Cayin A88T break in and biasing??

Just took a Jolida 302BRC back to a dealer to
get the A88 instead. I loved the Jolida no doubt,
but assumed the A88 would be a step up, and so far
all I can say is it has the potential but sounds
a little hard & brittle now.
Just wondering if anyone has had experience with it
and does it get better with time?
I need to know before I go drop another 1k on it.
Also...I never could get a handle on whether or
not the amp is self biasing or not?? Most people
say it is not and you have to take it out, flip it over
and bias it....that's crazy and would be a deal breaker
for sure!
Any help or thoughts on this would be greatly appreciated.

BTW... I only had about 6-7 hours on it when I started
to give it a listen.
Yep, your friends are right. You need to be able to handle biasing and, for me anyway, not being able to do it with the amp in place and connected to everything would be a PITA. Personally I prefer manual biasing amps which come with exposed bias pots and a meter built in. Easy, dead simple, and a good system to both control tube sound as well as to know how much life they have lost as time goes by.

I've never heard the Cayin but all amps/power tubes do require breaking in. Power tubes and tube amps can require anywhere up to 100 hours to really approach their best.

I'm sure that you have already read reviews and user comments on this amp. I have not noticed anyone comfirming that this amp is 'tube like' if your expectation of a tube amp is old fashioned warmth.

BTW, I recently read a similar post by another owner of a Cayin KT88. You might find it by looking into the archives.
No biasing needed. Changing out the tubes is plug-and-play. This is also why you can switch between triode and ultralinear on the fly - a great feature.

Why put another $1000 of tubes into it? You don't even know what you have yet. Judge it after a couple weeks of continuous play and see what you think of it then. Just relax and enjoy.

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 will find the A-88T and can click on that model. Then find hi-res pics that show the underside of the amp and it’s circuits. It will be a big help if you can look at the picture on the Acoustic Sounds site before you start to see “what’s what”.
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 won’t 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.
Hi Aball & Newbee,

Thanks for the reply's so far. Aball, The $1000 I will
have to spend is not for the tubes, but the difference
between it and the Jolida I took back to my local dealer.
BTW, My comments were based upon owners reading of the manufacturer's actual manual on your amp, not on the statements by dealers that they were auto-biasing. To clear up any conflict between two opposing posts I would suggest you obtain and read the amps manual. You might look at all of the various comments that a Google search can provide which includes professional reviews as well as user comments.
Hello Bonger,

Thanks, and you are exactly right! I called VAS to
leave a message, but they answered and told me that exact
same thing so now it can be put to rest. But it is
unfortunate for me, as I do know how to bias, but do not think
I want to go through that hassle. Sad they could not
put bias pots on the top or at least the side!?!?
It is starting to sound great though. I will have to give it
some thought the rest ofthe weekend.

Thanks to all!

Happy New Year!

I have noticed that , with My Cayin 88T , It took a while to get into the swing of things .
Even after turning it on to warm-up , for 30 - 60 minutes , it would sound 'off' until it had actually played for another 30-60 minutes .
Because this is my first foray into tubes , I don't know if it is typical .
I A/B it with a Cary Sli-80 and did not hear enough of a difference to justify the difference in price . They were really quite similiar . I enjoy the Cayin .
I do not believe it to be plug-and-play .
I am relatively new with this products but here is what I learned thus far:

1) Amp sound is on the warm side. I order both A70T and A88T. Both have same sonic signature.
2) I have about 40 hours on each unit at this point and they are improving with time.
3) They both sounded good with the Usher Dancers.
4) I personally think the A70T is a tad better than the 88T. With the A70T, it's a $100.00 cheaper, more power, and biasing can done right in the front of the unit (i.e. you dont have to flip the unit over on its side as mentioned above). Cosmectically, A88t looks a little better. Good luck

I spoke to the importer several weeks ago and the amp must be biased manually. I got the information here on the 'Gon on how to do it and performed the task in less than 20 minutes. I actually enjoyed it and got to see the innards of the thing in the process!
As far as sound goes, It started out as being part of a secondary bedroom system... The main system is seeing very little use since it arrived. Give it some time.

Thanks for all the input from everyone! I took back the
A88T and got back the Jolida and all is well again!
The Cayin is very sweet, but the Jolida is a better
match with my current system.
6 Moons has a super review on the A88, so I'm not sure if your comment on "brittle and hard" is justified.
I mean my Jadis OR KT90 does have its weakness, but overall its a superb image.
No tube amp in the under 2K range will be 'all things".
I've only heard good things on the A88, not one poor report. I will say tubes do make a huge difference. I bought a quad of EH 88's for my Jadis just to test as a comparison to the 90's, and did not care for the 88 at all. I also bought a 88 amp to test and same results, very flat.
Audio Research uses 88's and i do not care for ARC amp sound.
However Cayin makes a graet product as my Cayin 15 and 17's testify.
Bottom line, seek out some good KT88's and also play with the pre tubes. You have much more potential in this amp with the right tube.
I do not like the "british" sounding tubes, Mullards etc. I love RCA's NOS. Of course it can be expensive to roll tubes. Try to buy from a seller you trust and will take them back if you find that are not for you. Maybe a 25% re-stock fee may be part of the offer.
I have a local tech guy who helped me find incredible pre amp tubes for the Jadis and also for the Cayin 17.
Enjoy the amp in the meantime
Oops - sorry about my mistake. Glad you called VAS though because there is a lot of conflicting information about Cayin since they have different models for each market. One of my local buddies has the A70 and he loves it. His Cayin dealer says the A70 sounds better than the A88. But if you are happy with the Jolida, keep it.


I am not sure if you already know this but since you have already called Steve Leung at VAS and confirmed your question on biasing are you aware that Cayin's new amp does everything you are looking for? The new 100-T is a 50/100 watt integrated cloning of the famous Marantz 7/9 combo. Retail is suggested to be $2,995 and this amp has a bias meter and pots adjustments on top of the amp! They are due out this month, call Steve and ask him about them. I am a Cayin dealer in Hawaii and just ordered two, they are supposed to be incredible! VAS's website describes the amp with no picture. I have photo's if you want? email me at
Sringle, The new A100 is indeed one beautiful looking amp. The only drawback may be with the image of the 88 tube, which tends to be 'fluffy', that is big on the midrange, but lacking on the ends of the spectrum.
I need dynamics across the board, which the KT90 tube offers. A straight narrow tube, EL34/KT90 others have different dynmaics vs the 'tube-ier" 845, 211, 300B, KT88.
Though actually I want to hear a good 845 and may consider the big Cayin mono blocks 845.
Correct me if i'm wrong in any of the above.
I have the Cayin 100T. Its been about 6 weeks but I only have about 150 hours on it but so far so good. Being far too green at this hobby I can't begin to describe the positives and negatives but I really like the way it sounds. At first it did sound too harsh or brittle but now its begun to open up. I listen mostly to jazz and I love the way it handles female vocals. Triode sounds nice but is a little too laid back for me so I prefer Ultralinear. My dealer suggested that I swap out the stock KT 88's for 6550's.

One point - the bias meter is not like Rogue's, it pretty much just a center point that each pot is adjusted to. I only had to do this once. To my knowledge, there's no way to what is the exact test point or reading. Hopefully that makes sense. Enjoy the Music has a new review on 70T and I can also post pictures if anyone is interested.
Hey Bob - the Cayin 70T is auto biasing. I went and checked out my neighbor's yesterday and we looked all over the manual and the amp and there is nothing about biasing anywhere. That is what the dealer told us but we double-checked. He just plugs and plays whatever tubes he wants. So if you still want to try a Cayin amp, get the 70T. It sounds fantastic and you can switch between ultralinear and triode on the fly with the remote! You can also try all the KT tubes as well as the EL tubes in it. Really cool.

Also, the 70T for the US market puts out 55W in UL and 27W in triode. Don't get it confused with the asian market version that is 35W in triode, or some such.

Lastly, there have been reports of fake Cayin amps being sold. I would suggest getting one from your dealer to be safe and sure.

Mightyburner, you have an answer to my upgrade from my JOR. I was considering a Cayin 845 mono ($$$!!!) + nice Melody preamp, a real monster weighing i at 50 lbs!! But with your post on swaping the KT88's for the 6550's may be another option.
You see I've had EH88's in my JOR and was a flop. Also had a cheap chinese KT88 for demo, and was a flop on classical as well.
Also heard several other 88 amps, Audio Research, and didn't like the muddy imaging.
I believe the 6550 is close to the KT90's, slender tall tubes.
I love Cayin produts, and this A100 + 6550's may be my solution for upgrading.
Here it all depends on what 6550's are avaliable. I love RCA tubes, if I can loacte a NOS RCA 6550, then the Cayin A100 may very well be my next amp.
Telescope how ya doing with your A88? have you found tubes yet?
Also I think I'll roll the stock pre tubes on the A100.
Yes instead of forking out $$$ on a used Jadis DA60, this A100 at under $3K is a pretty good option.
Plaese post a review on your A100 when you get the new tubes.
Baton Rouge
No the 6550 is a close in design to the KT88, sorry that tube I do not think is gonna work for my orchestral. Back to KT90's. I wish some tube guru would post a comment on why the KT90 presents classical with the dimensions that other tubes fail at.
I think it has to do with the shape of the glass, its straight and narrow, so the musical energy doesn't get all sloshed around inside, as with the 'bulbier' 300 , KT88 and quite possibly with the 6550.
I just want to clarify some biasing issue with A-88T. Its true that A-88T is not auto-biasing and if you want to re-bias then you would have to flip/open/bias and put it back together. However, it is my understanding that you do not really need to bias it. It will work just fine if you just swap the tubes (KT88&6550). Its probably not going make a very big difference in sound, and depending on your preference you may actually like it.

I have the A-88T too and wanted to try the 6550. I took it to the local dealer, in san jose CA, to help me bias so I can see how it it is done. The owner is very knowledgeable about tubes and build his own tube amps, so I assume he knows what he is talking about. He told me that it is not necessary to bias the Cayin and would sound fine as it is. His own demo model, is using the 6550 and never biased it. This also explains why many A-88T owners who are trying different tubes but never re-biased thinking its auto-biasing and have never had any issues.

I bought the tubes 6550 from him and asked him to show me how to bias it anyway, which he graciously agreed(it is exactly as it is stated above). In fact mine is biased at 30mV with the 6550 and the recommended number is 42mV. I was told by this dealer that the Cayin will actually sound better (more upper extension) if you bias it a little lower. When you lower the bias then you are essentially lowering the power output a little, but in some cases it sounds better.

This is my understanding based on my research and talking to the distributor and my local Cayin dealer.

And one last point, if you have A-88T, then you must try the Tung Sol 6550 reissues. They sound very good as compared to the stock KT88. KT88 sounded a little bloated in the lower frequency in my system.
I have a Cayin A-70T and this is NOT auto biasing. There is a section in the manual which details how to bias the tubes, complete with recommended voltage settings. It's really a very simple process and you don't have to move a thing to do it, other than lift the cage off.

I searched the net as well and found that the lower wattage models state that those are auto-biasing. Maybe there's something about the US Version (VAS) vs. the others.
Your manual has biasing info ?
Mine , A-88T , is completely devoid of any info !
It took repeated emails to the European distributor to eventually receive some very skimpy instructions ! The North American distributor completely ignored my 3 emails to them !!!
Maybe this is a side affect of outsourcing ???
My dealer said that VAS is very slow in responding to emails and that I should call if I had any questions. I only needed to call once but I had no problem getting an answer.
I purchased mine from a dealer in PA who got it from VAS. I also noticed that some other A-70T's on the net that look somewhat different. There's some type of switch where mine has the bias adjustment and bias test points. Here are two pics of mine, including manual, fwiw.

Hi John
The pics of your 70T look nothing like my buddy's. He doesn't have any bias adjustment anything. Likewise for his manual. I am beginning to think there are several variations of every model Cayin! Very confusing.


So he didn't get it from VAS Audio? I agree with you, definitely some variations out there.

Oh yes, our local Cayin dealer gets everything from VAS. I don't think there is any other way short of importing it yourself which is sure to be a disaster.

There are simply different versions, that's all. His 70T came into the store back in November or so. My guess is the later ones are autobiasing whereas the early ones are based on the 88T.

There are some, and apparently you are one as was I, that think the stock tubes in the Cayin make it sound a bit hard and brittle.

I have listened to numerous amps, and the Cayin A88T however, is not in the hard and brittle catagory at all in my opinion and for my preferences, with the possible exception to some as to how it sounds with the stock tubes.

However, changing the sonic signature significatnly toward the sound you want with the Cayin A88-T, relative to the 'lively/stark' stock tubes, is an easy task with tube rolling.

Knowing what you think of the sound with the stock tubes, gives me a very good idea of what direction you want to go and what will work, as I have done alot of tube rolling and experimenting along those lines myself with the Cayin A-88T, prefering a strong musical midrange presentation and hating anything that smacks of hard or brital sound.

I recommend you buy a quad of SED KT88s (my preference) (or SED 6550), a pair of RCA round plate 6SN7s, and a pair of Raytheon 6SL7s for a wonderfuly warm and musical, open and non-harsh presentation which exceeds by my ears, the musical capabilities of most amplifiers around today.

Stay away from Tung Sol 6550s, ElectroHarmonix, and Genalex Lion power tube offerings, unless you want to bring in a level of extension that you will probably call hard and brittle.

Enjoy your Cayin A88-T. You have a wonderful amplifier.
Have you contacted Steve at VAS Audio regarding the biasing? I can't answer you question but what is strange is that there is no biasing procedure in the user manual. I would think that infered autobiasing. But I was also warned about the fact that one of the CAYIN amps required "cracking" the unit open to bias. Hard to believe that such a great amp would be so difficult to bias. I sure wouldn't want to do that on a regular basis. My opinion; - - for optimal performance, bias should be checked occasionally and re-adjusted if necessary. After 100 hours or so, this is important regardless of which power tubes you use. My preference is GENELEX "GOLD LION" KT88's. The amp will never sound better, but careful with the pre-amp tubes. I have an A-100T which I love. Biasing is super slick. Sound quality rivals virtually anything on the market except for perhaps AYON. I have one of those also. But the pre-amp tubes for the A-100T are custom configured for this amp specifically. I tried NOS tubes with terrible results. That's when I checked with Steve at VAS and found this out. I'm not a fan of 6550's. They are more rugged but tend to sound a bit brittle with certain types of music.

That's about all I can add regarding CAYIN. The A-50T is a stone bargain provided that you have reasonably efficient speakers. Only 18W in Triode mode. It also has a top biasing set up with the use of a meter. Easy to use. Great little amp. Very reasonable price.
I'm not certain if this is the CAYIN model that does require breaking the unit open from the bottom to bias, or not. I do know that this is the case with one of the CAYIN models, which is absurd to my way of thinking. Ask the CAYIN rep. (VAS AUDIO) I have an A-100T and do like it. pleanty of power to drive anything. I also have a JOLIDA 502BRC. Both are KT-88 designs, but have a different character. The JOLIDA is "darker" and softer textured in it's sonic signature, where the CAYIN products do sound a bit more up front and cold, especially with stock KT-88's. I switched to "GENELEX "GOLD LIONS". Anyhow I think the build quality of the CAYIN is much better that the JOLIDA products, but biasing can be a "snakey" situation with some tube amps. My main amp is the AYON SPIRIT II. It's more expensive but worth every penny and then some. I can forward you to a dealer that will give you a decent deal on AYON. I don't know if this helped at all but there it is.
please read what I wrote in 2006...this thread should be long dead.