I purchased this amp new in1979 and has worked perfect up until about a month ago. Still works but now I randomly get a very loud "Poping" sound from the left channel, even with no volume and no speakers hooked up, I can see it register on the speaker output meter when it happens. I would really like to fix it if possible.

Any repair advise would be greatly appreciated.

John, March 2010

I also have that problem.

I opened it, and cleaned everything including the on off switch, speaker selector and board. Relays seem to work fine.

Only then did I notice that the noise and popping came from the transformers. I restage the amp switch on and off, over and over. I think the transformers are shot. They seem to be sealed in their housings.

Aside from replacing the transformers I don't think there's anything you can do about it. If you're willing to live with that intermittent problem I guess you’re going to, unless!

However, when it gets running the popping and noise goes away and the sound is just incredibly out of this world. I believe that the old Hitachi transistors have to be the drivers of such good sound.

Nevertheless, keep the amp, they’re hard to find and worth every penny. The only thing coming close 1st and 2nd are my vintage Marantz 2235B and 4270.

I have tons of recent amps including a Sony ES series that don't even come close to the vintage amps.
By the way, I have the whole set, the preamp, the tuner and tape deck. Just awesome, beautiful set and strong build. They don’t make them like that anymore. It would cost a bundle to have this built nowadays.

If ever you get around the problem, let me know cause the Sanyo Plus Series are keepers. Thanks.

Regards,

Paul, an Audioman-Melophile
Montreal, Qc
Canada

paul whelan, March 2010

This happened to mine also. The first thing to do is make sure you have good conections with all your input cables. Clean the RCA connectors with 92% isopropol alchohol. If this doesn't work clean the relays which control the switching to speaker outputs A and B. They are somewhat difficult to get at. You must remove most of all the screws of the covers and sides to be able to slide the amplifier board away from the transformers so that the covers can be popped off. You could also replace the relays if you can find replacements. Cleaning the contacts with a relay burnishing tool fixed mine. It is one of the best sounding amplifiers I have ever heard after 50 years in the audio hobby. It's worth fixing.

Miles C., March 2010