TEAC BX-500 vintage stereo amplifier - imbalance sound

[Desmond82]

Hi,

I have a TEAC BX-500 stereo amplifier about 35 years old passed down from my relatives. Its still working good, its sound quality are crisp and clear. However, I observed that the right speaker tend to have slightly softer audio output than the left and causes imbalance. Balance knob was inspected and it was position in the middle. However, by observing the left & right power meters on the amplifier itself, it seems that the power output/dB on the right speaker seems to be lower.

I need some guidance pertaining to this problem, is it normal or does the amplifier have some defects due to component aging? I tried to open up the chassis and inspect the electronics components, I found 4 potentiometers on the circuits. Am wondering whether does this 4 pots related to the power gain of the amplifier. I do not dare to do anything as I do not have the schematic for this machine.

Please advise. Thank you.

 

[highfigh]

Hi,

I have a TEAC BX-500 stereo amplifier about 35 years old passed down from my relatives. Its still working good, its sound quality are crisp and clear. However, I observed that the right speaker tend to have slightly softer audio output than the left and causes imbalance. Balance knob was inspected and it was position in the middle. However, by observing the left & right power meters on the amplifier itself, it seems that the power output/dB on the right speaker seems to be lower.

I need some guidance pertaining to this problem, is it normal or does the amplifier have some defects due to component aging? I tried to open up the chassis and inspect the electronics components, I found 4 potentiometers on the circuits. Am wondering whether does this 4 pots related to the power gain of the amplifier. I do not dare to do anything as I do not have the schematic for this machine.

Please advise. Thank you.

All sources, or just one?

Just a reminder- never change connections with the amplifier power switch in the ON position.

If you only use one source (like a CD or DVD player for music, reverse the cables so the right channel connects to the left channel and left is in the right. If the problem remains the same, do the same with the speaker wires. If the problem moves to the left channel after swapping the audio or speaker cables, use different cables. If the problem remains in the right channel, clean the controls and switches but DO NOT change anything on those four potentiometers. I

 

[Desmond82]

All sources, or just one?

Just a reminder- never change connections with the amplifier power switch in the ON position.

If you only use one source (like a CD or DVD player for music, reverse the cables so the right channel connects to the left channel and left is in the right. If the problem remains the same, do the same with the speaker wires. If the problem moves to the left channel after swapping the audio or speaker cables, use different cables. If the problem remains in the right channel, clean the controls and switches but DO NOT change anything on those four potentiometers. I

I only connect to one CD player which is on the TAPE 1 PLAY. Do you mean that if I swap the cables and problem transfer to the left, it might be suspect either cable problem or selected output problem?

Additionally, how do we clean the control and switches? What cleaning agent do we need to use?

 

[highfigh]

I only connect to one CD player which is on the TAPE 1 PLAY. Do you mean that if I swap the cables and problem transfer to the left, it might be suspect either cable problem or selected output problem?

Additionally, how do we clean the control and switches? What cleaning agent do we need to use?

If you reverse the left and right cable positions in the Teac, the problem will move with the cables if:

The problem originates in the CD player,
The problem originates in the cables.

If you reverse the cables and nothing changes, the problem could be in the Teac, the speaker or the right speaker wire/terminal.

Try connecting it to an Aux or any input that's not for a turntable.

 

[Desmond82]

Alright, I will set it off by reversing the cable first. Come to think of it, currently my setup is connected none of any 'source selector' which consist of phono-mm, phono-mc, tuner & Aux. I am connecting to 'Tape 1' under Tape copy selection instead. Am wondering is it the wrong input connnection. Why am
I connected to tape is because I have such thinking where the CD player has been replaced by the obsolete tape player source. So all the while it has been connected to it and this problem arises.

 

[highfigh]

Alright, I will set it off by reversing the cable first. Come to think of it, currently my setup is connected none of any 'source selector' which consist of phono-mm, phono-mc, tuner & Aux. I am connecting to 'Tape 1' under Tape copy selection instead. Am wondering is it the wrong input connnection. Why am
I connected to tape is because I have such thinking where the CD player has been replaced by the obsolete tape player source. So all the while it has been connected to it and this problem arises.

Any of the inputs for Tuner, Tape, Aux, CD, EXT Adapter or anything like them will work for this application but you need to avoid using the Phono inputs because they're equalized for LPs and in the case of MC Phono, that section adds another stage of gain, so it will sound really bad.

Just occurred to me- make sure the cables are connected to Tape, not Rec. You shouldn't need to use the Tape Copy switch at all.

 

[Desmond82]

Alright. Thanks for your advise. Will try it out these method.