Looks like it's time to change filter caps. Visualize them at the electrodes if there are any residue.
47 responses Add your response
Maddog66blue, you need to identify the problem component. This is done by a process of elimination. Start at the source, and swap the L and R interconnects. If the problem doesnt shift from one speaker to the other, then the source component is not at fault. Move to the next component in the chain, and repeat the process until you notice a shift in the problem..
The final test would be to swap the speaker wires from L to R etc. If the amp is at fault, the problem will shift to the other speaker. If it doesnt, then something is wrong with the offending speaker.
Excuse me boys, but if the problem did not jump from R speaker to L speaker, when the OP swapped speaker cables from R to L and L to R, then he need go no further; the problem is in the speaker. This is assuming I have the correct understanding of what was done. Brf keeps saying this, too. I agree with Brf, but it's not merely a matter of opinion.
Dear Maddog, It would make sense to seek outside help to evaluate your speaker. Perhaps your dealer can help. One thing is sure: none of us can help from this distance.
02-12-13: Maddog66blueDoes this mean that you interchanged L & R at one end of the speaker cables, so that what had been the right amplifier channel was then connected to the left speaker, and vice versa? Or does it mean that you literally swapped the speaker cables, changing their connections at both ends, so that what had been the right amplifier channel was still connected to the right speaker?
If the problem stayed in the right speaker when you did that, and given that you've tried a different set of speaker cables, and assuming that there has been no crackling from the left speaker at any time, there are only two possibilities that occur to me:
1)The speaker has a problem, as Brf and Lew suggested. Perhaps there is a short in the speaker, that is causing the amplifier to have problems that in turn result in it supplying a crackling "signal," even when no music is playing.
2)The cable going to the right speaker is in close proximity to some source of radiated interference (RFI/EMI), such as a power cord, and that interference is entering the feedback loop of the amplifier (assuming it has one), and causing the amplifier to output a signal which causes the speaker to crackle.
I don't see how the problem could be caused by a defect in the amp or the preamp or a source component, given the findings you've described.
Just to be super super certain, when you switched speaker cables, the amplifier and everything upstream from the amplifier, that was driving the R speaker was then driving the L speaker, and vice-versa. If that is correct, then what I and Brf and Al have said has to be the case. Al brought up the interesting possibility that the speaker cable was picking up something. That's kind of a "zebra", but possible. (In medical terms, a zebra is a very rare cause of a common symptom or finding.)
I have a feeling this is something very simple going on in the speaker, but it depends upon your experience and sense of adventure whether you can fix it yourself. My advice remains the same: get your dealer involved if you have someone local. Why not call the US B&W representatives, if you have no local help?
I'm going to try moving some power cables that may be causing RFI/EMI and see what happens.Also, try turning off any dimmer switches, fluorescent lights, or compact fluorescent lights that may be in the vicinity of the cable to the right speaker.
Lew -- thanks for mentioning about the medical meaning of "zebra." Hadn't known that previously.
I had a very similar experience where i was getting a crackling/interference/whistley sort of noise on the left side and it was driving me bonkers. After all of the cable switching I read about this phenomena called Tube microphony. Since I have a tube preamp, I found that that the tubes for the left side were the culprit. I hope all goes well with your diagnosis because I know you won't stop til you have this thing sorted out. Keep us all posted.
Polk and Vinylmad, The OP's problem has to be in his Right speaker or the cable leading to it. That's been settled, I think. Good thought by Miner to check any jumper cable that is being used to connect among terminals at the rear of that speaker. A loose connection could conceivably be a factor, either inside the speaker cabinet or at the speaker inputs.
I brought the pre, amp and right speaker into the shop, the owner assured me it wasn't the speaker, he believes it's the input tubes in my amp, he loaned me a integrated amp and after hooking it up, the right speaker sounds fine. ill let everyone know what the actual culprit is as soon as I can.
thanks for all your suggestions
The owner assured me it wasn't the speaker, he believes it's the input tubes in my amp, he loaned me a integrated amp and after hooking it up, the right speaker sounds fine.That seems irreconcilable with the fact that switching the L & R connections at the amp outputs did not cause the problem to move to the left speaker. Did he offer any comments on that?
"I did some more troubleshooting"... Does that mean you repeated the experiment of swapping the speaker cables? And got a different result from what you reported previously? The impression I had is that swapping the speaker cable terminations AT ONE END, such that the L speaker is now driven by the R amplifier channel and upstream components, and vice-versa for the R speaker, did not move the problem from the R speaker.
But when you say you "swapped speaker cables", that could also mean that you took the R cable and used it to connect the L amplifier to the L speaker, and vice-versa. If you did that, only the speaker cables are tested. Which is correct?
Both the Rogue and your SF amp are very good. Its probably just a matter of personal taste on which one you will like better. If the crackling is a problem with you amp and you verified that you don't have bad tubes, the problem might be something very simple like an RCA connector or a tube socket. If it were me, I would have someone look at it before I did anything.
Lewn; I've done the following:
Changed speaker cables (tried different cables)
Switched Left and right speaker cables (the crackling moves from right to left)
Moved interconnects (right to left and vice versa)
Tried a different amp which didn't produce a crackling sound.
Replaced input tubes in preamp and amp.
Although I did notice that the crackling did become less after changing input tubes in the amp.
"Changed speaker cables (tried different cables)"
"Switched Left and right speaker cables (the crackling moves from right to left)"
[Lew]Do you mean to say that you attached the R side of the amplifier to the L speaker and vice versa?...
"Moved interconnects (right to left and vice versa)" [Lew] Do you mean to say that the L side of the preamp was then driving the R amplifier? Result?...
"Tried a different amp which didn't produce a crackling sound."
[Lew] you do realize that some of these results, most notably the effect of swapping R to L and L to R amp/speaker combos, assuming you swapped one end of the speaker cables, are different from your original post that started this thread, and different from some of your additional posts that were in response to questions. However, if the latest info is valid, you may indeed have a problem in one channel of your amplifier. Did you ever try swapping the amplifier output tubes from one side of the amp to the other? If that didn't move the problem from one channel to the other, then you probably have a bad solder joint or a failing tube socket or some such thing.
This sounds like an eminently fixable problem that should not require the purchase of a new amplifier, but I realize that competent technical assistance is not readily available in most parts of the US these days. This is the world of "if it's broken, throw it away".
Lewm; agreed I believe it is fixable but quite frankly I'm a bit tired of messing around with it. I have had the amp in the shop and they said that nothing's wrong with it. I am sort of at my wits end with it, It's a great amp, considering the issues I've had and I don't plan to throw the amp away but to sell it with full disclosure what has been the issue and what has been done.
@Bevis yes I have changed interconnects as well.
"Replaced input tubes in preamp and amp.
Although I did notice that the crackling did become less after changing input tubes in the amp."
With the system powered up and making the noise, very carefully move the tubes around in their sockets. Don't pull the tubes out, or even go up and down. Just move them a little bit from side to side. If the noise changes, that may indicate an issue with one of the sockets. If you have some contact cleaner, try that as well.
I had one of the tech's out today and they seem to think that the issue is a ground loop of some sort, we found a hum coming from the speakers, unfortunately we weren't able to narrow it down to what specifically it could be.
I also did try to wiggle the tubes a bit to see if any change, but no change better or worse.
On another note, I was borrowing a rogue eighty eight from the same shop and today when I was listening to some music, the amp just quit working.
Maddog, There is a distinct possibility that your house is possessed by demons. You need an Exorcist. However, this sort of paranoia is quite normal for audiophiles. I am going through it myself. One of my monoblock amplifiers keeps blowing very expensive output tubes. Yet on the workbench I can find absolutely no reason for it. (And I do understand the circuit, have all the necessary meters, 'scope, etc.) I am left with "bad tubes". This is most unsatisfying.
Nevertheless, if the tech's head was spinning around 360 degrees, run! Sell the house immediately.