Which KT-88 tube?

[FSHZ42]

Its not a good thing to run reissue GL Kt88 close to Max dissipation rate. I'd stay within 35-36W Max. I had the same problem with Quad forty II amps and GL Kt88 . It is self biased circuit which runs tubes at 39-40W i.e 90% of Max. After few hundreds of Hrs one of the went into thermal runaway meaning slowly creeping up bias up to the point when undersized 6W cathode bias resistor burned out. There are many stories like that with GL reisue. Its a good sounding tube though. I bought Penta labs chinese uprated Kt88 (also not cheap).
How do you find Odblock amps ? My dealer who caries ARC line also have a pair (with GL kt88 as well I did not listen to them but noticed how small Iron is in those amps. Aprox. 1/3 as big as in any other PP amps he's carring.

Hello Limono,

The GL KT88's that have been in my Odd Watt amps are set at around 90.5mV. Bruce and Rodney are partners with the company Odd Watt Audio, and I occasionally talk with Bruce from time to time. He is a great guy!


The 2 amps that I own have been upgraded. It has been reported that the GL tubes have had some issues in the past, so it is my understanding now, that Odd Watt audio, are using J/J tubes in their kits. I have listened to the J/J KT77's in the Odd Block amps, and personally prefer the winged "C" EL34's. I also favored the GL KT88 tubes the best. The El34 tubes will produce about 15 watts/per amp and the GL Kt88's produce around 25 watts.

I really enjoy my Odd Block amps, as they do perform very well! I am looking forward to trying out the Psvane T-series black bottle tubes, as I believe they will sound and perform better then the GL's!

Thanks again for your input!

 

[fandersen]

There is a company in China that claims to have the Shuguang KT88-Z (KT88) Treasure series. I tried emailing them about 5 days ago, but have yet to get a response. I am now very skeptical about ordering from them now.

I have read in a few places that some of the Treasures sold on epay on other places are second grade or possibly even factory rejects. Apparently buyer beware applies to buying Treasures, just like NOS tubes.

You have mentioned that the tubes you replaced your Gold Lion KT88's with are the Psvane T-series black bottle tubes. Would these have the same sound characteristics as the original Shuguang KT88-Z treasure series?

I would expect them to sound similar. They are built by the same factory. I think the only difference is that the Psvanes may have more quality control but that could be marketing hype

Based upon your experience with having listened to the Gold Lion KT88's versus these Psvane T-series black bottle tubes, how would you rate each one on a scale of 1-10.

Oh that's going to be tough. When I first put in the Gold Lions I was impressed. I had them for for about a year when I noticed the getter on one of them was slowly turning grey, though the sound did not appear to be changing. When I put in the Psvanes I immediately noticed a sound improvement. As they burned in they just got better. I'm hearing detail I never heard with the Gold Lions, and sound stage is wider and deeper. So on a scale of 1-10 I would say 7 for the Gold Lions and 9 for the Psvanes.

 

[FSHZ42]

I have read in a few places that some of the Treasures sold on epay on other places are second grade or possibly even factory rejects. Apparently buyer beware applies to buying Treasures, just like NOS tubes..

I agree with you on this!

I would expect them to sound similar. They are built by the same factory. I think the only difference is that the Psvanes may have more quality control but that could be marketing hype

I went to the Psvanes site that you had posted, and it appears that they have 3 selections to choose from, Factory T-Classic Grade (Good), Factory T-Collection Grade (Better), and F T-Collection Grade A (Best)

I am not sure what the differences are, maybe you can tell me which ones you have. I am really not interested in their gift box, but the price seems to be cheaper when ordering a quad set.

Oh that's going to be tough. When I first put in the Gold Lions I was impressed. I had them for for about a year when I noticed the getter on one of them was slowly turning grey, though the sound did not appear to be changing. When I put in the Psvanes I immediately noticed a sound improvement. As they burned in they just got better. I'm hearing detail I never heard with the Gold Lions, and sound stage is wider and deeper. So on a scale of 1-10 I would say 7 for the Gold Lions and 9 for the Psvanes.

That is very inspiring to hear! I guess my mind is pretty much set on the Psvane tubes. Do you know of any dealers here in the US that I may be able to purchase them from? Thanks again!

 

[fandersen]

I went to the Psvanes site that you had posted, and it appears that they have 3 selections to choose from, Factory T-Classic Grade (Good), Factory T-Collection Grade (Better), and F T-Collection Grade A (Best)

I am not sure what the differences are, maybe you can tell me which ones you have.

I bought the Grade A (Best). When I ordered they indicated they no longer stock Factory grade.

That is very inspiring to hear! I guess my mind is pretty much set on the Psvane tubes.

Note that this is my personal opinion of the tubes in my equipment. ymmv

Do you know of any dealers here in the US that I may be able to purchase them from? Thanks again!

I believe they offer free shipping world wide.

 

[scott17]

YMMV, but I have been running a pair of EH KT88s in my SE amp for about 4500 hrs, and they're still going strong.

Running at 70mA.

 

[FSHZ42]

Fandersen, Do you know what voltage your Psvanes tubes are running at?

Also, wondering how many hours would you expect to get out of them?

One last question- Have you heard of the Emission Labs tubes? Here is a link to the site: Emission Labs - Introduction

I just thought that you may like to take a quick look at them. I am not sure if they have the KT88 size and are not sure how they sound!

Thanks again!

 

[fandersen]

Fandersen, Do you know what voltage your Psvanes tubes are running at?

I don't remember. I do know I have a B+ of 440 and I'm running them in ultra-linear mode so a little below that.

Also, wondering how many hours would you expect to get out of them?

I would expect thousands.

One last question- Have you heard of the Emission Labs tubes? Here is a link to the site: Emission Labs - Introduction

I just thought that you may like to take a quick look at them. I am not sure if they have the KT88 size and are not sure how they sound!

Thanks again!

Yes, I have heard of them but have never listened to any of their tubes.

My decision to go with the Psvanes was based on the experience of a fellow DIYer who spoke enthusiastically about them in his amp. I was not disappointed

 

[FSHZ42]

Fandersen,

Thanks again for your info! I guess that I will be placing an order soon for a quad set. I guess the best place to order them would be through Psvanes web-site.

As far as biasing the GL KT88's, they were set at approximately 90.5mV per tube, so I am guessing the Psvane KT88 tubes should be close to that?

Once again, Thanks!

 

[FSHZ42]

Almost Forgot!

While it just came to me about the pre-amp tube. Each of my amps have 1- JAN 5751 Phillips ECC pre-amp tube.

My question is do I keep them and just replace the power tubes, or is there a better pre-amp tube that would be a better match for the Psvane tubes?

Thanks in advanced!

 

[fandersen]

While it just came to me about the pre-amp tube. Each of my amps have 1- JAN 5751 Phillips ECC pre-amp tube.

My question is do I keep them and just replace the power tubes, or is there a better pre-amp tube that would be a better match for the Psvane tubes?

There is no need to replace the 5751 tubes, unless you want to

 

[FSHZ42]

There is no need to replace the 5751 tubes, unless you want to

I was told that the NOS GE 5751 were among the best sounding pre-amp tubes. I went to a site that has them, but they are on the high $$$ side.

I was also told that the Phillips JAN 5751 ECC's, which I am presently using, are at the bottom of the pole.

I am not sure what to believe! Maybe someone here can give me their inputs!

Thanks!!!

 

[multi]

I don't think you need to run KT88's at more than 50 ma per tube.
90 ma would burn them out fast. GEC with the original KT88's, recommended that anything above 35 mills was plenty.
Phil

 

[FSHZ42]

Hello Multi,

I was referring to the voltage not amperage. The GL Genalex KT88's are run on my amps at around 90mV. I run my SED Winged "C" tubes at around 62.5mV. I have not had any problems, except for the GL tubes on one amp reading out of the specific range tolerances.

It has been known that the GL tubes have had these issues in the past.

Thanks for your reply!

 

[Jim McShane]

Hello Multi,

I was referring to the voltage not amperage. The GL Genalex KT88's are run on my amps at around 90mV. I run my SED Winged "C" tubes at around 62.5mV. I have not had any problems, except for the GL tubes on one amp reading out of the specific range tolerances.

It has been known that the GL tubes have had these issues in the past.

Thanks for your reply!

What do you mean by "specific range tolerances"?

 

[FSHZ42]

What do you mean by "specific range tolerances"?

I try to keep the voltages going into the output tubes at around a 2% tolerance. This means that if you are running a certain power tube at say 60mV (manufacturer specs recommendation @ 60mV), the 2% tolerance would be +/- 1.2mV.

This is what I meant by the "specific range of tolerances"

I left the "of" out.

 

[TonyTecson]

perhaps you mean mA?

or a 1ohm cathode resistor drops 60mV when a current of 60mA passes thru it....

 

[ScottLowe]

any input on a good cheap kt-88,looking for a back up quad. just in case.

 

[multi]

After many years of using Tungsol reissue KT88’s a friend purchased a large quantity of Psvane KT88’s. He runs an active system with 10 mono block amps then his troubles started the Psvanes took out all his amps. One or more tubes would blow the 10 Ohm cathode resistors, the G2 resistors when triode connected. Luckily he had bought the Psvanes from a USA distributer and they took the lot back. He has gone back to Tungsol and no problems for over one year much cheaper; I think the Psvanes cost $A100 each the tungsols in bulk less than $27.00 each. The amps run at 400-450 volts, 50 Ma.
The Psvanes came in fancy boxes: JUNK
Phil

 

[MelB]

Search ebay. There is a listing for a quad of Svetlana KT88 for USD 126.00 (77 sets sold!). I have run these tubes for years with no problems.

 

[sleiven]

try som KT120 instead ,if you have the heater capabilities