CCV hum

[glip22]

Gary brings up a good point about the foil. That CCV chassis is packed full and the pots ride low in it. It could be you have a pot dragging in the foil. That will create some awful shit. You got to be careful sliding that chassis back in.

I just remebered when I took delivery of my CCV channel two was not working. I immediately opened up the amp and found a pot shorting against the oil. Turned the pot a little and it was fine. The pots being low was another known blunder.

 

[glip22]

That is all ground hum and most likely not tube related. Same frequency whatever you engage, just more or less of it. If its a Bang-Bang era amp, it's probably from the A/C heater runs, being it is doing all this with nothing plugged in.

Yes, it's exactly like that. And it wasn't there before. I returned from a massive gig two days ago and fired the amp today and it was there. We played that show for 3 hours, on high volumes and the amp was being carried and tossed around by roadies... While I was in the hotel That was it's big premiere. I imagine something did happen while it was being transported back home.

Those amps are always going to be noisy with all of the clip stages engaged and the gains above 1:00 or so. If all of this just started, it may be less about wiring and more about getting knocked around and maybe the input ground or something else similar coming loose. Easiest way to find the culprit is to remove it from the chassis, fire it up with a cab plugged in and get out the chop sticks. Feel around all the solder connections and sometimes you can run up on a bad connection or component ground. There's a lot going on in the CCV circuitry and the wiring layout doesn't help it. The heater wiring runs right through the middle of everything and isn't well isolated. The input ground is always suspect though.

Not sure how you are tubed and biased, but here's a sure way to get the noise down.....

1) Put a Sovtek LPS in V1 and V5. V1 is the HG input and V5 is the PI.
2) Use a decent quality Chinese 12AX7 in V2/V3.
3) V4 can use anything that suits your taste on the LG channel as this is the input for it. A JJ or similar will get you a better Marshall type sound on channel 1. Your Tung Sol works here too.
4) Rebias the amp colder. Take those 34's down to about 30-32mA. If it still has ARS stock tubes in it, replace them with SED's. If you feel comfortable doing it, bias the amp with the volume up, watching the bias tool or DMM and you can hear where it goes quiet and then where it starts to make excessive noise.

That's a lot of cool info. Thanks!

Yes, this thing just started. It only had hiss when I bought it.

I don't feel comfortable getting through the circuit with a pair of chop sticks, to be honest I will take it down to my tech for a check out.

It had EH in V1 and V5 with ARS labeled chinese in V2-V4. 34's are SED's. These four tubes bring some of the light blue color when I hit the stanby switch, though. They could be biased a bit hotter than supposed to, and I don't know how much more life they have in them also.

I don't have LPS', I always hated those, so I gave them away to my friends. I guess it's a payback time

I'm running the amp with a step down transformer, since I was led to believe that the MM PT isn't tappable to 220V, but this guy Patrick from MM thrown in a bit of suspicion on the topic, but his mouth is zipped about Cameron stuff in general. Not to mention that I ran into an old topic here on RT, that the PT IS going to be tappable, but it was before they started shipping the first run, it could be that they changed their mind afterwards.

Nevertheless, that step down is a high grade tranny, built by a local amp builder, so I doubt it's causing any problems.

Oh, yes, I forgot to mention:

V1 - ARS
V2 - Mesa labeled chinese
V3 - ARS
V4 - ARS
V5 - TAD 7025 high grade

The amps were also suppossed to be regulated DC heaters but they were not.

There wouldn't have been enough room for it anyway.

True. Mark has a litle trick he showed me on how to only regulate V1 and V2. My Aldrich has it.

 

[jimmy274]

Gary brings up a good point about the foil. That CCV chassis is packed full and the pots ride low in it. It could be you have a pot dragging in the foil. That will create some awful shit. You got to be careful sliding that chassis back in.

I guess the previous owner, pbfoot, or someone else before him already tore up the foil beneath the pots. I'm taking it out all the way... Finally got a LPS. I did put it in V1 and the amp now still has, in traces, a bit of hum, which is audible when both gains are cranked. I'm comfortable with the noise for now, but nevertheless I'm going to measure voltage plate with my tech and check out everything thoroughly. Are there more weird spots we should be looking for?

 

[jimmy274]

That is all ground hum and most likely not tube related. Same frequency whatever you engage, just more or less of it. If its a Bang-Bang era amp, it's probably from the A/C heater runs, being it is doing all this with nothing plugged in.

Yes, it's exactly like that. And it wasn't there before. I returned from a massive gig two days ago and fired the amp today and it was there. We played that show for 3 hours, on high volumes and the amp was being carried and tossed around by roadies... While I was in the hotel That was it's big premiere. I imagine something did happen while it was being transported back home.

Those amps are always going to be noisy with all of the clip stages engaged and the gains above 1:00 or so. If all of this just started, it may be less about wiring and more about getting knocked around and maybe the input ground or something else similar coming loose. Easiest way to find the culprit is to remove it from the chassis, fire it up with a cab plugged in and get out the chop sticks. Feel around all the solder connections and sometimes you can run up on a bad connection or component ground. There's a lot going on in the CCV circuitry and the wiring layout doesn't help it. The heater wiring runs right through the middle of everything and isn't well isolated. The input ground is always suspect though.

Not sure how you are tubed and biased, but here's a sure way to get the noise down.....

1) Put a Sovtek LPS in V1 and V5. V1 is the HG input and V5 is the PI.
2) Use a decent quality Chinese 12AX7 in V2/V3.
3) V4 can use anything that suits your taste on the LG channel as this is the input for it. A JJ or similar will get you a better Marshall type sound on channel 1. Your Tung Sol works here too.
4) Rebias the amp colder. Take those 34's down to about 30-32mA. If it still has ARS stock tubes in it, replace them with SED's. If you feel comfortable doing it, bias the amp with the volume up, watching the bias tool or DMM and you can hear where it goes quiet and then where it starts to make excessive noise.

That's a lot of cool info. Thanks!

Yes, this thing just started. It only had hiss when I bought it.

I don't feel comfortable getting through the circuit with a pair of chop sticks, to be honest I will take it down to my tech for a check out.

It had EH in V1 and V5 with ARS labeled chinese in V2-V4. 34's are SED's. These four tubes bring some of the light blue color when I hit the stanby switch, though. They could be biased a bit hotter than supposed to, and I don't know how much more life they have in them also.

I don't have LPS', I always hated those, so I gave them away to my friends. I guess it's a payback time

I'm running the amp with a step down transformer, since I was led to believe that the MM PT isn't tappable to 220V, but this guy Patrick from MM thrown in a bit of suspicion on the topic, but his mouth is zipped about Cameron stuff in general. Not to mention that I ran into an old topic here on RT, that the PT IS going to be tappable, but it was before they started shipping the first run, it could be that they changed their mind afterwards.

Nevertheless, that step down is a high grade tranny, built by a local amp builder, so I doubt it's causing any problems.

Oh, yes, I forgot to mention:

V1 - ARS
V2 - Mesa labeled chinese
V3 - ARS
V4 - ARS
V5 - TAD 7025 high grade

The amps were also suppossed to be regulated DC heaters but they were not.

There wouldn't have been enough room for it anyway.

True. Mark has a litle trick he showed me on how to only regulate V1 and V2. My Aldrich has it.

Is it feasible on CCV as well? What is regulated DC heaters anyways? Don't bother explaining I will just tell it to my tech.

Is it enough to show him the pic, or you can give me more in depth explanation, like a schematic, etc, etc...?

 

[steve_k]

Gary brings up a good point about the foil. That CCV chassis is packed full and the pots ride low in it. It could be you have a pot dragging in the foil. That will create some awful shit. You got to be careful sliding that chassis back in.

I guess the previous owner, pbfoot, or someone else before him already tore up the foil beneath the pots. I'm taking it out all the way... Finally got a LPS. I did put it in V1 and the amp now still has, in traces, a bit of hum, which is audible when both gains are cranked. I'm comfortable with the noise for now, but nevertheless I'm going to measure voltage plate with my tech and check out everything thoroughly. Are there more weird spots we should be looking for?

You will never get the noise out with the gains above 1:00 or so and a level or two of clipping engage/brights. But, you can usually take care of some of it with this:

 

[jimmy274]

Gary brings up a good point about the foil. That CCV chassis is packed full and the pots ride low in it. It could be you have a pot dragging in the foil. That will create some awful shit. You got to be careful sliding that chassis back in.

I guess the previous owner, pbfoot, or someone else before him already tore up the foil beneath the pots. I'm taking it out all the way... Finally got a LPS. I did put it in V1 and the amp now still has, in traces, a bit of hum, which is audible when both gains are cranked. I'm comfortable with the noise for now, but nevertheless I'm going to measure voltage plate with my tech and check out everything thoroughly. Are there more weird spots we should be looking for?

You will never get the noise out with the gains above 1:00 or so and a level or two of clipping engage/brights. But, you can usually take care of some of it with this:

Yeah, I forgot to mention, I have a Rocktron HUSh in the loop already...

 

[steve_k]

Gary brings up a good point about the foil. That CCV chassis is packed full and the pots ride low in it. It could be you have a pot dragging in the foil. That will create some awful shit. You got to be careful sliding that chassis back in.

I guess the previous owner, pbfoot, or someone else before him already tore up the foil beneath the pots. I'm taking it out all the way... Finally got a LPS. I did put it in V1 and the amp now still has, in traces, a bit of hum, which is audible when both gains are cranked. I'm comfortable with the noise for now, but nevertheless I'm going to measure voltage plate with my tech and check out everything thoroughly. Are there more weird spots we should be looking for?

You will never get the noise out with the gains above 1:00 or so and a level or two of clipping engage/brights. But, you can usually take care of some of it with this:

Yeah, I forgot to mention, I have a Rocktron HUSh in the loop already...

You need to run something up front to gate the front of the amp. That Rocktron Hush can cause more noise than not having one.

BTW, when you take your amp to the tech, have him check the voltage at the FX loop board. That Metro board has a send level adjustable pot in it. Some of these amps left Bang Bang with them not adjusted properly. I had one with B+ coming from the board, one with B+ from a screen resistor and one not hooked up to B+ at all. If you are engaging the loop all the time, this could be a source of some noise if the voltage is too hot in the board. The loop board is in there upside down too. He will have to remove the jack nuts and flip the board over to expose the pot. Only takes a minute.

 

[ElMuchoDingo]

nenad,

no i didnt do anything to the amp, had to adjust the loop level once. 232cap had it first. i will tell you i had that thing pretty wide open with high gain settings a couple times and it didnt hiss like that

 

[ElMuchoDingo]

i hate electricity, i wont even use bias probes on terminal so there is no way i am poking around foil in an amp

 

[jcj]

i hate electricity, i wont even use bias probes on terminal so there is no way i am poking around foil in an amp

Pretty sure the foil is on the bottom of the headshell

 

[jimmy274]

Gary brings up a good point about the foil. That CCV chassis is packed full and the pots ride low in it. It could be you have a pot dragging in the foil. That will create some awful shit. You got to be careful sliding that chassis back in.

I guess the previous owner, pbfoot, or someone else before him already tore up the foil beneath the pots. I'm taking it out all the way... Finally got a LPS. I did put it in V1 and the amp now still has, in traces, a bit of hum, which is audible when both gains are cranked. I'm comfortable with the noise for now, but nevertheless I'm going to measure voltage plate with my tech and check out everything thoroughly. Are there more weird spots we should be looking for?

You will never get the noise out with the gains above 1:00 or so and a level or two of clipping engage/brights. But, you can usually take care of some of it with this:

Yeah, I forgot to mention, I have a Rocktron HUSh in the loop already...

You need to run something up front to gate the front of the amp. That Rocktron Hush can cause more noise than not having one.

BTW, when you take your amp to the tech, have him check the voltage at the FX loop board. That Metro board has a send level adjustable pot in it. Some of these amps left Bang Bang with them not adjusted properly. I had one with B+ coming from the board, one with B+ from a screen resistor and one not hooked up to B+ at all. If you are engaging the loop all the time, this could be a source of some noise if the voltage is too hot in the board. The loop board is in there upside down too. He will have to remove the jack nuts and flip the board over to expose the pot. Only takes a minute.

I get it. I don't have Hush as a stand alone unit, in fact I have Intellifex XL. I didn't find any more noise with the XL in the loop. I can set it like the amp is dead silent, with guitar volume pot turned down of course. I did try to play with the Metro board level pot, because I found out that the signal coming from the fx loop send is waaaaay too cold. Only managed to adjust it a bit with trim pot all the way up. I still have to crank input gain pot on XL to have a decent signal feed the processor, with channel masters around 1-2 o'clock. With full diode clipping on solo channel I have to crank master aaaall the way up. It barely lits -12db led on XL...

EDIT:

Hush sucks!

 

[jimmy274]

i hate electricity, i wont even use bias probes on terminal so there is no way i am poking around foil in an amp

same thing here I meant that you, or the guy before you, did that in a good way... That foil twist and raises every time you take the chassis out. Have to be careful with it... It could be more useful cooking some fish with vegetables

 

[oldmanmetal]

Man that is some serious quality.

 

[jimmy274]

Here's the clip, after changing the tubes.. I wasn't greatly inspired while playing, so sorry for mumbling, jumbling...

https://www.youtube.com/watch?v=E-jI4Cuk ... LQ&index=1

 

[ElMuchoDingo]

as you can tell, i have no working knowledge of the inside of an amp. foil what foil?

 

[jimmy274]

as you can tell, i have no working knowledge of the inside of an amp. foil what foil?

Foil that is glued inside a headshell, beneath the chassis.

 

[FourT6and2]

I was under the impression that the CCV's heaters were all DC...

I remember commenting on the original CCV thread where photos were posted of the first run of CCV's coming out of Berrang. I mentioned how all the heater wires were done in a sloppy way and would cause noise. But was told by Brad or George or whomever that they were DC heaters and it wouldn't matter.