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July 16, 2010 at 12:15 am in reply to: Help using a 1 spot and Damage from wrong polarity question #110262ranjamMember
If you feel comfortable doing this, peek inside each pedal, especially around the DC jack. Usually, there will be something like a diode, a series resistor/parallel capacitor acting as a filter, maybe a zener, whatever. Sometimes those will get burnt very badly, but the pedal will still work, especially if the part was in parallel. I had a Pigtronix Philosopher’s Tone that had the wrong adaptor plugged in, and it smoked a series resistor. Of course the pedal didn’t work until that resistor was replaced. But if you are getting a signal through, and you don’t smell anything, you are likely OK. Just on the off chance you took out a parallel diode or something, check anyway.
ranjamMemberIt’s your battery clip, and it can’t be saved. A new one is so cheap, anyway. And it will be easy to replace, so I wouldn’t worry at all. You’ll have it done faster than it takes to warm up your soldering iron.
ranjamMemberIt’s happened to me. What you can do is check all the board connections with a jeweler’s loupe. The wires from the jacks and the footswitch to the board could be flaky. Sometimes I’ve removed what seems like a pound of solder, and just have as little as possible to connect the wires. Check everything twice. Tighten the hardware, especially if it is used to make ground connections. If it is the jack that is intermittent, you can try and bend it back to being ‘tight’ against the cord, or just replace it.
ranjamMemberIt just may be that the adaptor you are using isn’t filtered as well as needed by the Soul Preacher. I am just as guilty of using cheap calculator adaptors just because they are handy, but you don’t listen to a calculator, so I know they aren’t filtered well. You can add filtering, or use a really good ‘guitar pedal’ power supply. The filter would just be say a 47-ohm or a 100-ohm resistor replacing the wire from the adaptor jack ‘hot’ lead. Then add a 100uF or a 220uF capacitor from where that wire went to over to circuit ground (observing polarity).
I have a older DOD adaptor, and they seem to work well. Or my board with a DC Brick has 1/8″ converter plugs, so I am covered no matter what. But with a fresh battery or a good adaptor, the SP does squash, you just have to crank it up. The treble boost switch is just too much.ranjamMemberReplace the battery clip carefully, and redo that yellow wire from the switch. I am guessing it is the input wire. The wiring looks a little sloppy (sorry), so chances are your luck ran out.
The battery clip will have the black wire going to the input jack sleeve connection, and the red lead will go to the adaptor jack. This should be a good start.ranjamMemberI have one as well, and I believe you are correct with the polarity. It’s actually a nice compressor; very Dyna Comp-ish. Any well seem to like the Dyna Comp, so what’s not to like about the Soul Preacher?
ranjamMemberDoes anyone have a working pedal that can make a few voltage measurements? Knowing my luck, I put a good transistor back in lined up askew, so voltage measurements would tell me if everything else is OK and the 3080 is bad. Thanks.
ranjamMemberWell, the transistors test fine, but I did find a shorted capacitor. I haven’t plugged a guitar into it yet, but a ‘scope check shows it isn’t all that much better. The waveform is leaning towards a triangle shape, and as soon as the tone control is turned up, it looks like a nice cranked Marshall. I don’t know what to think. I’ll plug a guitar into this thing tomorrow and continue. But is it looking more like the 3080? 😥
ranjamMemberWell, the new soup can 741 is in, and the volume is back. :thumb: However, it’s still very distorted. :angry: The volume and tone controls work, there is a big volume boost, and the sustain control seems to work. But it goes from ‘buzzy’ distorted to sounding like a broken transistor radio with no bottom end at all. I don’t believe this is how it is supposed to sound.
Should I think about swapping transistors? I can test them with a decent transistor tester. Hmm, maybe I will do that before I try and beg for some free advice. Or if anyone has other thoughts? Thanks.ranjamMemberI still have to try the 741 first, but now my mind is resting a lot easier.
ranjamMemberWell, my B+ is correct, and with what I think is an accurate schematic (a couple I do find have subtle differences), my signal dies at the output of the soup can 741. I may lift pin/leg #6 and see if the output is OK, or else it’s find a soup can 741. At least that seems less painful. I should have thought of that, but thanks for the tip. It is appreciated.
ranjamMemberYes, I mixed my meds right before I said only the treble frequencies were boosted. That’s the Screaming Tree. The LPB-1 is a full-frequency booster. Where is unity gain? To me that’s almost like asking ‘Is this the 3rd street on the left?‘ You won’t know unity gain unless you compare the bypass signal and the pedal volume. If you have hot humbuckers, unity gain might be lower on the dial. It will depend on the incoming signal. If my faulty memory is correct, the gain is something like ’20’ or ’25’. Depending on the taper of the volume control, and that can have a wide tolerance, it may be somewhere around 9 o’clock or 10 o’clock. Start there, and compare.
ranjamMemberMy take is that the Soul Preacher is a simpler VCA compressor, the White Finger is a FET optical, and the Black Finger is tube. The optical will have a slower attack by nature. I have a feeling they Soul Preacher and White Finger can sound similar, of course depending on the settings. The White Finger should have many more settings that are useful. To me, the Soul Preacher has just a couple of settings, although they do sound great. The White Finger has a lot of settings that sound cool, depending on what you want. I have never owned a Black Finger, so I bow out on that call.
ranjamMemberMy fear is that less B+ doesn’t decrease gain, but headroom. The noise may come up as well, although for the life of me I have no idea why I think that.
Has anyone seen a real schematic for this very pedal? Not a generic ‘Little Big Muff’ schematic, but the EHX with reference numbers for the parts? Maybe you can come up with some type of easy ‘snip, snip; less gain!‘ mod.March 11, 2010 at 2:28 am in reply to: I want to repair an old EH Memory Man 1338A, were I can find the schematics? #108378ranjamMemberThe Deluxe Memory Man schematic is out there, if you look hard enough (or not all that hard, really). A photo of the innards of a 70’s Stereo Memory Man you can find on Flickr.
Between these two ‘hints’ you should have enough information to get that pedal going. Good luck!
*WARNING!* I realize I don’t own this photo. If hot linking to it is wrong, I apologize.
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