What counts as channel balance in vintage gear?

[Natertots]

Is it reasonable for a vintage receiver to have equal volume through each speaker without adjusting the balance controls?


I was listening to the receiver and the left channel sounded quieter. Not trusting my ears, I checked the VU meters and they indicated that with the balance knob centered, the left channel was putting out less power. I verified that by playing a test tone and using a DB meter on my phone. While this is not a great test, the right side was playing 8-9dB louder at 3’ away.

After getting it back, it has the same problem. When the balance knob is centered, one channel plays louder than the other.

The receipts reads:

Symptoms: 1 ch weak
Service Performed: Cleaned all controls, switches and relay controls. Adjusted bias. Aligned tuner. Checked capacitors and entire operation - All OK
​

So, should I take it back and tell the shop it still has the same problem or should I expect to need to use the balance knob to adjust the output on vintage gear?

 

[AudioGMan]

Yes both channels should sound the same with the balance knob centered. What model receiver? What source did you use? Did you try a mono input into each channel?

 

[Natertots]

Realistic 2000D

Source was my laptop headphone out running Spotify.

I did not try a mono source. I also did not try swapping the left/right inputs, a different source, or checking if the B inputs behave the same. I ran the test real quick while my daughter was getting ready for bed. I will have to wait until tomorrow to do more testing.

 

[rothwellaudio]

Is it reasonable for a vintage receiver to have equal volume through each speaker without adjusting the balance controls?

Yes.

So, should I take it back and tell the shop it still has the same problem?

Yes.

 

[lini]

So, should I take it back and tell the shop it still has the same problem (...)

I'd suggest to first perform two checks:

1.) Swap the speakers cables at the terminals of the receiver, i.e. left <-> right. If it really is the receiver, that has a problem, the other speaker should sound weaker after the swap. Does it? If not, one of the speakers might have a problem instead, or you might have a pretty asymmetrical placement situation, like one speaker in a room corner, the other standing free.

2.) And if you've got headphones at hand, it would make sense to additionally check, whether the problem is also present on the headphone output - 'cause if it wouldn't be present there, that would leave much less to check for the technician, as the headphone output is also fed by the power-amp section (according to the schematic with a 1 kOhm resistor in series (per channel) to reduce the output level).

Greetings from Munich!

Manfred / lini

 

[gadget73]

Does the balance shift side to side as you increase the volume, or is it always down by about the same amount on one side? Shifting balance is often a sign of a bum volume control, the carbon tracks drift differently and it screws things up. If its consistently low, thats something else. I could take guesses but unless you're going to open it up and poke around yourself there isn't a lot of point.

but yes I would expect the balance to be pretty darn close side to side. If you really measure carefully many things are going to be ever so slightly off side to side, but its such a tiny difference that it wouldn't be audible. If its bad enough to notice it needs to be fixed. Measured at 9db is quite significant.

and +1 on confirming it isn't the speakers or the source first.

 

[JohnT123]

I'd also want to be sure the signal fed to the amp is balanced. IF the laptop is sending unbalanced signal to the amp you'll get an unbalanced output.

 

[Natertots]

Does the balance shift side to side as you increase the volume, or is it always down by about the same amount on one side? Shifting balance is often a sign of a bum volume control, the carbon tracks drift differently and it screws things up.

The difference appears to be consistent but I will do some more checking to be sure.

I'd suggest to first perform two checks:

1.) Swap the speakers cables at the terminals of the receiver, i.e. left <-> right. If it really is the receiver, that has a problem, the other speaker should sound weaker after the swap.

2.) And if you've got headphones at hand, it would make sense to additionally check, whether the problem is also present on the headphone output - '

I don’t think it is the speakers themselves (Klipsch Cornwall’s) as I haven’t noticed an issue in the past. However, that is a quick and easy check and I will make sure to do it before drawing final conclusions.

I will also dig out a 1/4” adapter and see if I can hear a difference using earbuds.