The ST-70 is a good place to start. Very nice output transformers and simple enough that the driver and power supply are easily upgraded/updated.
35 watts is about as high as you are going to see in an integrated and is not enough power unless your speakers are 96 db or more (for my listening tastes anyway... :)
In seperates 50-60 watts is the most you will see for the most part. The Dyna MkIII is, relatively speaking, avoidable compared to the sound of the ST-70, so you will have to concentrate on other targets if you want that kind of power. Of those, the Citation II is perhaps that best platform to work with as it has excellent power transformers and enough capcitance and driver layout space to allow for proper refurbishment, updates and upgrades such that it will keep up with a lot of modern amps with ease.
The Citation V has better output transformers but they won't make quite the same power and the amp for other reasons usually does not wind up sounding as good.
Fisher, Marantz, MacIntosh, and Scott made larger 50-60 watt power amps. The Marantz (model 9) is legendary and impossible to find. The Mac 275s aren't particularly easy either but in recent years was repopped. The Fishers and Scotts are rare too. You pay a lot for these names although the Citation II is much more recognized as a giant beater now then they were 15 years ago. The Scott is probably the least collectable.
In all cases an 'attic fresh find' will need the power supplies completely rebuilt, and all the sockets, connectors and transformers will have to be tested for integrety. I advise you to avoid a unit that is know to have a bad transformer- finding a replacement can be heartbreaking.
All vintage tube amps are now so old that ALL the filter caps in them should be replaced in them regardless of how they measure!
Coupling capacitors, particularly in the output section, should be replaced as even a small amount of leakage on their part can cause the output tubes to destroy some rare transformers! Similarly the selenium rectifiers that are often found in the bias supplies of vintage amps should be replaced.
Whomever does the service needs to be very aware that the piece is collectable and that new parts should be installed with respect to this fact. Often you can wind up paying more for suck a piece than buying something new- so stay on your toes.
35 watts is about as high as you are going to see in an integrated and is not enough power unless your speakers are 96 db or more (for my listening tastes anyway... :)
In seperates 50-60 watts is the most you will see for the most part. The Dyna MkIII is, relatively speaking, avoidable compared to the sound of the ST-70, so you will have to concentrate on other targets if you want that kind of power. Of those, the Citation II is perhaps that best platform to work with as it has excellent power transformers and enough capcitance and driver layout space to allow for proper refurbishment, updates and upgrades such that it will keep up with a lot of modern amps with ease.
The Citation V has better output transformers but they won't make quite the same power and the amp for other reasons usually does not wind up sounding as good.
Fisher, Marantz, MacIntosh, and Scott made larger 50-60 watt power amps. The Marantz (model 9) is legendary and impossible to find. The Mac 275s aren't particularly easy either but in recent years was repopped. The Fishers and Scotts are rare too. You pay a lot for these names although the Citation II is much more recognized as a giant beater now then they were 15 years ago. The Scott is probably the least collectable.
In all cases an 'attic fresh find' will need the power supplies completely rebuilt, and all the sockets, connectors and transformers will have to be tested for integrety. I advise you to avoid a unit that is know to have a bad transformer- finding a replacement can be heartbreaking.
All vintage tube amps are now so old that ALL the filter caps in them should be replaced in them regardless of how they measure!
Coupling capacitors, particularly in the output section, should be replaced as even a small amount of leakage on their part can cause the output tubes to destroy some rare transformers! Similarly the selenium rectifiers that are often found in the bias supplies of vintage amps should be replaced.
Whomever does the service needs to be very aware that the piece is collectable and that new parts should be installed with respect to this fact. Often you can wind up paying more for suck a piece than buying something new- so stay on your toes.