My new ST-120A custom amp chassis

Hi All:
This is my latest DIY project:

I finally figured out how to post images the one shown follows the original 2 piece ST-70 chassis format closely. The other on my photobucket link is a one piece chassis made for attaching cocobolo wood sides.

I will be doing the wood side model first and will post more photos of this build now that I know how to do it soon and hopefully of the other one right after that.

My new custom ST-120A (Aluminum chassis) amps are designed with "Front Panel Express" use a piece of aluminum plate (2.5 mm, thick) both are similar in layout to the Dynaco/VTA chassis on top but a little bigger and deeper to accommodate the bias meter and the caps on the driver board which are mounted on the bottom side of the driver board. I plan to use 3/8" solid Cocobolo slabs for the sides.
The driver board itself is offset so the tops of the tube bases are flush with the top. Only the driver tubes and the holes for the bias adjustment are showing through the top.
Everything else is 100% VTA/LATINO/Dynaco parts and layout.
I will be buying the parts from Bob as soon As I have the plate back from Front Panel Express in a couple of weeks. Top plate chassis for the wood side cost was $137.43 US.

Hi:
Thanks Bob, as soon as I get the chassis back I will start ordering all the components to go in it from you and try to photo document the build as I go.
I appreciate your support. I did use intend to use a 4PDT switch for the triode/pentode switch setup but I want to keep the switch size as small as possible and am still looking for a good one. Any suggestions?
cheers
Baddog1946

Your FPE top plate is looking great. Look forward to the final result.
For my custom chassis for the VTA board, I had to
diverge from the stock Dynaco design to accomodate toroidal
transformers from Trafomatic.
A pic here -

Hi Quad:
Nice job! Where did you buy those torroid trannies with the covers? Is the chassis aluminium or painted steel?

cheers
baddog

Baddog - very nice, looking forward to actual photos.
Quad - your project reminds me of one I did 4 years ago, and wound up selling

baddog1946 wrote:Hi Quad:
Nice job! Where did you buy those torroid trannies with the covers? Is the chassis aluminium or painted steel?

cheers
baddog

Thanks!
The chassis is painted steel.
I got the Trafomatic set from Boris Sasic of Engineering Vista, in NY.

SWEET!!!

I hadn't even thought of torroids
and <$150 is great for a custom chassis.

This just keeps getting
better and better!

I like the layout. Wood sides sound great, too.

I know next to nothing about the circuit, but I was once told that the circuit (and the aesthetics/symmetry in general) might be improved with a second rectifier tube. Your thoughts?

I think Bob has it dialed in when he recommends a Weber WZ68 solid state rectifier which has plenty of current flow even for the KT120's running at 60 millvolts. I plan to install the relay delay module he sells which should stabilize things further.
There is a point of over complication and overkill that goes against the KISS principle. the less you have in the signal path the better.

Baddog,
I like the Aluminum chassis design it is a logical update to the original. Big improvement. Is someone in the States cutting the aluminum? If so I would like to buy one if yours turns out to be the quality ordered. Please post that information.
JDM

I will keep you posted and try to photo document the build on this forum.
The chassis is being made by "Front Panel Express". I should have it by the first of November.
How long it will take will depend on getting all the parts from Bob to me as I live in Costa Rica. I am pulling the $$ together for that right now. Stay tuned.