CCV hum

[jimmy274]

https://docs.google.com/file/d/0B4c9EOq ... sp=sharing


Can anyone help? Is this hum caused by a bad preamp tube?

 

[jimmy274]

here is a YT link if that one doesn't work

https://www.youtube.com/watch?v=rWCfFtNrJhA

 

[garey77]

Oh man, that is fucked up sounding. Have you tried switching out the pre amp tubes yet? It sure sounds like you've got a flawed one.

 

[jimmy274]

Oh man, that is fucked up sounding. Have you tried switching out the pre amp tubes yet? It sure sounds like you've got a flawed one.

No, I'm too lazy, I guess.

You mean, take all of the pre's out and have a listen?

 

[rlord1974]

No, start by changing out one preamp tube at a time with one you know is good, to see if you can identify a faulty preamp tube currently loaded in it.

Change out V1 with a good tube. No difference? Replace V1 with the original tube and move on to V2. Rinse and repeat.

 

[EXPcustom]

Oooo.... yeah... I was going to ask but then saw/heard the video...

Barrang era CCV.

I know Mark had to literally rebuild a few of these because of these issues.

 

[jimmy274]

Oooo.... yeah... I was going to ask but then saw/heard the video...

Barrang era CCV.

I know Mark had to literally rebuild a few of these because of these issues.

Hmm, that's very comforting... Especially if you're from Belgrade, Serbia. Are there any particular issues or does it has goblins, in general?

However, I managed to lower the hum by changing the first two tubes, ironically the lowest hum is with the chinese 9th in the first place and Tung Sol in the 2nd/cathode follower spot and I've read all over the web that they constantly fail in these positions.

With JJ's the hum was even louder and so on... So finally a NOS Siemens kicked in V2. What a tone!!!! Chinese in all other spots.

I also noticed that the OT is kind of hot, really hot. This is normal, right? It's not a Barrang thing? Right? And that alu-foil scares the s**t out of me!

 

[EXPcustom]

OT running hot is normal for the CCV so no worries.

Yeah the alu-foil was because of Barrang's wonderful QC.

 

[jimmy274]

Tung Sol just died...

 

[steve_k]

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.

Seeing your post about Tung Sol died...not the best tube for that amp.

Also, if the preamp is wired same as the originals, be careful as V2 and V3 are cathode followers for V1 and V4 respectfully. You need something of the Chinese variety in 2/3.

 

[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.

 

[steve_k]

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.

 

[Anonymous]

dont put tung sols in cathode follower positions

is your amp voltage selector matching your wall voltage?

 

[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

 

[steve_k]

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 CCV is a fairly sensitive amp (to me it is anyway). It can be very susceptible to ground interference and also an unstable input power supply. These sorts of things annoy the shit out of me and I will try until hell freezes over to get rid of noise.

First thing, V1 on this amp is very important and can have a lot to do with how the amp responds. Which, is why I like the LPS in V1. They seem to be more quiet than anything else out there. Don't worry about gain, the amp has enough for that. The ARS is a relabeled JJ and is shit in V1 on this particular amp. Also, if you can find some old Chinese 8th generation 12AX7's (there's still plenty floating around), they seem to always work better in V3/V4. Same reasoning for the LPS in the PI.

In addition to supply a steady voltage supply, the input power needs to be conditioned and the cycles (Hz) stable as well. Having to step this amp down to 110V probably isn't helping and is probably lending a bit to the hiss. As for Patrick, the Cameron labeled MM's are proprietary and he won't tell you anything. Another thing is the 110V is dragging the PT a bit too. If you check (or your tech) checks the plate voltage, it will be low, somewhere in the 510-520 range. This somewhat browns out the amp a little which can lend to a bit of noise. The amp is set up to run at 550-560 PV.

Avoid the amp being around any rheostat and fluorescent lighting. Dimmer switches will rain down holy hell on this amp and not help the noise whatsoever.

Lastly, a good noise gate will knock the hiss back a notch. The MXR noise gate pedal works grate and will cut this hiss without gating the feedback and sustain, unless you set it that way.

Good luck....

 

[jimmy274]

Thanks a lot Steve!

 

[glip22]

Tear out the foil. That crap is only asking for trouble and does nothing really. It rips up easily and can short components. It shorted out my midi board on my Barrang CCV. These amps are noisy with the the drive switch left or right. Its known to many which is part of the reason for the redisign. I tried tyo lower my noise by going as far as retwisting the heater wires and redoing the input grid resistor properly. It did not affect it so I put it back to stock.

 

[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.

 

[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.

 

[steve_k]

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.