I opened up all 7 of the above units. I could not tell if any of these units were modded by exchanging the AC plugs. The transformers look more or less similar on all of them. Here’s the transformer numbers that I could see:

The Graphic Equalizer had no discernible numbers on the transformer.

Attack Delay: XA00 20 GP8010

Clone Theory: 1610 GP7808

Deluxe Big Muff: XA0020 GP8051

Hot Tubes: This one had two lines of numbers, 4363 XA-0050 and 524-[78A]8 [the numbers in brackets are not clear].

Deluxe Memory Man: This one also had two lines, E1-28-120-21 and AEC-9701
The DMM has the number 120 among those on the transformer, and since it also has the 3-prong US plug, as noted by The EHX Man, it’s likely a 120V unit. Although I bought this used in Japan, it could have been imported from the US at some earlier date prior to when I got it.

Ambitron: XE0010 GP7933
In addition to the DMM, the Ambitron also has the 3-prong US plug, and since I got this used from the US it’s likely to be a 120V unit.

Beside the obvious 120 in the DMM transformer numbers, I can’t see any other patterns in the numbers; perhaps a more trained eye can. There are, however, a couple of other points worth mentioning.

I looked more carefully at the 2-prong AC plugs, and noticed that the Clone Theory and Hot Tubes have a polarized 2-prong plug, with one prong slightly wider than the other, which might also indicate US 120V. I got both of these used in Japan, but like the DMM they could have been bought from the US and imported here at some earlier date before I got it.

What could clear up things further is if there is any info about whether or not EHX put internal 100V transformers in some of these big box pedals for export to Japan. I think they might have done that with 240V units for export to Europe, but not sure. Perhaps someone could verify that.

It’s clear that some of the big boxes with the external transformers were customized for Japan, since I have a couple with EHX branded wall warts but with 100V spec. That might point to a clearer answer, though I’m not sure if that logic can apply to those items with the attached AC plug.

In any case, some progress made! If anyone has other information about the voltage for these pedals and other big box pedals with the attached AC plug, I’d appreciate if you could share it here. I can also post some pics from the innards of any of the ones I opened, if needed.

• This reply was modified 2 years, 3 months ago by Jazz Padd.

Thank you, great advice! I’m unable to do that, but will bring one to my tech next time I’m in the city.

In the mean time, I’m curious about running the 100V pedals at 120V. Is that high enough to cause damage?

Good to know, thanks very much for sharing your knowledge. I appreciate it!

Hello fuzzbuzz! Here’s a couple shots of the innards of my DBM:

Hope they’re useful. Let us know the outcome of your project.

I ended up running my old AC pedals with individual step-up transformers I got off Amazon Japan, bringing the mains from 100v to 115v or 120v. It works OK, they sound much better. Coincidentally, I was in a shop in Kyoto yesterday and found an old Ross flanger with the attached cable. To demo they powered it with a Sugano step up transformer that had two 115v outputs. That’s no longer made, but seems to have worked quite well.

Yes, the Ross Flanger is definitely a keeper! Funny thing is, I had all those old Ross pedals back in the 70s & 80s but sold them over the years.

I’m unable to measure the EHX pedal voltage, sorry. I know you want to do a mod, but what I can say is that based on the research I posted above and the input from The EHX Man, I went with using a step up transformer for all the EHX big box pedals. They sound much better, so far no issues.