15w valve amp.

[moda]

http://www.valveheaven.com/diy-amp-designs/diy-amp/


This is what im building.

[Ciaran Haslett]

Looking forward to it Moda.

I don't see any harm in at least posting links to his website.  That way we can quickly access any info we may need AND he gets some extra traffic to his site.

And I see what you mean about unorthodox lol!  3 transformers just to power the thing!  Good way to keep the cost down I suppose.

Keep us posted on your progress.

EDIT...and maybe move this to Open Chat rather than verified amp layouts

[moda]

Good point Ciaran.
If any of the admin can move this thread it would be appreciated.

[moda]

Ok. So i have started this and photos will come soon.
The original design called for most of the components to be soldered on the socket pins. Now oddly enough a good friend on the other side of the country bought a 2w version of this amp but couldnt get the nerve up to solder anything.
Now im working on 2 amps. As im using his as a tester ( bit cheeky ) im not fond of the components on the pins. Quite messy and does not conform to my ocd.
On my version i have decided to go with some tag strip for all the components and wire to the sockets. Time will tell if this was a good thing.

[moda]

So i fired this up yesterday. Voltages all looked good without the tubes. Its an odd feeling having your hand hovering over 370vdc but patience and a clear head is the order of the day!
Tubes in and some more measuring. Looking good until a faint burning smell. Coming from the rectifier diodes.
Power down and was discharging the caps when a lack of concentration saw me short one of them.
Apart from scaring the bejezus out of me i have know no voltage coming in to the caps anymore.
Sigh. Updates soon i hope.

[Travis]

I know you didn't say anything about the OT, but did you have a speaker load connected when you power it up with the tubes?

[moda]

Certainly did mate.

[moda]

Ok so i pulled the whole voltage quadrupler out as im thinking this is where the problem is.
Charged each cap via a 9v battery and measured. All good with the same rate of dissapation.
Checked forward voltage of the diodes. Steady at around 7.5 volts.
Bleed resistors all check out.

Next is the supply transformer.

On a bright note did finish the 2w version of this amp so i can safely say im not a complete failure!