Cayin TA-30 Operating Instructions/Biasing

Paul's passing came as a surprise to me. I was hooked up with Paul on Linkedin and we had a friendly relationship. He was always good for advice.
I used to have a set of instructions from Paul, but I may have discarded them with the sale of my previous unit.
Thanks for the contact at Cayin USA.
John

"You will need a tiny screwdriver and the supplied digital voltmeter to set the 4 output tube bias adjustments. Switch the amplifier on. Let it warm up for at least a few minutes. Plug the digital voltmeter Black lead into the Black tip jack and the Red lead into one of the Red jacks. (turn meter on, set meter to the marked 2000mV range). MEASURE WITH THE VOLUME ALL THE WAY DOWN - NO MUSIC PLAYING. You should see a reading on the meter. Turn the corresponding 25-turn small adjustment screw for each red tip jack you are measuring till the meter reads 350 (mV). Now move the red probe to the next tip jack and adjust the next corresponding adjustment screw. Repeat all 4 adjustments a few times till all are reading 350 (mV) +/- 10%. Super easy! The bias should be checked immediately when new tubes are installed, then every 6 months there after. Unusual readings (after initial adjustment - very high or very low compared to the other tubes indicate a tube failure. Output tubes generally last around 3000 hours. So every 1-3 years you will need replacements. A computer matched quad is the best choice - but not absolutely necessary in this separate tube bias design."

*** NOTE FOR KT-88 TUBES *** Bias to 400

Bias into class A - using tubes 1 & 3 (pull 2 & 4 out) - set bias to 700(mV) (assuming 800(mV) for KT-88)
This will convert the PP amp to single ended

So sorry to hear about Paul's passing

Dwhall covered it perfectly.
I'm saddened to hear about Paul. I got an original TA-30 amp second-hand and had it sent directly to Paul for the upgrade/mods. Paul handled it as if I bought the unit directly from him. He offered lots of objective advice and wasn't afraid to tell things straight. You could tell this was his passion, not just a business. A true gentleman. He will be missed.
The TA-30 was a great unit made even greater with the BizzyBee mods. No other Cayin approached it's price/performance ratio imho. I still own this unit because, for the money, nothing beats it.

I had a Cayin TA-30 and really liked it. I sold it but still fondly recall its sound. It mated really well with my Klipsch Forte (I) speakers. I upgraded the tubes one day and it smoked the unit, which was a real surprise to Paul. But he fixed it without cost to me. I also recall how upset Paul was when another company absorbed the Cayin TA-30 franchise and began marketing it under the Prima Luna Prologue brand. They did some good things with it (auto-biasing, I seem to recall, good after-sales support, etc.) but I know that Paul felt the rug had been pulled out from under him.