Better SQ after warm up?

[jjasniew]

I think my LM1875T based amp sounds better after warm up for an hour or so.

- Anyone else have such an experience?
- Is it OK to leave these chips powered on continuously so it's ready to go when I have time for listening?

Perhaps change the power switch to just kill the tube input buffers (filament and B+), leave the +/- supply to the '1875 on continuously?

Has anyone ever used a resistive heating element to maintain thermal equilibrium when their amp is "off"? (Elaborate power switch that cuts filament and B+ to tubes, switches +/- power from '1875 amps to resistor in "off" position) I have a 4PST switch I've been saving for something for years...

Thanks,

 

[Mark Tillotson]

The only way to know for sure would be double-blind testing with two amps, identical except for when they are switched on.


In reality thermal equilibrium should be established quicker than 1 hour, more like 10 to 20 minutes, so its very easily attributable to human factors, such as your ears and brain warming up!

 

[benb]

Actually I would think the "tube input buffers" would change the sound more than the chipamp after an hour warmup, but then I agree with Mark, a DBT would be the only way to know for sure.

I've not heard of using a heating element like this, but yes, it could be done. It would be easier and no problem to just leave the amp on all the time. It would cost a little more on your electric bill.

 

[res07njc]

A hot amp always sounds better than a cold amp

 

[Panelhead]

I liked the sound of my LM3886 amp better with higher rail voltage. It did warm up more. Changed the power transformer to get back to +/-34 volts, was 38 - 39.

 

[jjasniew]

Thanks, guys. Back in the day, they used to say the large Phase Linear (400) transistor amps would sound better as the circuits warmed temperature wise. I was just wondering if I was hearing a similar effect in this tiny SS output amp - and if anyone else noted a similar effect in theirs!