Hi, I had the same questions about possible KT88 replacements for my orginal stock Valve Art KT88 and my tube guru gave me the following review to read about the current EH KT88's:
Additionally, he's a well respected SF Bay Area audio engineer who participated in a 2002 6550/KT88 Shoot Out that published in Vacuum Valley Tube publication. His private notes from the shoot out said the Gold Lions NOS ranked first (rare and expensive) while the EH's ranked second with the Tung Sols and JJ a discernable step behind. Consequently, I've decided to go with the EH's which are reasonably priced at $25/each at Tubedepot.com.
Also, on Ebay search "Amperex 6922", a seller has a batch of 1960's NOS for $35/each. Read the story and Feedback to evaluate his credibility. I ordered some. These are new, unused, discovered in a flood damage storage, without boxes and rubbed off lettering but test as new. Normally, these sell for $90-150. I thought it was a great opportunity and took advantage of it.
Good luck, it might be you won't do better than the EH unless you are looking for your tubes to address specific "sonic" needs.
My favorite KT88 is the KT88SC is from Penta Labs. This is also a Chinese tube by Shuguang, but is reportedly made to specs of the Genelex 88's. These tubes get rave reveiws over at Audio Asylum and several guys over there swear that these are comparable to their Genelex 88's. I can't speak to that claim, but they are excellent tubes in my system and the best new production tubes I have tried. In my system they better both the EH and SED KT88's. I have placed a link below (pentalabs.com), but if you decide to buy these you should call to make sure you get the the "solid plate" version. If not, you may get the KT88-98 equivalent, which is identified with three holes in the plates and, from what I've read, is considered inferior to the solid plate KT88SC. Also, you can do a search over at the asylum. Theres a lot of talk about this tube.http://www.pentalaboratories.com/product.asp?dept%5Fid=5020&pf%5Fid=KT88SC+SHUGUANG
JJ KT88's are very reliable and good sounding. Their plate have additional heat sinking wing. One of my friend use them in his Harman Kardon amp operating at plate voltage of 650V and they out-lasted any tubes he ever used.
I thing I've learnt: one brand of tubes that works well in one amp NOT NECESSARILY works as well in another brand of amp!
Ken, if you can search the archives here or AA or elsewhere & find out which tubes best/better suit your particular amp, you would be far better off than getting our resp. opinions (UNLESS someone w/ the same amp as yours posts a reply). Your research will probably give you a short list from which you can try tubes & that list might not incl any of the tubes listed in the VTV shoot-out!!
trying various tubes can be fun (I've done that myself) when one has time but is very painful (I've experienced this too!) grading each tube's signature when one doesn't have time or wants to simply get on w/ listening to music. In all cases, whether you like auditioning tubes & have plenty of time, I've found that a shorter tube list is always better. FWIW. IMHO. YMMV.
I believe Bombaywalla makes an excellent point about amps being voiced with certain KT88s.
In my recent journey, three KT88 tubes were heartily recommended by several audiophiles: Svetlana Winged "C", JJ Tesla, and Penta Labs KT88sc/Shuguang KT88-98.
Regarding the Penta Labs KT88sc, and the following comment that
My favorite KT88 is the KT88SC is from Penta Labs. This is also a Chinese tube by Shuguang, but is reportedly made to specs of the Genelex 88's.
This is not entirely accurate. The Penta Labs KT88sc are not made to the factory specs of Genelex KT88, nor are the Penta Labs KT88sc made with the same materials or on the same equipment as the Genelex KT88. Penta Labs has a disclaimer on their website that the Penta Labs KT88sc is designed to cosmetically resemble the Genelex KT88, and Penta Labs makes no further claims to the similarity of these two brands.
Also, I think it's intriguing that one selling point of the Penta Labs KT88sc is their similarity to the Genelex KT88, including the three oval holes in the plate, and yet folks recommend purchasing the solid plate version, which is not like Genelex KT88.
I purchased a set of Penta Labs KT88sc with three oval holes, because I found a lightly used set, and they appear to exctly match the stock VAC KT88 that came installed in my VAC Phi 110/110.
Ken, the Penta Labs KT88SC solid-plates... http://www.pentalaboratories.com/product.asp?dept%5Fid=5020&pf%5Fid=KT88SC+SHUGUANG ...are VERY highly rated by the inmates of the Tube Asylum... http://www.audioasylum.com/scripts/tv.pl?forum=tubes&s=U . I suggest you SEARCH there and learn a lot.
They were selling for only $22 each recently; be sure to call them to make sure you get the closed-plate versions.
The Penta version with the 3 holes in the plates is the KT88-98 tube that you can buy through several online outlets. Penta advised me that they substituted this tube for the solid plate "KT88SC", when they were sold out of the solid plate version. The solid plate which is the true "KT88SC" that "I believe" is sold exclusively by Penta. There's a thread on Tube Asylum in which a Penta rep confirms much of this. In any event, you have to call Penta to ensure that you get the solid plate version, if thats what you want. I haven't compared the two, but the solid plate tube is very good.
Cruz123, what you say makes sense to me now that I did a quick web search and found a photo of Genelex KT88 Gold Lion tubes that have solid plates.
It's confusing, because the photo of the KT88SC on the Penta website used to show three oval holes, but now it shows a solid plate.
Now, I know why my Penta KT88SC quad was sold at a nice discount.
Recently there has been a seller on ebay with these solid plate Shuguang kt88sc. I emailed him the Penta link and inquired whether his are the same tubes. He confirmed they were. His handle is "thenidge".
His BIN price for a pair has ranged from 42.50 to 46.50.
I don't see any there currently, so to see them, goto "advanced search" and do a "completed items" search for his name "thenidge". For some reason, searching on "kt88sc" doesn't return them...even though it is in the title.
Anyways, it looks like he might have some quantity and is dripping them into the market just a few pair at a time.
on Ebay, if you search on "kt88sc" you will find the tubes I referenced above. It looks like he puts up 2 pair at a time, and sells with BIN only.
Thanks guys for all the nice info and recommendations. When I first posted this question re: KT-88's...I was using a Cary CAD 50MkII, but now using a Cayin A-88T/KT-88 tubes. From what I understand, Cayin uses the Shuguang KT-88. and they have the 3 hole plates. I may seek out the solid plate version from the links provided. Does anyone else use the Cayin amp with these tubes and switched to the solid plate tube?,,,,,Thanks.
I love kt 88,s and I can attest that EH and jj,s are going to be hard to beat not to say it cant be done but really for the money diffrence there are no better tubes (kt88) out there.I also own a set of Tung-Sol 6550,s but they are a little to warm for my taste. And the JJ,s dont have the mids that the EH have but are comprable in highs and lows.
I own a VTL S-400 Reference amp. I went back and forth with Gold Lion KT-88s and Penta KT-88sc. The Pentas clearly are better. The GL were thinner and the highs were too bright. The sound in general was to thin and not enjoyable. I put the Pentas back in and I was happy again. Curious about the EHs
I have used several KT88's over the years. It seems as if every time, I go back to the EH or the Svetlana Winged C's as my defaults. The GLKT88's, though highly praised, and a costlier alternative to the EH's, seem middle of the road in my system, that is, they do not add or subtract from the musical experience and seem bland at times. Because the GL's don't do much but balance the frequency and musical spectrum so to speak, I feel that my system lacks some get up and go. With the EH or Winged C's, they each bring back the get up and go and make you want to listen more. I am not saying the GL's are bad tubes, because, many people like them, and in my Octave MRE 130 mono tube amp, they do bass well and they seem to do the midrange real well, but the highs fizzle, whereas, the EH's and Winged C's add more midrange and extended highs. It is a pronounced difference.
I am testing an octet of JJKT88's and they seem a little dry right now, but with very wide separation. I need to give them a few more hours to burn in. I was skeptical of the JJ's as the build quality seems a few notches below par of the EH, Winged C's, and GL's. The price is below market for other KT88's, and I wanted to experiment. I am also testing the Tung Sol KT120's, but that is for another story.
Has anyone tried the Sovtek KT88's?
In the end, I believe the EH's are one fine tube that equally benefit many tube amp owners in the same way as the GL's do for others. The sound is perceived differently on different equipment.
I guess I could say now, that having been there and done that, I prefer the EHs and Winged Cs over many other tubes I have tried so far. The story is still unfolding in regards to the JJs, but if history repeats itself, I might be going back to the EHs as my default, again.
No your right! EH KT-88,s are by far better than many tubes costing many times the price! I have heard many many tubes and Ive learned that no matter what equipment you are using they have the same signature sound. They are the blank slate or the proverbial "White canvas" as far as I am concerned. STIPULATION as long as the bias is right,but that being said these tubes are very forgiving if biased incorrectly. They are tough tubes to beat. I like a forward, dark tube in the pre like the New production JJ ECC803/12AX7 gold pin and the same tube sounds great in the phase splitter (ONLY IF it has a Phase splitter) I hate phase splitters! I didnt pay $20,000 for a pair of speakers with no crossovers to avoid unnecessary phase issues (crossoverless design, EX-Vandersteen,s) then buy an amp that does! Thats one of the best things about SET amps. Never buy a SET amp if it has a phase splitter! There are some great amps that have splitters but....Audiophiles...I / WE are picky! Why do phase splitters even exist? Why would anyone think that taking the signal then tearing it into two halves seperating the signal then putting the signal back together as one is a good idea? How do you do this and not lose something in translation??? I lose something from RCA cables so I can only imagine what Phase splitters do to signal! I have never understood this! WAIT!..Now for solid state it may be a necessary evil for power. Good ear! Happy listening!
How has the JJ burn-in gone? I am also at a crossroads. (I will be strapping KT88 rertomodded Dynaco MKIIIs into triode or maybe tetrode.)
I have boxed the JJ's and probably will sell them. My amps simply did harmonize with them. Straight out of the box, the JJ's were closed in and sounded like they were nasal sounding. I gave them a chance and about 75 hours. That was enough. I ordered another set of the EH KT88's and all was rigth again. I now know that the EH KT88's are the ebst choice for my amps and my listening. If you want the JJ's send me a private e-mail. I will never use them in the these amps.
I meant to say that The JJ's did not harmonize with my amps at all. I noticed some spelling errors. It was early in the morning and I was half awake. I wish spell check was enabled in Explorer like it is in Google.
Bottom line, the JJ's sucked when I tried them in my Octave amps.
Has any heard of ruby tubes 6550a 98str. They are made in china. I have a Von Gaylord amps Sounds great but just wondering if the kt 88 would sound better. Thanks. Steve.