Home Forums Vintage EHX Mains voltage for big box pedals with attached AC cord?

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  • #192319
    Jazz Padd
    Participant

    Hello. I am writing from Japan, where I have a number of EHX big box pedals. All have an attached AC cord. Would it be possible to know the mains voltage for which these pedals were manufactured? The mains voltage here is 100V. I bought all these pedals used fairly recently, but I don’t know the intended voltage. I also don’t have the documentation for the pedals in question, nor could I find information about their voltage.

    The pedals I’m asking about are listed below. I don’t know if it makes a difference, but if it does I added a description of the attached AC cord.

    Clone Theory (2-prong AC cord)
    Deluxe Memory Man (3-prong AC cord)
    Attack Decay (2-prong AC cord)
    Hot Tubes (2-prong AC cord)
    Deluxe Big Muff (2-prong AC cord)
    Ambitron (3-prong AC cord)
    Graphic Equalizer (2-prong AC cord)

    I purchased all of these used in Japan, except for the Attack Decay and Ambitron, which I purchased used from the US. I am not sure if the ones I bought in Japan were made for the Japan market, or imported after market.

    They all seem to work on the 100V mains, but some of them don’t sound very good. There’s some distortion and in general their sound is weak. I ran those through a step up transformer to power them with 120V and they sounded much better. But I am not sure whether this used long term would damage the pedals, so I’d like to know, if possible, the intended voltage for these pedals, and if necessary adjust the step-up voltage. I am not interested in modding these pedals. I just want to match their voltage.

    Any advice or info would be greatly appreciated. Thank you very much.

    ehx_bb_ac

    • This topic was modified 2 years, 4 months ago by Jazz Padd.
    #192321
    The EH Man
    Moderator

    I’m not sure what ac plug style Japan uses but I’m going to say that if it has the US plug it’s likely 120v. You can look at the top of the transformer and see what it says. It may say “120” on it in the model number.

    #192322
    Jazz Padd
    Participant

    Thanks for the reply. The older 2-prong plugs in the US and Japan are very similar, but there seems to be a difference in polarity. I’m not an electrician, but as far as I know in Japan they only use grounding for bigger appliances. Some of the newer US 2-prong plugs have one prong a little wider, which makes it difficult to insert in the outlet in Japan, while on some vintage US made items, the 2-prong plug slips in unimpeded.

    It was my hunch, too, that the 3-prong plugs can be 120V. They are on the Ambitron, which I got from a US seller, and the DMM, but which I got from a seller here. Of course, I imagine such items are traded back and forth, and I’ve also noticed that sometimes the power cords have been replaced.

    Someone on another forum in which I asked this question said that if the transformer chassis code has XE0010, it should be a 220-240V unit. That made me wonder if EHX pedals for the Europe/UK market were made with the 220/240V transformers then it’s possible that they they made pedals with 100V transformers for the Japan market. I also have later EHX big box pedals that have the external wall mounted transformers for 100V mains.

    I’ll open up my pedals to see if there are numbers on the transformers.

    • This reply was modified 2 years, 4 months ago by Jazz Padd.
    • This reply was modified 2 years, 4 months ago by Jazz Padd.
    #192352
    Jazz Padd
    Participant

    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, 4 months ago by Jazz Padd.
    #192383
    The EH Man
    Moderator

    What you can do is unsolder the transformer leads from the PCB then plug the pedal in and measure the voltage on the unsoldered leads (just the solid color ones. There may be a striped center-tap that doesn’t need to be unsoldered for this). It should be around 24VAC. If it’s much lower than that then the transformer may be 100v. Really, as long as the secondary voltage is higher than the voltage regulator’s rating it’s not going to make much difference.

    #192386
    Jazz Padd
    Participant

    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?

    #192387
    The EH Man
    Moderator

    Running a 100v pedal at 120v increases the secondary voltage only slightly. The internal voltage regulators should be able to handle it.

    #192388
    Jazz Padd
    Participant

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

    #196929
    fuzzbuzzfuzz
    Participant

    Any follow up to this interesting thread?

    I too am also in Japan (Hello Jazz Pad!).

    And likewise I have acquired a few big box units gathered over the years including a Deluxe Big Muff from the UK (3 prong 240v).

    My aim personally is to remove the (annoying) transformer/AC cord etc and install a simple power jack, and to use an appropriate AC adaptor of the correct voltage. However in order to do that I’d need to know what the internal operating voltage of the DBM is….(and then of course figure out the wiring).

    There are I believe a couple of versions which may complicate matters.

    Currently into the wall socket this pedal of course sounds rather weak (though splendid) operating as it is on 100v rather than 240v.

    Any ideas anyone?

    Thank you in advance!

    • This reply was modified 1 year, 11 months ago by fuzzbuzzfuzz.
    • This reply was modified 1 year, 11 months ago by fuzzbuzzfuzz.
    #196932
    fuzzbuzzfuzz
    Participant

    Jazz Pad – I would be interested to see the insides of the DBM if possible. Thank you!

    • This reply was modified 1 year, 11 months ago by fuzzbuzzfuzz.
    • This reply was modified 1 year, 11 months ago by fuzzbuzzfuzz.
    #196936
    Jazz Padd
    Participant

    Hi fuzzbuzzfuzz! Here’s a couple of shots of the innards of the EHX big box DBM I have, as discussed above:

    FE88-B5-ED-33-C8-42-D3-BF1-C-0-C6887-D2-F9-B3
    0-C77630-B-CDCF-4-EEB-AB6-B-C7-AAE10-F053-A

    I ended up using it, like the others shown in this thread, with the attached chord into a transformer to power it from 100v to 120v. I don’t know how to confirm the design intended voltage, but would like to know. If you are ever able to verify that for the DBM or any other old big box, post here. Thanks!

    #196937
    Jazz Padd
    Participant

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

    FE88-B5-ED-33-C8-42-D3-BF1-C-0-C6887-D2-F9-B3
    0-C77630-B-CDCF-4-EEB-AB6-B-C7-AAE10-F053-A

    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.

    #196973
    fuzzbuzzfuzz
    Participant

    Interesting!

    Those old ROSS are really rather nice.

    Do you think it might be possible to measure the voltage coming off the taps of your pedal and entering the circuit? That might give me an idea as to what the internal voltage is and what I might be able to change mine too.

    I`ll try and post some gut shots as well when I have a moment to compare with yours. Thank you for those.

    • This reply was modified 1 year, 11 months ago by fuzzbuzzfuzz.
    #196975
    Jazz Padd
    Participant

    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.

    #198795
    espinete
    Participant

    Hi ! Do you know how many volts are coming from the xe0010 (two wires) for the deluxe big muff ? I’ve got a deluxe BM here and its transformer is completely dead and the schematic doesn’t specify this.
    Thanks in advance

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