Twin Reverb Question

[angushung]

So, I am a guitar tech and avid amp enthusiast. The main guy I work with has been using the same 73' Twin for 20 years or so. The thing is, he always ALWAYS uses the normal channel. Never any reverb or tremolo. I dont even think he has ever even hooked the footswitch up to it. Anyways, it has become a huge part of his sound. My question is, how can I take the normal channel only and put it into a smaller combo box or a head box? Maybe just a 100 watt bassman circuit would be generally the same? I have no clue, this is the only Fender I have ever worked with. My experience comes from Splawn amps and Vox type stuff. Any help would be greatly appreciated. Thanks and I look forward to posting more on this forum!

[Tone Junkie]

This was the perfect place Look for the single channel ab763 section here that would be your best blackface version. no reverb no tremolo.     Bill

[PRR]

You won't save enough space or weight to be worth the risk of changing a known-GOOD setup.

The 2nd channel is one small tube. The reverb is a couple small tubes, a small transformer, and the tank.

The real space/weight is the big tubes, the OT, the PT, and the two 12" speakers in the right-size baffle. So pruning the circuitry saves maybe 10% at best, and more like 5% because you use the same PT even with the lesser tube-count (not worth making two PTs 10% different). And it isn't The Twin without that speaker array. Yeah, you can put that much power into a Ten in a sealed box, and get a good sound, but it won't be the same sound and IMHO not such an impressive sound.

Yes, a Twin does get heavier as the owner ages. We ain't 18 any more. At some point the aging owner may say "Fug it!", get a little transistor amp half the weight of a Twin, and re-find a musical sound with the new (lighter) tool. In that market, the small builder can't compete with the used-amp aisle at Banjo World.

[Dave]

Look at the schematic for a Showman or a Dual Showman. That will get you an AB763 Twin without reverb.
Then all you have to do is chop out the trem.

Dave

[angushung]

Thanks for all the input! I am not going to steer away from the 2x12 design, I may do a head and cabinet but those JBL's arent going anywhere! The AB763 has got me intrigued. I'm going to gather some research on a builld today. I think I can track one down after work and see what it sounds like before I get too deep off in it. Thanks again and I welcome any more help!

[Dave]

I should have been more clear.
AB763 is the name of a circuit design. It was the building block for many Fender amps including the Twin Reverb.
There are other iterations of a Twin Reverb, but AB763 is the most sought after.
As far as I know, all the AB763 amps had Tremolo, but not all of them had reverb.
A Dual Showman (or even a Showman) is equivalent to a Twin Reverb except that it does not have Reverb.
Link...

http://www.schematicheaven.com/fenderamps/showman_ab763_schem.pdf

From here you could either chop out the trem channel, or keep the two channels but chop out the trem itself.

Dave

[sluckey]

Here's a schematic for a "normal" channel only AB763. This schematic is for a two power tube AB763 so you would have to add two more tubes for a Twin. Just add the appropriate iron and power supply and you have a normal channel only AB763 Twin.

[angushung]

Another related question...Are the twin reverb chassis the same size in both the twin combos and the twin heads? Meaning, the only difference is in the size of the cab/box? Also, can anyone recommend new tubes for a Twin? Keeping in mind I dont use the reverb or tremolo, its all normal channel with a fairly clean, yet extremely loud sound. I am using a 1969 Telecaster (bridge pickup only) through a vintage DS-1 for distortion. I want all the screaming chainsawy high end that I can get out of this thing (1973 Twin Reverb). Does matching the power tubes in a twin matter much or does the adjustment pots on the back take care of it?

[bigdaddy]

By removing the other circuits even though not in use you drastically change the sound of the amp. It sounds that way for a reason. Some of my favorite Fender amps were used on the normal channel. I never used the reverb nor the trem and that channel to me did not sound as good on some amps. Removing that circuit will add a lot of gain, lows, mids and some of the character of the amp. It won't be the same amp and you'll be going crazy trying to tame that one channel into how that TR's normal channel sounded.

[Dave]

There was no such animal as a Twin Reverb Head. There was a Dual Showman Reverb head which was the "same thing" as a Twin Reverb in head form but no Twin Reverb Head. Dual SHowman Reverb and Twin Reverb chassis were identical.

Dave

[angushung]

I guess I'll save the trouble and build a head cabinet for the Twin. I can get away with a box that is a little smaller than the dual showman reverb since I wont need the reverb pan. Any help on my tube info?

[duke of earl]

Doug says the EH tubes he sells are great sounding.Check them out in the parts catalog.