5881 in EL34 mode on revG dual.

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2CDR

2CDR

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Gents, i have read that one can run 5881 power tubes in EL34 mode with tube rec selected to bring the bias up.
i gave it a try,at low room volume and must say the result was an amazing jump in tone and crunch..only did this for a few minutes before setting all back to normal..
My Question for the more informed,tech savvy on this fine establishment is....IS IT SAFE? i should also add that i use JJ GZ34 and my 5881s are sovtek WGC..it really was a day and night difference and i would love to run my amp like this all the time IF it is safe to do so..i would guess it probably shortens power tube life,i can live with that..just dont want to stuff my amp..i know people run KT88s in EL mode but im not looking to go that extreme.
Thanks for any help.
 
2CDR said:
Gents, i have read that one can run 5881 power tubes in EL34 mode with tube rec selected to bring the bias up.
i gave it a try,at low room volume and must say the result was an amazing jump in tone and crunch..only did this for a few minutes before setting all back to normal..
My Question for the more informed,tech savvy on this fine establishment is....IS IT SAFE? i should also add that i use JJ GZ34 and my 5881s are sovtek WGC..it really was a day and night difference and i would love to run my amp like this all the time IF it is safe to do so..i would guess it probably shortens power tube life,i can live with that..just dont want to stuff my amp..i know people run KT88s in EL mode but im not looking to go that extreme.
Thanks for any help.
Click to expand...
The 5881 is just a Military grade 6L6, 6L6GB to be exact, and should be run in the 6L6 bias setting. 5881 tubes dissipate approx. 23 watts, compared to 30 watts for the 6L6GC.

The real question is if these 5881's were selected by the vendor to run properly at Mesa's fixed bias voltage. Too hot of a tube and you risk red-plating and possible amp damage. Too cold and the amp will sound sterile and lifeless.

Do you have a way to measure cathode current (bias)?

Dom
 
thanks for the reply Dom,no i do not have a way to measure...
i ordered these two/three years ago now(have used ever since,amp does not see a lot of play time)..unlike ruby,they do not have PC TC on the tube or boxes.
i did ask them for a set to use in my 98 2 channel dual recto.
 
correction..after finding the boxes all that is written on all four boxes is Ip 44 and Gm4,500
 
2CDR said:
thanks for the reply Dom,no i do not have a way to measure...
i ordered these two/three years ago now(have used ever since,amp does not see a lot of play time)..unlike ruby,they do not have PC TC on the tube or boxes.
i did ask them for a set to use in my 98 2 channel dual recto.
Click to expand...
If you asked for these 5881's to meet Mesa's bias specs you should not be using the EL34 bias setting. This will run the tubes very hot.

Are these 5881's JJ's from Eurotubes?

Dom
 
no.sovtek 5881 wgc(not real 5881).not from dougs.
ill just use as normal...
 

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