ACT2.2 distortion/pops?

[hpfish10]

My left speaker has intermittent distortion(loud hiss and pop). I am trying to troubleshoot to isolate the issue if it’s from my CJ ACT2.2 or CJ Premier 350 amp. After switched the L and R output from preamp, the distortion followed to the R speaker, so it sounds like the issue is caused by the preamp. Even if I turned off upstream DAC, still there was distortion. Sometimes the music played a while before the hiss/pop started. Once it started, the only way to stop it was to mute the volume. I changed to new tubes 9 months ago, last night I put old tubes back to see if it happens again. Has anyone experienced similar problem? Thanks for any input.

[AnotherJohnson]

It is most likely one of the 6N30Pi tubes. That is a typical small tube sign of failure.

9 months is short life for a good new tube, but it does happen. Tubes fail in a stochastic pattern, which means that you can predict the average life of a model, but not the specific life of a particular specimen.

[hpfish10]

I can replace the L channel tubes, but I don’t know which tubes for L or R, not documented in manual. I can try to call CJ.

[AnotherJohnson]

You imply that the old tubes are OK.
If that’s the case, at least one of the newer tubes was bad.

You can try to call CJ, but current reports are that you may not get through. Lots of panic calls are making phone support difficult to impossible.

You could just live with the old tubes until things settle down in the world of tube audio.

You could leave the good older tubes in, but swap them with the new tubes one at a time until the noise comes back. It’s tedious.

Maybe Roberto has the schematic if you didn’t find it here. I would expect the tube sockets to be labeled V1 through V4 on the schematic and on the board.

[admin]

Like AJ says. If it is a tube, it should be a very easy narrowing down. If you have a spare tube, just swap each tube out one at a time. If the distortion goes away, you have identified which tube is bad. If nothing changes, then it's not the tubes and you have to go hunting inside the unit.

If you don't have a spare tube, you can just flip each tube position one at a time. If the noise jumps to another channel, you have identified the tube.

[hpfish10]

Swapping tube is good option, but it would consume time since the distortion is intermittent, sometimes it occurred an hour later. If I know which one(s) for left channel I just swap those.

[admin]

Unfortunately, the manual doesn't say which tubes are what channels and we don't have the schematic in our database. So I guess you can pop the lid and start hunting down the wires. But I think it's going to save you a lot of time by just swapping. With just 2 swaps you should be able to narrow down the tube.

[Big Dog RJ]

Had the exact same issues with both my ACT2 & S2 presmps! Very annoying.

It is intermittent and happens a while later... I had two issues:
1. It was two bad 6N30P's. When this happens, don't swap tubes! Unless you can determine exactly which tube then change the bad one. When you go around swapping tubes, it can also damage added circuitry related to that particular socket, causing further problems... In power amps it's different because you can clearly identify which channel!

2. The ACT2 has a longer than usual mains wire, which runs through and around some intricate components. In my case, they shortened this wire, and placed an extra copper plate for grounding. This sorted out the issue but the symptoms are different to yours. At first there were intermittent distortions and then all of a sudden, one side of the button displays would paralyse, shutting down the preamp. It was a real pain in the butt... half through listening sessions it would just crap itself!

Solution:
1. Change ALL four 6N30P's on your ACT2.
2. *Get that mains wire and grounding sorted out, only if this is an issue* usually it is with the ACT2 but not so much the case in the S2.
3. If the previous (old) set of tubes work perfectly without any of these distortions then just use these until you order another set.

*Note*

Try to get hold of a tube supplier who has a tube tester device. He can very easily test those 6N30P's and this will identify which tube/s are playing up. This is the only way to determine tubes measurement specs, not really by swapping... Not a good idea specialy in preamps.

Best, RJ

[AnotherJohnson]

Solution:
1. Change ALL four 6N30P's on your ACT2.
2. *Get that mains wire and grounding sorted out, only if this is an issue* usually it is with the ACT2 but not so much the case in the S2.
3. If the previous (old) set of tubes work perfectly without any of these distortions then just use these until you order another set.

*Note*

Try to get hold of a tube supplier who has a tube tester device. He can very easily test those 6N30P's and this will identify which tube/s are playing up. This is the only way to determine tubes measurement specs, not really by swapping... Not a good idea specialy in preamps.

Best, RJ

This really is the best advice.

An Australian company was making testers (MixMatcher 2 and a preamp tube counterpart) before Covid, but I’ve heard they’d folded up.

Testers show up on eBay regularly, but they’re generally being sold as parts, or with no declaration of actual function. Finding a guy with a tube tester is hard in the US.

Before the recently induced tube panic, I would have said to replace the lot of them too. If Kevin Deal is right, based on his comments yesterday, tubes are flowing again. So at least they can flow to countries that Russia is willing to ship to. Hopefully this minor issue (compared to the destruction of Ukraine) will resolve soon.

[Big Dog RJ]

Tube testers hard to find in the US...? I'm surprised.

Over here, we have very good access. There are two stores based in Melbourne that sell them and they're well known. A few years back, just before our new place was being constructed, I was just about to purchase one. For my luck, the local tube supplier whom I deal with for my tube supplies, has three testers. Whenever I visit the chap, all three of these things are firing away, testing various tubes, from mostly guitar amps, ARC, CJ, VTL, VAC, Prima Luna, Ayon, Lamm, Cary, Carver, Sonic Frontiers you name it!

His logic is, when a grumpy customer returns a so called bad tube and starts yelling at him... he firsts tests it out on his most expensive top of the line digital metered tester. This thing is so accurate, it's not even funny. Once he gets readings from that one, he then plonks the same tube on his old trusted analog metered tester for a second opinion. This thing is not very stable but still provides very good readings, with slight variations of the needles ... once that reads fine, he calls the customer and blasts them back! It's a beautiful thing when this happens because the customer who was previously yelling is now dumb founded, looks like his denchers fell off...

He's a no BS chap, doesn't believe in any tube rolling whatsoever, or any of the variants, just sticks with the original, and doesn't like people who are continually fixed to their phones getting the latest goss on the world..
He calls it complete hogwash! And says that we need to listen to more music rather than get caught up in all the hype... I agree!

He charges approx. $100 to test 10 tubes from any set, so if your amps had a total of 12, he'd still oblige. There are quite a few guitar amps on his bench, mainly due to their misuse. Says they're pretty hardy but at the same time very poor quality standards. Especially the newer ones, calls it absolute rubbish. I asked which ones are good, claims the much older classics from Masrhal, Messa, Fender, Roland mostly based on 60's, 70's & 80's design. These are the real work horses, solid stuff and extremely well built. The newer ones are like toys .. so he says. I saw a few with my own eyes, and can actually tell the difference straight away even without having to hold a part.

I guess that's another reason why he has such high regard for ARC & CJ gear, their circuits are very well designed and implemented. The best he's ever seen to date!

Cheers to the Classics!
RJ

[AnotherJohnson]

Gary Steinbaugh’s book “Make Your Own Tube Tester” may be our best bet here.

Some techs have tube testers, but the swap, or replace the lot, strategies are more common. Off hand I don’t know of a single store with a tester service. The one guy who probably had one retired with the onset of the pandemic and closed up shop.

A MixMatcher II showed up used at The Music Room the other day, and it was sold within a few hours.

[hpfish10]

Had the exact same issues with both my ACT2 & S2 presmps! Very annoying.

It is intermittent and happens a while later... I had two issues:
1. It was two bad 6N30P's. When this happens, don't swap tubes! Unless you can determine exactly which tube then change the bad one. When you go around swapping tubes, it can also damage added circuitry related to that particular socket, causing further problems... In power amps it's different because you can clearly identify which channel!

2. The ACT2 has a longer than usual mains wire, which runs through and around some intricate components. In my case, they shortened this wire, and placed an extra copper plate for grounding. This sorted out the issue but the symptoms are different to yours. At first there were intermittent distortions and then all of a sudden, one side of the button displays would paralyse, shutting down the preamp. It was a real pain in the butt... half through listening sessions it would just crap itself!

Solution:
1. Change ALL four 6N30P's on your ACT2.
2. *Get that mains wire and grounding sorted out, only if this is an issue* usually it is with the ACT2 but not so much the case in the S2.
3. If the previous (old) set of tubes work perfectly without any of these distortions then just use these until you order another set.

*Note*

Try to get hold of a tube supplier who has a tube tester device. He can very easily test those 6N30P's and this will identify which tube/s are playing up. This is the only way to determine tubes measurement specs, not really by swapping... Not a good idea specialy in preamps.

Best, RJ

My issue could be related to the left channel of preamp, not tubes:
- I replaced new set of tubes in 6/2021. Prior to 6/2021 I fed output signal from my ACT2.2 into my monoblock amps. I had intermittent problem of which my left mono amp got intermittently shut down and restarted. At the time I thought my L mono amp had issue so sent in for repair. After the repair it had the same issue. So I stopped using the monos and started using the Premier 350. It played fine on the 350 but still had issue on the monos.
- 6/2021 I decided to replace the tubes since the original tubes were too old. It continued playing ok on the 350 amp until recently. Then the distortion shows up, not all the time, sometime multiple times in a listening session, but like last night I put the new tubes back in and I listened for 90 mins with no distortion.
So it might not be tube issue. How did you get the main wire sorted out? Did you do it yourself or send it in to CJ?

[AnotherJohnson]

Historically RJ has used a local expert (he’s in Oz).

If you’re in the US, sending to CJ is recommended.

https://conradjohnson.com/conrad-johnson-policies/

If you’re in another country, check with your official importer.

[roberto]

Hola hpfish10,
You have to do three things only, You have one bad tube.
Having on hand only one 6NH30, change it for tube no1. If you still have the problem, the tube No1 is OK. Place back the tube No1, and now replace the tube No2...and so, until you find the tube that is bad.

Happy listening!

[Big Dog RJ]

Attn: HPfish

Yes, I'm based in Melbourne and lucky enough to have access to two very reliable service techs who know CJ & ARC gear inside out... including many other top brands. I also source all my tubes from a local supplier now, since he's got every tube possible, fuses for CJ and ARC gear, including various tube testers. So careful matching and specs are done on site with utmost precision. Now all of this may mean nothing to you because you're probably not in Aus...

If I were you, I'd check out some other local tech who has experience with such gear. Not the one whom you took the amplifiers to earlier because according to your last post, it seems like they really didn't fix anything?

I would get the ACT2 checked, also place in the new tubes so that when servicing the tech can experience this himself and understand what's going on...
The power cord adjustment and ground plate mod done on both my ACT2 versions, was due to a more serious issue, which I don't think your ACT2 has similar symptoms...

You might find the culprit by swapping around, I don't know but getting the unit checked out would also be a good idea. It's upto you on how you go about it and how serious you are in fixing the ACT2 with a "permanent" solution. It's not hard to find good reliable techies, they're out there you just have to search... most of the very good ones are quiet.

All the best, and let us know how it goes.
RJ

[hpfish10]

Attn: HPfish

Yes, I'm based in Melbourne and lucky enough to have access to two very reliable service techs who know CJ & ARC gear inside out... including many other top brands. I also source all my tubes from a local supplier now, since he's got every tube possible, fuses for CJ and ARC gear, including various tube testers. So careful matching and specs are done on site with utmost precision. Now all of this may mean nothing to you because you're probably not in Aus...

If I were you, I'd check out some other local tech who has experience with such gear. Not the one whom you took the amplifiers to earlier because according to your last post, it seems like they really didn't fix anything?

I would get the ACT2 checked, also place in the new tubes so that when servicing the tech can experience this himself and understand what's going on...
The power cord adjustment and ground plate mod done on both my ACT2 versions, was due to a more serious issue, which I don't think your ACT2 has similar symptoms...

You might find the culprit by swapping around, I don't know but getting the unit checked out would also be a good idea. It's upto you on how you go about it and how serious you are in fixing the ACT2 with a "permanent" solution. It's not hard to find good reliable techies, they're out there you just have to search... most of the very good ones are quiet.

All the best, and let us know how it goes.
RJ

Thank you very much RJ!
After putting the new tubes back, I listened for a total of 4hrs last 2 nights but the issue did not come up. Since it is intermittent it is tough to diagnose. I will continue using it to see and report back.

[Big Dog RJ]

Ah! Then it definitely sounds like a few naughty tubes in there... perhaps they behave when scolded and later play up to make a fuss, just like naughty kids!

Sounds like it's not anything remotely close to the issues I had... so yes, I would just wait it out and see how it operates over several hours.

I just purchased a pair of Sovteks 6N30P's (same tube used in the ACT2) for my CT5, which I needed to replace since the originals were in there since 2006! Not even a week, one started playing up with noises on the left channel. It was pretty easy to find the culprit, since the CT5 only has a pair. So that distortion hiss & burps... follows that tube. Just today, I picked up a new set from my supplier and I'm listening to it right now. Zero noise, quiet as a whistle and sounds supreme!

So looks like it was probably just a noisy tube... as our good mate Robbo identified!

Cheers, RJ

[latole]

Swapping tube is good option, but it would consume time since the distortion is intermittent, sometimes it occurred an hour later. If I know which one(s) for left channel I just swap those.

Tubes are bad all the time or never.

Intermittent distortion don't come from a tube.
IMO there is a bad solder or contact or ....

I would start to clean each tube socket an tubes's pin.
Just unplug and plug tubes few time may clean the socket and pins.

Tube testers can't show an intermittent issue and for many test, tubes testers are not reliable.

[Big Dog RJ]

Actually that's a very good point! I didn't read through the last post carefully... as HPfish said, it was an "intermittent " problem... comes and goes, so yes I agree, that's something else going on in there but who knows!

Correct analysis though, if a tube is bad / weak or noisy then it's always going to emit such noises continuously until the tube is changed. Mmm... definitely would need to be checked out I reckon but let's see how that goes.

Best, RJ

[AnotherJohnson]

Tubes are bad all the time or never.

I think this is a fair statement for power tubes.

But I’ve seen cases where small tubes did give intermittent performance.

I agree that a cold solder joint is also a candidate.

Tube testing is certainly NOT definitive. The more sophisticated the tester’s capabilities, the more likely the tester is to give reliable results.