plexi 50watt lead help

[gloeidraad]

Hey Tim,i am glad the amp is working now.
It only gets better when everything in the amp is settled.
Have fun

Erik
PS,just saw the picture of your amp.
Looks good, and a nice logo

[RiffRaff]

Thanks
Ya the logo is the one I use on my effect pedals
I build lots of pedals and not 2 many amps

[RiffRaff]

Man I just love this amp!!
just can't stop smiling when playing it!
and I have enough parts to build another one ( minus 1 10k resister ) and one sozo cap
Muahaaahaaahaaahaa!
this is how I spent my afternoon. hopefully I retained enough info to put this one together with minimum help
Also I put the wires on top of the board this time. just seems easier when you see them

[demonufo]

You might also find that it's easier to put the flyleads in before installing components, for your 3rd build. C'mon, you KNOW there WILL be one...

[gloeidraad]

Hey riffraff,thats good to hear
But BEWARE,before you know it you are addicted
I know that for 30 years or so!

Erik

[RiffRaff]

anyone ever try one of these in there amps?
http://www.hallamplification.com/main.html?src=%2F#2,2" onclick="window.open(this.href);return false;

[demonufo]

Not big amps, no. But tried VVR's in smaller single ended EL84 amps and was far from impressed. Removed them again, both times.

[Coot Boy]

Not big amps, no. But tried VVR's in smaller single ended EL84 amps and was far from impressed. Removed them again, both times.

+1 I never even tried em. How can you get a decent tone without moving some air but I'm from the good old days.

[RiffRaff]

Ok so I got the second build going
voltages are really close to the first build but I had to put in 270k bias dropping resistor to bring it up to -34 at the highest
and -64 at the lowest. should I put in a 330k maybe?
( I only had a 100k trimpot so I measured 50k on the pot and marked it. so thats where I set it to get my voltages)
v4 pin1: pin2:3.49ac pin3:508dc pin4:508dc pin5:-64dc pin6:508dc pin7:3.49ac pin8
v5 pin1: pin2:3.49ac pin3:508dc pin4:508dc pin5:-64dc pin6:508dc pin7:3.49ac pin8
so I put the tubes in and I get v5 redplating
when I turn it to -47 it stops redplating (and sounds pretty good)
What is happening here and what would be my next move to get biased properly?

Edit: just realized I don't get a measurement on v4 pin8
trying to figure it out
Ok so v4 pin 6 has 500v but pin 4 has zero could the 5w 1k be the problem?

[RiffRaff]

well thats what it was, a faulty 5w 1k. popped in a new one and away we go
Thanks again

[RiffRaff]

My new stereo system! or surround sound! how ever you want to look at it!
RiffRaff AmpWerks (TM)

[RiffRaff]

RiffRaff AmpWerks (TM)...sounds cool hey!

[Reeltarded]

Awesome! I got bit by the amp thing about a year ago after reading for 5 years and thinking. It's too much fun!

Nice builds!

[RiffRaff]

took one out to jam tonight.
at first I wasn't too impressed, the bottom end was pretty flabby at practice/gig levels
I was playing with another guitar player who also had a factory made plexi and I could hear the difference right away
his bottom end was much tighter and sounded like a marshall should.
But by the end of the night the other dude was drooling
After 4 or 5 hours of playing my amp just came alive and was just a rockin
It's amazing how much the sound improves during breakin

[neikeel]

Using 0.1uF PI caps on a stock lead amp you will never quite get the bottom end tight and crisp.

You may still get nice full legato lead tones with the mids and treble cranked but to get a crisp and punchy bottom end you will need 0.022uF (0.047uF maxm) PI output couplers.

By all means play around with it and see where you get but I came to these conclusions a few years ago after experimenting.

As you have two you could go Bass with one and lead with the other and blend amps not just channels!!