el34 tubes

[kajak12]

With a HT of around 350V, EL34's can be run up right to around 55mA but they may not sound best there.

The sweet spot will depend on the amp. I'd start at 30mA and edge it up slowly.

If installing new tubes bias them to 25mA and run them for 1/2 hr first then re check.

I'm finding often new tubes go into bias drift when they get hot and can take a while to stabilise.
So if you want to run them hard, ramp up to it slowly and check they are behaving (not drifting).

With EL34's, if you are measuring bias current at the cathode, for 35mA of plate current there will be 5mA or so of screen current.

Quick and dirty method to check if tubes are running close to each other (matched), compare voltage across screen resistors.

And be careful !!!!

T

screen resistors good idea will do that on my next biasing day

[kajak12]

check your bias people
http://www.youtube.com/watch?v=iD40DvztY4E&feature=related

[data]

I tried to replace EL34 in my stock Yaqin mc-10l with Soviet NOS 6P3S-E Military Tubes. they sounded pretty good. Did anyone try them with modified JLTI version?

I ran them in a stock MC-10L and thought they were nice enough, very good detail especially in the mids and upper end if I remember correct.

But after triode strapping the stock MC-10L the bottom end was noticeably rolled off to a large degree with the 6P3S-E's, so off they went as a freebie to a Guitar playing friend that loved them in his guitar amp.

I like others am partial to the Winged 'C's. Unfortunately one of them ran away... and for the moment I'm using the Shuguang EL34's in my new circuit, the mids are nice enough, but the highs are lacking and the bottom end a bit wooly.

[zenelectro]

check your bias people
http://www.youtube.com/watch?v=iD40DvztY4E&feature=related

I pulled one (EL34) out of an amp last week that had started to melt and cave in 

No picture- threw it out.

[kajak12]

I like others am partial to the Winged 'C's. Unfortunately one of them ran away...
[/quote
I had  winged c's run away, they glow red and blew a 5w bias resistor what a light show my wife ran out of the room i dived for the off switch(wall socket)I dont actually have a switch on the amp

[kajak12]

http://www.youtube.com/watch?NR=1&v=3pE43eXFZP8&feature=endscreen
I would like a pair as a showcase feature in my room