2. amps-preamps
  3. 175967-137666

Which tube spots for which affects?

Here's something I've now been pondering about tube sets in preamps.  Which positions in them are more likely to have what affect on the sound  when rolling?  For example my new-ish Raven Blackhawk has 3 pairs in the pre amp section that are noted as Preamp, Power amplifier first stage, Phase inverter/driver.  Is one set more or less likely than the others to affect say, warmth or another pair dynamics?  Which the sound stage?  Are some locations better for a "euphonic" tube or a very accurate set?  I'm sure it's really the sum of ALL the parts but maybe they each have their particular impacts.  Hearing differences but wondering if there's a pattern/ causal/predictability to it all.  I don't expect there's a single answer but maybe enough anecdotal evidence and experience might show a trend.  

akgwhiz

Showing 1 response by mulveling

mulveling's avatar
mulveling
1,774 posts
 

It depends the amp, but preamp tubes and amp input/gain tubes (V1) will usually have big overall impact, especially on tone and air. The preamp slot is also going to be the most sensitive to noise and microphony, by far - so careful selection here matters.

The drivers can have a big impact on dynamics, especially if you have a couple small crappy tubes like 12au7 driving a lot of big KT tubes. In my VAC 200iQ’s I found that Russian Tung Sol 6SN7GTB are the best driver / V2 tubes by far - not because they’re the best sounding tubes (they’re not) but because they’re the strongest tubes, stronger than any NOS you’ll likely find. They don’t stain at all driving the KT tubes. In V1 slots however, the old vintage USA tubes are killing it - way better tone and air versus the Russians in those slots.

The phase splitter can mean different things to different circuits, as far as its impact to tube rolling goes. Experiment and learn!

More to discover