Question for WildWest

[MikE]

My buddie Dan who was given the vintage Dynaco st-70 has a question. Is there a mod that will allow 6922 tubes instead of the 7199s it uses now? I thought you (or someone else) had mentioned this once. He has a slew of 6922s and would like to tap that resource when he refurbishes the amp. TIA


MikE

 

[WildWest]

He was given one? Wow, now here I thought that only happened to me when my older brother dropped one in my lap. LOL He's a lucky fellow especially if that amp has the output transformers with the cloth insulated leads and not plastic. Those sell anywhere from 300 to 400 bone stock on the Bay. Good score!

In answer to your question I want to say no. I know of no upgrade board in that amps section that uses the 6922. BUT! don't hold me to that. There are a number of suppliers that have modifcations for that section and they use a varity of tubes. Some are better sonically than others too so one wants to do their homework with respect to it before they make changes.

Myself, I don't want to change the design as some suppliers are doing with their kits. I feel this lil amp was already well thought out. I have done a TON of reading on the net from forums to suppliers on the ST 70, and from what my understanding is that if anyone wanted to dump the oringinall 7199's the best upgrade board design is from Ned at http://store.yahoo.com/triodeel/st70boards.html
I plan on some day doing this upgrade myself. Have already done the power cap section with one of Ned's boards and it was very sweet. Higher value, better quality caps and the kit changed out the old solinium rectifier to a new diode. OH HEY! Speaking of that why...You might tell your friend to yank that old rectifier and replace it with a diode asap. Those things are famous for blowing and he could smoke his nice driver tubes in the process.

Does his amp have any of the Dynaco label tubes still in it? If any are EL34's he needs to give them to me! (snicker)

Oh hey by the way Mike. Uhhhhh when you selling me that metal base 5AR4 that I am squirtin for eh?

 

[MikE]

Call me a "Tube Whore"

Thanks for the reply. He should probably do a search on AA, then pose that question to the tube gurus there. As far as my prized Amperex "metal-base" 5ar4? No way, I'm keeping it! Even if I don't listen to the 2a3 tube which uses the 5ar4 rectifier I don't want to part with it or the Mullard "fat base", which I actually perfer. Seeing that I'm not using either, do you want to BORROW both and try them just to get an idea of their sonic signature IYS? I know there expensive, this way you'll know WHICH one to pursue. Let me know.

MikE

 

[WildWest]

Yes without a doubt ask over at AA. Even a search there will yeild a wealth of information. You being more of a regular there, likely you would get some decent responses.

Oh of course I would LOVE to borrow those tubes but there is no way that I would ask. Your offering is extreamly kind but no no no no.... I would not ask you to subject them to the madness of shipping for one second. No way would I take you up on it. But thanks so very much for offering. I am gonna keep my eyes open and soon enough I will snatch something up. I always do...

 

[MikE]

OK...

... but I wasn't offering because I thought one of them 5ar4s was going to implode in route. Of all the tubes I've bought only one (1) that was "supposed to be good" on departure arrived DOA. Ironically, it was the very last tube I won on Ebay, a Sparton 182-b which is a variant of a 45 globe my Moth uses. Luckily the gentlemen stood behind his product and is issueing a refund.

God, my system is sounding fine right now. Well, I've got to drag my butt out in the 94 degree heat for a short run and then we're going up on the roof to watch the big fireworks display.

MikE

 

[WildWest]

Yeah...I bet those SET amps are to die for. Lucky you. Fireworks you say? Boy, here in SW Arizona they have banned all fireworks even by licensed professionals. They are going to arrest and toss in jail for the night anyone found with fireworks due to our dry conditions.