JOLIDA Issue

"I was able to turn two pots several revolutions without reaching the stop point."
Normal for multiturn bias trim pot, which the newer Jolida units has. Bias should have been checked after shipping before power up.
The multiturn pots make for more precise setting unlike the older single turn ones.

When replacing the tube make sure and turn the pot down several revolutions, it's a 12 or 13-multiturn pot.

Tubes can fade away or die spectacularly, both of which has happened in my 502p with no issues issuing from the amp. That's tubes for ya. A note on Shubert's post...I love my NOS UK origin Mullard 12AT7s, but I've had really good luck with Russian Gold Lion 12AX7s and KT120s, 150s, various new Tung Sol and EH stuff, Mullard reproductions (in my class A 18 watt guitar amp), JJs, etc., and I think you can learn a lot more from fooling around with tubes than paying much attention to fools around tubes.

Awesome news gents, it was indeed the tube, the new one arrived today, and the amp is purrin along as I type.

A bias check revealed numbers in the 500-550 range and not the recommended 400mv. I dig the easy bias feature and the heavy duty remote control, over all a well built amp.

BTW Mike at JOLIDA is helpful dude.

Happy in Houston.

RIGGED

My 502 has been cookin' along with new Gold Lion 12AX7s and KT150s for a couple of weeks now and I'm astonished at how good it sounds now that things have settled in even more...I've recently listened to some far more expensive stuff including an ARC REF 75 and a Rogers integrated (although not in my home system), and man...made me realize how good my little 502 really is.