DELUXE REVERB NORMAL:LEAD CHANNEL MODS

[ViperDoc]

I've seen several recommendations of putting a "Plexi"-style Lead circuit into the Normal channel of a Deluxe Reverb, but I can't find very many examples that show how to make it sound its best. Only examples I've seen sound quite thin. Considering the Normal Channel only has two triodes, would you recommend adding another gain stage? i.e. extra tube?

[sluckey]

You don't need another gain stage. You need a cathode follower. The CF can easily be replaced by a MOS-FET.

Or, if you just gotta have a tube CF, you can do a simple mod to the two triode tremolo circuit. The Trem-O-Nator only uses one tube, thus freeing up a triode, and it sounds much smoother and stronger than the original Fender tremolo. I considered doing this to my Bandmaster but kinda fizzled out after the Trem-O-Nator mod.

Either way, you can easily get a single channel Plexi preamp. But it's still gonna be connected to an AB763 power amp driving a Fender sounding speaker. Probably not gonna be the last amp you ever build.

[ViperDoc]

I'll check that out, thanks, Sluckey.

I've never used a MOSFET outside a 5VDC power supply. How would it be used?

[ViperDoc]

I just found this: http://www.geofex.com/Article_Folders/m ... tfolly.htm

[ViperDoc]

I drew up a few variants of a possible mosfet CF. Which of these is the best way to design it? I've only seen the CF used pre-tone stack in Marshall-style circuits.

For your entertainment:
[DELETED]

[sluckey]

None of those look like a plexi. Plexi topology goes---> input-gain-volume-gain-CF-TS-PI.

[pdf64]

A MOSFET equivalent isn’t going to cause the waveform asymmetry that is a notable characteristic of a DCCF though.
http://www.valvewizard.co.uk/dccf.html

[ViperDoc]

None of those look like a plexi. Plexi topology goes---> input-gain-volume-gain-CF-TS-PI.

Good point. I'll get back to the drawing board... My main question is where to put the MOSFET in the circuit, although you may have just answered that.

[sluckey]

None of those look like a plexi. Plexi topology goes---> input-gain-volume-gain-CF-TS-PI.

Good point. I'll get back to the drawing board... My main question is where to put the MOSFET in the circuit, although you may have just answered that.

Look at a plexi schematic. Locate the CF. Replace with the MOSFET.

[Ten Over]

Here are a couple of examples of the Normal channel modded into a somewhat Marshall topology.

[ViperDoc]

Here's another go:
[DELETED]

[ViperDoc]

Here are a couple of examples of the Normal channel modded into a somewhat Marshall topology.

Very nice, thanks for those files, Ten Over. I like how the second mixes both channels into the reverb. I wonder how you could design a Lead Channel Reverb level. Most likely a relay? I thought I also saw a Tremo-o-nator...

[pdf64]

Here's another go:

AB763 LEAD 2.0.pdf

C? isn’t needed, and such a low value will mess up the expected response of the tone stack controls.

[ViperDoc]

Here's another go:

AB763 LEAD 2.0.pdf

C? isn’t needed, and such a low value will mess up the expected response of the tone stack controls.

Thanks. I assume you mean the .0022 cap off of the cathode follower? I simply copied the tone stack from a Super Lead schematic. The drawings from Ten Over raised another question I had, which was whether to increase the value and/or number of power supply caps in the Lead circuit. The stock AB763 uses a single 16 uF power supply capacitor for four preamp triodes. I suppose you'd only be using two at a time, perhaps that's enough.

[pdf64]

...I assume you mean the .0022 cap off of the cathode follower? I simply copied the tone stack from a Super Lead schematic...

I can't think of any SuperLead with such a cap feeding its tone stack?