volume problem
Question:
I am using a late 60’s Ampeg G-22. At high volumes, it has great tone. The problem is unless you turn it up to 3, it has basically NO volume… and I don’t mean that 3 is the sweet spot, I mean there is virtually no volume at all, and then suddenly at 3 it is ON and loud. The issue is that at 3 it is too loud. I need volume at about 2 or 2.5 to work. Any ideas as to how to fix this? Do you think it’s the volume pot, or something more complicated?
Response:
Try the volume knob on the geetar 
cb — Some people have something to say… others have to say something!
Response:
courageously avow: >I am using a late 60’s Ampeg G-22. >At high volumes, it has great tone. >The problem is unless you turn it up to 3, it has basically NO volume… >and I don’t mean that 3 is the sweet spot, I mean there is virtually no >volume at all, and then suddenly at 3 it is ON and loud. The issue is >that at 3 it is too loud. I need volume at about 2 or 2.5 to work. >Any ideas as to how to fix this? Do you think it’s the volume pot, or >something more complicated?
Have you tried turning your guitar down and the amp up? Ken Wilson Proud Owner of Lord Valve, PMG, John Wheaton, Claude Lucas, Freep the Xenophobe, and the rest of the Union of Rightwing Idiots Needing Explanations (URINE) And at his own request, Lars GotShanked Supporting the Troops at http://www.resisters.ca
Response:
I’m not the one usually playing this amp and it is hard to get the person to adjust their guitar volume. I will try emphasize this, though it would be nice to have a solution at the amp. – Hide quoted text — Show quoted text – > courageously avow: >I am using a late 60’s Ampeg G-22. >At high volumes, it has great tone. >The problem is unless you turn it up to 3, it has basically NO volume… >and I don’t mean that 3 is the sweet spot, I mean there is virtually no >volume at all, and then suddenly at 3 it is ON and loud. The issue is >that at 3 it is too loud. I need volume at about 2 or 2.5 to work. >Any ideas as to how to fix this? Do you think it’s the volume pot, or >something more complicated? > Have you tried turning your guitar down and the amp up? > Ken Wilson > Proud Owner of Lord Valve, PMG, John Wheaton, Claude Lucas, > Freep the Xenophobe, and the rest of the > Union of Rightwing Idiots Needing Explanations (URINE) > And at his own request, Lars GotShanked > Supporting the Troops at http://www.resisters.ca
Response:
courageously avow: >I’m not the one usually playing this amp and it is hard to get the >person to adjust their guitar volume. I will try emphasize this, though >it would be nice to have a solution at the amp.
At lower amp volumes you are not getting the full tonal richness that you could. My usual practice is to run my amp as full as I can with the guitar volume set between 3 and 4. That way I can go up or down and don’t rob myself of any of the amp’s potential unduly. You will find a lot of seasoned veterans take this approach. – Hide quoted text — Show quoted text -> courageously avow: >>I am using a late 60’s Ampeg G-22. >>At high volumes, it has great tone. >>The problem is unless you turn it up to 3, it has basically NO volume… >>and I don’t mean that 3 is the sweet spot, I mean there is virtually no >>volume at all, and then suddenly at 3 it is ON and loud. The issue is >>that at 3 it is too loud. I need volume at about 2 or 2.5 to work. >>Any ideas as to how to fix this? Do you think it’s the volume pot, or >>something more complicated? > Have you tried turning your guitar down and the amp up? > Ken Wilson > Proud Owner of Lord Valve, PMG, John Wheaton, Claude Lucas, > Freep the Xenophobe, and the rest of the > Union of Rightwing Idiots Needing Explanations (URINE) > And at his own request, Lars GotShanked > Supporting the Troops at http://www.resisters.ca
Ken Wilson Proud Owner of Lord Valve, PMG, John Wheaton, Claude Lucas, Freep the Xenophobe, and the rest of the Union of Rightwing Idiots Needing Explanations (URINE) And at his own request, Lars GotShanked Supporting the Troops at http://www.resisters.ca
Response:
>I mean there is virtually no >volume at all, and then suddenly at 3 it is ON and loud.
Sounds like a bad pot. -DC
Response:
– Hide quoted text — Show quoted text – > courageously avow: >I’m not the one usually playing this amp and it is hard to get the >person to adjust their guitar volume. I will try emphasize this, though >it would be nice to have a solution at the amp. > At lower amp volumes you are not getting the full tonal richness that > you could. My usual practice is to run my amp as full as I can with > the guitar volume set between 3 and 4. That way I can go up or down > and don’t rob myself of any of the amp’s potential unduly. You will > find a lot of seasoned veterans take this approach. >> courageously avow: >>>I am using a late 60’s Ampeg G-22. >>>At high volumes, it has great tone. >>>The problem is unless you turn it up to 3, it has basically NO volume… >>>and I don’t mean that 3 is the sweet spot, I mean there is virtually no >>>volume at all, and then suddenly at 3 it is ON and loud. The issue is >>>that at 3 it is too loud. I need volume at about 2 or 2.5 to work. >>>Any ideas as to how to fix this? Do you think it’s the volume pot, or >>>something more complicated? >> Have you tried turning your guitar down and the amp up? >> Ken Wilson
Interesting that some players have no concept or consideration of how to use the V knob on the guitar. I had a bug that I’d like to buy another guitar (I think maybe I’m cured for a while), so I went to the store to shop and I went several times. The salesman (whichever store) was always kind enough to ask what amp I’d like to play through, and I usually ask for a DB or BJ and they are generally accomodating. But….they always put the amp volume on 2. I always have to go reset it. That’s because I’m willing to turn down the guitar! I guess the young bucks only know how to play with the guitar wide open. You know, the other thing they should learn to try is rolling off the treble at the guitar. You can really get a rich tonal pallete that way. It may be that the pot is bad, or it just might be that the circuit doesn’t see much comming at it until it hits 3. Another value pot might or might not make a difference. Whichever, it’s probably harmless to the amp. Tell the guy he needs to learn to turn it down. It’s faster and cheaper. Don’t young people learn anything about dynamics anymore? I dunno, my first instrument was piano, and second was ‘cello. I haven’t played either in the last 35 years or so and now forget how. One thing that I was taught was about dynamics! End of rant.
Response:
> Any ideas as to how to fix this? Do you think it’s the volume pot, or > something more complicated?
Replace the pot, even the CTS & Centralabs used in these wear out in time. The amp has a board & a packaged tone circuit, be careful in there.
Response:
Like he said. When the tech replaces the pot, have him check the coupling cap just ahead of the pot. It’s likely to be leaky. – Hide quoted text — Show quoted text ->I mean there is virtually no >volume at all, and then suddenly at 3 it is ON and loud. > Sounds like a bad pot. > -DC
Response:
Thanks! I will do that. – Hide quoted text — Show quoted text – > Like he said. > When the tech replaces the pot, have him check the coupling cap just ahead of > the pot. It’s likely to be leaky. >>I mean there is virtually no >>volume at all, and then suddenly at 3 it is ON and loud. >Sounds like a bad pot. >-DC
Response:
You are correct. People in general that play in rock bands are not taught about dynamics. However, you are preaching to the wrong person. I am the one in the band who is working very hard to get everyone else to understand dynamics and it’s an uphill battle to say the least for every single band and every single year I’ve been playing music. I use an old Fender Deluxe Reverb (only 22 watts) and yes I use the guitar volume technique. I am trying to make it very simple for the other guitarist and the other musicians I’m currently playing with to not go above a certain volume. Having an amp with this situation does not help. And YES, tell me about it… it is an ongoing struggle to find musicians that understand the way to play powerful music does NOT involve turning up. – Hide quoted text — Show quoted text ->courageously avow: >>I’m not the one usually playing this amp and it is hard to get the >>person to adjust their guitar volume. I will try emphasize this, though >>it would be nice to have a solution at the amp. >At lower amp volumes you are not getting the full tonal richness that >you could. My usual practice is to run my amp as full as I can with >the guitar volume set between 3 and 4. That way I can go up or down >and don’t rob myself of any of the amp’s potential unduly. You will >find a lot of seasoned veterans take this approach. >>>courageously avow: >>>>I am using a late 60’s Ampeg G-22. >>>>At high volumes, it has great tone. >>>>The problem is unless you turn it up to 3, it has basically NO volume… >>>>and I don’t mean that 3 is the sweet spot, I mean there is virtually no >>>>volume at all, and then suddenly at 3 it is ON and loud. The issue is >>>>that at 3 it is too loud. I need volume at about 2 or 2.5 to work. >>>>Any ideas as to how to fix this? Do you think it’s the volume pot, or >>>>something more complicated? >>>Have you tried turning your guitar down and the amp up? >>>Ken Wilson > Interesting that some players have no concept or consideration of how to use > the V knob on the guitar. I had a bug that I’d like to buy another guitar > (I think maybe I’m cured for a while), so I went to the store to shop and I > went several times. The salesman (whichever store) was always kind enough > to ask what amp I’d like to play through, and I usually ask for a DB or BJ > and they are generally accomodating. But….they always put the amp volume > on 2. I always have to go reset it. That’s because I’m willing to turn > down the guitar! I guess the young bucks only know how to play with the > guitar wide open. You know, the other thing they should learn to try is > rolling off the treble at the guitar. You can really get a rich tonal > pallete that way. > It may be that the pot is bad, or it just might be that the circuit doesn’t > see much comming at it until it hits 3. Another value pot might or might > not make a difference. Whichever, it’s probably harmless to the amp. Tell > the guy he needs to learn to turn it down. It’s faster and cheaper. > Don’t young people learn anything about dynamics anymore? I dunno, my first > instrument was piano, and second was ‘cello. I haven’t played either in the > last 35 years or so and now forget how. One thing that I was taught was > about dynamics! > End of rant.
Response:
>I am using a late 60’s Ampeg G-22. >At high volumes, it has great tone. >The problem is unless you turn it up to 3, it has basically NO volume… >and I don’t mean that 3 is the sweet spot, I mean there is virtually no >volume at all, and then suddenly at 3 it is ON and loud. The issue is >that at 3 it is too loud. I need volume at about 2 or 2.5 to work. >Any ideas as to how to fix this? Do you think it’s the volume pot, or >something more complicated?
Could be the control, have it replaced… Could also be oscillation in the amp blocking the signal at low volume settings… and that could be anything…. bad joint, bad cap, bad ground, etc. Listen CAREFULLY to the speaker with the volume below 3 where it doesn’t work, and see if you hear something… noise, whistles, notes, radio, Martians… Sometimes this can be fixed by installing a 1k or 10k resistor in series with the wiper… blocks the "dual stage to ground" effect of low volume settings. Bob 40 years experience.
Response:
– Hide quoted text — Show quoted text ->I am using a late 60’s Ampeg G-22. >At high volumes, it has great tone. >The problem is unless you turn it up to 3, it has basically NO volume… >and I don’t mean that 3 is the sweet spot, I mean there is virtually no >volume at all, and then suddenly at 3 it is ON and loud. The issue is >that at 3 it is too loud. I need volume at about 2 or 2.5 to work. >Any ideas as to how to fix this? Do you think it’s the volume pot, or >something more complicated? > Could be the control, have it replaced… > Could also be oscillation in the amp blocking the signal at low volume > settings… and that could be anything…. bad joint, bad cap, bad > ground, etc.
Oscillation typically occurs at higher settings rather than lower. If it oscillates at low settings, would it not get worst when cranked? Puzzling… > Listen CAREFULLY to the speaker with the volume below 3 where it doesn’t > work, and see if you hear something… noise, whistles, notes, radio, > Martians… > Sometimes this can be fixed by installing a 1k or 10k resistor in series > with the wiper… blocks the "dual stage to ground" effect of low volume > settings.
I’m not familiar with the "dual stage to ground" effect but am eager to learn. Can you please explain? > Bob > 40 years experience.
With a name like Flintstone, you must have at least 40,000 years experience.
Response:
> Like he said. > When the tech replaces the pot, have him check the coupling cap just ahead of > the pot. It’s likely to be leaky.
Sometimes true, and indeed often so when the lower range is gone. A bad coupling cap can be the cause of a pot’s demise this way. With a leaky coupler, the pot will also be noisy/scratchy throughout its range, as if it is quite dirty. It is the leaked DC arcing along the pot’s carbon element.
Response:
> Interesting that some players have no concept or consideration of how > to use the V knob on the guitar. I had a bug that I’d like to buy > another guitar (I think maybe I’m cured for a while), so I went to the > store to shop and I went several times. The salesman (whichever > store) was always kind enough to ask what amp I’d like to play > through, and I usually ask for a DB or BJ and they are generally > accomodating. But….they always put the amp volume on 2. I always > have to go reset it. That’s because I’m willing to turn down the > guitar! I guess the young bucks only know how to play with the guitar > wide open. You know, the other thing they should learn to try is > rolling off the treble at the guitar. You can really get a rich tonal > pallete that way.
But doesn’t that normally mean modding the guitar wiring so that rolling down the volume pot doesn’t lose all the highs? grol
Response:
> You are correct. People in general that play in rock bands are not taught > about dynamics. However, you are preaching to the wrong person. I am the > one in the band who is working very hard to get everyone else to > understand dynamics and it’s an uphill battle to say the least for every > single band and every single year I’ve been playing music. I use an old > Fender Deluxe Reverb (only 22 watts) and yes I use the guitar volume > technique. I am trying to make it very simple for the other guitarist and > the other musicians I’m currently playing with to not go above a certain > volume. Having an amp with this situation does not help. And YES, tell > me about it… it is an ongoing struggle to find musicians that understand > the way to play powerful music does NOT involve turning up.
Sorry for this glib reply, but if you can’t get the band to cooperate, maybe you need to find a new band. Being in a band is about working together. You’ve got a choice to make here. Phil – Hide quoted text — Show quoted text ->>courageously avow: >>>I’m not the one usually playing this amp and it is hard to get the >>>person to adjust their guitar volume. I will try emphasize this, though >>>it would be nice to have a solution at the amp. >>At lower amp volumes you are not getting the full tonal richness that >>you could. My usual practice is to run my amp as full as I can with >>the guitar volume set between 3 and 4. That way I can go up or down >>and don’t rob myself of any of the amp’s potential unduly. You will >>find a lot of seasoned veterans take this approach. >>>>courageously avow: >>>>>I am using a late 60’s Ampeg G-22. >>>>>At high volumes, it has great tone. >>>>>The problem is unless you turn it up to 3, it has basically NO >>>>>volume… >>>>>and I don’t mean that 3 is the sweet spot, I mean there is virtually >>>>>no >>>>>volume at all, and then suddenly at 3 it is ON and loud. The issue is >>>>>that at 3 it is too loud. I need volume at about 2 or 2.5 to work. >>>>>Any ideas as to how to fix this? Do you think it’s the volume pot, or >>>>>something more complicated? >>>>Have you tried turning your guitar down and the amp up? >>>>Ken Wilson > Interesting that some players have no concept or consideration of how to > use the V knob on the guitar. I had a bug that I’d like to buy another > guitar (I think maybe I’m cured for a while), so I went to the store to > shop and I went several times. The salesman (whichever store) was always > kind enough to ask what amp I’d like to play through, and I usually ask > for a DB or BJ and they are generally accomodating. But….they always > put the amp volume on 2. I always have to go reset it. That’s because > I’m willing to turn down the guitar! I guess the young bucks only know > how to play with the guitar wide open. You know, the other thing they > should learn to try is rolling off the treble at the guitar. You can > really get a rich tonal pallete that way. > It may be that the pot is bad, or it just might be that the circuit > doesn’t see much comming at it until it hits 3. Another value pot might > or might not make a difference. Whichever, it’s probably harmless to the > amp. Tell the guy he needs to learn to turn it down. It’s faster and > cheaper. > Don’t young people learn anything about dynamics anymore? I dunno, my > first instrument was piano, and second was ‘cello. I haven’t played > either in the last 35 years or so and now forget how. One thing that I > was taught was about dynamics! > End of rant.
Response:
– Hide quoted text — Show quoted text -> Interesting that some players have no concept or consideration of how to > use the V knob on the guitar. I had a bug that I’d like to buy another > guitar (I think maybe I’m cured for a while), so I went to the store to > shop and I went several times. The salesman (whichever store) was always > kind enough to ask what amp I’d like to play through, and I usually ask > for a DB or BJ and they are generally accomodating. But….they always > put the amp volume on 2. I always have to go reset it. That’s because > I’m willing to turn down the guitar! I guess the young bucks only know > how to play with the guitar wide open. You know, the other thing they > should learn to try is rolling off the treble at the guitar. You can > really get a rich tonal pallete that way. > But doesn’t that normally mean modding the guitar wiring so that rolling > down the volume pot doesn’t lose all the highs? > grol
Depends on what guitar, and what sound you want. IMO, there is nothing inherently wrong with rolling off some highs. It’s a matter of perference. Also, the amp you use contributes, so it’s really about the combination and finding how you like all the dials set. Lots of variables. YMMV.
Response:
- Hide quoted text — Show quoted text ->>I am using a late 60’s Ampeg G-22. >>At high volumes, it has great tone. >>The problem is unless you turn it up to 3, it has basically NO volume… >>and I don’t mean that 3 is the sweet spot, I mean there is virtually no >>volume at all, and then suddenly at 3 it is ON and loud. The issue is >>that at 3 it is too loud. I need volume at about 2 or 2.5 to work. >>Any ideas as to how to fix this? Do you think it’s the volume pot, or >>something more complicated? > Could be the control, have it replaced… > Could also be oscillation in the amp blocking the signal at low volume > settings… and that could be anything…. bad joint, bad cap, bad > ground, etc. >Oscillation typically occurs at higher settings rather than lower. If it >oscillates at low settings, would it not get worst when cranked? Puzzling…
Not necessarily… oscillation occurs when you have a stage with positive feedback above a gain of unity at 1 frequency… and a volume control is usually used with a capacitor, so it becomes a phase adjusting device as well as volume… so if the volume control changes the phase in the proper amount, feedback oscillation can occur. The position of the control is not that relevant, even at ground position there is resistance between it and all other ground points. Now if there is something broken in the amp that is causing this phase shift, it needs to be checked. It’s rare but it happens, I’ve seen it many times. > Listen CAREFULLY to the speaker with the volume below 3 where it doesn’t > work, and see if you hear something… noise, whistles, notes, radio, > Martians… > Sometimes this can be fixed by installing a 1k or 10k resistor in series > with the wiper… blocks the "dual stage to ground" effect of low volume > settings. >I’m not familiar with the "dual stage to ground" effect but am eager to >learn. Can you please explain?
Lets look at the volume control in the output stage of the first triode… it’s taking signal from the plate and sending it along to the next stage. The current in that circuit (AC anyway) is from the plate, through the pot, to ground. The grid of the next stage is grounded through a 1m resistor either near it’s socket, or better, at the star point. What happens now when you put the volume at zero? You have now grounded the second grid, a second time, at the ground point of the control at maybe the first stage. This is a ground loop, the ‘dual stage to ground’ effect! It can not only create hum but also oscillations. It comes and goes with the volume setting, so to get rid of it, a resistor is placed in the wiper circuit, preventing the second tube grid from being grounded. The signal is still grounded of course. – Hide quoted text — Show quoted text -> Bob > 40 years experience. >With a name like Flintstone, you must have at least 40,000 years experience.
Response:
Fender Deluxe Gibson SG Marshall Guv’nor OD Volume Pedal What I do crank the guitar into the Guv’nor to get my distorted tone. This feeds into the volume pedal into the amp. The amp is turned up to 4 or 5 depending on the room. During sound check I set the volume pedal for rhythm tone. I kick it forward for lead tone. The OD is for when all else fails.
Response:
– Hide quoted text — Show quoted text ->>>I am using a late 60’s Ampeg G-22. >>>At high volumes, it has great tone. >>>The problem is unless you turn it up to 3, it has basically NO >>>volume… and I don’t mean that 3 is the sweet spot, I mean there is >>>virtually no volume at all, and then suddenly at 3 it is ON and loud. >>>The issue is that at 3 it is too loud. I need volume at about 2 or >>>2.5 to work. >>>Any ideas as to how to fix this? Do you think it’s the volume pot, or >>>something more complicated? >> Could be the control, have it replaced… >> Could also be oscillation in the amp blocking the signal at low volume >> settings… and that could be anything…. bad joint, bad cap, bad >> ground, etc. >Oscillation typically occurs at higher settings rather than lower. If it >oscillates at low settings, would it not get worst when cranked? >Puzzling… > Not necessarily… oscillation occurs when you have a stage with > positive feedback above a gain of unity at 1 frequency… and a volume > control is usually used with a capacitor, so it becomes a phase > adjusting device as well as volume… > so if the volume control changes the phase in the proper amount, > feedback oscillation can occur. The position of the control is not that > relevant, even at ground position there is resistance between it and all > other ground points. Now if there is something broken in the amp that is > causing this phase shift, it needs to be checked. > It’s rare but it happens, I’ve seen it many times.
What you describe could occur if the feedback was coming through a narrowly tuned circuit with high Q. I could see this in a radio set perhaps but the chances of this happening in a guitar amp are remote especially if it’s as a result of a component failure of some sort. Besides, the gain effect of the volume control on the feedback signal is several magnitudes larger than it’s phase effect. The "squeal" might shift in frequency a bit but certainly won’t go away. – Hide quoted text — Show quoted text ->> Listen CAREFULLY to the speaker with the volume below 3 where it >> doesn’t work, and see if you hear something… noise, whistles, notes, >> radio, Martians… >> Sometimes this can be fixed by installing a 1k or 10k resistor in >> series with the wiper… blocks the "dual stage to ground" effect of >> low volume settings. >I’m not familiar with the "dual stage to ground" effect but am eager to >learn. Can you please explain? > Lets look at the volume control in the output stage of the first > triode… it’s taking signal from the plate and sending it along to the > next stage. The current in that circuit (AC anyway) is from the plate, > through the pot, to ground. > The grid of the next stage is grounded through a 1m resistor either near > it’s socket, or better, at the star point. > What happens now when you put the volume at zero? You have now grounded > the second grid, a second time, at the ground point of the control at > maybe the first stage. > This is a ground loop, the ‘dual stage to ground’ effect! It can not > only create hum but also oscillations. It comes and goes with the > volume setting, so to get rid of it, a resistor is placed in the wiper > circuit, preventing the second tube grid from being grounded. The signal > is still grounded of course.
Thank you for the explanation. I agree, ground loop hum would occur given the circuit you describe. Oscillation? I doubt it. The grid will be at a very low impedance point and the gain is near minimum. Besides, how does that apply to the problem described by the original poster. Remember, virtualy no output until pot is at 3 and then VERY loud. Hum was never an issue. OK, since we’re posting credentials, here goes. Doggone a.k.a. Dan 10 years – VHF/UHF radio technician 18 years – Radar technician 35 concurent years – Guitarzan 33 concurent years – amateur guitar amp tech. 48 years (my age) – Jack of all trades, Master of None My moto. "Don’t take youself too seriously" (not very original but it works) – Hide quoted text — Show quoted text ->> Bob >> 40 years experience. >With a name like Flintstone, you must have at least 40,000 years >experience.
Response:
- Hide quoted text — Show quoted text ->>>>I am using a late 60’s Ampeg G-22. >>>>At high volumes, it has great tone. >>>>The problem is unless you turn it up to 3, it has basically NO >>>>volume… and I don’t mean that 3 is the sweet spot, I mean there is >>>>virtually no volume at all, and then suddenly at 3 it is ON and loud. >>>>The issue is that at 3 it is too loud. I need volume at about 2 or >>>>2.5 to work. >>>>Any ideas as to how to fix this? Do you think it’s the volume pot, or >>>>something more complicated? >>> Could be the control, have it replaced… >>> Could also be oscillation in the amp blocking the signal at low volume >>> settings… and that could be anything…. bad joint, bad cap, bad >>> ground, etc. >>Oscillation typically occurs at higher settings rather than lower. If it >>oscillates at low settings, would it not get worst when cranked? >>Puzzling… > Not necessarily… oscillation occurs when you have a stage with > positive feedback above a gain of unity at 1 frequency… and a volume > control is usually used with a capacitor, so it becomes a phase > adjusting device as well as volume… > so if the volume control changes the phase in the proper amount, > feedback oscillation can occur. The position of the control is not that > relevant, even at ground position there is resistance between it and all > other ground points. Now if there is something broken in the amp that is > causing this phase shift, it needs to be checked. > It’s rare but it happens, I’ve seen it many times. >What you describe could occur if the feedback was coming through a narrowly >tuned circuit with high Q. I could see this in a radio set perhaps but the >chances of this happening in a guitar amp are remote especially if it’s as a >result of a component failure of some sort. Besides, the gain effect of the >volume control on the feedback signal is several magnitudes larger than it’s >phase effect. The "squeal" might shift in frequency a bit but certainly won’t >go away.
Not if the amp is broken… who are you to say what is broken? Maybe the ground of the pot is bad… could be forming a relaxation oscillator… who knows? Ever seen an amp hum when the pot is in the mid position and only the mid position? Ever seen an amp’s hum frequency change from 60hz to 120hz as you increase volume? Ever seen an amp oscillate only with cranked power chords? – Hide quoted text — Show quoted text ->>> Listen CAREFULLY to the speaker with the volume below 3 where it >>> doesn’t work, and see if you hear something… noise, whistles, notes, >>> radio, Martians… >>> Sometimes this can be fixed by installing a 1k or 10k resistor in >>> series with the wiper… blocks the "dual stage to ground" effect of >>> low volume settings. >>I’m not familiar with the "dual stage to ground" effect but am eager to >>learn. Can you please explain? > Lets look at the volume control in the output stage of the first > triode… it’s taking signal from the plate and sending it along to the > next stage. The current in that circuit (AC anyway) is from the plate, > through the pot, to ground. > The grid of the next stage is grounded through a 1m resistor either near > it’s socket, or better, at the star point. > What happens now when you put the volume at zero? You have now grounded > the second grid, a second time, at the ground point of the control at > maybe the first stage. > This is a ground loop, the ‘dual stage to ground’ effect! It can not > only create hum but also oscillations. It comes and goes with the > volume setting, so to get rid of it, a resistor is placed in the wiper > circuit, preventing the second tube grid from being grounded. The signal > is still grounded of course. >Thank you for the explanation. I agree, ground loop hum would occur given the >circuit you describe. Oscillation? I doubt it.
You doubt it – I’ve seen it… very strange effects with bad pots and things… I spent 4 months on a prototype tracking down strange things with bad pots and stuff… stop describing a working circuit! The boys amp is BUSTED! All bets are off… >The grid will be at a very low >impedance point and the gain is near minimum.
Not if the amp is broken… > Besides, how does that apply to >the problem described by the original poster. Remember, virtualy no output >until pot is at 3 and then VERY loud. Hum was never an issue.
Like I said, could be blocking… >OK, since we’re posting credentials, here goes. >Doggone a.k.a. Dan >10 years – VHF/UHF radio technician >18 years – Radar technician >35 concurent years – Guitarzan >33 concurent years – amateur guitar amp tech. >48 years (my age) – Jack of all trades, Master of None >My moto. "Don’t take youself too seriously" (not very original but it works)
I normally only present ‘credentials’ as a joke… but you mentioned radio… BTW some of the stupidest shit heads I know are radio tech’s!! (No offence…) Some of these ‘jobs’ run concurrently… 24 years VHF/UHF radio technician 12 years automated machinery tech 40 years musician/equipment tech/builder 15 years computers/fiber optic/RF link/signalization/radio repeater – field tech 3 years radio linked locomotive servo air brake and inf. telemetry tech other stuff I care not to mention but is indeed impressive…! I’m building my 17th guitar amp right now… you?
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– Hide quoted text — Show quoted text ->>>>>I am using a late 60’s Ampeg G-22. >>>>>At high volumes, it has great tone. >>>>>The problem is unless you turn it up to 3, it has basically NO >>>>>volume… and I don’t mean that 3 is the sweet spot, I mean there is >>>>>virtually no volume at all, and then suddenly at 3 it is ON and >>>>>loud. The issue is that at 3 it is too loud. I need volume at about >>>>>2 or 2.5 to work. >>>>>Any ideas as to how to fix this? Do you think it’s the volume pot, >>>>>or something more complicated? >>>> Could be the control, have it replaced… >>>> Could also be oscillation in the amp blocking the signal at low >>>> volume settings… and that could be anything…. bad joint, bad >>>> cap, bad ground, etc. >>>Oscillation typically occurs at higher settings rather than lower. If >>>it oscillates at low settings, would it not get worst when cranked? >>>Puzzling… >> Not necessarily… oscillation occurs when you have a stage with >> positive feedback above a gain of unity at 1 frequency… and a volume >> control is usually used with a capacitor, so it becomes a phase >> adjusting device as well as volume… >> so if the volume control changes the phase in the proper amount, >> feedback oscillation can occur. The position of the control is not >> that relevant, even at ground position there is resistance between it >> and all other ground points. Now if there is something broken in the >> amp that is causing this phase shift, it needs to be checked. >> It’s rare but it happens, I’ve seen it many times. >What you describe could occur if the feedback was coming through a >narrowly tuned circuit with high Q. I could see this in a radio set >perhaps but the chances of this happening in a guitar amp are remote >especially if it’s as a result of a component failure of some sort. >Besides, the gain effect of the volume control on the feedback signal is >several magnitudes larger than it’s phase effect. The "squeal" might >shift in frequency a bit but certainly won’t go away. > Not if the amp is broken… who are you to say what is broken? Maybe the > ground of the pot is bad… could be forming a relaxation oscillator… > who knows?
You’re right, I don’t know. > Ever seen an amp hum when the pot is in the mid position and only the > mid position?
No. > Ever seen an amp’s hum frequency change from 60hz to 120hz as you > increase volume?
Yes. > Ever seen an amp oscillate only with cranked power chords?
Yes. – Hide quoted text — Show quoted text ->>>> Listen CAREFULLY to the speaker with the volume below 3 where it >>>> doesn’t work, and see if you hear something… noise, whistles, >>>> notes, radio, Martians… >>>> Sometimes this can be fixed by installing a 1k or 10k resistor in >>>> series with the wiper… blocks the "dual stage to ground" effect of >>>> low volume settings. >>>I’m not familiar with the "dual stage to ground" effect but am eager >>>to learn. Can you please explain? >> Lets look at the volume control in the output stage of the first >> triode… it’s taking signal from the plate and sending it along to >> the next stage. The current in that circuit (AC anyway) is from the >> plate, through the pot, to ground. >> The grid of the next stage is grounded through a 1m resistor either >> near it’s socket, or better, at the star point. >> What happens now when you put the volume at zero? You have now >> grounded the second grid, a second time, at the ground point of the >> control at maybe the first stage. >> This is a ground loop, the ‘dual stage to ground’ effect! It can not >> only create hum but also oscillations. It comes and goes with the >> volume setting, so to get rid of it, a resistor is placed in the wiper >> circuit, preventing the second tube grid from being grounded. The >> signal is still grounded of course. >Thank you for the explanation. I agree, ground loop hum would occur >given the circuit you describe. Oscillation? I doubt it. > You doubt it – I’ve seen it… very strange effects with bad pots and > things… I spent 4 months on a prototype tracking down strange things > with bad pots and stuff… stop describing a working circuit! The boys > amp is BUSTED! All bets are off…
If I ever run into this problem, I’ll remember you told me so. – Hide quoted text — Show quoted text ->The grid will be at a very low >impedance point and the gain is near minimum. > Not if the amp is broken… > Besides, how does that apply to >the problem described by the original poster. Remember, virtualy no >output until pot is at 3 and then VERY loud. Hum was never an issue. > Like I said, could be blocking… >OK, since we’re posting credentials, here goes. >Doggone a.k.a. Dan >10 years – VHF/UHF radio technician >18 years – Radar technician >35 concurent years – Guitarzan >33 concurent years – amateur guitar amp tech. >48 years (my age) – Jack of all trades, Master of None >My moto. "Don’t take youself too seriously" (not very original but it >works) > I normally only present ‘credentials’ as a joke… but you mentioned
Sorry, I didn’t catch that. > radio… BTW some of the stupidest shit heads I know are radio tech’s!! > (No offence…)
None taken. I know shit heads of all kinds. > Some of these ‘jobs’ run concurrently… > 24 years VHF/UHF radio technician > 12 years automated machinery tech > 40 years musician/equipment tech/builder > 15 years computers/fiber optic/RF link/signalization/radio repeater – > field tech 3 years radio linked locomotive servo air brake and inf. > telemetry tech other stuff I care not to mention but is indeed > impressive…! > I’m building my 17th guitar amp right now… you?
Built my first amp in 72, (12AX7, 35W4, 50L6). Long gone now. I’ve got 5 amps in the house now, 3 of which I built. Rebuilt a Twin Reverb from the ground up a couple years ago. This one turned out pretty nice. Check it out. http://www3.sympatico.ca/zobotheclone/Twin I since built a Soldano SLO-50 clone. But with EL-34’s and 2X12 cab. No pictures posted yet. I’m gathering parts for my next project based on the Deluxe Reverb. We just moved to a new house so my shop is a mess (most of it still in boxes). The amp will just have to wait. So what’s number 17 going to be like? Based on a known model or your own design? What about the other 16?
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I would like to build my first low watt tube amp. Can you suggest a good kit? – Hide quoted text — Show quoted text – > Built my first amp in 72, (12AX7, 35W4, 50L6). Long gone now. I’ve got 5 amps > in the house now, 3 of which I built. Rebuilt a Twin Reverb from the ground > up a couple years ago. This one turned out pretty nice. Check it out. > http://www3.sympatico.ca/zobotheclone/Twin > I since built a Soldano SLO-50 clone. But with EL-34’s and 2X12 cab. No > pictures posted yet. > I’m gathering parts for my next project based on the Deluxe Reverb. We just > moved to a new house so my shop is a mess (most of it still in boxes). The > amp will just have to wait. > So what’s number 17 going to be like? Based on a known model or your own > design? What about the other 16?
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– snip – > I’m building my 17th guitar amp right now… you? >Built my first amp in 72, (12AX7, 35W4, 50L6). Long gone now. I’ve got 5 amps >in the house now, 3 of which I built. Rebuilt a Twin Reverb from the ground >up a couple years ago. This one turned out pretty nice. Check it out. >http://www3.sympatico.ca/zobotheclone/Twin
Interesting – where in Can. are you? >I since built a Soldano SLO-50 clone. But with EL-34’s and 2X12 cab. No >pictures posted yet. >I’m gathering parts for my next project based on the Deluxe Reverb. We just >moved to a new house so my shop is a mess (most of it still in boxes). The >amp will just have to wait. >So what’s number 17 going to be like? Based on a known model or your own >design? What about the other 16?
I don’t copy other amps, I’m working on perfecting my own ’boutique bedroom’ 3 watt amp… I am using modern techniques with tube circuits, for example, I use the 2 triodes in a 12AX7a for an active mid range control that makes all other mids sound like the crap they are! (especially Fenders’ mid control). I also use different wiring techniques, extra high filter capacitance, floating star power and grounding, all point to point. I’m also developing a unique case style, and built my own press brake to make it… the manufactures wanted too much and complained they couldn’t bend such a thing on their equipment! I have digressed from my ’stock’ amp a bit, building an 18 watter and a 50 watter, mostly for relatives and friends, but I’m sticking with my standard – every guitarist who has heard it has loved it – and taken one away! I have 4 amps loaned out now, one in a recording studio, the others on loan to local guitarists, some of whom gig with them, others record. There are 2 others that have been sold and are gone, one in New York, the other in Quebec. I don’t subscribe to the ‘audiofools’ crap, like certain colored caps and cloth wire and other shit, I only follow science and what my ears tell me – and more important – my customers ears! Check out my site – I need to re-do it sometime and get more space… http://www.geocities.com/flintstudio/index.html
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Sorry dude, but I’m not one for kits. Start a new thread and ask the group. Plenty of folks who frequent this group have done kits. They’ll tell you everything you want to know. – Hide quoted text — Show quoted text -> I would like to build my first low watt tube amp. Can you suggest a > good kit? > Built my first amp in 72, (12AX7, 35W4, 50L6). Long gone now. I’ve got > 5 amps in the house now, 3 of which I built. Rebuilt a Twin Reverb from > the ground up a couple years ago. This one turned out pretty nice. > Check it out. > http://www3.sympatico.ca/zobotheclone/Twin > I since built a Soldano SLO-50 clone. But with EL-34’s and 2X12 cab. No > pictures posted yet. > I’m gathering parts for my next project based on the Deluxe Reverb. We > just moved to a new house so my shop is a mess (most of it still in > boxes). The amp will just have to wait. > So what’s number 17 going to be like? Based on a known model or your > own design? What about the other 16?
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