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Hey! I've got a WEM Dominator MKiii on the way. According to this schematic it looks like there should be a tap for 110v on the power transformer, yes? I'd love to be able to operate it without a step up transformer.
The previous owner said that it has a hum as it warms up that goes away after 4 or 5 minutes, so the first thing I'm going to do is replace the electrolytic caps (there's only three!) I've done some of this before, so I know the safety precautions, but my experience has only been with axial caps. Looking that the blue filter cap in the picture, I'm not sure what to get as a replacement. I found a better picture elsewhere that reads "60+100uf KB420AT" on the cap. Trouble is I can't find anything that matches the description of 60+100uf online. What do I need to know here?
*this is not a picture of the actual amp coming to me

That big blue guy is a multi-section, or "can" cap (more than one in the same package with a common negative terminal). The schematic would suggest a 50 + 50 uF. 60 + 100 is going to be harder to find.

JJ make some can caps that look like this:


You don't necessarily need to use a can cap here. Modern electrolyics are significantly smaller and come in standard values, so you can just get individual caps and figure out a good way to mount them in there. I'd order the following:

100 uF 350 V radial to replace that first 50 uF after the diodes.
47 uF 350 V radial to replace the other 50 uF after the 1.5 k resistor.
33 uF 300 V axial to replace that pink guy
47 uF 25 V for the EL84 cathode bypass cap (the smaller blue guy on the PCB).

Awesome, thank you Nate. Just what I needed. Wow, Mouser is offline. I haven't ordered in forever but that was surprising. Looking at DigiKey I can get pretty much everything you mentioned, but the closest for the 33uf would be rated at 350v. Close enough? Would using the individual caps instead of the can have a benefit? Would the values you mentioned be closer to spec for the circuit compared to the 50 + 50uf can? Just thinking it would be easier to mount the can, but maybe not.

I really appreciate your help. Looking forward to this project. I haven't had a British amp in a long time and I've had my eye out for a WEM of this era for like 20 years.

Also really hoping I can wire the PT for 110v. Excited for it to get here and get a look inside. Seller seems nice but is slow to ship.

You'll be fine with the 350V rated cap. You'll probably see like 270VDC at that node.

No benefit to individual caps vs the can unless its for space constraints.

Do you have a pic of the amp in question? On some Dominators the voltage selector is on the front of the amp, as is here:

http://wem-owners.com/wp-content/upload ... efub-1.jpg

Tom Wanderer wrote: Wed Nov 09, 2022 10:26 am Wow, Mouser is offline. I haven't ordered in forever but that was surprising.

I just looked and they seem to still be going...

Dr Tony Balls wrote: Wed Nov 09, 2022 10:42 am You'll be fine with the 350V rated cap. You'll probably see like 270VDC at that node.

No benefit to individual caps vs the can unless its for space constraints.

Do you have a pic of the amp in question? On some Dominators the voltage selector is on the front of the amp, as is here:

http://wem-owners.com/wp-content/upload ... efub-1.jpg

It doesn't have the voltage sector, unfortunately. Thanks for the info!

tommy wrote: Wed Nov 09, 2022 11:11 am

Tom Wanderer wrote: Wed Nov 09, 2022 10:26 am Wow, Mouser is offline. I haven't ordered in forever but that was surprising.

I just looked and they seem to still be going...

Yeah, weird, I went to their homepage and it was there, but everything on their site that came up in google searches lead to a broken link that said they were offline and to consult your local supplier. Must just be a link issue.

Anyone an ace at wiring blade style switches for unique switching? I tried poking around for this but couldn't find it anywhere.

Here's what I want to accomplish with a 4-WAY switch for a 3-pickup strat pickguard:

1: bridge only
2: middle only
3: neck only
4: neck + bridge (parallel)

I don't really care about order, though I would like bridge only to be on the end

Alternately I could do 5-way and add neck + bridge (series) as well.

Honestly I think you'd be best served just understanding the whole process about wiring as a whole & from there it should be a lot less difficult to parse.

This article I think does a pretty good job explaining it & even shows a couple examples. Shouldn't be too much to sort out from there.

Garth wrote: Fri Nov 11, 2022 9:39 am Honestly I think you'd be best served just understanding the whole process about wiring as a whole & from there it should be a lot less difficult to parse.

This article I think does a pretty good job explaining it & even shows a couple examples. Shouldn't be too much to sort out from there.

I understand how 3 and 5 way switches work. I can accomplish what I want with a 5-way by switching the lug positions of the neck and middle pickups. But I still end up with a position combo I don't want.

I guess I'll look for how the 4-position works. What I'm asking may not be possible.