old MXR switching problem

[whiskeytown]

I ve got an old MXR distortion plus with spdt switch and led, but I dont know how to wire led so that switch can turn it of and on.Does anybody know?

[Mark Hammer]

If it has an LED then it is either not that old, or else it is one of the plastic chassis units from the early 80's. Which one is it?

[52 Bill]

If it is original, any bud box style mxr pedal with an led came with a dpdt switch. One side switched the effect on and off and the other side turned the led on and off.

If you want to use the spdt, try R.G.'s Millenium Bypass board.

[whiskeytown]

I think its not in Bud box but its also aluminium box with MXR logo inside, and got led and only spdt switch inside, so i was wondering how they manage to wire led with only spdt switch (Carling).

[52 Bill]

By bud box I meant any of the versions in that size and style box.

Like I said they didn't. Unless you use an outboard circuit like the millenium bypass, you can't operate the effect and the led on one spdt switch.

[Mark Hammer]

Bill is correct. You might be able to implement a status LED if the SPDT switch controlled an electronic switch (with Fets or CMOS switches), but a SPDT switch used in a direct fashion (i.e., it does not control something else that does the actual switching) cannot switch the audio and LED at the same time.

Is it possible the switch was changed before you got the pedal? Given that the originals had no status LED and used a SPDT switch, is it possible someone had a "brilliant idea" to install a status LED and didn't realize the switch coudn't handle it until AFTER the drilled a hole and installed an LED? Just wondering aloud.

[drewl]

When did they start putting LED's in them?
Mine has one, so I was curious.

[52 Bill]

Early 80's as far as I can remember. It was probably done to compete with the Boss line that was growing in popularity around that time.

[Mark Hammer]

MXR went through so many last minute changes during the early 80's that I suppose I might have missed something, but I cannot personally recall ever seeing a Distortion+ in a 1590B type case (Bud, Eddystone or whatever) with an LED prior to the Dunlop reissue in the 90's. If that's what Whiskytown means by "old" then so be it. The originals up to 1980 came with a nice Carling SPDT stompswitch, no LED, no true bypass, and sucked tone as badly as anything else of that era did.

[52 Bill]

Mark:
You're probably right, I'm not sure if I've ever seen a D+ with led from that time period either. I was remembering generically that the early eighties was when they added the leds to most of their pedals. We were a dealer back then, and mxr was becoming "old hat" by that time. Then they came out with the plastic case command series, and by the time they brought out the metal case 2000 series, it was too late.

[whiskeytown]

Well ok it aint so old, Im wrong, but one guy give it to me to check it out and try to fix it, and inside was realy spdt Carling switch and led, and I was wondering maybe you guys are familiar with it and tell me how to wire it(there wasnt any kind of milenium bypass, or stuf like that inside, just pcb, spdt and led), ok, thanks anyway.

Cheers

[drewl]

Funny, I can't remember buying mine which has the LED, but it had to be after 1980.
I bought an MXR flanger after the D+ and it had no LED, neither does my DynaComp.
I replaced the switch and wired it for true bypass around the time that sort of info mkade it's way to this here internet thang.

[Mark Hammer]

Even with a Millenium Bypass arrangement, you would need to opt for a different stompswitch, whether a DPDT or 3PDT. Given that the 3PDT can be had for the same price (or close enough to not matter) as a DPDT, make it easy on yourself and wire that sucker up for true bypass plus indicator without going through the hassle of installing a Millenium circuit.

The critical question is whether the box will support that switch choice. More specifically, will there still be room for a 9v battery when you complete the changeover? The Carling switches tend to be slender, while the 3PDT switches have a square footprint. You'd be surprised how much of a difference a couple mm this way or that can make in a box as small as a 1590B, particularly when the holes are already drilled out for you and you can't change the location of things.

[drewl]

They fit, that's what I have in mine.
Ditto with my Dynacomp.
I've recently gotten back into screwing around with pedals making a few for the heck of it and was looking at your Millenium bypass yesterday.
great idea, but the 3pdt switches are pretty cheap now,(think I got like 10 for $3 each) so it's alot easier to go that route.
there's even a bunch of dpdt switches with alot smaller footprint than the older ones, guess they were made for alot of the mini pedals on the market now.

[Mark Hammer]

Yeah, when the "X-wing" DPDTs were the cheapest thing around at just under $4 and 3PDTs were $10@ or more - when you could get them - the Millenium Bypass was a hip thing to do. With the cost and size of stompswitches the way it is now, there just doesn't seem to be any point to going to all that bother any more.