Asteroid Layout

[bnwitt]

Isn't the negative voltage to the bias pot taken from the negative side of the other 8uf cap?

You know what, it depends on what you are looking at. The schematic agrees with you but the power board layout doesn't. I have to defer to Allyn on this one. Allyn, which is correct?

[Allynmey]

Barry, the bias pot connection comes off of the other 8uF caps negative side (bottom of your drawing).

Allynmey

[bnwitt]

Thank you Allyn, I'll make the change. The way it is now, is from the note on the power board drawing. This a good process. I encourage everyone to keep looking for any other errors. I did use the schematic to vet this layout out but I missed that one. New version will be up shortly. Thank you russoloco for catching that error.

[bnwitt]

Version 9 is now uploaded with the bias connection changed.

[russoloco]

No problemo. Thanks for the layout.

[bnwitt]

You are mucho welcome.

[blargh]

I haven't visited this forum for a while but recently got the urge to build another amp, and I've always wanted to make a Komet... my apologies for being out of the loop, but what are the specs for the Komet trannies?

[rhinson]

also the nfb resistor should be 47k, not 4.7k. rh

[rhinson]

I haven't visited this forum for a while but recently got the urge to build another amp, and I've always wanted to make a Komet... my apologies for being out of the loop, but what are the specs for the Komet trannies?

for a power trannie, you want something along the lines of 365-0-365@ 250 - 300ma; 6.3vct @5 - 7a, and a 5v@3a rect winding. you can roll your own bias tap and adjust the values on the board, or you can also have a bias winding on there, say 70- 80v. output transformer is the same physical size as a 50watt marshall or a vox ac30, etc. i believe it was noted on the weber forum many moons ago that the pri. was like 5.8k---essentially a slightly larger express trannie with a different pri. imp. , more or less. there are plenty of options to try, all of which would give a slightly different tone. rh

[bnwitt]

also the nfb resistor should be 47k, not 4.7k. rh

The 4k7 came right off of the schematic but, from the photos of the amp I have it appears you're right. We'll get this thing right yet. Thanks rhinson.

[rhinson]

also the nfb resistor should be 47k, not 4.7k. rh

The 4k7 came right off of the schematic but, from the photos of the amp I have it appears you're right. We'll get this thing right yet. Thanks rhinson.

hey there, no prob. i really not much of a computer type guy, but i must say that whatever software you use to draw layouts like that with is really nice. i'm relagated to sloppy pen and paper. rh

[bnwitt]

hey there, no prob. i really not much of a computer type guy, but i must say that whatever software you use to draw layouts like that with is really nice. i'm relagated to sloppy pen and paper. rh

I use Microsoft Visio 2003. It is very easy to use.

[benoit]

Is there a schematic for the Ko.. er.. Asteroid somewhere that I missed? Is it floating around PM world somewhere?

[bnwitt]

Final change to layout. I noticed that I had the 120 leads and the common leads of the PT's primary reversed at the power switch. It wouldn't matter either way but I had to fix it cause I'm retentive.

[dobbhill]

I appreciate your retentive-ness. Thanks so much for your efforts.
D