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EL34's that can handle it


 
7/6/2003 11:46 PM
Nathan
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EL34's that can handle it
Just finished an amp that runs about 495 volts to the power tubes (matched Electro-harmonics EL34's). I'm getting some ugly distortion. Could some one recommend some reasonably priced EL34's that can handle heavy voltages.  
 
 
 
thanks  
 
Nathan
 
7/6/2003 11:59 PM
Satamax
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EL 34 should be able to cope with 800 volts. Are you sure you've biassed right?  
 
Best regards.  
 
Max.
 
 
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7/7/2003 12:28 AM
Richie
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i think the 800v rating can be misleading.  
To run them that high there is more you have to do.  
but in what your posting,any of the current made tubes should be able to handle the plate voltage.  
The EH are suposed to run 600V in more of a way a guitar amp is set up,with the screen voltage.  
Then again, any tube will have to have the biased checked,and depends on how you run the tube.  
Heres the data on the Svet.  
http://www.svetlana.com/graphics/products/pdf/EL34.pdf  
Richie
 
7/7/2003 9:40 AM
pef
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Sorry Richie but the EH EL34 are rated to :  
 
plate voltage, 800 volts  
cathode current , 150 mA  
plate dissipation, 25 watts  
Screen voltage , 425 volts  
screen dissipation, 7.5 watts  
 
it's the MAXIMAM value.  
 
maximum grid circuit resistor;  
 
fixed bias, 100 K.ohms  
self bias, 0.5 M.ohms.
 
7/7/2003 1:03 PM
Satamax
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Absolute maximum plate voltage on EL 34 for 0 mA is 2000 volts!  
 
Best regards.  
 
Max.
 
7/7/2003 4:45 PM
Bruce /Mission Amps
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[QUOTE]Sorry Richie but the EH EL34 are rated to :  
 
plate voltage, 800 volts  
cathode current , 150 mA  
plate dissipation, 25 watts  
Screen voltage , 425 volts  
screen dissipation, 7.5 watts... etc.[/QUOTE]  
 
Sorry, but here's where my hard experience has the upper hand.  
Regardless of what specs you have, after blowing up +13 tubes in 32 matched pairs, I personally have NEVER been able to get a set of EL34EHs to last more then a few hours with plate voltages above 495!  
They absolutely sucked at high voltages and high output.  
 
Bruce
 
7/8/2003 3:29 AM
Richie
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I posted below too to explain.. But  
I got the 600V from talking to EH tech. When these were first coming out, they told me they had tested them at that voltage,and ran with no problems.So i wasn't going by there data sheets.. Just what they told me.  
 
Richie
 
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