dynaco st 70 what tubes to replace first

SED EL34's.Musical,liquidy.Don't get the ones that say Svetlana.The name changed to SED.$100-$120 quad.The 7199's don't make that much difference as long as they are good.You could get buy with a Sovtek 5ar4 if you don't have any Mullard's laying around.The SED EL34's are the best choice for what you want.

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.

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.