Another bias question...

stargazer76 · 08-31-2009, 05:22 PM

Hey Marshallers,
If your biasing a 100 watter, using 4 EL-34's that you have been led to believe were "matched", and your using one bias probe, how important is it to check the draw on the other 3 valves to ensure a more or less equal performance?
Also, will my 900DR head run @ 50watts with two of the valves pulled? I think older heads can do this, but is the 900 different? Not interested in the triode operation as is provided on the 900, just a strait forward two valve 50 watt pentode sound, since it seems I can't use all four of my 34's together.

American Viking · 08-31-2009, 05:54 PM

Quote:

Originally Posted by stargazer76

Hey Marshallers,
If your biasing a 100 watter, using 4 EL-34's that you have been led to believe were "matched", and your using one bias probe, how important is it to check the draw on the other 3 valves to ensure a more or less equal performance?

Not necessary if you have faith in who picked your matched quad. No set of tubes is ever going to be dead accurate as the other one but withing a few mA is ok.

As for your other question, read through here and decide if you still want to. There's a method to doing it, I may not agree with it but here it is.
took out 2 power tubes.......

stargazer76 · 08-31-2009, 06:28 PM

Mucho Thanks, American Viking!
I'm not really interested in doing this cause of sound, but because out of the 4 "matched" 34's I used to have, one of that bunch now seems bad and now I only have a usable pair. I can't manage the purchase of four more....yet.
I will hold off until I can, still have the 800......
Thanks

American Viking · 08-31-2009, 07:34 PM

For much better prices on tubes and a great quality I recommend buying from Eurotubes . They have tubes for much cheaper than I have found in the chain guitar stores and you are almost buying direct. The quality of the JJ's is much higher than the Groove's, Ruby's, and Mesa tubes that stores typically sell, IMO.

ToddOwnz · 09-03-2009, 02:41 PM

^^ I completely agree. I ordered a complete retube set from eurotubes (DSL100) and they had them at my house in 2 days. Great tubes...I really like the EL34L's they sell. Not to mention their website has sooooooooo much information on it

08-31-2009, 05:22 PM	#1 (permalink)
stargazer76 Member Join Date: Mar 2008 Location: Dallas, Texas Posts: 42	Another bias question... Hey Marshallers, If your biasing a 100 watter, using 4 EL-34's that you have been led to believe were "matched", and your using one bias probe, how important is it to check the draw on the other 3 valves to ensure a more or less equal performance? Also, will my 900DR head run @ 50watts with two of the valves pulled? I think older heads can do this, but is the 900 different? Not interested in the triode operation as is provided on the 900, just a strait forward two valve 50 watt pentode sound, since it seems I can't use all four of my 34's together. __________________ JCM 900-4100 JCM 800-2204 1960A/G12T75 1962RI Stratocaster

08-31-2009, 06:28 PM	#3 (permalink)
stargazer76 Member Join Date: Mar 2008 Location: Dallas, Texas Posts: 42	Re: Another bias question... Mucho Thanks, American Viking! I'm not really interested in doing this cause of sound, but because out of the 4 "matched" 34's I used to have, one of that bunch now seems bad and now I only have a usable pair. I can't manage the purchase of four more....yet. I will hold off until I can, still have the 800...... Thanks __________________ JCM 900-4100 JCM 800-2204 1960A/G12T75 1962RI Stratocaster

08-31-2009, 07:34 PM	#4 (permalink)
American Viking Senior Member Join Date: Jan 2009 Location: RICHMOND, VIRGINIA Posts: 1,510	Re: Another bias question... For much better prices on tubes and a great quality I recommend buying from Eurotubes . They have tubes for much cheaper than I have found in the chain guitar stores and you are almost buying direct. The quality of the JJ's is much higher than the Groove's, Ruby's, and Mesa tubes that stores typically sell, IMO. __________________ -I'd rather be a good liver than have one...

09-03-2009, 02:41 PM	#5 (permalink)
ToddOwnz Member Join Date: Aug 2009 Location: Northern Ohio Posts: 46	Re: Another bias question... ^^ I completely agree. I ordered a complete retube set from eurotubes (DSL100) and they had them at my house in 2 days. Great tubes...I really like the EL34L's they sell. Not to mention their website has sooooooooo much information on it

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