What potentiometer to substitute with please?

[peteb2]

So i've all but completed a resto on an early 80s era basic well-loved stereo amp... Yamaha A-460. It's been a full recap, bulb indicators changed to LED, a full clean of the filthy PCB with every join desoldered and resoldered with fresh, new interconnects direct to the pcb, rebuilt power-supply with rear mount fuse and ever remounted the output transistors with better heatsink coupling.

So the last thing is the Volume. The pot is working fine without any induced scratching crash sounds of dirty wiper on track but it's mechanically really worn and rotates way too easily. A slight brush against the big alloy volume knob and the sound would go full volume.... all too easy.

So the pot is a 70k dual log and it seems unobtainable. Could i use a 50k or 100k dual ganged log? These appear to be the only values easily obtained where i live.

My concern is any possible Zload issue reflected back to the RIAA phono amp stage or to the tone control's input stage causing any marked change to the sound the owner might notice. Presently the amp is OK for a good 45Wrms output into 8ohms and is running fairly flat 20Hz to 20kHz response all tone controls at unity.

The project has received work classifiable as over kill but then it was an exercise in seeing just what kind of result is possible.

The schematics might help.... (appreciate your advice).

[james_s]

I don't know how well a sub will work but you could try, it might make little difference.

You might try cleaning the shaft and lubricating with some thick grease though, that may smooth it out and stop it from spinning so freely.

[amspire]

If you are worries by the impedance, use the 100K pots and put a 300K resistor across it. That makes it 75K.

I am sure it will be fine.