18Watt.com

I was wondering if there is a schematic to show how to wire up just a normal tremolo 18 watt trem for a cascade option only. Not a tmb. I already wired one jack on the normal Chan so it parallels but I’d like to add a switch to then cascade. Maybe something like Robs one wire 5F6a cascade mod to a switch? Anyways, thanks for your help yall.

Figured it out

What was the answer?

Yes, what was the answer? Do you have a schematic?

It's in our Downloads section: files/Zaphod_Phils_18W_Cascade_Mod.pdf

FWIW I have performed that mod once. I found it not that great honestly. You’d have to tweak it really down to get acceptable overdrive characteristics. It’s hard to dial in a good tone at both settings. I think this requires extra tone controls and such.
But that’s my opinion and by all means: go ahead! Explore!!!

Bieworm wrote: ↑

Tue 12/19/23 3:13 am

FWIW I have performed that mod once. I found it not that great honestly. You’d have to tweak it really down to get acceptable overdrive characteristics. It’s hard to dial in a good tone at both settings. I think this requires extra tone controls and such.
But that’s my opinion and by all means: go ahead! Explore!!!

I like the switched mod a lot. I did tweak values of course, but the end result is excellent in the Xtra TMB series.

JMPGuitars wrote: ↑

Tue 12/19/23 9:49 am

Bieworm wrote: ↑

Tue 12/19/23 3:13 am

FWIW I have performed that mod once. I found it not that great honestly. You’d have to tweak it really down to get acceptable overdrive characteristics. It’s hard to dial in a good tone at both settings. I think this requires extra tone controls and such.
But that’s my opinion and by all means: go ahead! Explore!!!

I like the switched mod a lot. I did tweak values of course, but the end result is excellent in the Xtra TMB series.

I know, but it’s not an easy journey such as “justt” cascade the channels. That’s all I’m saying

I found this on el34world.com. Tried this version out, but I think the tubes are being overdriven to clipping. Any suggestions?

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Re: 18 watt tremolo cascading
« Reply #5 on: August 31, 2020, 04:45:49 pm »
I modified my 18W schematic to cascade the tremolo channel into the normal channel. You can see my original schematic on my website. I eliminated the input jacks and paralleled the triodes, connected R35 wiper to the grids of the triodes, removed the normal tone control, and grounded C18 (lower PI input).

If your amp is built on a turret board it will probably take less than 1 hour to do this mod. Gator clip leads allowed. This will give you the basis for your cascade idea. Tinker away, You may want to remove C11 and increase the size of R2 (maybe even to 10K cold clipper size). Heck, it may be just what you want without doing anything else.
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kelstabmm wrote: ↑

Thu 12/21/23 5:21 pm

I found this on el34world.com. Tried this version out, but I think the tubes are being overdriven to clipping. Any suggestions?

Overdrive and distortion are both words for clipping. But you're probably getting ugly distortion (blocking distortion or otherwise).

I would start by adding at least a 10K resistor at the grids on the normal channel. If that's not enough, you can create a voltage divider before it to reduce the signal.