Posted by Thermionic [ 70.178.41.42 ] on January 31, 2005 at 17:31:46:
In Reply to: Re: Proud Papa Syndrome (Check out my new amp...) posted by Wayne Parham on January 30, 2005 at 10:27:20:
Wow! There's some very talented DIYers here at ART! Beautiful and very impressive work everyone. My hat's off to ya!
As I had promised Wayne, here's a pic of a current amp project. Nothing special at all, just a clone of a Dynaco ST-35 for a friend, with some different component values here and there, a better power supply with Fairchild Stealth hyperfast/soft recovery diodes and choke filtration, and a slightly changed circuit. I'm still using the 12DW7 driver, and the iron is all vintage Dynaco pulled from a scrapped ST-35 that my friend's buddy fished out of a dumpster!
He wanted it to have as warm, smooth, and romantic of a signature as possible, so all the resistors are carbon comps and the coupling caps are paper in oils.
It's not completed yet, but I threw some tubes in it and snapped a quick pic with my cheap, totally blurry camera. Sorry for the poor quality snapshot! I've had to shelve it back for several weeks now due to the avalanche of amp service jobs I've been getting.
The left hand control on the Dynaclone is the volume, while the right hand knob is a variable negative feedback control, with 0, 6, or 12dB of feedback. It also changes the voltage amplifier section's bias on the fly with the feedback, to increase the gain a bit in compensation as the feedback is increased. You may be able to see that a couple of transformer mounting screws are missing. There's a bracket inside with the choke and filament tranny on it that mounts on those screws, that's not in place yet.
The chrome acorn nuts on the iron are something I do on every amp I build, to me it looks classy and gives a well-finished look. The hammertone bronze and midnight black finishes were at my friend's request.
Pretty soon, I'll be building a DRD 300B, DRD 2A3, an EL34 PP with transformer phase inversion, and some various other stuff. All three amps will have choke loaded, battery biased 6C45 drivers, Plitron OPTs, and the DRDs will have motor run oil caps in the PSU. Can't wait!
Once again, mungo beautiful amps everybody, one and all! Congratulations!
Thermionic 
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