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scottvMember
i love these pedals but they have alot of potential quality issues, cheap plastic jacks that are soldered to the circuit board, delicate and flimsy circuit traces, cheap potentiometers alot can happen to these especially if its put thru “rugged” use. once i learned enough about circuits and these units i have replaced the jacks, pots, wiring and switch (3pdt to make it true bypass)
also recommend running a circuit trace, start if you have signal at the 2nd lug of the volume pot (thus is the circuit output) then check the transistors and the jack (not as likely if you hear it actually switching, but could have a bad solder point to one its lugs)
scottvMemberThis is from the manual, i’m abit confused on what you are actually using, a Boss ac adapter or the actual EH supplied adapter, make sure its the correct current/voltage… otherwise you may have a dud (either the pedal itself or the ac adapter) and need to return it for another? i would see if you can take it to a music store and if they have another compatible adapter to plug into it first.
9V Power Jack
Plug the output of the SMMH’s supplied AC Adapter into the 9V power jack located at the top of the SMMH. The SMMH requires 9 – 9.6VDC at 200mA with a center negative plug. The SMMH accepts Boss style AC Adapters.
WARNING: Use only the US96DC-200BI adapter that the Stereo Memory Man w/ Hazarai comes supplied with. Do not use any other AC adapters. Using other AC adapters, even those made by Electro-Harmonix, could cause harm to the unit, the adapter or you. The SMMH does not use batteries.
scottvMemberit might be the pot, i would use a multimeter on it and check the resistance at various points in its rotation. that may give you a clue if its bad.
scottvMemberhttp://www.diystompboxes.com/wiki/index.php?title=Debugging
2nd section from the top is on using an audio probe.
scottvMemberIts the same components to pull from ground (R5 & C8), i did it on this newer version of the circuit board and it worked fine.
I followed the circuit trace and lifted one leg of each component (the leg to ground) from the board. That is when looking at the component side up with the pots at the top the leg on the right hand side for both the resistor and capacitor is the one i pulled out (i’m pretty sure of this as i just did this about a week ago). I actually replaced the crappy ceramic .01uF cap with a poly film .01uF.I referred to this: http://www.muzique.com/lab/tbypass.htm
and
I used this as a guide: http://roadsideguitars.blogspot.com/2009/04/adding-tone-bypass-to-ny-big-muff.htmlI’ve seen another method of “tone bypass” on youtube that i’m pretty sure is wrong and does nothing but mimic the tone of just turning the tone pot full CCW, but never really tried that other method as this one is more logical.
scottvMemberIt could be a number of issues, an audio trace is I believe like an “audio probe” there is a step by step guide on DIY stompboxes dot com on how to do this, basically its using a cable with a signal source plugged into it on one end (something that gives a constant sound, plucking a guitar is too cumbersome, so maybe a portable cd player or ipod) and capacitor on one lead of the opposite end and the other lead grounded. use the open lead of the capacitor as “the probe” contacting various places on the circuit board, not randomly as you should “trace” through the circuit from start to end, the output of the circuit is plugged into an amp to listen for the input signal, what this will find is if there is:
bad solder point or trace on the circuit bad
or
bad component (capacitor, transistor, diode… resistors are tougher to destroy but…)
December 23, 2011 at 8:04 pm in reply to: Deluxe Memory Man which trimpot that controls feedback??? Help! #116582scottvMemberOK i figured this out with help from a kinda person over at the DIY stompboxes forum…
This is what they said:
“None of the five trims directly control the feedback amount. However, a properly adjusted DMM will self-oscillate, no problem. There are two “gain” trims; they adjust the varying gain levels that BBDs would (or wouldn’t) produce. These allow you to either boost or attenuate the signal coming out of each BBD (usually the later because BBDs have a problem with clipping). And the last key point is that the higher the amplitude of the signal going through the delay line, the more repeats you will get from the feedback loop.
Can’t say for sure, but i would ask your tech if the ‘optimal’ adjustment was dropping the gain through the delay line to keep distortion to a minimum (and ask him if he used a signal generator/ oscilloscope or not). If you do it TOO much, you’re just sacrificing signal level (and as you found out, the amount of repeats). You have to realize that DMM’s are quite prone to clipping, and thats what the external GAIN control is there for.
If you want to bump up the internal gain yourself for the self-oscillation thing, very gradually turn each one, alternating between the two. And sorry, i can’t remember which direction is boost, and which is attenuate, just mark where they are set before you start turning. Pluck a signal through the unit while you adjust, and it should start to self-oscillate like you want.
From your picture, here is the order of the trims (from left to right): post-Gain (BBD2), post-Gain (BBD1), bias (BBD2), balance, bias (BBD1)
Also, be very careful around that power switch in the upper right-corner of the box, thats got 117VAC!”
I adjusted trimpot#1 from the leftside (this is the post-gain BBD2) with little perceived difference so i left it where it was adjusted by the repair tech, so I adjusted trimpot#2 from the leftside (this is the post-gain BBD1) and it only took a very slight adjustment for me to make a difference, it started to oscillate and runaway with a very slight turn CW on this trimpot, so i just turned it slightly more maybe 1/8 rotation from where it was and now i got runaway oscillation at about 75% rotation on the “feedback” pot (this seems to be abit later in rotation in the 3 deluxe memory man pedals i’ve had in my life, most begin to oscillate at about 60% rotation of the feedback pot) but this is just fine for me as it also gives more abit more control the delay repeats and it seems its also recovered some of the delay gain with the blend pot, as some of the delay signal seemed to be missing and overcoming the dry signal. the only problem is that the sound is abit crunchy (clipping) on the delays with a hard attack on the strings, whcih i’ve read is not uncommon on these pedals and can be improved by switching op amp IC chips for a cleaner sound.
just passing this on for anyone else…
scottvMemberwhy not find where those wires connect to the circuit board and/or jacks and re-solder new longer wires?
or you can make a sort of extension wire and solder another wire to get additional length to the ends of the existing ones, just use some heat shrink tubing at the exposed section of wire (to avoid contact and shorting out of any other contact points)…
i dunno just some suggestions if you feel handy/confident enough.
scottvMemberKinda sounds like a bad switch, normally its a relatively easy fix with a new replacement 3pdt type switch, but (i’m assuming it the new modern LBM?) these are soldered to a mini circuit board with a soldered ribbon cable to the main circuit board, so the best thing though its more complicated is to replace the switch and ribbon cable with new wires from the circuit board to a new 3pdt, but you need to know where each wire connects to, can’t help much there but it can be figured out with patience and going thru the circuit.
or…
i had a similar type of problem with my newer LBM, where i had thought the switch quit, thus it only worked in bypass mode. i found that the ribbon cable is made of pretty cheap thin wire and if fiddled with enough (doesn’t take much) it can fail and stop making contact at certain wire/solder points, i had to resplice and resolder the ribbon cable where it connected to the 3pdt miniboard to get the effect to work again. this may be the case for you, that means the 3pdt is fine but the ribbon cable connections have gotten loose making intermittant or no contact…
…but if this is the old style LBM, i assume its using either a dpdt or spdt switch which has stopped working and thus its not true-bypass, i suggest replacing with a 3pdt and true bypass it.
scottvMemberLike EH Man has said it could be a disconnected wire or bad switch…
or it could be a bad solder point to the board/jack/switch, if you gently knock on the pedal while its bypassed you may be able to listen to the signal coming in and out… its not likely a power supply issue (battery power connection) as the pedal wouldn’t be powering up at all or intermittingly. as in your case, you get the distorted signal but not the bypassed.
It sounds like you don’t have much soldering experience or much knowledge with circuits, so its best you find a service rep in your area or contact EH for repair.
November 22, 2011 at 6:34 pm in reply to: Deluxe type pedals: LED for effect “on/off” not Power “on/off” How-To? #116410scottvMemberActually I want to do this on my Deluxe Big Muff, as it will make it true-bypass…
Not on the Deluxe Memory Man because I like to keep the gain adjustment ability when bypassed on my old deluxe memory man.Is there a way to add an effect LED on the old memory man without making it true bypass?
November 21, 2011 at 8:36 pm in reply to: replacement vintage muff cases – if youre into that thing / beware collectors #116388scottvMemberNot cool… oh well, beware.
scottvMemberMy first DMM I purchased was in the early 00’s and had the power adapter, my bandmate had a DMM with the 3-prong power cord that he said he bought in the 90’s. my guess would be the 90’s…
scottvMemberJust also want to state that the first mod i had done on a pedal was on the black russian muff (2002 models) a couple of years ago, just when i was starting to explore what was inside effects units and i had two of these units and knowing that they were fairly inexpensive i gave it a shot figuring the risk was low. the first “mod” i discovered pretty accidently that i have never read anyone else do was bypassing the .0039 cap which i found by placing a wire across both ends of this capacitor. It provides a pretty good volume and bass (maybe also more of a scooped sound) boost. I’m finding it abit similar to the scooped sound on the 3-way switch mod in this thread though with more volume added. It worked well on one unit and not another when i attempted it again, perhaps due to the inconsistent tone from unit to unit on these pedals or inadvertantly damaging a component while connecting a SPDT during soldering (probably the latter in my case) because on the 2nd unit i did this with i get as best as i can describe it an undesirable increase delayed clipping effect when playing the bass strings on my guitar (i’m using humbuckers) as if when the strings are plucked the sound is being instantly sucked away for a split second and then suddenly appears… this doesn’t occur on the 1st unit i did this mod with.
scottvMemberQuote:To bypass the tonestack you just remove one end of the 10nF and 22k from ground.
As for the convert diagram, just make any necessary changes.Thanks for the response Ned and for providing drawings for just about anyone of any skill level of electronics to follow! i did figure out that by lifting one end of each of those components removes the tonestack, but when i do this i’m finding in my muff that there still is some subtle tonal changes when i adjust the tone knob (though only at full clockwise and counterclockwise i can hear a difference) so this mod doesn’t actually completly remove the tone stack or is it supposed to? it was most apparant when switched on to the feedback mod i did around Q1 & Q3.
Also, i found that by only lifting one end of the 22k resistor (leaving the 10nf cap alone) increases the volume and slightly increases the mids… i did this late last night and tested it on a tiny solid state amp, i’ve yet to hear how it sounds on my fender twin that will be later.
I was also testing how i would like the 3-way tone switch and its nice though i hear very little difference switching between normal and flat… i also ended using a slightly larger cap (6.8 nF) than recommended (i think 9.4 nF) for the scooped sound and that was pretty apparant sounding. though a more scooped than normal muff sound is not what i’m really looking for, i’m sticking with the tone bypass mod.
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