measure the plate voltages at one point, but I'd have to do it again, cus I don't remember. Like I said, it's been a while since I last had a crack at this amp. Last time I looked, I noticed a grid wire that never had the shielding grounded at either end, so I'll also need to sort that out to rule it out. I dunno if it would cause this problem though, but no harm in doing it.
    Please post pics of the inside chassis and amp as a whole. Machine gun sounds could possibly be motorboating which would sugesst filter capacitors failing which makes sense based on your description as the caps cannot put out the required voltage when driven.

    Pics will help for sure. If there is a dogbox will also need pics of caps in there.

    Thanks,
    nosaj

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    Bent Member Chuck H's Avatar
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    If the amp has six preamp tubes, a cathode follower and an effects loop it would be an ambitious build for diy. But with no manufacturer indicated this might be the case. So it might be an instability since diy builds of this order often suffer in areas that manufacturers have worked out having to do with lead dress and component layout. Since the amp has always had the problem I have to ask how it was acquired and if you know it's approximate age. That might help determine if the problem could be a failing filter capacitor.

    Maybe you could rundown the control layout for us. We know there's a volume and a master volume. Is there an additional gain knob and the usual tone stack features? Multiple channels? Boost or bright switches, etc.

    You should not start arbitrarily replacing things or even swapping out the OT, etc. In an amp like this it can only serve to complicate the issue. We see it all the time. Someone has no reason to replace or otherwise solder on some part of the amp and then things about the problem change and troubleshooting now involves two problems instead of one. Complicating things exponentially. Amps that suffer this kind of servicing commonly end up as dusty closet decor. Unless you know the preamp transformer is the cause of the problem you should not do anything to it. I will even add "please".

    After you report on the control layout and/or provide some pics the next likely request will be to ask if anything other than low volume setting for the preamp or master affects the problem. That is, if you turn the treble up all the way, what happens? If you have the treble and the preamp volume up high? Does the amp make any noises at certain control settings with nothing plugged in? Do the tone controls affect the sound of the noise? That sort of thing. This will be an effort to isolate the problem and I hope you'll be gracious and play along.

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    Bent Member Chuck H's Avatar
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    Holy shit.

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    Quote Originally Posted by Chuck H View Post
    If the amp has six preamp tubes, a cathode follower and an effects loop it would be an ambitious build for diy. But with no manufacturer indicated this might be the case. So it might be an instability since diy builds of this order often suffer in areas that manufacturers have worked out having to do with lead dress and component layout. Since the amp has always had the problem I have to ask how it was acquired and if you know it's approximate age. That might help determine if the problem could be a failing filter capacitor.

    Maybe you could rundown the control layout for us. We know there's a volume and a master volume. Is there an additional gain knob and the usual tone stack features? Multiple channels? Boost or bright switches, etc.

    You should not start arbitrarily replacing things or even swapping out the OT, etc. In an amp like this it can only serve to complicate the issue. We see it all the time. Someone has no reason to replace or otherwise solder on some part of the amp and then things about the problem change and troubleshooting now involves two problems instead of one. Complicating things exponentially. Amps that suffer this kind of servicing commonly end up as dusty closet decor. Unless you know the preamp transformer is the cause of the problem you should not do anything to it. I will even add "please".

    After you report on the control layout and/or provide some pics the next likely request will be to ask if anything other than low volume setting for the preamp or master affects the problem. That is, if you turn the treble up all the way, what happens? If you have the treble and the preamp volume up high? Does the amp make any noises at certain control settings with nothing plugged in? Do the tone controls affect the sound of the noise? That sort of thing. This will be an effort to isolate the problem and I hope you'll be gracious and play along.
    So, apparently, it's built from a kit made by Torres Engineering. I have a schematic somewhere, but, if I remember, the schematic shows 2X 6L6 power tubes, rather than the 4XEL34 in this amp. The lead dress is horrendous. I'm considering pulling all the wiring out and re-doing it, just for the Hell of it. I bought this amp off the guy who put it together, and I can still get in touch with him if needs be. He demonstrated the problem to me before I even bought it. Yeah, it's a twin channel amp and has an effects loop and reverb. There seems to be a missing filter cap, but I vaguely remember needing it for something else. It's been a long time. I bought this amp almost 20 years ago. I even recorded an album with it and gigged with it for a few years. I just had to mic it up cus of the problem it has. It has a bunch of push-pull pots that seem to be bright switches and a gain boost? I don't know if they're part of the original design or not. I looked at the Torres web page, and this seems to be a Dual Marshall, and the description mentions various gimmicky switches.
    IIRC the tone controls have no effect on this problem. Controls from left to right looking at the front of the amp, are: Channel 1 volume, treble, bass, mid. Channel 2 Gain, "Lead master", treble, bass, mid. Then there's reverb and then the master volume

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    Quote Originally Posted by Chuck H View Post
    Holy shit.
    Yeah, every time I look at it, I remember the scene in lost boys where David offers Jason the noodles. I have room in the enclosure to actually extend the chassis by 2 inches backwards. I'm tempted to do that. Or maybe even fab a whole new chassis with more room, and mount the filter caps on the outside under a cover like on old Fenders to get more breathing space. I'm not sure I can tidy that wiring with so little space

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    " it would be an ambitious build"

    I'll remember that description.

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    Quote Originally Posted by Dark Mavis View Post
    Yeah, every time I look at it, I remember the scene in lost boys where David offers Jason the noodles.
    I think it was rice. And yeah. Believe it or not I was actually thinking "Torres mod" when I saw the pics.

    Well the good news is that the amp has actually worked for the most part. I know I said that arbitrarily replacing parts was bad (Mkay), but after such a time and disuse it's probably a good idea to replace the filter capacitors (and put the missing cap back in). I know those IC caps get really grumpy with age and lack of charging in less than the age of this amp. So this would just be a matter of course to avoid complicating troubleshooting. That and some blowing out and cleaning, along with pot and contact cleaner would probably be the first order of business.

    After that we could chase any instabilities. Dan Torres was typically very good about actually testing his circuits for the modular mod kits he sold. Curing instabilities in this case will likely involve adding HF bleeder circuit/s and hopefully that would be enough. Rewiring the whole thing may or may not actually improve circumstances. There's a lot of peripheral circuits to account for. Lot's of opportunity for error and in this case it may be a wish to get a more stable lead dress in the end. So if there's only a few snarky issues it might be easier to just address those if possible.

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    Quote Originally Posted by Chuck H View Post
    I think it was rice. And yeah. Believe it or not I was actually thinking "Torres mod" when I saw the pics.

    Well the good news is that the amp has actually worked for the most part. I know I said that arbitrarily replacing parts was bad (Mkay), but after such a time and disuse it's probably a good idea to replace the filter capacitors (and put the missing cap back in). I know those IC caps get really grumpy with age and lack of charging in less than the age of this amp. So this would just be a matter of course to avoid complicating troubleshooting. That and some blowing out and cleaning, along with pot and contact cleaner would probably be the first order of business.

    After that we could chase any instabilities. Dan Torres was typically very good about actually testing his circuits for the modular mod kits he sold. Curing instabilities in this case will likely involve adding HF bleeder circuit/s and hopefully that would be enough. Rewiring the whole thing may or may not actually improve circumstances. There's a lot of peripheral circuits to account for. Lot's of opportunity for error and in this case it may be a wish to get a more stable lead dress in the end. So if there's only a few snarky issues it might be easier to just address those if possible.
    Rice first, then noodles. The rice looked like maggots and the noodles were worms. I'll start by replacing all the filter caps. The big grey ones were substitutions anyways, but I couldn't find enough lying around to sub them all. It's been at least 15 years since this thing was last plugged in, so I've forgotten a lot of stuff. I'll start by just replacing all the filter caps and reconnecting the output trans properly. I don't like seeing "electrical" tape. I found the missing filter cap, but I'll replace that, too. I see the resistor there is missing, too, so I gotta replace that as well

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    Quote Originally Posted by Chuck H View Post
    Holy shit.
    Roger that ... looks like an explosion in the spaghetti factory!

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    Quote Originally Posted by Leo_Gnardo View Post
    Roger that ... looks like an explosion in the spaghetti factory!
    If by any chance please scan or attach a schematic. It will be very helpful.

    nosaj

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    Lemme see if I can find it


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    On the bright side, if you've swapped the preamp tubes around and did not affect the problem, then it's not cathode-heater voltage that's the issue. Sorry, that's all I've got...

    As has been said, replace the filter caps first to see what that gets you.

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    I keeped to test an 12at7 for a week with 150V into cathode hoping something to happen as time it have 90v max specification. Very disapointed, nothing was going on. The tube is intact and work perfectly in my amp. I elevated the heaters just for confidence, not sure if need it

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    I've tested several Sovtek 12AX7LPS up to 500V and seen no evidence of heater to cathode breakdown. For that reason I doubt that this is ever much of an issue in the average cathode follower stage at 100V or so.

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    In spite of everything else going on in there, that's not a lot of tubes to check basic DC voltages. That could go along way to troubleshooting a simple issue like a cathode or plate resistor failure (which would be a lot easier than total gut & rebuild ).
    Idle DC voltages at plate and cathode for all preamp and power tubes.

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    Quote Originally Posted by Dark Mavis View Post
    Lemme see if I can find it

    Got the power supply section?

    nosaj

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    Quote Originally Posted by nosaj View Post
    Got the power supply section?

    nosaj
    I'm trying to get hold of it. If I can't, I'll just draw it out. I got a whole bunch of papers off the guy. There was a manual...which seemed to be just a bunch of drawings of the circuit board, with different wires labelled in each one, but I think there were separate pages for things like bias supply, power supply, output tubes, etc. I think there were datasheets for the output trans, showing all the windings and stuff.

    Edit: yup. Got them. There's nothing in great detail about the power supply. And the cap values in the amp itself are different, but I'll post it anyways. I also just realised I have to order some replacement fuses cus last time it was powered on, I got a short reading the plate voltage and the fuse and filament resistors went up in smoke. Guess I should buy a probe that's fit for purpose, too instead of poking around with those stabby ones. The empty eyelets next to the last filter cap, are confusing me. I don't remember if they were always empty, or if I took something out of there. There IS one other filter cap, but it's all the way over by the input jack...for some reason. And I definitely have a 22uf 350v cap in another amp that I'm sure came from this one. I just can't be sure, since it's been so long. It's not part of the bias supply, cus that one is over by the driver. It's entirely possible that I'm just convincing myself that I took a cap out of this amp almost 20 years ago

    [IMG][/URL][/IMG]
    That's copied verbatim from the manual/instructions. That's not what's in the amp, though. I THINK the first stage was 2X100uf caps, I dunno. I subbed them for some 250uf caps just to try to rule them out. The other three are all 47uf. Dunno what the resistors are. I'll just draw out the power supply that's actually in the amp. The drawing from the manual also doesn't show the resistor between the first and second stages, or the cap that's o0ff on it's own by the input jack
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

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    Last edited by Dark Mavis; 03-04-2019 at 03:35 PM.

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    Quote Originally Posted by g1 View Post
    In spite of everything else going on in there, that's not a lot of tubes to check basic DC voltages. That could go along way to troubleshooting a simple issue like a cathode or plate resistor failure (which would be a lot easier than total gut & rebuild ).
    Idle DC voltages at plate and cathode for all preamp and power tubes.
    Will do. I'm just waiting on a replacement fuse

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    Okay, I got a replacement fuse. In fact, I got a bunch, but hopefully my hand doesn't slip again. I'll measure all the plate and cathode voltages, the bias voltage, the voltage at each filter cap and either side of each tone cap and coupling cap, and write them on the schematic then post it here

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  25. #25
    Bent Member Chuck H's Avatar
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    Please measure DC voltages at grid pins as well.

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    "Never bet your life on somebody else doing their job." SoulFetish's good friend

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    Hmmm...I just powered the amp up for the first time in like 15 years. Just for a smoke test, really. After, I went to discharge the filter caps - Which I normally just do by reading their voltage until they discharge themselves through the meter to a level where I'm happy to just short them to the chassis through a screwdriver - but they were reading like 10 volts, even though the amp had only just been turned off. I GUESS they've deteriorated that much, just sitting there...?
    On the plus side...no smoke, nothing went pop, and there was sound from the speakers..though also the occasional crackle as everything warmed up.
    Guess I'll put the new filter caps in and get measuring

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  27. #27
    Bent Member Chuck H's Avatar
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    That seems typical to me. I see that more often than high voltage hanging on caps after shut down. There are bleed resistors in the circuit (the balance resistors) and if you shut down power with the standby switch in the play position the tubes will draw some current before they cool, and therefore some voltage off the caps since there's no longer an AC wall connection.

    That doesn't mean the caps aren't bad. But it does mean it's hard to tell with that criteria.

    The cracks and pops are also expected. The old caps and perhaps other components, tubes included, need to re acclimate to having voltage on them. There may also be oxide buildup on unsoldered connections or any cold solder joints.

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    "Back to the amp. It makes horrible sounds when I play my guitar thru it... because I suck at playing guitar." Mike6158

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    Quote Originally Posted by Chuck H View Post
    That seems typical to me. I see that more often than high voltage hanging on caps after shut down. There are bleed resistors in the circuit (the balance resistors) and if you shut down power with the standby switch in the play position the tubes will draw some current before they cool, and therefore some voltage off the caps since there's no longer an AC wall connection.

    That doesn't mean the caps aren't bad. But it does mean it's hard to tell with that criteria.

    The cracks and pops are also expected. The old caps and perhaps other components, tubes included, need to re acclimate to having voltage on them. There may also be oxide buildup on unsoldered connections or any cold solder joints.
    I definitely remember that they would take far longer to drain before. I guess it doesn't matter anyway, I'm gonna replace them anyways. But I think I'll measure all those voltages with the old caps first Maybe it would help to have both.
    Edit: I noticed that one of the 100k plate resistors in the drawing is 220k in the amp, so I think I'll also check all the values of all the resistors and caps and update the schematic to also include what's actually in the amp.

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  29. #29
    Bent Member Chuck H's Avatar
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    Using higher plate loads for typical guitar amp stages to raise gain was one of Dan's favorite things to do. That is, the different value was intentional. Again, since the amp "basically worked" once upon a time I would probably leave that value in place for now.

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    Yeah, I Googled Dan Torres. Almost wish I hadn't. I'll leave the parts in place, but, since the amp has never worked correctly, and is a home-assembly job, I'm to go over the whole thing right now and make sure there are no obvious mistakes. Then, this afternoon, I'll measure all those voltages

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    Okay, just gotta pop out for a bit. Here's what I got so far.
    Filter caps:

    Starting at the first cap -
    #1 482v
    #2 452v
    #3 396v
    #4 380v
    #5 (the one over by the input jacks) 379v (not sure what's up with that. Need to check that the 10k resistor really is 10k, I guess)

    Preamp tubes

    First tube

    Pin #1 377v
    pin #6 381v
    Cathodes and grids all at 0v

    Second tube

    Pin #1 362v
    Pin #6 381v
    Cathodes and grids at 0v

    Third tube (assuming this one of the ones wired as cathode followers)

    Pin #1 372v
    Pin #6 380v
    pin #7 380v
    All other pins 0v

    Fourth tube

    Pin #1 378v
    Pin #2 0v
    Pin #3 0v
    Pin #6 376v
    Pin #7 0v
    Pin #8 0v

    Fifth tube

    Pin #1 395v
    Pin #2 0v
    Pin #3 0v
    Pin #6 244v
    Pin #7 0v
    Pin #8 2v

    Sixth tube

    Pin #1 208v
    Pin #2 62v
    Pin #3 90v
    Pin #6 222v
    Pin #7 60v
    Pin #8 90v (jumpered to pin 3)



    Edit: The 10k resistor IS 10k Unless the colour band has faded. I dunno why it's not dropping more than one volt

    Okay. Power tubes:

    All pin #3's 481v
    All pin #4's 445v, except tube #3, which was 447
    All pin #5's -40v
    all pin #6's 448v

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    Last edited by Dark Mavis; 03-09-2019 at 03:54 PM.

  32. #32
    Bent Member Chuck H's Avatar
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    I have to assume that these measurements were taken with no tubes in?

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    Quote Originally Posted by Chuck H View Post
    I have to assume that these measurements were taken with no tubes in?
    Umm...nope. Should they have been?

    Edit. I mean nope the measurements were not taken with no tubes in. All the tubes were in place.

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    Last edited by Dark Mavis; 03-09-2019 at 04:26 PM.

  34. #34
    Bent Member Chuck H's Avatar
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    Not for initial testing to see that there aren't any obvious problems. But the only useful voltages for any operational diagnosis would need to have the tubes in place. The reason you're not seeing much voltage drop across those resistors is that there are no tubes drawing current though them. My concern right now is that you DO show some considerable voltage drop between some nodes. This could be indicative of shorted or partially shorted power filter caps. You would do well to make yourself a light bulb current limiter to use for the initial power ups between efforts. It could save you some troubles. It's just a 100W incandescent bulb in series (rather than parallel) with the wall AC.

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    "Being born on third base and thinking that you must have hit a triple is pure delusion!" Steve A

    "Back to the amp. It makes horrible sounds when I play my guitar thru it... because I suck at playing guitar." Mike6158

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    Quote Originally Posted by Chuck H View Post
    Not for initial testing to see that there aren't any obvious problems. But the only useful voltages for any operational diagnosis would need to have the tubes in place. The reason you're not seeing much voltage drop across those resistors is that there are no tubes drawing current though them. My concern right now is that you DO show some considerable voltage drop between some nodes. This could be indicative of shorted or partially shorted power filter caps. You would do well to make yourself a light bulb current limiter to use for the initial power ups between efforts. It could save you some troubles. It's just a 100W incandescent bulb in series (rather than parallel) with the wall AC.
    The tubes were all in place. I was asking if I should have tested with them out. All these measurements were taken with the original filter caps. I have replacements, but I wanted to get measurements either side of the swap in case there was anything to learn from it. I think I have some light fittings I can rewire to use as a current limiter.
    so...the problem may have been the filter caps all along? I guess I'll replace them all right now and see what's what after that

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