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The EH ManModerator
Sounds like your power supply is OK. The op-amp may do the trick for you.
It’s really not that complicated for replacing the NE5554. Just a matter of matching pins up with a couple of 15v regulators. If you really need to replace it I’ll post the details here for you and others.
If you can, while you have it apart attach a heat sink to the NE5554. Might make it last longer and you may never need to replace it.The EH ManModeratorAssuming your power supply is working correctly and you have +15 and -15, I’d replace the first op-amp because that’s where your bypass signal comes from. If your power supply is bad, replace the NE5554 IC w/ a couple of 3-legged voltage regulators.
The EH ManModeratorWhich one do you have? See this link:
http://electroharmonix.ronsound.com/index.php?option=com_content&task=view&id=30&Itemid=45The EH ManModeratorI already have a DMM (custom w/ blue graphics for a former EHX employee) so I’ll be picking up a Time Machine sometime soon. I’ve started collecting EHX clones since I can’t find EH stuff I don’t have.
February 8, 2009 at 3:11 pm in reply to: Holier Grail – Intermittent Fault: due to overheating? #92921The EH ManModeratorI would suspect a bad solder joint somewhere, possibly on the Blend pot where it solders to the board.
February 7, 2009 at 1:54 am in reply to: Layout Photos of 1978 Electric Mistress with EH 5200-1C circuit board #92847The EH ManModeratorEH-5200 should be the Attack Decay pedal. Can you post some pics of your circuit board?
The EH ManModeratorI think you’d be better off asking your question here:
http://www.diystompboxes.com/smfforum/index.php#2Lots of good DIY info to be found!
The EH ManModeratorHe already has it on ebay w/ a starting bid of $125.
The EH ManModeratorYou’ve got one of those odd MN3007-only versions from 1980. The other one like that I had info for was from 1981. Thanks for the info. I’ll add it to my list.
The EH ManModeratorQuote:i think theres more administrators than actual members. im not sure whos who anyways. they should have more descriptive usernames…anyways, i just think i figured it out. its just a weird pedal. hahaha. basically it seems to work like this…
it seems to create two very separate tones. a low toned drive sound and a high range fuzz. with the fuzz knob all the way to the right, youre getting the loudest volume of the drive tone. as you turn it to the left the volume of that signal drops. a little ways into turning, you hear a very quiet high toned fuzz sound start to rise in volume, eventually the low tone dissapears completely, until you get all the way to the left where the high toned fuzz is at its loudest volume. …thats what it sounds like is happening to me anyways… so you fiddle with it until you get something you like, and then adjust the volume knob till its at a matched level to the clean signal. i think it sounds best around 10pm. at 12pm it sounds sort of flubby and weird, like either tone isnt very defined at its low volume…
this is strange and foreign to me, as im used to my typical method of EH fuzz pedals of “crank all the knobs and thats how it sounds best”
i dunno, im sure someone with some proper background can shed some more light on this..
The Axis is a 2 transistor fuzz but not like a Fuzz Face. It’s more like the Double Muff. The way the FUZZ control works is that it’s taking the signal from stage 1 at the extreme counter-clockwise rotation and from stage 2 at the other end. Anywhere in between is mixing the stages. Each stage runs through a fairly small value cap that drops a lot of the bass out. Just think of the FUZZ control as a blend control.
FWIW, some very early Big Muffs also had a FUZZ control instead of a SUSTAIN, although they used the standard Big Muff circuit.The EH ManModeratorThat was quite a while back. Now you can read it at my site and I update it when I get the chance.
The EH ManModeratorThe schematic is not publicly available. I can tell you that it’s a completely different circuit from the standard Big Muff.
The EH ManModeratorYou may need to get a Rolling Thunder to produce a really good kick drum effect.
The EH ManModeratorMy guess is that the bias pots for the delay ICs are off. Probably just needs a little tweak.
Since you’re an engineer, what you need to do is monitor the output signal of each BBD while adjusting the trimpot. Set the trim where the signal is least distorted. You’ll need to repeat this for each delay IC.
The EH ManModeratorLooks like that’s one of the newer ones with the relay true-bypass. The blue wire on the INPUT jack goes to the lug with the blue wire on the DIRECT jack.
I was just thinking today I should put together some pages with EH boards that show where the wires go.
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