TAD-60 Owners

Paul recently added the following language to the Bias Instruction page for the TAD-60:

*NEW SINGLE ENDED CLASS A BIAS: This amplifier will operate class A for the first 10 watts and class A/B 10-50 watts if final biased this way: V1, V3 set to 175, V2, V4 set to 500. See if you notice improved smoothness in the midrange and richer bass compared to regular all 350 bias. Only giving up 10 watts on top (50w instead of 60w) for class-A mode. Single ended - because the 500 biased tube is doing most of the amplification 360 degrees up to 10 watts while the 175 biased tube is acting as an out of phase damping brake, offering little in phase amplification under 10 watts. Have it all, single ended class A and 50 watts A/B when needed.

Check it out!

Are you using yours biased in this fashion? How does it sound?


I just re-biased my unit this morning. I listen to the TAD-60 mostly in triode mode, but Paul suggests using ultralinear in this new bias mode. It may take me a little listening time to truly discern the differences, but it does sound great. Right off the bat I hear more pronounced bass and more overall dynamic "punch." I would be curious to hear what others think.
Are you using the stock tubes?
I am using the stock Svetlana EL34 tubes. I have replaced the others. I am currently using NOS RCA "clear-top" 12AU7A tubes and a cryo grade gray plate Ei 12AX7.
I'm currently enjoying the class A setup with the stock 34s (improved bass and dynamics, while maintaining those great mids), and both triode and UL are much improved - I mostly listen in UL mode. I also tried it with a mix of KT88s and 34's. The class A bias cannot be had with all 88s so Paul suggested trying a mix for a quasi-class A bias, and while bass was just amazing, the mids and highs were a little rolled off, which was great for those "hot" recordings but overall not as good as having all 88s with the standard bias setting. If you check out the TAD-60 review link here on Audiogon you'll find comments by other TAD owners. Btw, I'm using Paul's excellent pre, the TAD-150 Signature, and the 88s are Electro Harmonix. Next on the list are Pentas or Groovetubes.