led idea for a GC

[elizard]

Ok, I thought of this one a few days back. Not sure if its a good idea or not, but here it comes anyway.

Instead of taking the power from the rails for the led after rectification (taking dc), why not take before rectification (ac)? (right out of the transformer)??

Or would that introduce too much noise as well which wouldn't/couldn't be removed?

Now I know Peter will be the first to say "add additional windings to your transformer", but I'd rather not go that far.

Just an idea I had after not touching the GC for a LONG while (no money to do any other projects)

[moamps]

Originally posted by elizard

Instead of taking the power from the rails for the led after rectification (taking dc), why not take before rectification (ac)? (right out of the transformer)??
Or would that introduce too much noise as well which wouldn't/couldn't be removed?

Hi,

Many designers use LEDs in very sensitive segments of amps (current sources etc.). Try in your amp both version (AC and DC powering), but I don't think that overall noise will be higher in any version.

Regards

[elizard]

Originally posted by moamps
Hi,

Many designers use LEDs in very sensitive segments of amps (current sources etc.). Try in your amp both version (AC and DC powering), but I don't think that overall noise will be higher in any version.

Regards

I didn't think so, but there's a number of people who advocate otherwise. They say they removed their LED's from their amps (alephs, gainclones, etc), and they've noticed quite a difference in sound overall (sound becomes clearer). That's why I had this crazy idea.
I guess I'll try it when I get a case built.

Thanks man.

[Peter Daniel]

I wasn't the one

Didn't test LED effect yet.

[cowanrg]

what about a separate power supply running the led, and a relay to trigger it on/off with the amp ultimate isolation.

[elizard]

Originally posted by cowanrg
what about a separate power supply running the led, and a relay to trigger it on/off with the amp ultimate isolation.

Peter's idea (which he implemented) is to add a winding to the toroid .. just a few turns of wire.
I don't wanna rip apart my transformer to do that (the center potting compound), so that's not feasible
i could possibly add another transformer, but what if the primary transformer burns out or there's a problem w/ it .. amp doesn't work, but the led is on .

[Pedja]

Elizard,

I did added LED and plugged it to the rectified voltage of the GC – did not note the difference in sound, i.e. did not find a reason to make an “extensive tests” regarding this. As said, LEDs are often used as voltage references in critical applications (in voltage supplies or constant current sources) just because they are considered as relatively low noise generators. So, IMO you’ll not have a problem here, but if this anyhow worries you, plug it to the AC line (low voltage, of course), take one rectifying diode, one humbly cap, resistor and LED and that’s it, LED will be additionally isolated from the chip (and it won't blink at higher power which happens if you plug it to the rectified line with no more than 1000uF capacitance).

Pedja

[elizard]

Originally posted by Pedja
Elizard,

I did added LED and plugged it to the rectified voltage of the GC – did not note the difference in sound, i.e. did not find a reason to make an “extensive tests” regarding this. As said, LEDs are often used as voltage references in critical applications (in voltage supplies or constant current sources) just because they are considered as relatively low noise generators. So, IMO you’ll not have a problem here, but if this anyhow worries you, plug it to the AC line (low voltage, of course), take one rectifying diode, one humbly cap, resistor and LED and that’s it, LED will be additionally isolated from the chip (and it won't blink at higher power which happens if you plug it to the rectified line with no more than 1000uF capacitance).

Pedja

Thanks Pedja, and the rest.
What I'll do is first acquire a decent case to stuff everything in, then i'll install the LED's (not installed now).
Probably will install it on the AC side, but regardless, i don't think it'll make much of a difference. I guess you can't believe EVERYTHING you read on here, now can you?

[Peter Daniel]

Originally posted by elizard

I guess you can't believe EVERYTHING you read on here, now can you?

What I can't believe, is that you still didn't finish your GC

[cowanrg]

what im doing for my alephs is adding a second power supply that will run the lighting for the meter (see avatar). this will not run through an on/off, but rather it will be a kind of voltage sense (relay) from the amp. so when the amp turns on, it triggers the relay to turn on the lights. if the amp isnt getting power, the relay wont click on, and no lights...

you can find transformers for an led CHEAP if you have a good surplus place around. maybe a buck or two.