Gold Lion KT88 & MC275/MC2301

[MC352]

Originally Posted by Ron-C

Chuck,

In all fairness I suspect one of your GL tubes may have been damaged in shipment. If they are up to snuff I think they sound pretty good. I have four that sound and measure good but I also once had one go bad.
I would suggest you have someone check them or measure your amp with the tubes installed.
I am impressed with the KT88-Z tubes but once again I had one that was low in output which the supplier covered. These fragile tubes get a lot of banging around in freight if sent all the way around the world.

thanks,

Good idea, Ron.
I know someone who is very knowledgeable with tubes. He repairs, rebuilds and sells tube gear. I'll hook up with him and have the tubes tested.

Thanks

[m.tonetti]

I found two quartets of Gold Lion KT88 Platinum with the value of Ip and Gm respectively 72 and 8,500.

Are they good values?

[vintage_tube]

Originally Posted by m.tonetti

I found two quartets of Gold Lion KT88 Platinum with the value of Ip and Gm respectively 72 and 8,500.Are they good values?

Is that what the box is stenciled or what you or someone tested for you?

IME, it's been hard to find GL Reissues sold today that register above 8,000. When they first came out 8-8500 was the norm per se.

Anyway, in answer to your question -- that is an excellent reading for reissues.

Bob

[m.tonetti]

Originally Posted by vintage_tube

Is that what the box is stenciled or what you or someone tested for you?

IME, it's been hard to find GL Reissues sold today that register above 8,000. When they first came out 8-8500 was the norm per se.

Anyway, in answer to your question -- that is an excellent reading for reissues.

Bob

Label on the box.

Thanks, Bob.

[nsgarch]

Only three KT88's break the 8000 -- 8500 micromho threshold, and yield truly spectacular sound (i.e great dynamics, detail, and a kind of "electricity-in-the-air"). When new, they all test between 11,000 and 12,000 micromhos transconductance. They are:

1. The vintage M.O.V. (better known as GEC or Genalex) Any of the three versions will do: Gold Lion, Gold Monarch or the GEC 'blue label' domestic version. These wil cost $1400/quad and up for truly NEW Old Stock tubes. Caution -- there are some 1980's tubes that say "Made in the UK" etc. They have black bases (as opposed to the authentic brown.) These were made in China from parts supplied by the English company when they shut down manufacturing in England. They are inferior (mostly because of poor vacuum pumping.).

2. The Shuguang Black Treasure Series KT88-Z, which Ron mentioned. Also my current favorite, but not by a super-wide margin. Very reasonably priced @ $357 per premium quad directly from China incl. PP and insured DHL airfreight Shuguang,Shuguang treasure,Fullmusic,Guiguang tubes,amplifier chassis,tube sockets,capacitor,resistors,coil meters,toggle switches,tag boards,transformer covers,various parts for tube guitar amps diy <meta name="keywords" content="tube sockets,shugua Note: these tubes must be burned--in for the full recommended 300 hours in order to achieve their full specs; probably to allow the carbon coating to cure.

3. EAT's from EuroAudio Team @ $1600 per matched quad: KT88 DIAMOND Tube Valve - - - EUROAUDIOTEAM - -

As you can see, the Shuggies are an excellent buy. If you just want the best bang for your (cheap-out) buck, buy a quad of Shuguang (Penta) KT88-SC. They are less expensive and better built than the "Reissue" (sic) Gold Lions from New Sensor, and are in fact EXACT replicas of the original Gold Lions (they just don't test as high as the originals ;~)

Hope that clears the air a bit ;~)

[Tonepub]

We've also had excellent luck with the Shuguang and the EAT tubes. The EAT's are kind of spendy, which might make them a little crazy for a 2301 owner, but they are great in an MC275!

[Jerome W]

Originally Posted by nsgarch

Only three KT88's break the 8000 -- 8500 micromho threshold, and yield truly spectacular sound (i.e great dynamics, detail, and a kind of "electricity-in-the-air"). When new, they all test between 11,000 and 12,000 micromhos transconductance. They are:

1. The vintage M.O.V. (better known as GEC or Genalex) Any of the three versions will do: Gold Lion, Gold Monarch or the GEC 'blue label' domestic version. These wil cost $1400/quad and up for truly NEW Old Stock tubes. Caution -- there are some 1980's tubes that say "Made in the UK" etc. They have black bases (as opposed to the authentic brown.) These were made in China from parts supplied by the English company when they shut down manufacturing in England. They are inferior (mostly because of poor vacuum pumping.).

2. The Shuguang Black Treasure Series KT88-Z, which Ron mentioned. Also my current favorite, but not by a super-wide margin. Very reasonably priced @ $357 per premium quad directly from China incl. PP and insured DHL airfreight Shuguang,Shuguang treasure,Fullmusic,Guiguang tubes,amplifier chassis,tube sockets,capacitor,resistors,coil meters,toggle switches,tag boards,transformer covers,various parts for tube guitar amps diy <meta name="keywords" content="tube sockets,shugua Note: these tubes must be burned--in for the full recommended 300 hours in order to achieve their full specs; probably to allow the carbon coating to cure.

3. EAT's from EuroAudio Team @ $1600 per matched quad: KT88 DIAMOND Tube Valve - - - EUROAUDIOTEAM - -

As you can see, the Shuggies are an excellent buy. If you just want the best bang for your (cheap-out) buck, buy a quad of Shuguang (Penta) KT88-SC. They are less expensive and better built than the "Reissue" (sic) Gold Lions from New Sensor, and are in fact EXACT replicas of the original Gold Lions (they just don't test as high as the originals ;~)

Hope that clears the air a bit ;~)

Thank you very much Neil for all these informations !
As always, a priceless post.
As I told you before, I wish you would post more often.
I can't find the KT88-SC on the site. Only the Z.
I ordered a Maximatcher tube tester on Bob's advice.
Can't wait to test my Gold Lions ( reissues) and order 16 of these "treasure tubes"....Damn, that is an investment... !

[m.tonetti]

Originally Posted by nsgarch

Only three KT88's break the 8000 -- 8500 micromho threshold, and yield truly spectacular sound (i.e great dynamics, detail, and a kind of "electricity-in-the-air"). When new, they all test between 11,000 and 12,000 micromhos transconductance. They are:

1. The vintage M.O.V. (better known as GEC or Genalex) Any of the three versions will do: Gold Lion, Gold Monarch or the GEC 'blue label' domestic version. These wil cost $1400/quad and up for truly NEW Old Stock tubes. Caution -- there are some 1980's tubes that say "Made in the UK" etc. They have black bases (as opposed to the authentic brown.) These were made in China from parts supplied by the English company when they shut down manufacturing in England. They are inferior (mostly because of poor vacuum pumping.).

2. The Shuguang Black Treasure Series KT88-Z, which Ron mentioned. Also my current favorite, but not by a super-wide margin. Very reasonably priced @ $357 per premium quad directly from China incl. PP and insured DHL airfreight Shuguang,Shuguang treasure,Fullmusic,Guiguang tubes,amplifier chassis,tube sockets,capacitor,resistors,coil meters,toggle switches,tag boards,transformer covers,various parts for tube guitar amps diy <meta name="keywords" content="tube sockets,shugua Note: these tubes must be burned--in for the full recommended 300 hours in order to achieve their full specs; probably to allow the carbon coating to cure.

3. EAT's from EuroAudio Team @ $1600 per matched quad: KT88 DIAMOND Tube Valve - - - EUROAUDIOTEAM - -

As you can see, the Shuggies are an excellent buy. If you just want the best bang for your (cheap-out) buck, buy a quad of Shuguang (Penta) KT88-SC. They are less expensive and better built than the "Reissue" (sic) Gold Lions from New Sensor, and are in fact EXACT replicas of the original Gold Lions (they just don't test as high as the originals ;~)

Hope that clears the air a bit ;~)

Thanks, Neil. As usual very detailed post.

I had already read with great interest this your post on the Shuguang Treasure Series KT88-Z.

I should ask a matched quad of Premium Grade A KT88-Z's with Ip >= 50?

Otherwise, what are the good values of Ip and Gm of the Shuguang Treasure Series KT88-Z?

[nsgarch]

Originally Posted by C220MC275

Thank you very much Neil for all these informations !
As always, a priceless post.
As I told you before, I wish you would post more often.
I can't find the KT88-SC on the site. Only the Z.
I ordered a Maximatcher tube tester on Bob's advice.
Can't wait to test my Gold Lions ( reissues) and order 16 of these "treasure tubes"....Damn, that is an investment... !

Hi Jerome.

You can get PENTA KT88SC from Doug's Tubes 6550/KT88 Power Tubes for $180/matched quad. I like Doug because he burns and matches tubes before shipping (and intl. shipping is VERY reasonable)

I mention the shipping because I don't know/think if the KT88SC is available outside the US. PENTA LABS is a US company Penta Laboratories: Product Details SHUGUANG MP

BTW, their website lists the transconductance spec on the KT88SC as 11,500+ umhos. I never found any over 7500, but I'll reserve judgement until you test them with your new tester ;~)) Or maybe just email Doug at Doug's Tubes and ask him.

[nsgarch]

Originally Posted by m.tonetti

I should ask a matched quad of Premium Grade A KT88-Z's with Ip >= 50?

Otherwise, what are the good values of Ip and Gm of the Shuguang Treasure Series KT88-Z?

Massimo, the KT88Z plate current (mA) as these tubes come off the production line, range from 30 mA to 60mA. As I mentioned elsewhere, it's not possible to accurately measure these carbon-polymer coated tubes until after 300 hours of use (standard power tubes can be measured and matched after +/- 24 hours.) So the initial plate current is only a guide (it will get better.) Generally speaking, tubes under 45mA are considered 'B' grade and over 45mA are "A" (Premium or Luxury) tubes.

If you specify to the seller (or at least to my seller ) that you want matching plate currents of no less than 50mA, you can be confident that after the 300 hour burn-in period, the tubes will provide best measurements and best performance. Just be prepared to wait 3 + weeks for a new production run so he can hand select them for you