Leoturetsky, I am surprised that the term 'RF' has not arisen before now! You are describing classic RF interference issues.
I doubt very much that the Goertz cable is responsible for oscillation in three different amps. A speaker cable that can cause oscillation?? Really, an amp has to be pretty unstable for this to be an issue and the amps you mention don't have the reputation for that. So I will use Occam's razor and go for the simple explanation: its not the cable, you have an RF problem.
Digital equipment by their very nature are RF generators. If the designer has done his homework, then this is usually not a problem, but a malfunction can throw out all bets. I would not be trusting of the PS Audio until this matter is resolve either.
So, I have a test for you. Plug the amp directly into the wall. MAKE SURE that the PS Audio is not plugged into anything. Also MAKE SURE that your digital equipment is completely unplugged too. For that matter, let's make sure that the amp itself is the only thing that is plugged into the wall. Does it still behave the same way??
No, its OK= the cable is fine and you have a malfunction in something other than your amp.
Yes, its the same= we still don't know its your cable or not, but it **isn't** your associated equipment.
The next thing I would do is look for RF sources. How many feet are you from that AM/FM?TV broadcast station tower? Can you see if from your house? Have you ever heard garbled radio programming on your amp at any time since this issue arose or before that? If you have RF from outside the house there are things that you can do. But let's answer the initial questions above with the test I gave you first. |
Alright, I guess the Cary goes to the dealer. And I'll pull the Goertz temporarily as well.
Don't you guys think the Classe is already shot? Or will it recover because its own protection circuitry says nothing is wrong?
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Dave_b, how does a guy with MIT and Transparent cabling tell anyone not to add extra networks in front of their speakers? Is your Zobel better than mine? |
Who built the Zobel networks? I have heard that these can cause problems when improperly designed/implemented.
If not the Zobels,then look at the pre-a trip back to Cary?? |
If the Goertz Alpha-Core RC networks were damaged it might explain the oscillating on some amps, but that the oscillating also happened with the Krell amps which don't require the RC networks, leads me to believe the problem is elsewhere. |
Hi, I have a Classe amp, very similar to yours, of the same series. The Classe has a protection circuit that shuts it down (flashes green) if it senses any DC from the preamp. With my tube preamp, I have to turn the Classe on last, and off first, or it will not work. My Classe also dislikes my PS audio ps-200, which is basically two Ultimate Outlets in one box. From experience, I never use a power conditioner with any big solid state amp. Your PS audio ultimate outlet, however, will do wonders for the Cary Cinema 11,and your CD player, particularly in keeping the noise from the Cary's built in DAC OUT of the other gear.
I would seriously doubt if the Goertz cables were to blame,as these amps can drive any cables; or the UO were at fault(a passive balun type isolation device, I believe). The amps you are losing are extremely reliable. I really would plug the amp straight into the wall, and borrow a different preamp. I suspect your Cary needs service, it appears to be a very complex unit. Volume control noises are the fault of the preamp, not the amps, they just amplify what they receive, in this case a noisy, dirty, possibly shorted volume control. |
My guess goes to the goertz cables being the culprit. I was wondering if you had goertz cables even before I read through. I had the same cables on an electrocompaniet eci3 integrated amp. The amp started shutting down a few months after i bought the amp. my dealer even gave me a new eci3 as they couldn't figure out the problem. The goertz cables causing problems with amps wasn't common knowledge at the time. Anyway, I figured out it was the cables, because, I had the new amp on, with the cables, but no speakers connected, and the amp shut off. I changed the cables, no more problems with that amp. I think it was 4 years later that goertz started putting the zobel network on their cables. |
Just trying to point out that somtimes one can be completely unaware of the obvious while looking toward the obscure for an answer. Adding extra networks across your speaker terminals in front of speaker cables that would be better served pulling in tv channels is naive at best. System synergy is also very important and seems to be lacking in your choice of gear. Quality gear and great cables will avoid a multitude of potential mismatches. |
Reb1208, Gs5556, can you explain how DC from the pre affects the amp? Why would the amp care what signal it amplifies? I'm not arguing, just not understanding.
Gs5556, how does DC come from the wall socket? Or do you mean the UO?
Jsd52756, the lines from the wall to the outlet are Romex, no issues there. The PC on the Classe is a brand new PS Audio molded cord that has never been used anywhere else so I can't imagine it can be a problem. The PC to the UO is a Belden 83803 cord I made myself and I've used it without issue in multiple other places. Also, wouldn't the low amperage you describe be an audible problem? The Thiels would have VERY harsh treble without enough juice, no?
Justlisten, no kidding, huh? I don't even want to put more gear in my system and I have the money for an SACD player ready to go. :-(
Tobias, how do I check the preamp's output? I don't even have a guess here. And the AC is a sine wave... I have graphed it for kicks before. :-)
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Dave_b, we're you being helpful, insulting, humorous, or stupid? I totally missed anything useful in your entire post. |
Leoturetsky, the "simple test" I was referring to is basically what you have done: voltage and polarity. My idea of anything more sophisticated would involve an oscilloscope and a check of the AC waveform. Maybe you should do that if you have any doubt that the AC wave may be sinusoidal. Otherwise, not.
Next step would be to check the preamp's output and the integrity of your speaker cables. I have real trouble imagining that even the reviled-by-some Goertz cables would cause what you describe unless they (or the connectors) were damaged--partially shorted, for example.
If you were looking for an alternative (and cheap) speaker cable for a swap test, though, I would second Newbee's recommendation of Canare QuadStar 4S11. |
GS5556, You have a good point. I fried an amp (and subsequently a tweeter) with DC from a tube amp into a SS amp w/out transformers (contrarty to the pre-amp designers intention). I'm so provincial, I'm not familar with his stuff and I just assumed that the poster was using integraded amps. Oh well - but FWIW when my amp went down it did so quietly, no pops, burps, or noise whatsoever. Would that be typical? |
Leoturetsky, how did you wind up with such an eclectic bunch of gear? Get a good integrated amp with a top quality PC from Transparent or MIT for line filtration. Use a decent CDP and well designed cables that work well with any components and reduce noise in your system such as MIT. For God's sake get rid of the Zobel networks and the Goertz cables (excellent for pulling in VHF but horrible for audio). Thiel speakers aren't exactly music makers either. Power strips and ultimate outlets are worthless as well...keep the krell amp maybe and get a krell 280p or older ARC LS15 preamp for starts and some MIT shotgun cables. Cary Cinema preamp?? Really now. |
A preamp can, in fact, cause that kind of damage if its DC blocking caps are not doing their job. I think your amps are being slowly poisoned by DC, whether it's from the preamp or the wall socket. |
Yep, I think you are right about the appearance/design of the cable causing (or not) high(er)capacitance. My fading memory of problems not personally encountered. I read a lot of stuff but have zero retension skills. But, I think I did get you to the right church, now you just need to find the right pew. Zobels or not. :-)
I still think you should take out the Goertz and Zobels and see what happens. Challenge your assumptions and let me know what you discover. I'm curious. |
There maybe a short in the speakers crossover, preamp could be putting out DC. I'd also can the goertz cable. Certainly don't hook up the repaied amps until you find the problem. |
In regards to the power; A loose wire connection, wire nut or frayed wires could enable the power meter to still read 123.0 volts BUT not allow enough emperage through. Your meter only needs a fraction of an amp to read. You amps could pull a lot more amps when powering up or cranking them up. If this is the case, when the amps are trying to pull more amperage through poor wiring, say for instance only one or 2 strands are allowing the juice through, the voltage may drop down considerably to even 40 or 50 volts. That could fry the heck out of them. Just a thought worth checking out. Good luck! -John |
Mental note--never let Leoturetsky borrow my gear...
You mention Zobel networks on the end of your speaker cables. Have you removed them and has it reduced any of the pops/noises? Just a guess, but I beleive the Zobels change the load on the amp, which seems to be the damaged items |
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Newbee, thats the other way around. Goertz cable causes oscillation because the wires are so closely spaced together that they have very high capacitance. Still, this should be an issue with Zobels and these particular amps from what I know.
Maybe the Zobels came loose? Hmmm. |
FWIW, as I recall the speaker cable types than can typically cause osscillations in an amp are those which have widely spaced positive and negative wires. I suggest that you take a few moments and do some research on this issue in Google - there are a lot of articles on this subject, which discuss the issues involved and which may have some application to your system. Other that a little time you've nothing to lose, and might gain a better appreciation for the terms 'inductance', 'resistence', and 'capacitance' and how they interface.
Re your question about 'what should I hear', the answer is nothing at all. Whether cheap 12ga cord sounds good to you or not what it will not introduce is the problems you have described. For test purposes, and actually some fairly good sound, I would recommend some 11 ga Canare Star 4S11. I use it regularily and I consider it a great bargin in non-exotic copper cable and I have used it regularily.
Hope that helps a bit. |
Ait, just plugged the polarity checker into the wall outlet and the UO outlet. Reports polarity correct. I've wired my entire house and numerous others and been through state inspections. We can call me an electrician. |
Tobias, what is this simple test of an outlet?
I just broke out my Fluke MM. The voltage at the wall is 123.0. The voltage at the power cord to the UO is 123.0. The voltage at the outlet end of the UO is 123.0. The voltage at the power cord to the amp is 123.0. Both UPSes in the computer room report 123.0.
What else is there to look at please? What principle of electricity in physics that isn't voltage can cause this anyway?
Newbee, if I swap in some lamp cord, how will I know the problem is gone? These amps aren't even supposed to be susceptible to oscillation from what I understood and the Zobels are there but I too seem to think this is where I should be looking. |
Honestly, I know nothing about electricity. To me, it's black magic. All I know is rain.
But, my feeling is if you can simply use different outlets and the amps behave themselves, this is simplest test. Be certain it is a completely separate run of course. This won't cost you any $. Normally, I'd say this is a very, very long shot.
However, since you now say that YOU ran some dedicated lines (especially if it were ME who ran the lines), then why not double check them by using my experiment? Cheap, won't hurt.
A line conditioner could be bad as well. If the same conditioner was in the loop with the Adcom, Classe and Krell, it might have been damaged, now defective.
These are all uneducated, wild, off the handle guesses.
I used conditioners and power surge protectors for a bout a month many years ago. I feel they have no value, just make things more complicated and may even poorly affect the sound. But that's just my opinion.
Luckily, here in stormy Oregon, I have not had a surge.
All these power conditioner things are hokus-pokus.
Also, i turn my equipment off whenever I'm not listening.
These are my srewy, rain sogged opinions. |
Don't know about your speaker cables, but some designs do cause ossilations in an amp. Remove your present cables and try some old fashion 12 guage copper cables and see if that solves your problem. If so, you can then simply refocus your attention on proper cables. |
You may have the polarity reversed in your wall socket. Even though the plug only fits one way, the wires may be switched (i.e. hot wire on neutral screw and vice-versa). If so, that can definitely fry capacitors in your amps. Have an electrician check it out ASAP. |
A simple test of the outlet would tell you if there were an AC problem. From your description, it really sounds like the AC supply would be the first place to look. |
The Adcom was plugged directly into the wall. The Krell was plugged into the wall for half its life. Can't see what a functioning line conditioner can do to an amp, either its getting non-shorted power of the right voltage or not, right? And I ran my own dedicated lines, three in fact, though I'm only using two currently.
Oregon, what in the power system could slowly fry an amp except for under/over voltage which would affect everything else in my house too? |
Probably obvious, but did you try plugging amps into different sockets? If all amps developed problems from the same sockets, maybe something is wired incorrectly or there is a fault someplace.
Just to be certain you've isolated suspect socket run, try an extension cord from a completely different run.
It is odd that 3 amps developed trouble.
Also, remove the line conditioner for a while and see what happens.
Another consideration is- for the price of a new amp and line conditioner, you could have an electrician run dedicated lines to your room.
Just ideas. Hope they help. |
