Bias Question-ur thoughts

has anyone the different levels biasing the is recommended in the manual. i have been at the max and it felt bit stiff now im at the min level and i think im digging it. i have el34's in the middle and 6L6's on the ends.

You mean at the end of the recommended bias ranges and not at the end of the pots travel.....right? :shock:

If you aren't using a meter and biasing it within the ranges suggested in the manual for a given tube you need to right now. Otherwise you will be spending a lot of money on tubes.

correct the recommended bias ranges and yes i am using a meter too.

I started in the lower suggested ranges and found that I like it more towards the higher ranges. I have 34's and 6CA7's in a RM100 and keep them at about 35ma. I also use a 5751 in the PI so that helps tame some of the hair in the gain.

If you haven't tried a 5751 in the PI yet, I would highly recommend it. Along with many others, I have found that it opens up more usable range on the gain knob with adding a good bit of clarity to the tone.

I bought a NOS JAN 5751 and it sh!t the bed within 20 minutes of play time. To add to it, it happened at my band's first show seconds after I took the amp off Standby to start the first song. Luckily I had a few spare 12AX7's and my multimeter handy (I troubleshot the power tubes first) But I just got two JJ 5751's in and put one in the PI this evening. That **** JAN cost me like 35 bucks give or take but hey, tubes right?! :roll:
I did notice when I first got it that the pins had that rainbow-ish discoloration as if they had been exposed to extreme heat. I didn't think anything of it until after the fact. Still don't know if that was anything indicative.

Also, I have a pair of EH KT88's in the outer pair that the bias range is from 35mV to 45 mV. However, the bias adjust knob when turned to the absolute left (or lowest voltage) doesn't take them any lower than 40.2mV. Still within tolerance so I guess that's good.

Sounds like someone sold you a used JAN. Who was the supplier?

It was actually tube depot. I would have tried to get a refund or try to contact them about it but my inner-hulk came out after the show and I smashed it. Muahahahahahaha *when laughing turns to crying!*

Jaymzrock said:

It was actually tube depot. I would have tried to get a refund or try to contact them about it but my inner-hulk came out after the show and I smashed it. Muahahahahahaha *when laughing turns to crying!*

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Oops. The Jan GE 5751's I have had all been very robust tubes. (knocks on wood)

Who knows what happened to yours in transit though. I have had tubes double boxed and bubble wrapped to all hell arrived smashed and others shipped out in a plain old thin bubble envelope (not recommended) show up just fine.

Jaymzrock said:

It was actually tube depot. I would have tried to get a refund or try to contact them about it but my inner-hulk came out after the show and I smashed it. Muahahahahahaha *when laughing turns to crying!*

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Hahahaha I bet that was very fulfilling for sure. I have been having trouble here lately with Tung-Sols going bad on me. Very common and they were quite used but man they sounded great up till then. Sticking with Ruby HG+ when I can now.