any instructions on how to make a basic passive pre-amp?

[faster100]

help me out, what parts are invloved to make a simple volume controled single input/output passive pre? this will be for the sonic impact amp setup i have... Thanks


parts needed?

project box
what kind of volume pot? and what ohm? 5k 10k, 100k ohm?
any resisters involved?

where to find insulated input rca jacks?

Thanks a million for any help

[RuSsMaN]

I'd start with a 50K pot, make sure its tapered, not linear. Linear will work, but tapered pots work better for audio applications.

Parts express has input jacks with a plastic 'disc' to keep the ground off the chassis.

Cheers,
Russ

[unc2701]

This should answer some of your questions:

[unc2701]

That's a mod squad line drive- it's actually on ebay right now for $80... Note that all the grounds are shared & attached to the chassis. One improvment would be to get yourself a rotary switch that will switch both ground & signal on both left & right, but they aren't cheap- you'd need a 4 pole, x position (where x is your # of inputs). That would do a lot to eliminate any crosstalk.

[steveinaz]

FWIW I sent an email to Gary at Dodd requesting a totally passive pre based on his mid-level tubed Dodd chasis. 3 inputs, 1 output;

$650 w/Alps
$850 w/Dact

Now that would be unique, and I'm seriously considering it...

[RuSsMaN]

That would be interesting Steve. I think you should go for it, that way I can play with it before it gets shipped out.

;)

Cheers,
Russ

[steveinaz]

If I do it, absolutely--take her for a test ride. I love runnin my system passively, it's just a pain in the ass trying to balance 2 knobs on the back of the amp.

I'm still debating going fully passive or maybe go the Monolithic PA-1, just in case I ever run into a source that needs a little extra push...

[faster100]

would be cool far as the custom job.... But way to much money. for a passive IMO..

Thanks for the info guys, I'll make this if i can find a cool project box.. or a match to my SI amp project. Were talking sonic impact cost on the passive pre for my bedroom not "High end" LOL... :)

[steveinaz]

I kind of figured you were wanting to build one, just thought I'd throw that out there.

I've done a ton of searches lately on "DIY preamp" and found lots of info...give it a shot.

[BlueMDPicker]

Since it's for the bedroom, here's an fairly inexpensive kit w/remote:

Passive pre with remote (http://www.apogeekits.com/preamp.htm)

[faster100]

cool kit.....