I own a Sony TA-4650 int. amp that,to my ear,sounds excellent with almost any pair of decent speakers....The problem I am having is that when I switch it on or off,I get a loud "pop" through the speakers. What causes this and what can I do to avoid it? i have a number of other integrated amps that do not exhibit this anomaly. My guess is that the caps on the sony have something to do with this..charging and discharging. I am planing on using the front end of this unit as a preamp for an extra Onkyo M504 I would like to set up in another system....thanks for any advice you can give....the reason I am using the front end of the sony VS other preamps i own is that it seems to impart a very "smooth" "Tubey" laid back sound to a lot of cd's that might sound a bit more sterile with my Carver or Nakamichi preamp. Perhaps if I am only using the front end of the Sony this will not be an issue???? Thanks again for your response!!!
The caps may be old and tired- after all, it could be 32 years old at the very least. They stopped making them in '78 but some dealers, like the one I worked for, still found them in all kinds of nooks and crannies.
If you replace the caps, DO NOT, FOR ANY REASON, BRING THE VOLTAGE UP SLOWLY WITH A VARIAC!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Just replace the caps and turn it on. This amp is not like any others that I know of, other than the TA-5650, TA-8650 or the VFet power amps.
This amp does have a turn on delay and it could be that you have a bit of a DC offset issue. Have it set up by someone who knows this amp- don't take it to just any repair shop. There's a guy at AK who supposedly knows how to work on these, or I have a friend who knows them very well and I can ask if he has time to work on it.
If you don't want to spend anything for repairs on it, just turn the speakers off before shutting it off.
BTW- it's the power amp that has the "tubey" sound, not the preamp, other than the phono section. The output transistors are 2SK60 and 2SJ18 but if they go, it will also need some new diodes. This is not a typical amp and it needs to be serviced correctly, or it will launch all kinds of parts. OTOH, it's the best sounding low powered integrated amp I have heard and I had one for a long time. They were spec'd at 30 W/ch, and no more than .1%THD from 20Hz-20KHz, although the actual bandwidth +/- .1dB was more like 1Hz-100KHz. All of the ones that were reviewed and tested met all of the specs, except for the power- that always came in at 56W/ch.
