Krell KSA 50 PCB

input stage current consumption...

...is quite low, though it depends where you decide the input stage ends...

If you include the drivers, you could have to source about 1/100-1/20 of whatever output current you 'plan' on using, i.e. if you want greater than 20A out you'd probably want to make sure you have at least one amp for the drivers, more like two if you like to overbuild things.

Excluding the drivers, I think the total current consumption is probably 20-50ma, 100ma to be safe...

HTH

Stuart
 
Hi Gewa,
the volt amp board alone draws lo current, lets say 15mA.
that equates to 1.1W. You could use a 3W PSU for this and technically that would be correct, but I think you would obtain better performance by using something between 50VA and 100VA.
The drivers can draw very large current (upto 500mA or worse into a short circuit) when the output stage feeds a low impedance load.
In this situation I would use a low power regulated feed to the voltage amp board and a medium current supply (possibly fused?) to the drivers from the same low power transformer. Then a separate high power supply to the output transistors.
 
On one of my 3 amps I'm building I am planning on trying Zang's regulator boards on the front end.

I have both Zangs brds and the Krell clones so implimenting them will be easy once I get the rest of the issues in line.. Chassis, components to stuff the PCB's and time.

Edit:

Do a user search for digi01 and you will find his regulator GB. Really nice compact brds.

Edit 2:

Found it for you:

http://www.diyaudio.com/forums/showthread.php?s=&threadid=39816
 
Hmm, I also have those ;)

Regards
 

Attachments

  • digiregbrdm.jpg
    digiregbrdm.jpg
    63.3 KB · Views: 607
Mouser parts arrived.

Digi-Key and Welbourne have not as of this morning. I am hoping by tomorrow so we can kit and ship next week.


Now is the time to suggest an easy, repeatable method for testing the transistors.

I have 2 Fluke 87's and common sense. The test procedure needs to require no more than that! :clown:

Edit:

Oh, and picked up my heat sinks yesterday. I will try to photograph and post some time this weekend. 12 peices (4 per chassis) all bead blasted and anodized black. 8 x 8 inch squares of this mounted side by side (fins vertical):

http://www.mmmetals.com/extrusions/drawings/mm10332.jpg

# MM10332

http://www.mmmetals.com/pages/extru...back_heatsink_aluminum_extrusion_4_and_up.htm
 
Others may be able to tell you if I messed up or not.

Should work just perfect! I am using 2 watt 25 ohm .5% tolerance current sense resistors that I got surplus and they also work fine. I thnk 2 watt in this position is plenty for a stock unit. If you run at hogher than about 40 volts then higher wattage would be necessary.

Troy,

Will that be enough sinking? I am using about the same number of square inches of sinking with a much denser number of fins and they run hotter than blue blazes.... thats why I settled on an air tunnel arrangment.

Mark
 
diyAudio Member
Joined 2004
Audiophilenoob said:


preamplifier is .... you will laugh.... a very high end sound card the Audiotrak Maya 1010...

That's a bit misleading ;)

What you have there is an entry level pro audio card.

High end would be a Lynx Two and very highend would be something like ProTools HD. :)

Manufacturer SNR number means nothing BTW thats fact. Clocking and jitter is the most important IMO.
 
ShinOBIWAN said:


That's a bit misleading ;)

What you have there is an entry level pro audio card.

High end would be a Lynx Two and very highend would be something like ProTools HD. :)

Manufacturer SNR number means nothing BTW thats fact. Clocking and jitter is the most important IMO.


/hehehehe my mistake shin ;)

we obviously differ on what high end components are :D

to me anything above a Soundblaster live is a "nice" sound card... something like the audiotrak I have is feature rich and amazing SQ...

very high-end would be the protools I suppose... whenever I get a couple thousand I'll look into it :p