This amp is NOT AUTOBIASING. I owned a Jolida 302 also and now the a88t and it needs at least 10 hours breakin before sound improves.
Here's the biasing instructions graciously provided to me by another Cayin owner:
"Unless you swap out tubes, you do not need to bias the amp more than once every few months. Anytime you change tubes however, you must re-bias.
If you can go to the Acoustic Sounds web site and enter Cayin in your search...you will find the A-88T and can click on that model. Then find hi-res pics that show the underside of the amp and itâs circuits. It will be a big help if you can look at the picture on the Acoustic Sounds site before you start to see âwhatâs whatâ.
Be careful of course when doing this. Be certain the amp is turned up on its side (supported by something) - The amp needs to be up on it's side and plugged in, but no interconnect or speaker cables should be connected- it should just be plugged into the wall....
Okay, the directions:
You will see under the tube sockets where the wires are soldered. You will
also see the blue plastic pots (with screwdriver slots on their tops) next
to the sockets.
You want to use the blue wires on the front two Kt-88 (front of amp) and
use the Orange wires on the rear two Kt-88's as your + test points. They
are the only wires that are single wires on the sockets and have a double
solder connect. The second soldered connect (with NO wire attached) is the
test point for the + Positive probe of your multi-meter...The - Negative
test probe attaches to any black (- neg.) speaker terminal on the rear
binding post. Doesn't matter which one.
The test point is 0.4V or 400mV on your meter. Make sure to set it for
Volts or mVolts DC- NOT Amps or Voltage AC. I use a Sperry DM 4100A
meter purchased from Home Depot or Lowe's.
This may seem a bit confusing. But if you pop the bottom cover, you'll see
the KT-88 sockets from the bottom- then locate the Blue (front of amp) and
orange wire (rear of amp) and you will also see the 4- blue plastic pots for
adjustments. One by each tube socket. It wonât take much turning to find
the 0.4V...Adjust slowly with the probe on the test point and you'll see that.
Allow it to warm up for about 10mins before checking the bias. After
you've made the initial adjustments, wait 10 mins. and check again for drift.
They will settle a bit, but not a lot. You can fine adjust at this point"
Having said that, don't judge your amp untl you get it some time to really burn-in or perhaps tube role.
Here's the biasing instructions graciously provided to me by another Cayin owner:
"Unless you swap out tubes, you do not need to bias the amp more than once every few months. Anytime you change tubes however, you must re-bias.
If you can go to the Acoustic Sounds web site and enter Cayin in your search...you will find the A-88T and can click on that model. Then find hi-res pics that show the underside of the amp and itâs circuits. It will be a big help if you can look at the picture on the Acoustic Sounds site before you start to see âwhatâs whatâ.
Be careful of course when doing this. Be certain the amp is turned up on its side (supported by something) - The amp needs to be up on it's side and plugged in, but no interconnect or speaker cables should be connected- it should just be plugged into the wall....
Okay, the directions:
You will see under the tube sockets where the wires are soldered. You will
also see the blue plastic pots (with screwdriver slots on their tops) next
to the sockets.
You want to use the blue wires on the front two Kt-88 (front of amp) and
use the Orange wires on the rear two Kt-88's as your + test points. They
are the only wires that are single wires on the sockets and have a double
solder connect. The second soldered connect (with NO wire attached) is the
test point for the + Positive probe of your multi-meter...The - Negative
test probe attaches to any black (- neg.) speaker terminal on the rear
binding post. Doesn't matter which one.
The test point is 0.4V or 400mV on your meter. Make sure to set it for
Volts or mVolts DC- NOT Amps or Voltage AC. I use a Sperry DM 4100A
meter purchased from Home Depot or Lowe's.
This may seem a bit confusing. But if you pop the bottom cover, you'll see
the KT-88 sockets from the bottom- then locate the Blue (front of amp) and
orange wire (rear of amp) and you will also see the 4- blue plastic pots for
adjustments. One by each tube socket. It wonât take much turning to find
the 0.4V...Adjust slowly with the probe on the test point and you'll see that.
Allow it to warm up for about 10mins before checking the bias. After
you've made the initial adjustments, wait 10 mins. and check again for drift.
They will settle a bit, but not a lot. You can fine adjust at this point"
Having said that, don't judge your amp untl you get it some time to really burn-in or perhaps tube role.