which diy bass preamp?..

[Kipper4]

Cool pedal man. I really hope i get that good at it.

[JebemMajke]

Rob this looks @#$%in awesome. Sick one.

[deadastronaut]

cheers guys..

[deadastronaut]

i just re-jiggled the bass layout/pcb. the cap switch was popping too much ...one of those irritating things that needed ironing out..

and yes, i 'm quite anal about such things...

very quiet now.


https://dl.dropboxusercontent.com/u/7464107/bassmanlayout.pdf

https://dl.dropboxusercontent.com/u/7464107/bassman%20pcb.pdf

etching a new pcb for it now...

[Kipper4]

Where abouts are the BAT85.s Rob ?
I'm not familiar with the schematic and I want to build this tonight
thanks
Rich

[deadastronaut]

hi rich, the bat85's are the 'orange diodes'..

i left the pads for those in as 'optional' i didn't use them, they made no audible difference imo.

the 1n4001 'black diode' is optional too (power protection)

^ use the layout above ok.

use small trimmers too.

have fun, i'm just drilling my new pcb.

[Kipper4]

I am using the above layout.
for some reason i thought it ddint have a protection diode so im putting mine next to the top left trimmer. oops
It sounds amazing.
What is the foot note about the switch resistors 1M-10M ? was there a problem ?
It's such a low parts its amazing it sounds so good.
i think i might use it in a Bass box. If thats ok with you?
I'd like to incorporate a Pre/Di compressor and distortion with blend.
I intend to have fun mate. I love the smell of flux in the early hours.

[deadastronaut]

hi rich,   i rebreaded it as its small just to get rid of a 'pop' when switching caps...its ok now.  stick 1M to 10M in there (where the 2 paralell 1M's are...)

yeah no problemo help yourself man, , i'd like to knock up a compressor to go with it too, but i want a compressor to serve bass and a guitar..probably just cap switching again.

as i just record at home now..

[JebemMajke]

Just one thing be careful with dirt boxes and this thing together. It hates big muffs, loves Fuzz Face, Loves light overdrives ( zendrive, tubescreamer ). Chorus, delay, phaser ... it all works great with it. But you should be careful when choosing dirt boxes for this preamp. I remember that last summer I've been on a quest for right kind of muff for my bass. And supercollider was the best, and still is. But this preamp ( both of them ) hated it. Especially with the drive knob over 11 o clock. It would turn into gated, over compressed muddy kind of a fuzz.

On the other hand it loved my sili-germ hybrid FF. So it's not on a war path with fuzz boxes. Just with muff's .

[Kipper4]

I built a 3 knob seymour duncan fuzz when i first started building that i think will go well with this bass pre if thats the case.

Heres a link to the schematic

http://www.seymourduncan.com/tonefiend/wp-content/uploads/DIY-Club-Project-2-v02.pdf

Do you think this would sound good with Bass and play well (interact) well with the Bassman pre JebemMajke?

[JebemMajke]

Don't know bro. You should try it and see for your self. But always be prepared to make alternations.

[Kipper4]

will do then buddy
thanks
The main board is now populated and ready for some pots in the morning.

[Kipper4]

Ok its built but it needs a debugg
i ommited the bat 85 as suggested.Not a peep.
Do i have to set the trimmers somehow?If so how and to what.
Im going to need 3 pairs of hands
First i'm going to go over the board with my DMM.

[Kipper4]

OK since i missed out the bat 85 does the + side of the 47uf cap (bottom left of layout)go to the 1k or 1m resistor?

[JebemMajke]

- to the ground. And plus touches 1k. Yes.

Trim both to 4.5 or 6 if you please. Or even better trim to your liking.

[Kipper4]

Trim both to 4.5 or 6 if you please. Or even better trim to your liking.


Kilohms or volts?

[Kipper4]

im getting there now the probe says signal is getting as far as the volume pot and all the tone pots but struggling to go further. Some how i've got mains type hum on the 680k output resistor.

[Kipper4]

I had made a wrong connection from Q2.
It's all working fine now.
It sounds sharp and quite (no pedal noise) but with lots of headroom.
The tone stack is amazing as usual with Robs designs.
I even tried it on guitar and it has such a wide variety of tones its amazing on that too.
Thanks guys
Rich

[deadastronaut]

cool glad you got it going man...

yeah masses of headroom...i put the 680k there to tame it back a little as it was way over the top level wise otherwise.

the cap switch is nice eh...2 tones in 1. for hard/soft.

on guitar with distortion in front its really chunky as f..., i'm going to mess around with this stack to make it suitable for guitar too...and add a presence too.

finishing up today too.

[JebemMajke]

I've played it with bandaxall, with mid shift and it was really good sounding. For guitar that is.