Tube rolling in Cayin A-88T


Anyone changed out the stock KT-88 tubes?What have you found that beats the stock jobs?..I understand Cayin uses the Shuguang KT-88. As good as these are, they are the 3 hole plate which is said to be inferior to the solid plate version. Can anyone comment in regards to what they are using? Thanks.
128x128kehut
i am Cayin A-88t user almost 1 year.i am very happy with the stock KT-88 tube, i find out that stock tube is exact design like U.K GOLD-LION.as you can see the same type
KT-88 tube are very popular.It use on: VAC,Quicksilver.....
this KT-88 Tube use in the Cayin A-88t amp is musical, warm,rich, powerful tube,
is like music with all the good's there !! why change !
or may be i buy new quads same tube to replace the old....
I also own this great amplifier. In addition to the stock tubes, I own a quad set of tung-sol re-issues 6550, and a quad set of Svetlana KT-88's. Both sets outperform the stock tubes handily. the Tung-sol are lush and a bit warm-sounding, but have midrange to die for. The Svets are more neutral and give the Cayin a solid-state like low end bass. I don't think you can go wrong with either of them.

As much as I enjoy this amp, I may have to sell it to go (reluctantly) back to a solid state system, as I need something that can stay powered up all the time. I only listen to 1-2 tracks at a time, once or twice a week..

Try these tubes and be happy!
Audiolverb..Thanks for your insight.

Soniqmike... Sorry that you may have to sell it..though I understand your point here. Another read of a thread somewhere mentioned that the EH tubes were not as good as stock.. and I always found the EH tubes very good in any amp I used.

Now,the New Tung Sol 6550 is said to be a better tube in the mids. Does it match the bass in the Cayins stock Kt-88?

Im assuming your speaking of the Svet =C= winged C tube. that you liked. I think Id rather have the mids of the Tung Sol as long as it doesnt suffer on the bass....Many thanks.
Sorry for the late response....The stock tubes are actually not too bad. The Tung-Sol are great in the bass also, I would say better than the stock tubes, but it's a toss-up. Yes, we are talking about the C-winged Svets. My tubes are Upscale Audio labelled on the box.

I keep the stock tubes installed for my occasional 2-3 tracks at a time during the week and for FM listening during dinner ( Cayin tuner, nice. ). Come Firday night, I might put in the Svets, keeping the Tungs in almost unused condition in their box. But if I have a hard-edged or badly recorded, bright cd I wish to listen at length, they come into action...ah, the beauty of tubes.

These last two quads sets (Svets and Tungs) have limited usage.

Hope you like your Cayin A 88-T, nice machine isn't it ?
Thanks Mike! Yes indeed. Been around many amps over the years and always seem to find that well designed modest power tube integrateds offer the nicest sound. My other favorite was the Manley Stingray, which does well by the music with a punchy mid bass and smooth highs. The A-88T is much better in resolution and has better image and soundstage abilities, as well as deeper bass with the Kt-88's. The level of refinement of the sound is amazing, especially concidering its sub 2K price.. Seamless and coherent driving my Usher 6371's.

I took your advice and scored both quads of the Tung-Sol and Svet Winged "C" Kt-88's..It should keep me tuned in for awhile. The Cayin 17A CD is also another nice piece. Highly resolving and dynamic without glare or artificial edge, which I distain about digital. Only the Rega Apollo did this as good, but doesn't have quite the Dynamics of the 17A. Im trying some 1972 vintage orig. Tesla Mil. Spec. E88CC in the player which should out do the stock Russian 6922 EH.

Overall, Cayin is highly musical and complete in its portrayal of the music, which suits me very well!....Ken
I also love the Cayin A88T which I have owned for the last 7-8 months now. I am using the stock tubes and have been thinking of upgrading to the PentaLabs or the TungSol re-issues. This thread was just what I wanted.

I hope you guys are biasing the amp after tube rolling as this is not an auto biasing amp as some mistakenly believe.

I found one of my tubes having zero bias and I changed it immediately. The amp sounds much better now.
Kag,

I got the biasing info from Steve at Vas Audio in NJ. Seems relatively simple. Bias point of 0.4V (40mV) per tube. Clark at Acoustic Sounds was nice enough to have Vas Audio send the info to me. I will definately check bias and make sure the Tung Sols are set properly.

Ive had new tubes show 0 readings too. I have had more trouble with Ei tubes than others. The KT-90 TypeIII are notoriously bad for QC issues.

From what Clark says..he hears that the new re-issue Tung-Sols are wondeful in this amp, but take a bit of time to open up. Ill get back to this thread after they are in for awhile//Ken
Have you'll tried rolling the preamp tubes? I changed the stock 6sn7s to RCA 6sn7 GTBs and the sound improved a notch. Better soundstage, mellower and richer mids, surprisingly more detail in the mids and bass.

I did find trumpets on some recordings to be bright/hard on the stock tubes... for example, the trumpet on the track 'Papa a boo boo' on the German pressed CD of Harry Belafonte live at CG Hall was quite bright and hard sounding. This reduced considerably on the RCAs but it is still there. I wonder why? Could be due to the stock output tubes. I heard the Primare drive my speakers (Dyn 82s) and there was no hardness at all. My CDP is the Rega Planet which is known to be smooth. Interconnects are Transparent which is also mellow. So I guess the amp is the culprit.
Kag,

Haven't rolled the input tubes as yet. I have experience with the RCA grey glass VT-231 GT tube from the 50's. I thought it was definately a smoothie, but I actually liked the linearity of the stock EH tubes in my former Cary amp. The Cary definately needed the EH to sound alive. The RCA in the Cayin may be indeed a nice sound as you mentioned.

Ive yet to hear harshness from the Cayin with anything Ive played, except those discs/LP's known to be so.I recently played some trumpet from Rick Braun(Full Stride) and Chris Botti( A Thousand Kiss...) and man they sounded excellent!

Perhaps the RCA/Tung Sol combo would be very good together.

One thing to keep in mind is that the amp/speaker interface is all telling as well as you know.. It's likely the reason why you may have NOT heard the harshness with the Primare.

On my Ushers, if anything, I have a sound presentation that is more relaxed, yet very dynamic with the Cayin. I found that the 4 ohm tap didnt work as well as the 8 ohm tap and by a big margin. The 4 ohm limiting the dynamics and bass. And the Ushers are 4 ohm nominal

maybe try the 8 ohm tap if not being used would also be a suggestion. You shouldn't need the 16 ohm tap unless your speakers are rated as such or very high ohm/hi-sens types.

Just a thought.

Hoping the Tung-Sols arrive here soon!

As a aside note: When I ordered my 88T from AS's..I spoke with Clarke who recommended going with the KT-88 version. He thought it sounded better amp for amp and the 6550 version comes with EH 6550's.FWIW.
Are you guys using aftermarket powercords with the A-88t? If so, any suggestions on which works or sounds good? Thanks
Great sound with VH Audio Flavor 4 cord. I think this cord works well with many components. Im very impressed with it on both this amp and my Cayin 17A CD.
Which speaker terminal are you guys using? There seems to be a pretty good difference between each one. The flexablity this amp offers is a strong plus. You can change tubes, switch between UL and Triode, and use different speaker terminals.
I've tried all the taps and definately prefer the 8 Ohm. In my system the 4 Ohm limits the dynamics, bass..everything is flat sounding. The 16 Ohm is a bit bright..8 Ohm perfect! I listen exclusively in UL mode. The Triode less coherent and < dynamic overall.

Just biased some Re-Issue Tung Sol 6550's and they sound very good indeed. Bass is not quite as prodigious as the stock tube.. being somewhat less focused, but the mids are more lush with a nicer top end IMO.. A Very listenable tube/ Im sure they need to break-in for a time.
I just got one Cayin A-88T, unbelievably it sounds a bit harsh compared with my TEAC DR-L700, a tube amp !!!

Should I use supports with it, or is it unecessary ?
Lowrider, How much time do you have on the amp? Break in of tubes as well as the amp itself is quite important. If you have less than 100 hours on a new tube amp I'd reserve judgment. Ultimately though you might roll in some warmer power tubes (I like SED KT88's) and/or some NOS small tubes.
"harsh compared to TEAC". Are you refering to TEAC that japanese c**p that came out in the 70's?
Spam. The Cayin needs zero breakin time btw Newbee.
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Bartockfan,

Spam? Reconsider your musings about Tyler speakers and the Cayin Amps. Frankly, that IMHO, is SPAM. You have no first hand knowledge of either yet you ponder on, an on, and on to the benefit of no one except yourself by seeing your thoughts in print!

Sorry, but I'll spare you the dubvious benefit of advise or comments in the future. :-(
My stock power tubes are EH6550. I have been using GEC KT88, much better sonically. You should replace the stock input tubes, which will result in big improvement. Syl 6sn7w will shine from top to bottom. And RCA 5891 is a good match. The final result is the brilliant sonic house blowing up lots of much more expensive amps. I will be trying the GEC copy version of the Chinese KT88 very soon.
A Tripath TEAC sounds very good with my 96 db speakers, better than the Cayin so far...

I changed to the 8 ohm terminals, and the sound improved a lot, still a bit bright with some recordings, but acceptable now...

I guess some more playing will make it fine...

But I am worried with a THUMP on the left speaker when I switch off, only sometimes, and loud HUMMM, also from the left speaker, and also only a few times, when I turn it on, it stops after a while...

Thanks for your help...
I switched the pre-amp tubes, left with right, to check if it was a bad tube, so far no more THUMPs or HUMMM, knock on wood...
I always read that amplifiers shouldnt be connected to mains filters, but, as the Cayin only uses 280 watts, I connected it to my ESE labs Balanced isolation transformer...

Well, it did almost the same it did to the TEAC, smoother highs, more body, darker background...

Its getting there, and no more THUMPs or HUMMM yet...
Tubes are not for me, no patience for HUMMM, and THUMP, and adjusting bias, and not so good sound, so it is packed and will be returned today...
It arrived back to the vendor, the pre tubes where malfunctioning, he replaced them with premium units, says the amplifier sounds great now, wants to ship it back...

No thanks, I have no warranty it wont happen again, and it costs almost 200 euros one way shipping...

The very alive front row center sounding Cayin A-88T is still one of the very best tube amps out there! The Cayin A-88T with its 45 tube watts and the less powerful Almarro 318B SET tube amp with its 18 tube watts, bettered over a dozen top flight amps (VTL, Cary, Musical Fidelity, Unison Unico, Prima Luna (a relative), etc) that I owned for my preference in sound in my system. (as you may know, it seems that you can often get effectively twice as much power out of a tube watt than you do out of a solid state watt)

Better late than never for a review of tube rolling. The following combination was found after an A-B shootout and careful listening with all popular tube combinations that I could find in my system:

In the Cayin A-88T, for power tubes I preferred the SED Winged C KT88 tubes (sadly no longer in production as Svetlana got bought out (kept the name) and the St. Petersberg SED factory closed) are now relatively costly unless you get the less popular SED Winged C 6550 which are slighter warmer and softer, although not bad, not the same). However, I found some Svetlana KT88 which had the same plate structure and coke bottle appearance to the glass as the winged C SED (not straight, with three holes in the center of the plate) to sound close to the SED Winged C KT88 and recommend them over the Winged C 6550, unless you want the slightly softer and warmer less dynamic sound that the 6550 produce. I found the Gold Lion tubes as well as E.H. a little too sterile, overly detailed and lean to me.

For the pre-section tubes, I found that the best combination was two RCA VT231/6SN7 made for military tubes and two military Sylvania VT229/6SL7. Or for more detail, I replaced the Sylvania VT229/6SL7 with 1940's to 50's Mullard ECC35/CV569/6SL7. The constant winner for best amp sound on balance resulted in the 6SN7 tube slot always occupied by the military RCA VT231/6SN7 regardless. I found in general that the military versions labelled VT229 and VT231 sounded the best over civilian versions without the VT prefix (with the possible exception of some 1940's tubes).

Note: if you want to go for the ultimate lush midrange, and forgo some treble and dynamics, a combination of Sylvania VT231 and Sylvania VT229 seemed to do the trick, although for balanced sound, was not optimal to me.
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