KT88 vs 6550 Power Ratings

[JWH]

I just noticed something that surprised me. I've read in various places on the web (so it must be true) that the KT88 is typically rated at 42 watts plate dissipation and the 6550 is rated at 35 watts. I've read this over and over.

However, I was casually browsing the New Sensor website and looked up their specs on the Gold Lion KT88 reissue and the 6550 reissue. Their specs are the opposite. KT88 is listed as 35 watts and the 6550 is listed at 42 watts.

I must be losing it ... Does this suprise anyone else?

Wes

[jdandy]

Wes.......Yes, I am surprised to see the the Gold Lion KT88 plate dissipation rated at 35 watts, although the specification sheet clearly states that the tube is primarily designed for audio frequency amplifiers for which two valves will provide up to 100 watts output.

Here are various KT88 data sheets.


Svetlana KT88 Plate dissipation 42 W

Telefunken-Elektroakustik-JJ Tubes KT88 Plate dissipation 42 W (click Specifications)

Genalex New Sensor Gold Lion KT88 Plate dissapation 35 W

Penta/Shuguang KT88 Plate dissapation 50 W

JJ Tubes KT88 Plate dissapation 42 W

[JWH]

Yes, I did notice the comment on 100W output for the GL in an audio amp as well. The Penta's 50W rating is interesting as the so called SC version is supposed to be a "strict copy" or SC of the original Genelax KT88. Thanks Dan.

I read an old thread where Ron-C said that there was a correlation between the strength that a tube measures to its perceived audio performance and I've read elsewhere that the Shuguang Treasures measure stronger than most current production KT88's. Not sure about the Pentas.

[JWH]

I looked up the Shuguang Black Treasures. They're rated at 42W according to the Grant Fidelity site.

[jdandy]

Wes.......I believe Penta tubes are no longer made. There may be some new old stock still available.

[JWH]

You may be right Dan, I see The Tube Store has their so called Preferred Series and say that is the same as the Penta SC.

[Bombadil]

Tube manufacturers do confuse things nowadays. They repackage or closely copy 6550s as KT88s, 5U4s as 274Bs, 6SN7s as CV181s, 6L6CGs as KT66s, and more.

Some of these tubes are quite nice, they just aren't exactly what they say they are.

The Tungsol KT66 does not draw the current as spec'ed for a KT66, but rather the exact same as a 6L6GT. The Psvane CV181 is really a 6SN7.