I need to find someone that will build a pl-20/pb-10 replica!!

[Andy's Junky Music]

You can buy the schematics from fender and since these are nearly impossible to find I figured I'd look into having one built.  I though since people rave about running the lead with the bass have channel a be the bass circuit and channel b be the lead circuit so when I play through the combined jack I'll get the best of both worlds...only problem is there's only 2 amp techs/builders in my area and neither of them will touch the project.  Any ideas?

[JoeArthur]

Shirley you jest. 

If you find anyone to do it for less than several thousand dollars worth of labor cost alone I'd be surprised.

Just consider that without a full sized PCB pattern you are looking at a week or so of labor just to create and verify a layout. Hunting down the parts isn't going to be as simple as stopping off at the neighborhood radio shack - since some of them, such as the chip that controls channel switching is no longer being made. I searched for one several years back and never found one.

Much cheaper and more practical to find a beta lead or bass and pretend it doesn't have a power amp.

[loudthud]

Joe, that chip shouldn't be that hard to find. It's just an old Motorola CMOS chip. I found a couple of places that claim they have them in stock. I have to agree that there are a lot of parts on those boards though. OTOH, maybe someone has the preamp boards from Beta Lead/Bass that was scrapped.

[EdBass]

Would this do the trick?
http://cgi.ebay.com/SUNN-PB-10-Preamp-RARE-MUST-SEE-BE-THE-MELVINS_W0QQitemZ330163488934QQihZ014QQcategoryZ2384QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

[Andy's Junky Music]

see I thought about trying to snag that pb-10 but Im talkin with a guy right now about a pl-20.  Im currently playing a carvin x-100b but would LOVE to get my hands on this pl-20!  I've got some big plans for that guy....4 cabs at once

[loudthud]

Apparently, both use the same circuit board. On the bass version, the reverb parts are left off and there are a few component changes in the midrange. Can anyone confirm this? I've never seen the insides of one of these.

[rick.heil]

Yes, that's about it.

If you're curious exactly what, look in the service manuals section of the site, the full schematics and PCB layouts are there (at least for the Lead and Bass).

[loudthud]

Where exactly are those service manuals? I dug up my own copies. The layouts were stapled to a Concert Slave power amp (Those Fender people!!!). I'm wondering what kind of caps were used. Those green poly films or ceramic? I've got a lead on a Beta Lead 2-12 that doesn't work, supposed to go look at it tomorrow. The only part I have trouble with so far is the reverb pot with an "S" curve and the reverb pan that can be driven by a 74C04 run at 8V.

[rick.heil]

Link to the folder with the Beta service manual:
http://sunn.ampage.org/site/svcmans/beta/
They're in JPEG format, so they're large, and not dial-up friendly (just a warning in case you use it)

At the point the Betas were built, it was Hartzel, before the Fender acquisition I believe (correct me if I'm wrong).

I can take a peek at my Beta in the next few days if you need to know what kind of caps (I don't remember offhand).  Reverb pot... hmm. An "S" curve you say?  Interesting...

[loudthud]

Thanks for the link. I got a bunch of schematics that were distributed by Fender in the days after they purchased Sunn. Mostly solid state stuff. They are all mixed up and some of them aren't too clear.

I went to look at a Beta Lead 2-12 on Saturday. The store had it marked $499 and it is in pretty good condition cosmetic wise, however it didn't make a sound. I offered them $150 and now it's mine. Finally got it apart Monday. The first thing I found wrong is the +15 regulator is dead. I'll try to get the transistor I need tomorrow. It has those green poly caps. Date codes are mid 79 to mid 80.

[rick.heil]

Sounds about right.  $150 isn't bad if you can get it running again.

$499 is a bit steep for a non-working amp!