Stereo Memory Man w/ Hazarai mod?

All about modern commercial stompbox circuits from Electro Harmonix over MXR, Boss and Ibanez into the nineties.
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88mark
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Post by 88mark »

DWBH wrote:You don't solder the transistors to that pad where it says R41/R42, you solder them directly on the encoder.

Actually, I don't know what's the value of those resistors, but if they're not big you probably could solder. I don't know, just checking. Solder directly on the encoder, just in case.

Hey DWBH, Thnx again for the answers!

Made another scematic. It would be really great if you could take a last critical look (especially at the wireing of those switches), and confirm that its the right way to solder. If it's not, feel free to edit the picture if you'd like to.
mod.png
Thnx!

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dodgypete
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Post by dodgypete »

I'm a bit late on this one :lol:

Your pull up resistors on the 2 inputs are wrong. You are correct in putting the resistors from the inputs to +5v, but your switches should be connected directly to the inputs.
If you wire it up like the drawing, the switches will pull the +5v supply to ground :shock:

The jack I used gets its GND from the enclosure, hence only 2 wires.

The GND for the arduino board goes directly to the centre of the 9v power jack.

I used the arduino pro because I had it lying around. I'm now using attiny chips for projects. I haven't got around to writing new code this project yet though.

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88mark
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Post by 88mark »

Thnx Dodgypete! :thumbsup
I think i have the final scematic right now :)
mod.jpg
would be great if someone could confirm that it's correct this way :lol:

dodgypete wrote:I'm a bit late on this one :lol:

Your pull up resistors on the 2 inputs are wrong. You are correct in putting the resistors from the inputs to +5v, but your switches should be connected directly to the inputs.
If you wire it up like the drawing, the switches will pull the +5v supply to ground :shock:
Ok, so then it's like as on the scematic, right?

But, just for my curiousity, i don't understand what happens. there is 5v (or a little lower cause of the resistor) on the inputs, then i press the footswitch. and the voltage is still on the inputs, as well as it goes to ground through the switches. so I can't understand what changes to the inputs, when pressing the switch.. I'm a little confused here :scratch: :)

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DWBH
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Post by DWBH »

Open this link:
http://www.falstad.com/circuit/#%24+1+5 ... +1+true%0A

When the footswitch isn't pressed, the input is always HIGH. When it's pressed, the input pin on the arduino goes LOW.

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Post by 88mark »

DWBH wrote:Open this link:
http://www.falstad.com/circuit/#%24+1+5 ... +1+true%0A

When the footswitch isn't pressed, the input is always HIGH. When it's pressed, the input pin on the arduino goes LOW.
huh? but that's not how dodgypete connected his board, is it?
this one is from the scematic I posted yesterday.

So, which scematic is right in your opinion, the last one i posted (like dodgypete said) or the one before that?

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Post by 88mark »

BTW, I ordered some of the parts today. So I will be starting soldering soon. That would not be possible without your help, so thnx a lot!!!

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dodgypete
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Post by dodgypete »

88mark wrote:
DWBH wrote: When the footswitch isn't pressed, the input is always HIGH. When it's pressed, the input pin on the arduino goes LOW.
huh? but that's not how dodgypete connected his board, is it?
this one is from the scematic I posted yesterday.

So, which scematic is right in your opinion, the last one i posted (like dodgypete said) or the one before that?
That is exactly how I connected it.

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88mark
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Post by 88mark »

dodgypete wrote:
88mark wrote:
DWBH wrote: When the footswitch isn't pressed, the input is always HIGH. When it's pressed, the input pin on the arduino goes LOW.
huh? but that's not how dodgypete connected his board, is it?
this one is from the scematic I posted yesterday.

So, which scematic is right in your opinion, the last one i posted (like dodgypete said) or the one before that?
That is exactly how I connected it.

aaaah, I got it (or at least, I think so.. ;) ).. The arduino is at the right of the scematic in the simulator, not at the top, true?

Thnx for the drawing DWBH.

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Post by cookieshoes »

Hi all,

I found these pics online of a mod for the volume drop on an EHX Stereo Memory Man with Hazarai.

Pics are from this site: http://www.vertexeffects.com/blog/tom-buk-pedalboard

I had reached out to the builder regarding the mod some time ago but was told that the mod isn't currently offered.
(BTW, I'm familiar with the recent discussions regarding this builder. For the thread here I'm just looking for any help with this mod, thanks.)

Anyone have any idea how this mod is being done? I see boards for the AMZ Op Amp and V Dub in there.

Can anyone steer me towards how to do the same, or a similar mod? Getting ahold of the AMZ boards is easy enough, just not sure how they are being used here (dual Op Amp makes sense, but not sure about the V Dub board). Anything else that could fit in there that would do the trick?

Image

Image

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cookieshoes
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Post by cookieshoes »

Bump.

Anybody know what function the V-DUB board is serving in the above pics?

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Post by dodgypete »

As requested here are the missing photos:

Image

Image

Image
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Impckmr.jpg

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Post by imemine »

Hi. Thanks @dodgypete for the pictures above and thanks to everyone for the useful info on this thread. I tried this mod and it works! However, I have a problem: whenever I use the encoder (not everytime, but often) the mod stops working and I need to move the encoder again and again until it suddenly works again. Does it happen also to you?

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Post by dodgypete »

Occasionally I have had trouble if the encoder is between steps (probably bumped when I've been setting up/putting away my pedal board).

If the encoder is sitting in one of the notches the mod always works for me.

When the encoder is between positions it will be pulling to ground, effectively shunting the transistors.

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