Fluctuating volume in one channel: Part II

I posted a few days ago about my left channel volume fluctuating from time to time. I got advice saying that it was most likely either the tubes in the preamp or a bad solder joint on an interconnect.

I switched the tubes in the preamp from left to right and right to left and the problem stayed the same (left channel fluctuating). Then I switched the ICs between the preamp and the amp from right to left and left to right. The problem stayed the same (left channel still fluctuating).

I did not bother switching the ICs from the cd player to the preamp because the problem remains even if I listen from a different source.

What is next in line for me to test? If you would like to see the other thread, it can be found here:
Forgive me for starting another thread, but I know old threads don't always get read.
You have probably reached the point where you need to take it in for service as you probably don't have the testers that can find a short.

On new vs. old threads I have found that the people who have been of previous help on a problem are often the ones I would first go back to and your new posting appears in their "My Threads" page and I, for one am usually curious enough to check out the latest.

Also, I am attracted to even the old threads that have multiple responses.
I had a similar problem many years ago. The volume would fluctuate in one channel with a little static. I narrowed it down to the crossover pot in one of my speakers. I twisted the pot quickly back and forth for a couple minutes and my problem was solved. I followed up with some Radio Shack tuner cleaner.
Hello Ketchup. Did you get your system working properly yet? I hope you haven't had to go without music all this time.

Earnest, I have been listening to music for about 5 minutes at a time... after that the left channel cuts out. It's pretty rough :(

I narrowed it down (without a doubt) to a faulty amp. I spoke with Classe and will be sending it back as soon as I get it packaged up safely. I hope their customer service is good!
Bummer...sorry to hear that Ketchup. You surely don't need a double-whammy of FedEx or UPS shipping damage, so be Super Careful on the packaging. I know you know the original box is insufficient for safety.

I recommend you get a big 4'x8' sheet of foam insulation from Home Depot and a larger box from U-Haul. You need at least 2 inches of the sturdy foam on all 6 sides of the original box for protection from the "gorillas."

Nearly EVERYTHING HEAVY that has been shipped to me over the past couple years has arrived damaged! I'm still fuming about a vintage amp and several sheets of granite. Please forget about 3 things: The UPS Store, bubble wrap, and peanuts. Good luck!

Also, be sure to read Lester_ears "A Packing and Shipping Manifesto" in the forums.
Correction: bubble wrap is cool for light weight items. Styrofoam peanut factories should be terminated, IMHO.
I posted a similar cry for help several weeks ago, concerning one of my Bryston 7B-ST's, but never followed up with Bryston's fix: they found, and replaced in a very quick turnaround, a faulty switch (the one which selects series or parallel operation).

Now get this: I sent the unit from TN to Bryston's repair facility in NH on a Thursday. It arrived in NH the following Monday; they repaired it and had it on its way back to TN Tuesday, scheduled for delivery on Friday. In fact, however, although UPS tracking showed it "out for delivery" all day Friday, it was not delivered until the following Monday! I'm still convinced the guy in the brown truck on Friday decided to start his weekend early and let some other schlub deliver the amp later.

I was relieved to find no damage. That would have been the icing on the cake.

Bryston is a class act!
Earnestmoney, I can't believe what you wrote about packaging up the amp...

I already went to Home Depot and found that 4'x8' sheet of foam insulation and decided that it would make great packaging material. Right after I left Home Depot I went to U-Haul and bought a box!

I do not have the original box, but I am going to double box it with the 2" insulation in the first box and something a little thinner in the outer box.

I am worried about the return home, though. Classe told me that they will put the amp in an original box before they send it back to me, but I'm wondering if they will put that box in another well packaged box.

I don't know what sort of packaging Classe uses, but if it's up to the quality of Bryston's---and I'd be surprised if it isn't---you've got nothing to worry about.

Bryston uses a double box, of course, surrounding a two- piece construction of thick, resilient, tough, cellular plastic, which totally fits and surrounds the amp. I think it would survive anything short of an attack by a mad forklift.
Hey 914. I could rant endlessly about UPS and FedEx screw-ups as I was at their mercy to deliver $120 Million annually in aircraft engine hardware. They delayed my engine lines countless times over the years.

Bryston must indeed be a class act based on the service you received and the testimonies of many other A'goners.

Ketchup, you cracked me up with the Home Depot/U-Haul story! LOL. Had you already made the rounds prior to my post, or was their some kind of mental telepathy going on here? ;)

Based on my experience, overkill packaging is always worth the peace of mind. Classe's original box and internal packaging is probably of superb quality. However, I would offer to pay extra for double boxing.

I like Counterpoint's return policy. They require that you ship your amp in a wooden crate and they will return your amp in the same crate. They supply decent crates for $80 plus shipping.

I design and build gorilla proof crates myself, that I plan to market to A'goners. I think they are good for several shipping cycles of serious abuse. Sorry I don't have anything already built that would suit your needs.

Earnestmoney, I had already gone to the stores before you replied. I'm a few steps ahead of you :) I actually ended up going to Lowe's and found a different 4 x 8 sheet of foam. This stuff was actually white styrofoam and offered a little more cushion than the stuff that my Home Depot had (very hard yellowish looking stuff). It was a few more bucks, but worth it.

After a few hours of sculpting foam I ended up with 4" above and below the amp and 3" on the sides. This is all inside a double walled box. Then, I wrapped the box in thick carpet underlayment and encapsulated that with another box cut to fit tightly around the padding. I did this to offer some shock protection in the event of a fall. Overkill? Probably, but at least I'm not going to worry about it.

If anyone wants to ship me a loaner amp for the time being feel free!
Hello Ketchup,

I have a similar problem. I have Classe CAM 200 mono's. I have narrowed the problem down to one of the amps. In my case the volume doesn't entirely cut out, but when it goes, it goes down to about 1/4 of the normal amp's volume. It just started a few nights ago, and doesn't always happen (sometimes volume and quality are just fine from the amp). I was wondering what model you had, and what had happened with your repair.

thanks, Bill
Good news!
I got my ca-200 back from Classe a few days ago. Including shipping time it was gone for about 2.5 - 3 weeks, but I figure Classe only had it for about one week.

I called them to find out exactly what was done to the unit because it's been working perfectly for the past few days and even seems to sound better.

They went over the whole amp and did necessary repairs.
One problem was the shield wires, which connect the input boards to the main boards. A third party used to terminate them and apparently weren't doing the best job, so they were replaced (this is now done by Classe). They also replaced the RCA jacks (probably due to normal wear) and made some updates. The updates included changing some output resistors, 2 caps, and a few diodes. The updates were, according to Classe, intended to improve reliability and stability.

They did the repairs at no cost and even sent it back to me free of charge... that's at least 50 bucks right there. I was very impressed with the whole experience and am now putting Classe up there with Thiel for unsurpassed customer service. I should also mention that I am not the original owner of the amp and it's warranty had already expired.

Bill, that's how my problem started... slight volume level changes now and then followed by more drastic level changes more often. I would call Classe and ask for Arman in tech support. If you can be helped he will help you.

thanks for your reply. Good to hear that everything worked out with Classe- it is nice to know that they stand behind the product!

In my case I am using the XLR inputs, not the RCA's. I suppose the input board/shields that you mention are common to both RCA and XLR. My units are 2 1/2 yrs old.

I'll be darned but the amp has been running great for the past 48 hours. As soon as it acts up again I will be giving Classe a call.

thanks, Bill
Just an update . . . I sent in my amps to Classe via my dealer, and just got them back. So far so good after one night of listening. Armin mentioned replacing the shield wires, and replacing a resistor and cap, which he said wouldn't affect the unit sonically. Everything is sounding great once again!

gnobber, that's great! i hope it wasn't too painful being without your amps for tha time. it sounds like the switched the same things in our amps for the same reasons... they must be very similar inside.
i'm glad they're working well again. enjoy some music!