B1 Buffer Preamp

[Face]

New wiring, Mike?

Kinda. ;)

Daytons in mine. Finally checked tonight.

Good! Be glad.

[zingo]

Are those really the same value caps? WOW

Whats' the wiring for your power supply? I was originally wanting to use batteries, but I haven't been able to find anything to fit the bill.

[Face]

Are those really the same value caps? WOW

Yes, but unfortunately the cover no longer fits.

Whats' the wiring for your power supply? I was originally wanting to use batteries, but I haven't been able to find anything to fit the bill.

Beats me, but I know it's not the same as the schematic.

[zingo]

The schematics don't have a power supply, but it should be pretty easy to replicate.

[Face]

Sorry, not the PS, but by the 15,000uf caps, a trace on the board was removed and something else was changed. I should have taken a picture when the board was free of film caps.

[strider]

Mine looks pretty similar to Mike's, Jake. I've got the top off and my caps don't have elephantitis, I'd be happy to take a couple pictures of it if it would be of help.

My transformer's much smaller and only has 2 leads going in and 2 going out. Other then that it looks to be the same.

[zingo]

Thanks but don't worry about it. It's easy enough to throw an 18v transformer on there with a rectifier, or just a regulated wall wart. :D

[zingo]

Would I be able to use a 20000uF cap in place of the 15000uf filter cap?

http://www.diyaudio.com/forums/showt...hreadid=135652

[ShinAce]

The 26000uF is smaller and cheaper and still meets voltage spec.

One of the caps is a filter, so bigger is fine. The second 15000 uF is part of a voltage divider and can still be replaced with a bigger one.

[zingo]

But who doesn't like Big Blue? :D

(But I'll probably just use the spec'ed caps to save space.)

[zingo]

For the selector switch, will any two way switch work?

http://www.parts-express.com/pe/psho...number=060-424

[GV#27]

For the selector switch, will any two way switch work?

http://www.parts-express.com/pe/psho...number=060-424

If you only want to switch between 2 sources then a DPDT switch is needed.That switch at PE is only a single pole(1 channel).Check the C&K toggles at Digi-key.7202 I believe is the #

[zingo]

http://www.parts-express.com/pe/show...number=060-310 :D

[zingo]

I also need a good source for a stereo pot/attenuator...

[GV#27]

http://www.parts-express.com/pe/show...number=060-310 :D

That would work ,but my preference would be for a better one like this.http://search.digikey.com/scripts/Dk...ame=CKN1032-ND I suspect that the internal contacts will be superior.


As for attenuator one of the stepped variety would be ideal,I have seen some decent looking ones on Ebay(Asian sourced) for $30ish.If you want dual 25K's as in NP's schem then the Bourns 91 series or Clarostat conductive plastics from Digi key would be good choices. http://search.digikey.com/scripts/Dk...V4NAYSD254C-ND
Partsconnexion sells the Blue Alps ganged pots but only in 10k and 100k.The 10k would likely work fine.

[GV#27]

25k dual stepped atten. http://cgi.ebay.ca/25K-24-Step-Ladde...742.m153.l1262

[nikolas812]

How far along in your build are you?



I got in on a group buy for a B1 board over the DIY forum. So I'll be building one of these at some point and time...:)




Nick

[fredv]

How far along in your build are you?



I got in on a group buy for a B1 board over the DIY forum. So I'll be building one of these at some point and time...:)




Nick

Why not calling Collins to get a genuine Pass board and order the jfets at the same time? Many members got one shortly after contacting Collins. I will do p-2-p if I am building ones. I have all the parts needed but no time, sigh ....

Have fun!!

[zingo]

I am starting to collect the parts for the B1 and will probably start the build within the month. I will not be using a printed board as I thought this would be good P2P practice, and the boards themselves costs as much as the collective parts.

[nikolas812]

Why not calling Collins to get a genuine Pass board and order the jfets at the same time? Many members got one shortly after contacting Collins. I will do p-2-p if I am building ones. I have all the parts needed but no time, sigh ....

Have fun!!

I'm pretty sure these are coming straight from Nelson Pass...

There should be a thread in the Group buy forum at the DIYF with specifics...




Nick

[fredv]

I'm pretty sure these are coming straight from Nelson Pass...

There should be a thread in the Group buy forum at the DIYF with specifics...




Nick

I know you are talking about the Rhys GB. They will be made with the approval of Nelson using the First Watt Gerber file, not coming straight from Nelson. There is nothing wrong with this, but not much of a saving for that price.

[zingo]

I just saw on the DIYaudio site, a builder who installed the B1 circuit into his Goldpoint. If I had a choice, that would be my new build direction, but one of those units is anything but cheap.

[Face]

I have one of those and thought about doing the same thing, but I thought space would have been too tight. He must have installed the filter caps externally...and he used Solen caps(yuk).

[zingo]

How much power supply filtering capacitance do I need on this preamp? Is 15000uF required for the pair of caps? (It's just that they are pricey and a little hard to find)

[GV#27]

....

[zingo]

Would a value like around 10000uf work okay, or should I stick with 15000uf?

[SoundEngine355]

What potentiumeter did you use?

[Face]

It's an alps unit. I have a spare goldpoint there will eventually be swapped in there.

[SoundEngine355]

It's an alps unit. I have a spare goldpoint there will eventually be swapped in there.

Is that the Goldpoint Precision Mini-V Level Control? I heard DACT is very good. Is the Goldpoint on the highend side?

[Face]

Same brand, older model though: http://www.cleanandquiet.com/upload/...nuator%202.jpg
It's a step above the DACT I have installed in the B1.