STK4141 on batteries

[Zoodle]

I have a STK4141-II based receiver that I've been tweaking. It's now a power-amp only. Thanks to advice from this forum (thanks!), I recently uprated the smoothing caps (tripled). Wow!

The amp seems to run from 26-0-26 (the app note for the chip recommends up to 32v). I can get old 12v Lead Acid batts for free. So, I was thinking about four batts in two banks: '+'24V--0--'-'24V.

Then I read about offset problems that might occur if the battery banks are not equally charged, or if one bank depletes more rapidly than the other.

Can anyone comment on this?

[Mooly]

Safety first ! If using lead acid batteries ensure they are fused at the terminals. Never underestimate the amount of current that can flow.
Any normal DC coupled configuration of opamp (the STK's are really just power opamps) is unaffected by unequal rails. The output zero point is determined by the ground referenced inputs and internal offset imbalances... nothing to do with the rails.

[sakis]

that this will work from batery ....really what is the point ???

[analog_sa]

Originally posted by sakis
that this will work from batery ....really what is the point ???

Quite obviously to experiment with "battery" sound. Did you expect it to be for a portable disco?

[analog_sa]

Originally posted by Zoodle
I can get old 12v Lead Acid batts for free.

Not sure if you can draw any conclusions based on old batteries. Quite often they don't sound nearly as good as new ones.

[sakis]

on a decent amplifier ...presuming that power supply is as clean as possible this will have some effect on sound

but in an stk amplifier is there a point realy ???? i would bother to play with a better amplifier but nothing like that

[Zoodle]

Mooly,
Thanks. Yes, fuses at the batt end! Good reminder.

Analog_sa,
I'd read that different batteries have different noise levels, so it makes sense that old will sound different to new. Fortunately, I have a good choice of batts, some better than others.

Sakis,
You might be right, but the STK (which I found on the street) is the best I can afford at the moment. Besides, I enjoy turning 'junk' into something useful.

[sakis]

Originally posted by Zoodle
Mooly,
Thanks. Yes, fuses at the batt end! Good reminder.

Analog_sa,
I'd read that different batteries have different noise levels, so it makes sense that old will sound different to new. Fortunately, I have a good choice of batts, some better than others.

Sakis,
You might be right, but the STK (which I found on the street) is the best I can afford at the moment. Besides, I enjoy turning 'junk' into something useful.

..... hmmm yes you must be right stk is junk !!! but then the good thing is that you might get something out of it by learning the benefits of the batery issue or by simpli working arround in this circuit ....

carry on .... let us know about ""before and after"""

keep an eye on the "dynamics" play demanding things to be able to see the diference

try to notice the briliance of the high

let us know

[analog_sa]

Originally posted by sakis

but in an stk amplifier is there a point realy

You are probably right, the STKs i've heard did not sound too good. There is at least one diyaudio member who really liked some of the STKs though and he seemed to know what he was talking about
http://www.diyaudio.com/forums/showt...9669#post29669

[Zoodle]

I contacted the author of the post mentioned above: he seems to think that an imbalance between the '+' and '-' battery banks will cause trouble with this chip. So, that's one opinion 'for' and one opinion 'against.'

Anyone else have experience using a twin rail chip with a battery supply?