I bought a Yamaha CA-2010 integrated amplifier from 1977 with a balance control which doesn't work. Opening the device, the problem is immediately apparent: a technician has disabled balance control. See picture.
Why would such a thing be necessary? I am asking here before I restore it to stock condition.
Why would such a thing be necessary? I am asking here before I restore it to stock condition.
Attachments
First thought is that the balance control has become faulty (actually a common issue) and that obtaining a replacement of the correct type wasn't possible. I think some of these balance pots are a dual gang log/anti log type. So not a common stock part.
The balance pot is a variable resistor from the signal path to ground,
it is made to reduce the higher audio signal level when the input level is not equal.
Some people have very good well balanced high quality attenuation pot so they don't need the balance pot to get in the signal path.
We seldom or never use the balance pot when the audio signal is well balanced.
Less component, more high fidelity.
Some amps even don't have "balance" installed.
it is made to reduce the higher audio signal level when the input level is not equal.
Some people have very good well balanced high quality attenuation pot so they don't need the balance pot to get in the signal path.
We seldom or never use the balance pot when the audio signal is well balanced.
Less component, more high fidelity.
Some amps even don't have "balance" installed.
This is a genuine balance control (half of the rotation is just a shorting contact, for each side)
and not just a dual pot, so all that the jumpers do is bridge a contact when the control is centered.
If the control is noisy after removing the jumpers, try DeoxiT spray cleaner before replacing the control.
https://www.amazon.com/Hosa-D5S-6-D...ocphy=9018935&hvtargid=pla-382003658380&psc=1
and not just a dual pot, so all that the jumpers do is bridge a contact when the control is centered.
If the control is noisy after removing the jumpers, try DeoxiT spray cleaner before replacing the control.
https://www.amazon.com/Hosa-D5S-6-D...ocphy=9018935&hvtargid=pla-382003658380&psc=1
Last edited:
Blance/volume pot is an integrated unit in the CA-2010. Mine failed, I was able to strip it down, clean, still didn't work, needed to insert a shim to improve wiper contact. Some people are not so lucky. Most people run with balance centered so don't "need" that feature...
Attachments
Last edited:
Indeed, the technician had unsoldered and resoldered the pot onto the board. Sometime in the past, the pot must have developed a fault. The jumpers were put in to solve a problem of some sort. I think I'll leave them as they are.
I did the same thing in 1982 when my 2 yr old Fisher SS amp had a faulty balance control. They were a poorly made item and I didn't need it in the circuit, so I just bypassed it. I bet the one in your amp is the same. Don't need it? Leave the bypass as is.
Very common problem with the Kenwood C-2 preamp, just a cheap little control. Bypass is the usual fix.
Craig
Craig
The Kenwood control a cheap part, I don't know what's in the Yamaha. There are nice Alps and not so nice Alps.
Craig
Craig
Well.. I own several DJ consoles & mixers and they don't have a balance pot. My Sony mini system doesn't have it either and on my 40 year old Pioneer amp the pot has been sitting at midway position. Perhaps it isn't indeed needed....
mbz already mentioned it, it's very hard to get a replacement of the potentiometer unit, I've seen one sold for more than for the whole amplifier.
Besides the obvious reasons of faulty pots, there are other reasons. The amplifiers coaxial balance wheel behind the volume knob isn't available anymore. The switch tips and potentiometer knobs were used on other models of the series and even for later models but the coax ring dial was only used by the models CA 710 - 2010 and are much more rare than you'd think. That means, the only way to get a replacement would be to get it from another amp or to build one yourself. So if your amp is missing that wheel then that's very likely the reason, to save a bundle.
Nope. I think they're there to solve a problem, and will just let them be.
It's curious because the amp, though old, looks mint on the outside. Very little dust inside too. To have a high quality Alps pot fail so early on a top-of-the-line device is strange.
You call 44 years early? May I remind you that this is not a single or stereo potentiometer but a 6x pot? If you multiply the rate of failure that's an extraordinaire long life! These amps usually get faulty at the Mercury relay, the often used switches or contact problems of the connectors of the wiring or the wires itself.
Well, early as in low operating hours. This amp hasn't been used much.
I think one of the "channels" of this multi-channel pot may be beyond repair, so the channel for the balance was used instead, since it was judged to be the least essential.
I think one of the "channels" of this multi-channel pot may be beyond repair, so the channel for the balance was used instead, since it was judged to be the least essential.
That doesn't work because the balance potentiometers are linear instead of logarithmic for the others.
Old thread revived, but just bought a ca. 1973 Kenwood KA-8004, and balance control is not operating. Upon inspection, leads have been snipped. I will measure the resistance of the pots, but perhaps indeed it had failed and wasn't worth fixing. It does look cheap, but all 70's pots looked cheap... Cheers!
--Christian
Absolutely correct. Had a Sansui years and years ago and that is a fact. Could never have figured what I can use this silly control for when eventually it was broken up for the parts bin. What Mooley say is probably the case, the fixer could not find afford the part, it was specifically made and very rare to find a spare in a shop.