I have rebuilt a few ST70's and have been very pleased with them. I've used them with a variety of speakers from Klipsch LaScalas, Polk LSI's, many different NHT's, KEF's, AV123 Encore's, Advents and many more. I love the Dynaco's and bass control has never been a problem, even when using the stock driver circuitry. Try one out, you won't lose money they hold their value.