2. tech-talk
  3. 1264972698

How to safely bias Cayin A88T Tube amp

I know this amp has been the target of much talk on this subject, but does anyone have a step by step guide to biasing this fantastic amp? I realize there are some dangerous voltages in there, and to do the job, you have to take the back plate off and switch the amp on right? But, where do I take the readings from, once I'm in there?

I'm sure there was a post on here with pictures, but I can't find it for love nor money.

Kindest regards

JP
peaman
buconero117
2,311 posts
 
If you take the bottom cover off you will see the exposed pots. But do call Steve he will step you through it.
sonicbeauty
324 posts
 
This is one flaw in an otherwise stellar product.

I once opened this thing years ago for biasing, as I had photographed instructions taken off a web forum (cannot find it anymore).

Trust me on this one. Anyone that will tell you it's an easy and SAFE procedure, ABSOLUTELY PAY them to do it.

If not, endure it as it is or sell it to get an amp that is either self-biasing, or that has external pots.

Good luck!
peaman OP
2 posts
 
Thanks guys!! I'm scared to death of electricution. Seems such a crazy thing to hide the biasing pots inside like that...

Maybe it's a trip to get it serviced then.
marakanetz's avatar
marakanetz
5,473 posts
 
The way to do it safely is to connect dummy load resistor to the speaker binding posts of your amp such as 10Ohms/50W available at partsexpress.com. Watch your multimeter not to go way over or under the tolerant bias voltages. Ask the manufacturer or use the bias manuals to do so. Giving it to someone else might be safe but it's just another way of giving out easy money for no work.
trelja
3,223 posts
 
Peaman, in what part of the country are you located? If you are local to me, I'll do it for you.
More to discover