Blues Jr Screen current correction, and why I do it

In this video I explain the reason behind correcting the screen current in Blues Jr. amplifiers instead of simply re-biasing them.

[@mattharbert4374]

Thank you Charlie for these videos I absolutely love them all!!! You’re the absolute best on the planet!! Very interesting and informative videos I enjoy them all!! It literally makes my day when one pops up! I can’t even describe how amazing all my guitars and amps are when they come back from your shop! You make a a good guitar and amp Into a great one!! I appreciate this man’s work so much!

[@guitarc.p.r.9675]

Thanks Matt.

[@richardshryock8111]

"A tube manual, you know, the things that the tube manufacturers wrote years ago......pre google." I think that pretty much says it all. Thank you Charlie.

[@guitarc.p.r.9675]

Thanks for the comment. I was holding back! :) I just mentioned above how much grief I get for free information.

[@reggiewallace260]

Very welcome video...been a while since you've posted. As usual, this one really illustrates some of the nuance involved in this kind of work.

[@guitarc.p.r.9675]

I have stepped back from KZbin, I put this one up to test how it was received. Funny how viewers like to complain or make demands on free info. I appreciate viewers such as yourself. Thanks for following the channel.

[@57stratblues]

Charlie, you are the man !!! A wealth of knowledge.

[@guitarc.p.r.9675]

thanks, just a guy with a toolbox and a LOT of bench time! :)

[@Lu_Woods]

Very well explained, and I'm no tech...thank you

[@guitarc.p.r.9675]

You're welcome!

[@MrDiscomfortzone]

I see a lot of Blues jrs in my shop, and I often recommend replacing the IC brand filter caps, but haven't done any mods to the screen grid ckt. What value resistors do you install? Do you change anything else?

[@guitarc.p.r.9675]

I covered that in the video. If you notice there is also the old sheet detailing the changes laying on the bench. I change all kinds of stuff. Look back through the channel at all the BJ videos. The mods are constantly evolving. Take note of the previous Blues Jr video about the phase inverter.

[@drewbarries]

Great information. Why on Earth did they design it so out of spec? I wonder how many of my amps are off spec.

[@guitarc.p.r.9675]

Good question!