Modern turn on a classic ST-70 tube amp

Here is my version based on a Dynaco ST-70 updated for the new age. The only original parts are the output transformers. It now sports a bigger power transformer with a lot more filtering, Shannon Park's new driver board and a one off custom chassis and cabinet.

 

Wow, that is a gorgeous amp!

 

Thanks - my bid at DIY for the discerning listener.

 

So many amp chassis design's I've seen use wood in a way that just looks gaudy. Yours on the other hand is such a beautiful and graceful design; truly functional art!

 

Thank you. Esthetics are importasnt to me. Make it functional and all the more better. I made the chassis from a flat sheet of aluminum I bent down at the back. It slides into grooves I cut in the cabinet.

 

That's incredibly beautiful! Love the woodwork and the overall design.

 

What's up with the new driver board?

 

It's a very attractive amp but if you are going to this much time and expense why use ST70 transformers? There are much better outputs for not all that much money. Japanese ones like Tango or Hashimoto also have pretty potted cans that look nice too.

 

Spectacular.

 

Here is the working side. The test point wiring isn't hooked up yet in this pic.

 

From Shannon's site: "single 12AX7 and a pair of 12AU7's for pure triode perfection allowing use of an almost limitless selection of NOS and new tubes...classic modified Mullard topology with constant current source in the tail of the phase splitter."

 

OP, your project posts are so cool... Really nice work.

 

Looks great. What power trannie did you use? My main listening system is still a modified ST70 with the driver board found here: http://www.tubes4hifi.com/ST70.htm

 

Long live the Stereo 70! I'm listening to mine as we speak.

 

Holy cow that is awesome! So, when is mine ready to pick up?

 

Dude, you have got to make it over to San Antonio some time.

 

PA060 from Dynakit

 

Oh! That's the one I'm using now. Same for the new L&R, same company. Great irons.

 

Sure you may have gotten all the talent but I got all the thumbs. Seriously your skills are top notch

 

Ward, super nice job! Very impressive. I like the Russian Birch plywood, and you did a great job with the veneer. How did you treat the aluminum to get it shiny?

 

Nice job-looks great

 

I shall, and when I do, I'll bring the Ultimate 70 with me.

 

What a beautiful looking amp. Here's another modern version of the ST-70, courtesy of Bob Latino, that I built last year. It's got a really nice balanced sound with an NOS Mullard GZ34 as the rectifier, Mullard CV4024 tubes on the driver board, and NOS Russian 6N3C-E power tubes from Jim McShane. I tried the EL-34s as well as the Genelex KT-66, but the 6N3C-E were the most balanced. I'd love to hear your amp!

John K.

P.S. Not my amp shown; I have to take a picture of mine, after I clean off all the dust!

 

I just got my Mullard GZ34 today in the mailbox. Sounds great. I need to stock up on some more Mullards! Ah the Master Valve!

 

The chassis is triple plated: copper, nickel and chrome.