Amp Workshop

Merry Christmas

feeds@yuku.com (StoSoStu) — Thu, 24 Dec 2009 16:08:33 GMT

Merry Christmas to all at the AWS, from South Oz, where it's already 7.30 am Christmas morning, and thanks to the grandkids, I've already been up for 2 hours, ain't that what Christmas is all about.

New Forum

feeds@yuku.com (jbmojo) — Tue, 22 Dec 2009 21:26:35 GMT

How about a Bass Forum? Anyone?

Reverb mods/ideas/questions

feeds@yuku.com (fredg) — Mon, 21 Dec 2009 22:36:43 GMT

I've been working to try and tone down an overly bright/harsh/agressive reverb on a Deluxe reverb clone. I've BF'the circuit and installed a 250K audio pot. These changes have worked very well - I had tried a 12EU7 driver tube, but I didn't get the results I wanted. It's almost there, just still too bright.

All that really remains is to tame down the still-too-bright reverb. I'm wondering if upping the input cap value from 500pf to a higher value would...

Beatles Tribute

feeds@yuku.com (jbltwin1) — Mon, 21 Dec 2009 09:44:08 GMT

NOT mine but a friend of mine put this together in case any of you guys are Beatles fans. Really good job.

http://www.youtube.com/watch?v=2HU3Cly1pvg

VOX Cambridge Reverb

feeds@yuku.com (Andy ZZ) — Fri, 18 Dec 2009 14:24:08 GMT

This amp showed up on my bench, and is ready to go except for one thing:
The Power and Standby lamps. They are connected in series, with a center tap to ground connected through the standby switch.
None of the schemos I found make note of the lamp numbers, and they were missing from the amp when I got it.
#44 and #47 are wrong, #51 is closer but still wrong (too dim) and I believe that each lamp may be a different model.
Anyone know what actually belongs in there?
-andy-

Studiomaster Showmix 24-4-2

feeds@yuku.com (StoSoStu) — Tue, 15 Dec 2009 05:23:50 GMT

Just picked up a Studiomaster Showmix 24-4-2 desk, at very much the right price, as spare/second live FOH desk. Anybody have any manuals, schematics etc for this desk?

1968 Princeton Reverb Drip Egde question

feeds@yuku.com (mxvin) — Mon, 14 Dec 2009 22:59:15 GMT

I just aquired a blackline 68 PR that I am turning around for resale.. The head is totally stock and original except for three of the pre amp tubes. The cab, grill cloth, speaker(12 inch Celestion Alnico Blue) , and reverb pan are all replacement parts. I have drip edge from another amp I can fit to the PR to make it look the part of 1968. Just wondering what you guys think if that is worth it or not. I would have to trim the baffle and and the drip edge moulding since it is from a...

Circlotron Amps

feeds@yuku.com (jbmojo) — Fri, 11 Dec 2009 18:56:19 GMT

Just ran across some info on this. Anybody got an opinion on it?

Tweed era 5F8A build. Presence circuit bad design!

feeds@yuku.com (Fenderonly) — Sun, 06 Dec 2009 15:34:23 GMT

The presence circuit of the high 5F8A (high power tweed Twin) allows around 12VDC on the 5K presence pot. Makes for a scratchy pot.

Any thoughts on improving that? Perhaps a 22 to 25uf tantalum cap in series with the pot leg to decouple the DC and hopefully still pass enough low end thru the pot to ground?
I have had a lot of success with using tantalum caps in place of electroytics between the gain stages in the Peavey Nashville 400 steel amp mods I have done. They have...

New website for Fox Vintage Amp Repair

feeds@yuku.com (Fenderonly) — Sat, 05 Dec 2009 20:46:40 GMT

Check it out. Finished writing it this week and published it today. My first shot at a website design. Used WebEasy 8.0. Made for dummies like me!!!

http://foxvintageamps.com/

Mid Life toy acquisition

feeds@yuku.com (Andy ZZ) — Fri, 04 Dec 2009 15:04:34 GMT

I have arrived at mid life, and it seems to be pretty much the same as previous life.
I thought a new toy might be interesting though, and I've been gassing for one of these for a few years:

http://milwaukee.craigslist.org/rvs/1467626095.html

Finally found a sweet deal on one.
The better (smarter) half wasn't happy about it, but...

Oddball schematic request.

feeds@yuku.com (Psycho Bass Guy) — Mon, 30 Nov 2009 07:35:56 GMT

I'm looking for a skit for a Krell FPB 200 solid state power amp. Since Krell is an audiophile brand, none of the usual sources have one online, nor will Krell even sell one. I'm not working on this particular amp, nor is it in my possession, just trying to help out a buddy.

Newbie with 6973 amp!

feeds@yuku.com (akimball442) — Sun, 29 Nov 2009 20:33:08 GMT

Hi there-

I am not new to tube amps, but I'm new to this forum.

I have more than a few vintage Fenders, and a 50W Marshall, but I have been getting more and more interested in small amps, which seem to be a lot of fun.
One of my favorites is a small Supro I have, which has only two tubes, a 50L6 and a 12AX7, connected in a power transformerless death arrangement. I figure it's safe enough for the living room.

I recently acquired an old RCA...

BXR Spectrum Cabinet

feeds@yuku.com (jbmojo) — Sun, 29 Nov 2009 07:39:27 GMT

I need to replace the 2x10's in a BXR Spectrum cabinet (2x10,1x18). Anyone know what Fender used in there? I'm pretty sure they were 8 ohm but got no idea on the power rating...and no old speakers either.

Weber Shipping Times

feeds@yuku.com (4willieC) — Sat, 28 Nov 2009 09:44:48 GMT

Ive often wondered just why it takes the folks as Weber as long as it does to ship out most of their orders. I know they claim to not hold stock or inventory on their speakers, though you have to wonder why not at least get a bit ahead on the most popular models. Plus, you have to wonder why not build inventory on some of the amp kits?

Most recently, we ordered a 6A20HP kit from them with no cabinet, no tubes and no transformers...should be a quick ship I would have thought...but we...

Get a load of this

feeds@yuku.com (jbmojo) — Mon, 23 Nov 2009 22:59:37 GMT

Bob, is this average for your neck of the woods?\

Caught in Houma...

champ amp and speaker load

feeds@yuku.com (fuzeman) — Mon, 23 Nov 2009 18:26:02 GMT

I've been fooling around with my '72 champ that I modded a while back to 5f1 specs. and was wondering, what are the consequences if any of running it thru a 12" , 8 ohm speaker ?

steve

Standby lamp shorting?

feeds@yuku.com (jbmojo) — Sat, 21 Nov 2009 10:36:07 GMT

There's a neon standby lamp in my Sound City connected between the two bridge rectifier circuits and I was wondering that if it was shorted would it cause the mains fuse to blow? The bridge circuits are in series for the center tap at the OT and the bulb's connected in parallel with the two B+ outs.
Here's the schematic:

Alnico or Ceramic or PM?

feeds@yuku.com (4willieC) — Fri, 20 Nov 2009 23:06:12 GMT

I like to think that after 47 years of servicing guitar amps and other electronic devices that I know one thing from another....but I have to tell ya, I often am at a loss for explaining how to identify a speaker with an alnico magnet versus a ceramic versus a permanent natural magnet. Other than by shapes, is there a truly definitive way to ID one from the other? I always wanted to ask Ted Weber about this but never got around to it...and now it's too late.

I got to thinking...

Legacy Tribute Premium

feeds@yuku.com (x24guitarman) — Fri, 20 Nov 2009 19:42:36 GMT

I traded a Hohner 335 copy for this guitar today. It's a butterscotch transparent finish with AlNiCo V pickups and the PTB control layout. That layout has the single volume like a strat but the first tone controls High frequencies and the rear the lower end. This makes for some interesting tones with the traditional 5 way switch. The neck is maple with a maple cap fingerboard and the body is a two piece ash. It's hefty compared to my 1988 Strat Plus. The pickguard is m-o-toiletseat....