Thanks to Scott Clark for sending me these little amps to play with.
There is a big thread on these in the Cheap and Cheerful circle. http://www.audiocircle.com/index.php?topic=122152.0
When I first listened to a stock amp I knew it had potential. It did sound really good considering how cheap the volume pot was and all the cheap connectors with steel screws, etc. I knew there was a lot of upside potential as it was easy to see a lot holding them back. I really didn't need more amps, but these would be ideal for burning stuff in. And they are so efficient that they could probably play for weeks on my 100 amp hour battery that typically power my little tube amps.
I pretty much stripped these things and got rid of almost all of the parts on them. And since my Dodd pre-amp has coupling caps in the output I really didn't need additional coupling caps for the input of the amp. I used two of them to make some mono-blocks using just one channel on each amp. This improved stereo separation. And why not. They're dirt cheap.
Just getting rid of the junk on the board and using good quality wire and connectors really went a long way. I used a Cardas RCA input and connected it to the board with Vampire's continuous caste Copper wire. For power in I used a Neutrix connector and our 16 gauge solid core OFC wire with the polyethylene jacket. It is the same stuff I use for internal speaker wire. I used the same wire on the outputs to tube connectors. I had to drill out the holes on the board for the bigger wire and then scraped the varnish off of the back side of the board exposing the bare Copper underneath. So the larger wire was inserted through the holes then bent over against the Copper trace and soldered on. I then doctored the top side with some hot glue to help hold the wires in place.
And I made some neat little wood boxes for them and veneered them in some scrap I had left over from an old project. The box has holes drilled in the bottom right under the heat sink that the chip is mounted to and matching holes drilled into the lid. So air can flow in and out of the box.
I made some little amp stands for them too.
And yes the veneer is book matched. So the amps match on all sides.
The tube connectors are on the outer facing sides.
I have to also thank Dave Elledge for the mini-battery buss for each amp. That has to be really helping as well.
Okay, how do they sound? So far pretty stunning, and they are still burning in and opening up. I also had Electra Cable make me a new set of speaker cables with the tube connectors on both ends. The speaker cables are still burning in too... So more on the sound after some more time on them. Right now they are just about 40 hours in.
I think I need to add tube connectors to all of my amps now.
And I didn't put an on/off switch on the amps. I have one on my big battery. So one switch turns them both on or off.
No, they are not for sale and I am not building any more of them. They doesn't cost anything to buy the little amp to start with and you can copy what I did for next to nothing. I'll sell you some tube connectors and wire.