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Octols that can handle 700+ plate voltage

Boytbpc

Senior Member
Messages
1,588
My Fuchs ODS MusicMan 75 came stock with EL-34. The plate voltage on that sucker is 705. I wanted to test some 6L6s in it, but most are only rated to 500 volts. Besides the EL-34, what other tube with the same pinout will work with a plate voltage that high?
 

Fuchsaudio

Member
Messages
7,834
No, a KT-88 won't work. It A) won't fit the socket and locking clip and B) will draw more filament current than the amp is designed for. The JJ and TAD 6L6's work in Music Mans (we use either) as the plate voltage is high, but the screen is half the plate voltage (about 350) and they run at 20-ma each. While technically the tubes are not rated for that, they work. If you like, and your wallet agrees, the 7581 Sylvania's are good, as are NOS RCA or GE's, which are a likely a little stronger a tube than current production 6L6's for sure.

Music Man switched when the 6CA7 Sylvanias and Philips stopped being made in the early 80's. They changed the bias voltage, and not much else, and got away with it....:)
 

Boytbpc

Senior Member
Messages
1,588
No, a KT-88 won't work. It A) won't fit the socket and locking clip and B) will draw more filament current than the amp is designed for. The JJ and TAD 6L6's work in Music Mans (we use either) as the plate voltage is high, but the screen is half the plate voltage (about 350) and they run at 20-ma each. While technically the tubes are not rated for that, they work. If you like, and your wallet agrees, the 7581 Sylvania's are good, as are NOS RCA or GE's, which are a likely a little stronger a tube than current production 6L6's for sure.

Music Man switched when the 6CA7 Sylvanias and Philips stopped being made in the early 80's. They changed the bias voltage, and not much else, and got away with it....:)
Thanks Andy!
 

wyatt

Member
Messages
4,169
You can also try the JJ KT77 or JJ 6CA7, which both beam pentodes (like the 6L6GC and original 6CA7), with that "rounder" sound and anode voltage max of 800V.

But, at those plate voltages, I wouldn't expect to note a lot of differences between EL34's, 6L6GC, KT77's or other unless you really crank the amp. Their differences really only shine when overdriven. People always seem to be under the misconception that a EL34 tube will make an amp sound like a Marshall or a 6V6GT will make it sound like a Fender.
 

Ben S.

Member
Messages
2,186
The New Sensor Gold Lion KT-77 would be an ideal choice.
If you really want to go the 6L6 route, have the amp modified for a plate cap and try 807's, but that is more involved obviously ;)

I would try the Gold Lion KT-77 any day over the JJ. Just my preference.
 

Blue Strat

Member
Messages
30,595
I don't think you guys realize that NEW tubes rarely meet the specs of old tubes...especially things like max plate voltage. You can "call" a tube anything you like (and it's done regularly), it doesn't mean it will behave like the REAL version of that tube.
 

wyatt

Member
Messages
4,169
I don't think you guys realize that NEW tubes rarely meet the specs of old tubes...especially things like max plate voltage. You can "call" a tube anything you like (and it's done regularly), it doesn't mean it will behave like the REAL version of that tube.
Well, I tend to trust the JJ specs as much as anyone's because they seem to actually generate their tube data and are up front that they are unique designs; neither do they copy tube data from elsewhere nor have they ever been in the business of BS marketing "clones" of specific tubes. They won't even call their KT77 a tetrode and rate it below the original British tube.
http://www.jj-electronic.com/pdf/KT77.pdf
http://www.jj-electronic.com/pdf/6CA7.pdf

As for the Genalex, New Sensor literally photocopied the old British datasheet.
Original....
http://frank.pocnet.net/sheets/086/k/KT77.pdf

New "Gold Lion"...
http://www.newsensor.com/pdf/genalex/kt77-genalex.pdf

I highly doubt the New Sensor claims, but I gave up on the Russian New Sensor/Reflektor power tubes a long, long time ago and won't go back. I stick to NOS, JJ and TAD.
 

trobbins

Member
Messages
382
I reckon tolerances in all aspects of manufacture can account for probably all performance experiences and perceptions. There are just soooo many aspects of a valve that can move out of tolerance. Probably a very skewed and somewhat flat bell curve.

Maturity and control of manufacture affects that bell curve.
 

neteraser

Member
Messages
1,994
I highly doubt the New Sensor claims, but I gave up on the Russian New Sensor/Reflektor power tubes a long, long time ago and won't go back. I stick to NOS, JJ and TAD.
This isn't objective. What I know for sure is that really nice people work there. You can call them and they'll explain the real technical differences between the different brands of tubes. Nobody is trying to fool you around the brand name. They haven't copied the original design, but they did what they could. And often (and many people would agree) their power tubes sound better than competitors.

I don't think you guys realize that NEW tubes rarely meet the specs of old tubes...especially things like max plate voltage. You can "call" a tube anything you like (and it's done regularly), it doesn't mean it will behave like the REAL version of that tube.
... So buy tubes from KCA NOS Tubes? No, thanks.
 

Blue Strat

Member
Messages
30,595
This isn't objective. What I know for sure is that really nice people work there. You can call them and they'll explain the real technical differences between the different brands of tubes. Nobody is trying to fool you around the brand name. They haven't copied the original design, but they did what they could. And often (and many people would agree) their power tubes sound better than competitors.


... So buy tubes from KCA NOS Tubes? No, thanks.
LOL at anonymous guy trying to make it personal...when it's not.
 

wyatt

Member
Messages
4,169
This isn't objective. What I know for sure is that really nice people work there. You can call them and they'll explain the real technical differences between the different brands of tubes. Nobody is trying to fool you around the brand name. They haven't copied the original design, but they did what they could. And often (and many people would agree) their power tubes sound better than competitors.
No? Maybe not the factory, but New Sensor?

Then why buy up the North American rights to their competitors brand name, Svetlana and release tubes? Why trade of the brand equity of Tung Sol, Mullard, and Genalex at all?

"This tube has been recreated down to the finest detail..."
"Built just like the original..."
"Exact copy of the original..."
"Copy of the original..."

And then they reprint the original tube data sheet from 40, 50 or more years ago. I know they aren't close to the real thing, they know they aren't close to the real thing, but they certainly sell them as being just like the original.

But none of this has any bearing on why I don't buy them anymore. I just had too many problems with reliability with some of their power tubes in the past, specially the 6V6EH, 6L6EH, Mullard EL34, Sovtek 6L6WXT, and the Tung Sol 6V6GT. Now, I grant you the 6V6EH, Mullard EL34 and Tung Sol 6V6GT all have a history of being problematic, but Mike Matthews/New Sensor blames many of these issues on a bait and switch from the factory. I still love the Sovtek 5881WXT (most durable tube they sell!) and their preamp tubes (depending on application), but I could never recommend any of their offerings for high voltage situations, the only high voltage situation I deal with is an Ampeg SVT, and the New Sensor tubes are infamous for not surviving that amp. Without a reference, no one is going to identify what power tube is in an amp on stage...not even what type of tube...but they sure the hell notice when that amp doesn't work.

My choices are based on my experience, YMMV.
 
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Blue Strat

Member
Messages
30,595
Nothing says "we're proud of our product" better than buying the competition's brand name out from under them. :D
 

pdouds

Gold Supporting Member
Messages
771
There us still so much good quality NOS glass out there I don't bother with the new production crapshoot.
 

Abe

Member
Messages
571
I've been using the Chinese Shuguang el34's in my HD-130 for a long time with great cleans and great reliability. I can't say how their overdriven tone is as I always use that amp as a Twin Reverb substitute. But there's my take...
 

cpike

Member
Messages
657
You can also try the JJ KT77 or JJ 6CA7, which both beam pentodes (like the 6L6GC and original 6CA7), with that "rounder" sound and anode voltage max of 800V.

But, at those plate voltages, I wouldn't expect to note a lot of differences between EL34's, 6L6GC, KT77's or other unless you really crank the amp. Their differences really only shine when overdriven. People always seem to be under the misconception that a EL34 tube will make an amp sound like a Marshall or a 6V6GT will make it sound like a Fender.
In my old Ampeg VT40 w/685v on the plates, the difference between EL-34s and 6CA7s is not subtle, and I play at low volume (knob on the first of 7 marks). The differences are more dramatic the more it's turned up, but power tubes, at least in that amp, make a difference at any volume.
 




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