Members colejustesen Posted January 26, 2006 Members Share Posted January 26, 2006 I am wanting to replace my power tubes in my Engl Fireball. So I emailed Engl to see what the plate voltage is, this is what I got in response: HiThe voltage is about 430V DC in idle and about 405V DC in load.RegardsAlex I guess what I need to know is what voltage to do I go off of to calculate where I need to bias my power tubes? I would think that idle would be in standby and load would be actually playing, but I really don't know. If someone could shed some light on this for me I would appreciate it. Thanks! Cole Link to comment Share on other sites More sharing options...
Members colejustesen Posted January 26, 2006 Author Members Share Posted January 26, 2006 Also, I am doing the calculation with the 430 volt that Engl sent me in this equation: (30/430) x 700 = 48.837 mA Is 48 mA too much for 6L6 type tubes? I thought I read somewhere that for 6L6 tubes you don't want to go over 37 mA. Thanks for any input! Cole Link to comment Share on other sites More sharing options...
Members Duesentrieb Posted January 26, 2006 Members Share Posted January 26, 2006 use your ears as well - and use the 30 Watts for 6L6GCs only, and IMO a bit less than 70%, but 65% or 60% - but its all a matter of taste and how much you want to spend for tubes. HTH Link to comment Share on other sites More sharing options...
Members colejustesen Posted January 26, 2006 Author Members Share Posted January 26, 2006 Duesentrieb - Thanks for the chart, I don't understand it fully. I don't get what each line stands for, could you elaborate? red = ?black = ?blue = ?pink = ? If you could explain what each line is displaying I would appreciate it. Thanks again. Cole Link to comment Share on other sites More sharing options...
Members Duesentrieb Posted January 26, 2006 Members Share Posted January 26, 2006 Originally posted by colejustesen Duesentrieb - Thanks for the chart, I don't understand it fully. I don't get what each line stands for, could you elaborate? red = 6L6GCs (30 Watts max.) @ 70%black = 6L6 (25 Watts max.) @ 70%blue = 6L6GCs (30 Watts max.) @ 60%pink = 6L6 (25 Watts max.) @ 60% Link to comment Share on other sites More sharing options...
Members inferno79 Posted January 26, 2006 Members Share Posted January 26, 2006 Originally posted by colejustesen Also, I am doing the calculation with the 430 volt that Engl sent me in this equation: (30/430) x 700 = 48.837 mA Is 48 mA too much for 6L6 type tubes? I thought I read somewhere that for 6L6 tubes you don't want to go over 37 mA. Thanks for any input! Cole The calculation is for 30 Watts and 70%. I'd be careful, not every 6L6 is rated for 30 Watts output. Don't try more than that, 37mA should be fine, too. Last but not least, let your ears decide as Olaf said: a hot setting might sound a bit muddy at high volumes. Edit: ah crap, Olaf already said everything I wrote. That's three minutes of my life I'll never get back. Link to comment Share on other sites More sharing options...
Members colejustesen Posted January 26, 2006 Author Members Share Posted January 26, 2006 When I bought my amp I bought it used so the tubes in it aren't the original Engl tubes. I just looked at my power tubes to see that they are JAN/Philips 6L6WGB how would these compare to TAD 6L6GC-STR or the TAD 6L6WGC-STR? I mostly play metal and it sounds as if the TAD 6L6GC-STR would be good for that style of music. Thanks for the input, I appreciate everything! Cole Link to comment Share on other sites More sharing options...
Members Duesentrieb Posted January 26, 2006 Members Share Posted January 26, 2006 I'm not too familiar with Engls and 6L6 tubes but if I remember correctly the 6L6 guys on this forum often recommend the Svetlana 6L6GCs. And please ask Derek www.rocksolidamps.com too, he sells those amps and should know better than me, esp. what to suggest for your style. Link to comment Share on other sites More sharing options...
Members gtarbastrdchild Posted February 10, 2006 Members Share Posted February 10, 2006 Just thought I'd add to the original question....Ive trying to find the same thing! My tech sent me this: A 6L6gc tube has maximun rating of 30 watts and the bias should be set to 60-70% of the maximum rating of the tube at idle (no input signal) Link to comment Share on other sites More sharing options...
Members The Boogie Man Posted February 10, 2006 Members Share Posted February 10, 2006 Go with the manufacture recomdation, don't trust your ear. Bias is not a tone control, 48 mv seems about right for most 6L6's in that amp, that's the a good starting point. Link to comment Share on other sites More sharing options...
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