Bassman Project Problem

[Jana]

Is that an error is your drawing or is that really the way the caps are as far as which side is + and - ?

What voltage to you have on the grids of the tubes? pins 5?

[Subjecttochange]

Yeah. The positive side is toward the ground.

I switched back to the 27k + 25kL bias pot since the 56k was just a little too much. Grid and right of the 15K resistor are the same at -47.6V.

Sounds right- right?

[mlp-mx6]

You're in the ballpark. It always depends on the tubes and how they pull current. Do you have 1-ohm resistors on the tube grounds? Easy conversion from mV to mA that way.

I think if you head over to the London Power website he has a free schematic for switching between fixed-bias and cathode-bias.

[Bob-I]

Regarding colors... I am colorblind-

Me too... funny story...

My first semester in electical engineering college I had a quiz on resistor color codes. We were handed a bunch of resistors and had to sort them according to value.

I went up and told the professor that I was colorblind and if he could tell me the colors I'd sort them. He said no, that if I couldn't do it I'd fail.

In the front row of the class was a guy who's just come back from Vietnam where he lost his right hand and had a hook instead. He said to the professor, "are you gonna fail ME because I can't pick up the resistors?"

I rattled off the values as fast as the professor could tell me the colors and aced the quiz.. and the course.


Back on topic, sounds like you made progress, congrats.

[Subjecttochange]

Yep- I had the same thing. Actually- I was a TA for a lab course in basic Physic/Engineering. The Prof. was teaching a lab about basic circuits and lecturing briefly regarding resistors and caps. He, while lecturing handed me a resistor and said... "Anthony can tell you what your values are- if you are having a hard time. Go ahead Anthony, whats the value of this resistor?"

I quietly said "I have no idea... I am colorblind"

He said... "I am too- what the heck did I hire YOU for" and proceeded to ask a near by student the colors.

The class all got a laugh.

I memorized color names pretty early since my teacher in grade school thought it was strange I'd color the grass brown or water/sky purple. Oh well. Good times. Learned to read by crayon names... kind of... hah

Yep- the amp is finally up and kicking in a healthy sort of manner. Thanks to all. I am still a bit green in this whole world- but when it came down to it... I am using the exact same circuit that I started with... Which means my soldering skills need a little work.

It's a pretty cool amp- but I do want to up the gain a bit of the EF86 channel. Since this amp is larger/fixed bias it, doesn't have the OD that the same circuit gets in a small AC15 (since the power tubes aren't helping out). Any advice on that? I have got an available triode in a adjacent 12AX7 that's going unused- if it comes down to that.

Thanks again!