dynaco st 70 what tubes to replace first

A Dynaco brought up to spec's is ok done right.A repainted one hides the transformers.There are transformers with cloth leads that sound totally different that the early ones.I went through about 20 or more of them.When everybody went to SS,there wasn't much choice for someone who wanted tube amps.You had to buy vintage amps.Some say they started out sourcing the transformers without the employees knowing about it.You could make them bias up for a 6L6 family tube,but any tech knows it is not made for them! At 4300 ohms for the A470 vs. the over 6000 ohms compatible for the 6L6 family.It's easy to buy a rusted Dynaco cheap and repaint it.There are people out there putting different transformers in the old Mac amps too.If there is a buck to be made,somebody ruthless out there sure will jump in.The early Dynaco 70 that has transformers similar in shine to the old Mac gear are the best ones.

Gentlemen: Esp Dave65mus, Rodman99999,& Viridian
I am so gratefull for the time you have taken to respond.

As a novice in this field of audio I appreciate your knowledge and passion.

I"ve got the new NOS ordered and look forward to Listening but also following your opinions on the threads.

Lawrence

I also own a Will Vincent rebuilt ST-70 wired in triode. I ended up changing all the tubes. RCA 7199's made a positive difference. I tried SED "winged C" el34's and a quad of Siemens el34's. I much prefered the Siemens, winged c's being too rolled of at the top for my taste.

But getting a Mullard fat base gz34 made it sound like a whole new amp. A much better amp. I actually couldn't belive what a positive impact it had on the sound. So if I had a limited budget for tubes, I'd spend my money on a Mullard gz34 first.

If you want the top(price doesn't matter) EL34,go for the Bugle Boy "square D" double getter.It gets along with every EL34 amp I've owned,and heard it in.At $800 and up for a NOS quad,watch out for counterfeits.They will out do all of the above mentioned.

Tommy 583, that is a great description of the sed winged c in my amp also.

IF I had tone controls on my preamp(good gear does not use them so I have none) the winged c's would be like turning the treble adjustment all the way down..... dull and lifeless.

I just put in a new quad of jj kt77's tonight... I had one go out after about 1 year of use and had been using kt66 gold lions since.... now with the vintage mullard gz34, rca blackplate 7199's, and jj kt77's, No more tube rolling for me! I am going to stock up on jj's and rca blackplates and enjoy the music!