Nakamichi SR-4A - left channel out

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viggen

Nakamichi SR-4A - left channel out
« on: 3 Feb 2014, 02:15 am »
For all I know, this is the great grand daddy of all Nak receivers.

My very first receiver I bought when I was like 12 years old was a Nakamichi TA-1A.  I loved that receiver, and it stayed with me for about a decade until the amp section died because of user error.  I always wondered what the higher end Nak amps could do.  I eventually ended up with a pair of CA-7A and PA-5A II.  I wasn't exactly in love with the amps and turned it over quickly.  Many years later, I bought a SR-4A.  I had read that the older Nak's use of Stasis technology was more "true", and I did read that the second version of the separates are not as good as the first.  So, had to try out some of their old technology, hence, I ended up with the SR-4A.

I bought it via ebay for about $200 if I recall correctly.  It arrived with the source buttons loose.  The volume and balance control was a bit noisy.  The volume control is motorized for remote controlling, but the motor is very loud.  Forgot the reason, but the receiver ended up in my garage for a few years probably because I've been favoring my 1 wpc SET flea amp during this time.

Well, I set up a bedroom system last week, and I've been experimenting with different equipment to try to make it sound good.  I bought a "new" pair of Altec Lansing 601C drivers in custom cabs.  I thought the SET amp would be perfect.  It did sound good but not very good.  It still lacked something.  Tried different preamps and sources and things did improve here and there but not dramatically. 

Then, I took the amp I am using in the living room which is a nuforce DDA100 to use in bedroom with the Altecs.  The sound is great.  More there there.  I can live with this.  DDA100 is already very good with the Linn Kan MK1 in the living room.  So, thought this digital dac-amp is doing good things with speakers from yesteryear. 

After I am settled with the DDA100 in the bedroom, I moved on to experiment with my headphone system.  I thought to try to use the SR-4A as a headphone amp.  I plugged the amp in then plugged the headphones in, and I get no sound out of the left headphone speaker.  I unplug the headphone but, with the TRS half way plugged in, I get sound coming out of the left, but not the right.  Fiddled around a bit checking my inputs so forth but couldn't solve the issue. 

Sorta frustrated, then I decided to give the Nak a go with the "new" Altecs.  Hooked up the speakers and DAC into CD input, turned the amp on, and I hear utterly heart wrenching beautiful music out of ONLY the right channel.  Even with the left channel out, the Altec is sounding great with the Nak perhaps even better than the DDA100 powering them.

So, I got a small menu list of repairs to do with the Nak.  Noisy nobs and volume motor, bad headphone jack connection, and left speaker channel not working.  As for the input buttons that fell out, I glued them back using rubber cement. 

Would you recommend fixing the amp or buying another one from fleabay?  And, is there a recommended tech in so cal for fixing Naks?  I think their US HQ used to be in Irvine which is where I am at....

PRELUDE

Re: Nakamichi SR-4A - left channel out
« Reply #1 on: 3 Feb 2014, 03:12 am »
For anything Nakamichi this is the first place you want to contact. He was the original Nakamichi repair man.

  http://www.classicaudio.com/index.html

Good luck :thumb:

viggen

Re: Nakamichi SR-4A - left channel out
« Reply #2 on: 3 Feb 2014, 07:08 pm »
For anything Nakamichi this is the first place you want to contact. He was the original Nakamichi repair man.

  http://www.classicaudio.com/index.html

Good luck :thumb:

Thanks!  I contacted/messaged the site owner just now.

mtroxel

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Re: Nakamichi SR-4A - left channel out
« Reply #3 on: 29 May 2015, 01:32 am »
For any Googlers, I've been fighting one or other channel dropping in and out for 3 years now - especially at very low volumes (I run my flat panel TV sound through the Nak).   After cleaning every pot I can find and the little slide switches controlled by the input knobs, I've finally got it.  It's the old JR2A-DC24V relays for the A and B speaker outputs.  You can find them online, it's not easy.  But you can also just desolder them, work the little plastic cover off, and bend the contacts back so they are closer.  I thought they'd be dirty.  They were very clean.  But over years of use they've just become a bit too far away and barely make contact. 

Bent mine closer to each other, put the plastic cover back on and resoldered to the board.