[CButterworth]

Having completed the AKSA 55 (non-Nirvana), I am amazed at how poor my old HiFi amp was - well it was a cheap WalMart sold Sony music system.

I have not installed any LEDs into the amp yet.  I was going to install two of them - one for left and one for right.  I bought two blue LEDs.  However, my wife thinks that two LEDs would look weird and I am reluctantly inclined to agree with her.

My question, is that if I connect a single LED to, say, the left power supply, will the 2mA draw (maybe I'll drop it to 1mA) cause a sufficient drain to create an imbalance between the L and R power supplies?  

My guess is that 1 or 2 mA 2V pull from a power supply is not going to be a problem, but please let me know.

Thank-you,
Charlie

[andyr]

Charlie,

There have been posts on this before so maybe you need to go back through the pages and find em ... the purposes of the LEDs and associated resistors) is:
a)  to give you a visual indication that all is well in the power department, and
b)  to bleed off charge from the PS caps, when you turn off the AKSA.  If you don't have these, then the PS caps always stay a bit charged.

As the PS is +XV/-XV, you need 2 LEDs per channel ... so you'll have to buy 2 more!

Regards,

Andy

[stvnharr]

Looks area in the eye of the beholder.   I found that 2 blue leds close together look fairly good.   And it is a good indicator of power to that channel.   I wouldn't think one led would make for any imbalance, but others make know more.

[CButterworth]

How important is it to fully discharge the power supply caps?

It is certainly no difficulty to wire four LEDs, in fact I'll buy the cheaper coloured ones and wire them inside the amp chassis so they will not be seen.

The only reason why I wanted to have an LED is to provide an indication that the amp is switched on.

Charlie

[CButterworth]

OK,

I want to set the LED to 0.5mA this means using a 68K resistor.  Ihave enough of these and they are rated at 1W.

So, according to a previous post on bleeder resistors, it seems that I could wire a single LED to the positive of one of the power supplies.  To the negative rail, I would wire a 68K bleeder resistor and then to the power rails of the other power supply, I'd also wire a 68K resistor.

Does this sound OK?
Charlie

[AKSA]

Charlie,

No problem with one, two, four or n! LEDs, where n is a number in excess of 2 but not larger than four.  This gives reasonable scope.....

Take care with blue LEDs.  They look great, but over time, particularly as you lie back in your favorite chair late at night listening to and watching fondly your wondrous creation, they will bore a hole in your head.....

Some of the BLEDs are extremely efficient.  I have a couple which require only 0.15mA;  any more, and they look as bright as meltdown indicators on the reactor of a nuclear sub.

You don't really need bleeder resistors on the storage caps because voltages are very low and the amp will continue to draw quiescent current almost to zero voltage.  However, if you want to fit them, no problem, I'd suggest 2 x 10K half watt for each supply.

Cheers,

Hugh

[Malcolm Fear]

I didn't put leds on my AKSA 55 for a very long time. My intelligence told me if music is coming out of both channels, everything is OK.

I must have lost some intelligence along the way (one too many chardonnays). I now have one led on the front in the middle. I use red, tamed down. I don't want to sit and listen to music, watching red lights.

[Jens]

I use four yellow LEDs, tamed down to give off an orangey, tube-like glow (Hugh will like this   ).

What's more - only two of the LEDs are on the front panel. The other two are fitted inside the amp, and can be seen giving off their glow through the perforated top of the enclosure.

I thought that using four LEDs would be best - one for each rail of each channel.  

Cheers,

[CButterworth]

Well,  here is what I ended up doing.  Following Hugh's advice, I decided that I really did not need to add LED's or bleeder resistors to all power supply points. So, I went with a single clear blue LED set at 0.5mA.  It looks great, and is not too piercing - in fact the music seems to sound all the better for the addition of the LED or is it my imagination javascript:emoticon(':lol:')

While I had the chassis open, I took the time to wire the chassis to mains earth.  Hmmmmm......yes the amp did!  For some reason this did cause a hum.  So, I wired the star earth to mains earth via the chassis bolt and the amp run very quiet, except for the music which sounds good.

I'll give it a month or so before I install the Nirvana upgrade.

Regards,
Charlie