Re tube MKIIC+

[cjvolker]

I don't know for sure but maybe this will help: http://koichiise.web.fc2.com/pdf/EL34.pdf

 

[JOEY B.]

I had a STR 416 fail today in the outer socket of a MKIIC+
I dont have anymore STR 416 but I have a few old mullards I can use so does anyone know what sort of MA current draw I should look to be getting from each tube
The STR 416 that were in the amp running very cold the plate voltage was 460 and the STR 416 were only pulling 22 ma which I think is really quite cold for an el34
so what should the ball park current draw be for each mullard el34 tube does anyone know for certain
I have a few mullard to choose from, some will run very cold some will run VERY hot

IF you are going to run anything other than a STR-416, connect pins 1 and 8 of your outer power tube sockets if it has not already been done. Trust me on this one. Another thing is that Mark IIC+ amps do not require much power tube distortion, unless you are wanting to drive the hell out of the clean channel. My STR-416's draw in the low 20 mA range, but that is with 485 plate volts. Still very cold, but sounds very good and superb reliability. 8)

 

[JOEY B.]

I had a STR 416 fail today in the outer socket of a MKIIC+
I dont have anymore STR 416 but I have a few old mullards I can use so does anyone know what sort of MA current draw I should look to be getting from each tube
The STR 416 that were in the amp running very cold the plate voltage was 460 and the STR 416 were only pulling 22 ma which I think is really quite cold for an el34
so what should the ball park current draw be for each mullard el34 tube does anyone know for certain
I have a few mullard to choose from, some will run very cold some will run VERY hot

IF you are going to run anything other than a STR-416, connect pins 1 and 8 of your outer power tube sockets if it has not already been done. Trust me on this one. Another thing is that Mark IIC+ amps do not require much power tube distortion, unless you are wanting to drive the hell out of the clean channel. My STR-416's draw in the low 20 mA range, but that is with 485 plate volts. Still very cold, but sounds very good and superb reliability. 8)

Hi Joey , thanks for the heads up on the pin 1-8 thing , I do trust you on it and I will get that done for definite.
if pins 1-8 are not connected what is at risk is it the tubes or my transformers ,I am guessing there will be a problem if a tube fails
what do I need to do exactly I dont want to misinterpret this and get it wrong and fry something ...do I just need to put a jumper like buss wire between jumper pins 1-8
thanks Ian

Yes the pins 1 and 8 are internally connected in the STR-416. Many of the other EL-34 types are not. It makes the tube run more stable. I got this info from Mike B. at MESA, FWIW.