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A computer UPS will not help and could makes matter worse. Computers have different power needs. You would need an audio power center. It could be the preamp causing the noise as well as the amp. If you switch the pre-outs left and right, does the sound then come out the other channel? If so, it is the preamp.
If its not the amp, but it is coming from the amp and not a source to the amp, then I am stumped. Maybe you have a bad interconnect cable?
If you have consistancy problems with the electric, it sounds like those power regenerators or voltage correctors from the likes of PS Audio and Exact Power would work, but they are expensive. If it is just a bad ground, most decent power conditioners will help, such as the Monster HTS 2000 or even better something from Chang Lightspeed. Has anyone like an electrician ever checked the AC outlet, or have you tried the amp on another circuit in another room??
This seems a bit of a stretch but since you haven't isolated the source of the problem maybe try switching the speaker cables left side for right to see if somehow you have an intermitent short starting to develop in the speaker wiring or connecting cables and it's affecting a protection circuit in the amp. If the problem switches sides you have a start.
If not, obviously your goal is to isolate their source of the problem. If you have balanced interconnects throughout your system you may be able to carefully disconnect components starting at the Theta transport and working your way toward the speakers. If the noise goes away when you diconnect a component or a cable then you're making progress. Balanced interconnects can also be carefully switched left to right to see if you can get the noise to switch sides.
Hang in their! Remember your experiment is to make only one change at a time.
Hy whatever you do don't listen to your wife - she has not the slightest appreciation for what you have there, which is a very nice rig esp. for a newbie. Beside that, someone else will end up with a steal of a deal on this equipment & then go have it fixed anyway, & you will not be able to sell bad equipment for a decent recovery price.
You seem to have an intermittent connection in the power amp. The suggestion to reverse speaker cables is a good one; you could swap the input cables at the same time to keep left = left etc. The UPS experiment was indeed worthwhile to eliminate a possible line-voltage problem situation; however while a computer UPS is not the best from an audio sonic standpoint (the output waveforms aren't very clean) it shouldn't have hurt anything, & was a good thing to try from a troubleshooting perspective.
Focus closer on the Rowland; leave it powered on with no inputs connected (for however long it usually takes) to see if it noises up again. It could even be just a bad input cable connector that is causing this. Indeed, only make one change at a time, pursuing a process of elimination, or else you'll really confuse yourself.
If it is for sure the amp itself, then the intermittent connection is probably clearing up as the unit is moved around, shipped, etc. Then it reverts to intermittent/noisy again after settling awhile. It could even be the AC switch but this would probably affect both channels? It could be a dirty wiring connector or a PC board edge-connector inside, it could be an old cold solder joint or solder bridge on a PC board. This will take some time & patience from an experienced & knowledgable tech. but it can be found; I do this for a living in the Telecommunications business & can fix many things that others can never find. Shoot me an email inquiry with phone contact if you'd like to discuss in detail some evening.
Hy there's one other very basic issue that I forgot to mention, which could be the cause of this intermittent noise. We sometimes "look too deeply" into a technical problem, neglecting the basics which those of us that are more-experienced tend to take for granted.
This very basic issue is cable contact cleaning. As you are new to this, I'll explain again briefly here & then drop in the link to Galen Carol Audio's excellent website; under the "archives" section are many tech. tips that you should become more familiar with. Look over his whole website, read & learn a lot!
What happens over time is that your interconnect cable ends, panel-mounted equipment jacks, speaker cable connectors & ends attract dust, dirt, oils from skin contact, metallic oxidation occurs. This contamination causes (1) sonic degradation (2) possibly noisy connections esp. at the signal-interconnect level. One of the best & most popular contact cleaners is a product called Kontact, widely available, & one of Galen's favorites as well. If you're hesitant to spring for a $40 bottle of this "magic sauce" then at least get a small container of pure denatured alcohol from the drugstore; do not use isopropyl alcohol etc. as it contains lanolin, an oil which attracts dust right back into the connections, and water among other contaminants.
Cut some pipe cleaners into 1/3 sections & use those as your mildly abrasive applicators. Dip into the solvent & then scrub the cable connectors clean, both inside the contact point tips & around the shields. Also go around the outers & inners of your components' jacks, first ensuring that power is turned off. Also clean your AC cords, the mating female IEC's, speaker output posts, posts on the speakers themselves, & speaker cable ends. Change applicators when they become dirty looking & be sure to do that critical "second cleaning" as Galen explains all in great detail. If your intermittent noise is related to dirty contacts then this should fix that, & even if not then you'll still benefit from sonic improvements that can sometimes be dramatic in cases of gross neglect.
Here's that link:
I took Bob's advise and cleaned all contacts with denatured alcohol. I plugged the amp back in and ... no power!
After checking around, I found a blue wire from the PC board on the side to one of the connectors on the back had become threaded between two speaker wire contacts. When I moved it, the amp powered up fine.
Then I hooked up everything else, and at least for now, the stereo sounds GREAT!!
Hyoster, I have a same problem withn my low-fi Yamaha based surround system. The Amp/pre amp is now 11 years old and white noise problem started 2 years ago with my front surrounds ( this is 7.1 channel system. I did not need those so I used only 5.1. Now the rear right channel has started same problem, intermittently, and I can't find a problem. I assumed 2 years ago that thoes two channel was 'shot'. May be it is as simple as speaker cables or interconnect having a short.(like a post above suggested) Try using diffrent cables (new from radio shack or equal)and see if still comes back. I will try the same.
Yes, I have isolated the problem to the Amp, I think. Here is a symptom that I am hoping will lead some of you toward solving this problem.
After I cleaned the contacts, I plugged in the amp to the power, and it would turn on and off. Then I attached the left speaker, and I could still turn it on and off. Then, I attached the right speaker, and boom here comes the static. And when the static noise is occurring, the amp will not power up. The switch does not catch when depressed.
I had the top of the amp off, and decided to monkey with the fuse to see what would happen. I unscrewed the top of the spring-loaded fuse holder, and the sound went off, and a red light lit up on the circuit board near the fuse. Then I re-engaged the fuse by screwing in the top of the fuseholder again, and the noise was gone!
I decided that this was strange, but that I would just keep the screws out of the lid to the amp so I could do this if I had to. I ran the amp for several hours with no problem, then turned off the power supply, effectively unplugging it from the wall. When I turned the power supply on again, there was the static. So I repeated my fuse trick and voila, no static. After playing for 10 minutes, the static returned, and I powered down the system.
Does this help in the diagnosis department?
Please be careful removing and re-inserting fuses while the amp is plugged in!!! In some products, the fuse is "live" and directly connected to the AC from the wall. Your problem is fascinating and we would hate to have your experimentation and detailed reporting cut short by a "hair-raising" experience.
Definitely don't mess with the fuses with the power on. It sounds to me like the problem may not be the amp at all, but rather the speaker you have attached to the right channel. I say this for two reasons. First, Rowland has had the amp twice and can't find anything wrong. Second, the problem exhibits itself when you hooked up the right channel in your last experiment.
I haven't read the entire thread, so I don't know exactly what you have tried, but here is what I suggest. Swap the speakers between channels. Hook up the left speaker to the right channel and see if the problem occurs. Alternatively, hook up the right speaker to the left channel and see if the problem moves to the left channel.
I have model 6 monoblocks without any problems;on the powering up and then turning off;in my manual it references a dc offset is being detected greater than spec and the amp is turning off;I don't know if that helps you out with info but note that this thread is from 2001.
These are the best solid state amps I have owned and are on par with my audiovalve challanger monoblocks(6550'c tubes).