Started restoration on my CA-810 !

Great, thanks! The transformer of my CA-810 is also humming loudly. I will try this!

About the LED's: I have exact the same problems with diffuse LED's in my B-2 and CA-810. Running respectively on 15 mA and 20 mA. They start to fade slowly and are completely dull after a month's use. I went back to the seller and he said that while you limit the nominal current, the peak currents in 'vintage audio gear' can be much higher. These peak currents would only be visual with a scope. So he said. Apparently these LED's can't handle those peak currents and will die. I'm not sure about his story.

I use LED's from led1.de for years in my gear (sometimes even at 25 mA) and they never fade, even after years of use.

So I think there might be differences in quality ;)
Is the hum coming through to the speakers or does it hum with out the speakers connected?I'm getting a hum through my speakers and I've been trying to get rid of it with no luck yet.
 
Hello everyone.

I'm in the process of restoring a CA 810. I am going by the schematics, and I have couple questions.

First is that I noticed capacitor C813 value on the soldered cap on the board was a 33uf, but I read on the schematics 3.3uf. I placed the 3.3uf and it sounds nice as long as the main in is fed directly by a DAC or a phono preamp (no using the ca 810 preamp) However!, using the yamaha integrated preamp I am having trouble with the highs. They do not sound detailed at all. It sounds cheap, at lack of better words. Also, there is something going on causing ear fatigue after 1 hour of listening. It's somewhat sad to have the CA 810 being used as a stereo amp...

So I have two questions. Capacitor C 813, is it 3.3uf or 33uf?? How this cap affects sound? I used elnas on the tone board... Should I try different caps? What should I be looking for?

I doubt this is the signature sound of this amplifier. Cymbals and air instruments does not sound like metal at all. Electric guitars are somewhat painful on the highs.

Any advise might help.
 
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So I have two questions. Capacitor C 813, is it 3.3uf or 33uf??
Probably a typo in the schematic. There are alot of them..Always go with what is installed. Unless your absolutely sure someone else has replaced the OEM cap.
 
And after a long period of time, I think would be good to keep it maybe all together? If not I would create a new thread. The Yamaha CA-810 is still in great shape. Nonetheless, I plugged in some more efficient speakers and they do reveal a hissing noise through the speakers. It's a 3 way and the noise is most distinct in the mid and tweeter.

Now, for what I have read I wonder if this might be related to the resistors as I did not change any of them. I was looking at the schematics and I would be clueless as to what resistors might be involved in this issue; that if it is the case that is old resistors the issue I am facing. Note that I tried using an external pre, and even like this I still get the hissing sound, so nothing to do with the pre-amp section I believe?

.
 
Hi Bastian,
Some hiss is to be expected from an amp this age. How sensitive are the speakers you are using?
Usually the hiss comes from transistors, not from resistors or capacitors.

Oh well, that's bad news because I do not believe anything can be done regarding those Transistors. Am I right?

I have not used the unit for about 2 months, busy with some other things. Now, after checking up today results are: with an 88 dB pair of speakers is fairly faint for a living room area, but annoying if on a desk environment. When everything is quiet, even if one drops volume to 0 you can hear the buzz under 1mt away. If one increases volume past 70% you get more of a tape hisssss. But I have a pair of stated 99dB (feels more like 96dB though). On them, the electrical Buzz is just blatantly sparkling the whole time - Too annoying.

I am concerned about these noises causing listening fatigue... Any suggestions at this point?

Thanks for your attention beforehand Bert.
 
A hiss at 70% volume is normal. Imagine how loud your music would be at that level. Crazy loud, enough to blow amp, speakers and ears.
Now, a buzz is something completely different, and the first thing to look at is a ground problem.
Is the buzz present with nothing connected but amp and speakers ?
 
I apologize for the long time it took me to get back to both of you guys. I have been busy and it took me a bit to look into these things. -



As per this, I followed previous recommendations. I verified and yes, the cap has the same values as the one I removed.

A hiss at 70% volume is normal ...
Now, a buzz is something completely different, and the first thing to look at is a ground problem..

Yes, the buzz was a consistent thing. I checked onto the grounding and sanded off a piece of paint, grounded again the Pre-amp board and Voilá! the buzz was gone. As per the Hizz, when I have them plugged into an 87 dB pair of speakers it's no problem. It's just a tiny bit notorious when listening to VERY quiet-dynamic classical pieces (cranking it up to 65%). Else, it's all great (when I first got it the hiss was very prominent, but not any more) - But using a 99dB pair of speakers and the hiss is just there at 35% / so I'd steer away from high sensitivity speakers on this one.

I might just be accustomed to the silent amps sitting around. Regardless, if this is normal on these units, it's ok. So I can safely say, the thing is working like a charm now. It sounds sweet. Now I really like those relaxed smooth highs. Very enjoyable amp. I've been using it with a pair of PSB Targa for a week now, love it.

Thanks so much for keeping the great community up. You guys rock!
 
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