LPB-1: first 1590a build

[jtn191]

Hey guys, I built this for my friend Jon. It came together really easily until the last little bit...
Luckily, I already had the drilled enclosure from an early failed Green Ringer attempt and I built the circuit on vero. I don't have a drill press/saw nearby so I just used a flathead screw driver to cut the vero board and make trace cuts! When it was all wired up, I fired it up only to hear a misbiased 2n5088! I would really recommend this build to those wanting to get into vero or 1590a builds but a) breadboard it first or b) use a trimpot to bias the transistor!!



when all was good

[whitebread47]

Nice!  I might give this one a go, because a) I could use a simple signal booster and b) I need use these 1590a's I've got lying around.

My biggest fear is everything not fitting after drilling; this piece of vero seems small enough to give me some wiggle room/practice.

[GrindCustoms]

Great first mini! You'll see it's not the last one....hehe

Blake, there's some drilling templates in the baby board build docs, you can't go wrong, use one as reference and suit it to your need

Rej

[jtn191]

yeah planning is KEY. I have always worried about the jacks--and then the DC jack and pots only make matters worse!

As far as the LPB-1 goes, it's a pretty dark and colored boost. But you can modify input impedance, the caps or put in a bright/dark switch accordingly.

I used this layout, but changed the 100k resistor to 43K and the 2nd 1M resistor to 430K to be more accurate with vintage schems. Maybe actually this was what caused the misbiasing (if you use a 2N5088 those values should be fine)... Then I put in a 50k trimpot in series with the 390R resistor, between it and ground.

[whitebread47]

Awesome, thanks!  I didn't think the LPB-1 was that colored, but I've never played one either so I'm not sure where I got that idea.  With that in mind, I'll play with the values to taste.  I need to use some of this vero I got as well.

Rej, I forgot about the baby board docs; I'll check 'em out for sure!

[midwayfair]

These things are like candy! Welcome to the 1590A addicts' club (whether you know it or not!).

[nzCdog]

These things are like candy! Welcome to the 1590A addicts' club (whether you know it or not!).

Lol. I concur with this statement.  Well done jtn191!

[jtn191]

here's a demo, whitebread47. I had the gain up a bit on my amp to show how you can kick it into overdrive...got a noise complaint from my hot neighbor after doing this!

[jkokura]

Some guys would see that as incentive to keep playing at loud volumes...

Jacob

[jtn191]

haha! +1. I say we meet again to resolve the issue

[whitebread47]

Awesome, thanks for the demo.  Glad that your decision to do so got you a little moment of eye candy as well!

I plan to bust one of these out and maybe a 1590a buffer (no knobs!) sometime this weekend.