Sony TA-F707es - Noise/hiss on on one channel

Gattaca83

Member
2016-06-05 9:32 am
Hi all,

I just bought a second-hand 1994 Sony TA-F707es Integrated Amp (90w), smaller brother of the TA-F808es. These amps were the top line for Sony during that era, weighing a whopping 50lbs or so.

The amp works well and is amazingly sweet and powerful. However, it has a noise (continuous hiss that is not very high-frequency but audible) in the right channel that can be heard when speakers are connected. When the volume is turned past the "12" oclock position, the noise increases noticeably and becomes coupled with a slight hum. If music is playing, the noise is audible (especially for songs with vocals and less music) and sometimes vocals appear to be "distorted" by the hiss at some points.

It doesn't seem to be a grounding problem as the noise can be heard even when there are no sources (turntables, CD players etc) connected to the amp. The left channel is perfect and has no such problem.

I did some online research and there were people saying it could be due to leaking capacitors, and suggested running the amp with its power on for a few days to ameliorate the situation - how true is this?

I am a young hifi enthusiast, but with no electronics background....Really love this amp, and would be very grateful if any kind soul can advise on whether and how the amp can be salvaged. Tks!!
 

Welcome

Member
2013-03-11 10:52 am
Definitely not a capacitor problem. Sounds more like dying semiconductors to me. I'd start by opening her up and heating up/cooling down some TO-92 transistors. Particularly those in the input stage. If the noise changes, you've found your problem.

Does the noise go away when you press the line straight button?
 
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