my preamp is almost done!

[Cowanrg]

im nearing completion on my preamp and i couldnt be happier. here are a few pics.

back:

http://www.cowanrg.mesanetworks.net/projects/images/bosoz/preamp7.jpg

guts: (not complete yet, mising volume control)

http://www.cowanrg.mesanetworks.net/projects/images/bosoz/preamp10.jpg

front panel:

http://www.cowanrg.mesanetworks.net/projects/images/bosoz/preamp12.jpg

[Patt]

I've never seen a home made one before and that looks nice. :T

[Cowanrg]

thanks a lot. its a LOT of work. its been over a year in the making.

but every project i encounter, i try to make it look as little like a homebrew project as i can. this one was very hard because i wanted to make something that didnt look like anything commercial, but still make it look like it could be. no one is really doing wood face plates except for home built stuff. but i wanted it to have a little extra style. i have about 30 different solidworks renderings of prototypes for faceplates and around 5 actual prototypes that i milled to test different designs.

[Spearmint]

thanks a lot. its a LOT of work. its been over a year in the making.

but every project i encounter, i try to make it look as little like a homebrew project as i can. this one was very hard because i wanted to make something that didnt look like anything commercial, but still make it look like it could be. no one is really doing wood face plates except for home built stuff. but i wanted it to have a little extra style. i have about 30 different solidworks renderings of prototypes for faceplates and around 5 actual prototypes that i milled to test different designs.

Very nice, and most impressed with your workmanship on the internals as well.

BTW Redgum still does the timber faceplates.

[ThomasW]

Rob,

I think you need a bigger transformer .... :wink:

[cjd]

you're not going with balanced in/out? (curious, since I'm considering the BOZ for that very reason since I'm also working on an X-amp which really prefers a balanced source)

Regardless, looks great. Very clean wiring, nice layout.

What are you going with for volume control?

C

[Cowanrg]

ThomasW,

hehe, everyone says that. the idea was cost. i wanted to do a full dual mono supply, which would hav been two transformers. well, i couldnt find a small transformer for that size. i found a few that could be custom wound for the voltage i needed, but they would have been like $40-$50 each.

the 800va was the voltage i needed, and more than enough power, and only $70. so it was a no-brainer. plus, it makes the case feel substantial.

Spearmint,

wow, that stuff almost looks DIY! i dont know, something just looks a little TOO plain about it. it looks good, but not quite "there".

cjd,

i get that a LOT too. im not doing balanced because this is actually a present for my dad for his new house. it is going into an exisiting system which doesnt have balanced on the amps. so, i understand that the preamp really shines with balanced, but for this purpose, it would have just been more complicated to add, and it would have never been used.

for volume i have a noble black beauty stereo pot. it took awhile to figure out what to use because the bosoz has SO many trimming options. it originally caled for 4 pots, two on input and two on output. i couldnt find a reasonably good quality 5k pot, so i opted to put a 10k pot in the inputs and leave the outputs alone. so, the signal goes in, to the selector, gets selected, then to the noble, then to the preamp, then goes straight out without being touched.

a few people didnt like this idea either (a lot of critics huh?) because supposedly a volume control is best on the output. well, this will really only be used for 1 to 2 sources MAYBE. and both sources will have a signal input trim on them, so both can be the same relative output levels. and, 5k pots are very hard to find and i just didnt want to mess with a stepped attenuator.

well, back to work i guess. i hope to have it "finished" by today and do some testing. i just need to wire the pot and attach the faceplate.

[cjd]

Ahh. Good reason.

And, I think I'm actually thinking SOZ not BOZ, but not sure now. :P Haven't looked at it in a while.

5k pots huh? I've been considering some of those 9mm Alpha pots (gotta order from Jaycar or something) and thought they did 5k, but can't find them - 1k, 10k, 50k, 100k, etc. no 5k. Ahh well.

BLUE LED's though? :P (I like red or green, but red is nice 'cause it doesn't do funky things to the eyes and be obnoxious in a dark room)

C

[Cowanrg]

cjd,

the design originally had red leds. BUT, after showing it to a few people in person with red and blue, it was unanimous (sp?) that everyone thought blue looked better. i think so too, it just had more wow factor. the red looked pretty plain. but the blue really stood out.

[TacoD]

Very nice cabinet, how did you make the lettering/ silk mask on the back plate?

[Cowanrg]

tacoD,

the lettering and silkscreening was done by a company called frontpanelexpress. they dont charge a whole lot (i think that panel was like $20 plus shipping) and they even did the holes and the rectangle for the IEC receptacle. its a great deal for adding a bit of professionalism to your projects. im definately using them again.