Albert Kreuzer's J-Fet Bass pre Amp

[unclejam]

Any body ever Build or use one of these?

Looking for a nice little project to build and i thought it would be nice to build.

 

[A9X]

Any body ever Build or use one of these?

Looking for a nice little project to build and i thought it would be nice to build.

Yes.
It sounds good, is simple to build on veroboard and very cheap.

 

[unclejam]

Vero board?

 

[A9X]

Vero board?

Dunno what it's called in Yankland. Stripboard maybe?

 

[unclejam]

oh perf/bread board

 

[unclejam]

Btw where can i get a 1u rack chassis for under 35?

 

[fdeck]

Btw where can i get a 1u rack chassis for under 35?

Buy an obsolete rack mount network router, and gut it. Or, build up from scratch starting with a 1.5 inch aluminum ell, which can be gotten at Home Depot. The standard is 1.75 inch, but 1.5 is adequate.

The Musical Instruments forum at www.diyaudio.com just happens to have a couple ongoing discussions of the AK preamp. I have built JFET and op amp preamps, but never in the particular combination of stages that AK uses. However, his circuit seems straightforward. Given that it is easier to debug simpler circuits, I suggest building it in stages.

 

[BillyB_from_LZ]

For those (like me) who have never heard of this before today...

Invalid Link Removed

 

[Passinwind]

Btw where can i get a 1u rack chassis for under 35?

Get a blank rack panel and bolt on a Bud or Hammond project box to the back of it. I have yet to find any decent new 1RU chassis for less than 50 bucks shipped.

I've been reasonably happy with rack chassis products from these two vendors:


Invalid Link Removed
Sescom, now Invalid Link Removed.

Have fun, and post clips!

 

[A9X]

If you want to build it in a rack, and want the front panel to look professional, try Frontpanel Express.

 

[unclejam]

If you want to build it in a rack, and want the front panel to look professional, try Frontpanel Express.

Thanks now Where to get the rest of the enclosure?

 

[fdeck]

Thanks now Where to get the rest of the enclosure?

Something to consider is that if you have a rack panel, but not a lot of knobs, then the enclosure doesn't have to be full width. Now you can look at brands such as Hammond at the Mouser Electronics website. If you find the size of that site to be forbidding, then All Electronics is a viable hobbyist source for parts including enclosures and pots.

But be prepared for sticker shock on enclosures. One thing to consider is to make some sort of generic front panel and box that you can re-use for later projects. You can hardly go wrong with a row of 3/8 inch holes on 1-1/2 inch centers, for either jacks or pots.

For drilling metal and plastic enclosures, I swear by something called a UniBit, which you can get at Home Depot in a couple sizes. I typically use the smaller size that goes from 1/8 to 1/2 inch in 1/32 inch steps. Truth be told, I do all of the drilling for my product with a UniBit on a cordless drill. It cuts clean holes without grabbing.

[Invalid or Expired Link Removed]

I don't do the rack thing, so instead, I build my prototypes into a Hammond 1590DD metal box that has become like swiss cheese. And (another dirty secret) I do my prototyping with a good old fashioned solderless breadboard strip:

http://www.circuitspecialists.com/prod.itml/icOid/6885

The breadboard fits inside the 1590DD box, and I have even taken such prototypes to gigs.

There is a Murphy's Law that the more professional your build, the sooner you will want to change it. In my view, DIY is not about pic-worthy gear, but about learning and trying things.

 

[A9X]

Thanks now Where to get the rest of the enclosure?

fdeck gives good advice. Enclosures will need to be sourced from parts Express or the like. The use FPE to make a new front panel that works for your design. Keep the original paceplate as a blank spare.

I'm going to build all of my electronics (pre, power and PSU) into my can and use the rack panel vertically as the control faceplate.

However, if all you're using the enclosure for is the AK pre, there are plenty of small metal enclosures out there you could build it into, either with an internal PS or a plugpack. One idea I had in the past and never developed was a small pre case with a clamp to the mic stand.

 

[BillyB_from_LZ]

Thanks now Where to get the rest of the enclosure?

Call the Dallas area Music Go Round and Guitar Center stores...or any place that repairs electronic gear and ask 'em if they have any broken rack gear for cheap and reuse the enclosure from that.

Search eBay and Craigslist for the same thing. Used electronic crossovers can be dirt cheap. Depending on how it's built, you might even get a power supply out of the deal too.

 

[BillyB_from_LZ]

Something like this...

http://cgi.ebay.com/DBX-234-2-3-Way...ryZ23792QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

Opening bid is a buck with $15 shipping (and it's not even broken). Plenty of knobs and jacks, etc.

Or this one...

http://cgi.ebay.com/Furman-TX-3-Tun...ryZ23792QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

Being an older piece of gear, it's likely that the jacks are made by Switchcraft and not pcb mounted and the pots are probably higher quality too.

 

[adam.beauchene]

Here's mine:

My first stab at building electronics. I'm still working a couple bugs out of it, but it sounds good!

 

[n0ukf]

Are there any new valid links for this circuit?

 

[tom-g]

https://web.archive.org/web/20040812220025/http://www.albertkreuzer.com/pics/el/pre/schem/onboard_sch.gif