Dear all,
Somewhere last year I’ve bought this wonderful amp as a good bargain. It worked ok for about 6 months. After that trouble started. When powering on the amp, you could hear some crackles on the powerbutton. After a while the center and right channel would crack also (like you would turn a dusty volume knob) and once and a while the sound would drop and come back, drop, come back. Switching the amp on and off again (sometimes 2 to 3 times) would “fix” the issue.
The amp was sent for repairing to a well know tech service center. The powerbutton was replaced (no crackles anymore) and the amp was working ok.
After 2 to 3 months again, the channel drops started all over again. Switching the amp on/off would fix the issue. I’ve sent a message to Tony at Parasound, describing the issue, and he told me the culprit would probably be intermittent speaker relays or faulty input level control potentiometers. I had informed the technician about this, but he told me this was not likely the cause. It went back to the service center and after two weeks I got a call that the issue was found (95% sure). Some transistors on the power amp would be causing this behavior.
Got it back again, but even the first time I’ve tested it, the problem was still there. Cgreegg, cgreedd, sound gone, back, gone, back… Now, to solve the issue , I just need to put the volume a bit higher and the sound is back. This worked for about one week.
Yesterday evening, the sound in both channel center and right was OK, but I missed sound from… the left channel!! I did put the volume higher, but this didn’t work. I went to my AV receiver to run the speaker calibration tool and did get the test signal in all speakers right away… after that, the amp worked fine for the whole evening.
It seems that now on low(er) volumes it happens there is no sound, or crackling sound and when putting it up, or sending a test signal everything is back OK.
I can return the amp again (check under guarantee), but I’m at a point that I ask myself to leave it like it is and buy a new amp. Although I’m sure this is a wonderful amp, I’m a bit afraid the cost at the end might be very high and not worth it.
I do understand one need hours and hours to search for a solution, I’m a total noob if it comes to electronics etc and one can tell me everything of course. Given the reputation of the service center, I’ve no doubts about the skills/experience etc… I’m just looking around and getting as much info as possible from other people who are experienced in this audio stuff…
Relays have been tested fully. If I want them swapped, this is no issue, but it will be an additional cost and the technician can not assure this will solve the issue…
I’ve received schematics from Parasound here.
Thanks for any tips, suggestions!
Regards!
Somewhere last year I’ve bought this wonderful amp as a good bargain. It worked ok for about 6 months. After that trouble started. When powering on the amp, you could hear some crackles on the powerbutton. After a while the center and right channel would crack also (like you would turn a dusty volume knob) and once and a while the sound would drop and come back, drop, come back. Switching the amp on and off again (sometimes 2 to 3 times) would “fix” the issue.
The amp was sent for repairing to a well know tech service center. The powerbutton was replaced (no crackles anymore) and the amp was working ok.
After 2 to 3 months again, the channel drops started all over again. Switching the amp on/off would fix the issue. I’ve sent a message to Tony at Parasound, describing the issue, and he told me the culprit would probably be intermittent speaker relays or faulty input level control potentiometers. I had informed the technician about this, but he told me this was not likely the cause. It went back to the service center and after two weeks I got a call that the issue was found (95% sure). Some transistors on the power amp would be causing this behavior.
Got it back again, but even the first time I’ve tested it, the problem was still there. Cgreegg, cgreedd, sound gone, back, gone, back… Now, to solve the issue , I just need to put the volume a bit higher and the sound is back. This worked for about one week.
Yesterday evening, the sound in both channel center and right was OK, but I missed sound from… the left channel!! I did put the volume higher, but this didn’t work. I went to my AV receiver to run the speaker calibration tool and did get the test signal in all speakers right away… after that, the amp worked fine for the whole evening.
It seems that now on low(er) volumes it happens there is no sound, or crackling sound and when putting it up, or sending a test signal everything is back OK.
I can return the amp again (check under guarantee), but I’m at a point that I ask myself to leave it like it is and buy a new amp. Although I’m sure this is a wonderful amp, I’m a bit afraid the cost at the end might be very high and not worth it.
I do understand one need hours and hours to search for a solution, I’m a total noob if it comes to electronics etc and one can tell me everything of course. Given the reputation of the service center, I’ve no doubts about the skills/experience etc… I’m just looking around and getting as much info as possible from other people who are experienced in this audio stuff…
Relays have been tested fully. If I want them swapped, this is no issue, but it will be an additional cost and the technician can not assure this will solve the issue…
I’ve received schematics from Parasound here.
Thanks for any tips, suggestions!
Regards!
To me this failure description appears as it would be the output relays though, just like Tony from Parasound suggested!
Once I had exactly the symptoms You describe with old power amp modules.
Turned out the relay contacts where worn out.
The reason for this behavier that everything is fine when You turn up the volume or run a test signal is that at lower volumes, below a certain threshold, the current through the contacts is not sufficient to "punch through" the oxide layer of the relay contacts.
Well, just my 2 cents:
Your service center failed once to succesfully repair the amp when they changed transistors which obviously did not solve the problem.
They didn`t even run a proper test run to see if the problem was solved.
Also, given the symptoms You describe, saying that the output relays or control pots "are not likely the cause" I find is a somewhat strange statement. I`d suspect this the N°-1 cause for the described effects.
When the relays are supposed to have been "fully tested", then why the technician "can not assure" if this will solve the issue?
Either they are okay or they are not!
If they are not okay it`s very likely that this will indeed solve the problem, if they are okay it will of course not solve anything.
No need to "speculate" about this if they have been "fully tested", so again, strange statement IMO.
BTW, testing the relays is simple: when the amp has powered up, defeat the relay contacts with clip leads or a piece of wire. If this solves the issue the relays have to be replaced (which doesn`t mean that there couldn`t be other, additional issues as well).
My suggestion, try to get another "service center" or You`ll end up paying a fortune alone in shipping back and forth the amp with this "trial & error" repair method.
I`m aware that it`s not always so easy to find the failure(s) but this is not rocket sience either, at least it shouldn`t for a pro repair shop.
Parasound HCAs are fine amps, they`re built reasonable well and IMO would be worth to get repaired and overhauled even today.
However, if You can`t DIY and if You want to get this done right (and if it would be my amp I´d change the output relays + all but maybe the large electrolytic capacitors by all means) by a repair shop might get indeed too expensive. Difficult decision!
Thanks a lot Christoph for you feedback, this is very helpful! And your arguments really make sense. I've now paid around 650 dollars already for 2 check/ups...it's remarkable everyone keeps saying it must be the relays, so I'll try to get someone and test these thoroughly I guess.
thanks again
thanks again