Anyone know the Yamaha CA2000 Amp?


I just bought a vintage Yamaha CA2000 amp and am very impressed with it (got some NS100m speakers with it which are very tight if lacking in the very low frequencies.)

Two questions. When I change the switch from "Normal" to "Class A" the sound starts to break up. This is probably a fault but is it worth fixing? What would I get if the class A was working? At the back there is a "DC"/"Normal" switch which seems to make no difference when I change it. What is it for?

Any suggestions for a small subwoofer for the NS100M speakers? I don't want to lose the lovely precise sound but I do miss the fuller lows of my old bass reflex speakers.

Thanks a bunch! Derek
Your post is somewhat vague, however I'll take a shot.

I believe you are referring to the CA-2010 integrated amp, if I am correct, then you'll find this link useful:


Paul :-)
Thanks Paul! Mine is a CA2000 (Japanese domestic model) and it looks just the same as the 2010. The manual answered my questions except whether I will hear the difference between class A mode and normal.

The same shop has some NS500 and NS451 speakers very cheap. Both are bass reflex so I might get one of them to use and speaker stands for the NS100Ms. This should be better than a subwoofer. cheers, derek
I have a CA-1000 which I'm looking at as I type. I bought this new in 1976 and listened to it until a few years ago when I got a new set-up. Yup, I still have the original box and manual. Only thing it needs is to go through it and clean the pots and switches, kinda noisy. Purchased a pair of NS500's, which are bass reflex, at the same time. Still have those too but the foam speaker surounds surrendered.

The class A switch gave me a more refined sound but if I remember correctly the manual warns not to listen at high levels or for long periods of time in class A mode because of heat build-up. Not sure what you mean by sound breaking up. Could it be a dirty pot or switch or is it directly linked to going to class A mode? Mine doesn't have a DC/Normal switch so I'm not sure what this is for.
The problem is when I switch it to Class A the sound slowly starts breaking up until it is just a weak, crackling noise.

From that manual I gathered that the DC switch is to allow you to bypass the DC speaker protection if you are using the power amp directly (without the preamp.)

Sounds like the class A difference may be almost inaudible to most people.
I don't know the amp but I do know the symptoms, on rare occaisions it can be caused by a dirty volume pot, but due to the nature of it only occuring in class A, I would suspect due to the high bias current/voltage, MOS/Tran that the coupling caps if they are there are going, or the main power supply caps could sag and cause the same problem.

I can't speak to the amp and tell you to repair it or dump it.

Thanks a bunch Loon, I'll try to get it looked at as it may be worth having the class A working. cheers, derek