Just got ST70 and have some questions.......

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Hello All,
I've now officially ventured into the tube world. Bought a very nicely refurbished ST70. It has the Curcio board that maintains the original driver circuit (7199 tubes) and the rest of the amp is also true to the original design. It has a new quad cap and it really couldn't be nicer. It looks and sounds great.
For the first time, I felt like real music is coming from my speakers! (A completely different sound from my highly regarded SS kit amp.) While the ST70 doesn't have the low end punch of the SS amp, the presentation is just so much more musical and not so "in your face". I really like it.
My current setup is as follows: Jolida JD-100 CDP, DIY Sowter TVC, ST70 and NCMS Borealis speakers (rather inefficient ~86dB). I have a few questions:
1. Bias was set by the previous owner. When I checked, it is 1.25V on both channels. I know this is below the spec of 1.56 (I believe). Should it be increased to spec?
2. Does low bias reduce output, amp gain, or have any other good/bad effect?
3. With the passive TVC, the ST70, while quite listenable, isn't able to drive the speakers to a very high volume. Is this because I need some pre-amp gain, or is the amp just underpowered for the speakers? (I don't need ear-splitting levels.)
4. Is there a more powerful vintage tube amp that has the same sort of sound as the ST70? (I assume the Dyna mono-blocks would.)
5. I've seen references in the archives that suggest the ST70 power supply is "marginal" and the amp could "motorboat". What is this? Oscillation?
5. If I add powered subwoofers, and use the ST70 for the high pass (say above 85 hz), would that put less strain on the power supply or increase the stability margin? (I'm in the process of building subs anyway, that's why I ask).
I know almost nothing about tube amps, so I'll apologize in advance for what are probably simple questions. Thanks in advance for any help/thoughts/suggestions!
Rick

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Topic - Just got ST70 and have some questions....... - rwalton 20:18:19 11/15/03 (4)

Re: Just got ST70 and have some questions....... - NewbieBaby 15:32:47 11/20/03 (0)

Re: Just got ST70 and have some questions....... - mkmelt 22:01:26 11/15/03 (0)

Re: Just got ST70 and have some questions....... - apaya 21:45:52 11/15/03 (0)

Re: Just got ST70 and have some questions....... - Bare 20:36:06 11/15/03 (0)

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