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MuTron III schematic?

1/22/1997 5:36 PM
Craig	MuTron III schematic? I have been attempting to put together a scematic of my friend's 70's Musitronics MuTron III so I can make my own, (they're $300.00+ used!) but have run into a problem. There are 3 metal transistors and a funny looking cap that I can't read the numbers for. Does anyone happen to have, or know where I can locate, a schematic on this baby? Besides this setback, I'm done with the schematic, and will gladly share it. I have to cop to my novice status and admit that these unidentified components my be other than what I assume; here's a brief description: 3 ea - stout metal cylander; 8 pins (4 ea in opposing rows) extend from bottom circular plane. On top, two rows of alpha and numeric characters: lower row ends with T. Of course, there's no reason to assume they are alike, but I can make out similar looking characters on all 3. 1 ea - looks like an egg-shaped ceramic capacitor; has 3 horizontal color bands: lowest band = green, center band = violet, top band = yellow. Has white dot on one side. 2 leads extend from bottom. Thanks, Craig

1/22/1997 5:36 PM

Craig

MuTron III schematic?

I have been attempting to put together a scematic of my friend's 70's Musitronics MuTron III so I can make my own, (they're $300.00+ used!) but have run into a problem. There are 3 metal transistors and a funny looking cap that I can't read the numbers for. Does anyone happen to have, or know where I can locate, a schematic on this baby?

Besides this setback, I'm done with the schematic, and will gladly share it.

I have to cop to my novice status and admit that these unidentified components my be other than what I assume; here's a brief description:

3 ea - stout metal cylander; 8 pins (4 ea in opposing rows) extend from bottom circular plane. On top, two rows of alpha and numeric characters: lower row ends with T. Of course, there's no reason to assume they are alike, but I can make out similar looking characters on all 3.

1 ea - looks like an egg-shaped ceramic capacitor; has 3 horizontal color bands: lowest band = green, center band = violet, top band = yellow. Has white dot on one side. 2 leads extend from bottom.

Thanks,
Craig

1/22/1997 9:41 PM
CJ Landry	The 3 metal cans are op-amps. Which ones, I could not tell you. But, I worked on a Mutron Auto wah for Analog MIke and found that Mutron matched this metal can and another op-amp for some unknown reason because I could not get just any old op-amp to work. Mike sent me a set from a broken auto wah and that fixed the problem. Good luck The caps, I have never been good at reading color banded caps. I have to break out my engineering books every time and even then I doubt my final answer. try puting one on a cap meter. Good luck Christian

1/22/1997 9:41 PM

CJ Landry

The 3 metal cans are op-amps. Which ones, I could not tell you. But, I worked on a Mutron Auto wah for Analog MIke and found that Mutron matched this metal can and another op-amp for some unknown reason because I could not get just any old op-amp to work. Mike sent me a set from a broken auto wah and that fixed the problem. Good luck
The caps, I have never been good at reading color banded caps. I have to break out my engineering books every time and even then I doubt my final answer. try puting one on a cap meter. Good luck Christian

1/23/1997 10:55 AM
Craig	Thanks for the reply. What's the deal on subbing op-amps? I went to a local (small) electronics shop looking for 2N5088's that I need for a distortion circuit, and they didn't have any. I know that you can sub if you observe power and polarity, but what else should be considered? Is there a good reference book that lists all common components and describes their characteristics and general applications? I'm still pretty new at this stuff and it seems like I need a "Electronics Bible" of some kind. It's probably too much to hope that it also be music-project oriented. (A man's gotta have a dream...) Is there a "cap" meter that's different than a regular voltohmeter? I also remembered there was one other mystery cap in the MuTron: - rectangular green, 100v, XX =/- 20%, located near the power switch. I can't read the 1st 2 numbers. Thanks - Craig

1/23/1997 10:55 AM

Craig

Thanks for the reply. What's the deal on subbing op-amps? I went to a local (small) electronics shop looking for 2N5088's that I need for a distortion circuit, and they didn't have any. I know that you can sub if you observe power and polarity, but what else should be considered?

Is there a good reference book that lists all common components and describes their characteristics and general applications? I'm still pretty new at this stuff and it seems like I need a "Electronics Bible" of some kind. It's probably too much to hope that it also be music-project oriented. (A man's gotta have a dream...)

Is there a "cap" meter that's different than a regular voltohmeter?

I also remembered there was one other mystery cap in the MuTron:

- rectangular green, 100v, XX =/- 20%, located near the power switch. I can't read the 1st 2 numbers.

Thanks - Craig

1/22/1997 10:57 PM
Steve Morrison	... 3 ea - stout metal cylander; 8 pins (4 ea in opposing rows) extend from bottom circular plane. ... The fact that those eight pins appear to be in two rows of four would suggest that the pc board was designed to accept 8-pin DIPs. This is consistent with MuTron IIIs that I've seen the insides of, which all used common 4558 dual op-amps in plastic packages. I'm surprised you're not asking about that big black thing that resembles the nose-cone of a space ship.

1/22/1997 10:57 PM

Steve Morrison

... 3 ea - stout metal cylander; 8 pins (4 ea in opposing rows) extend from bottom circular plane. ...

The fact that those eight pins appear to be in two rows of four would suggest that the pc board was designed to accept 8-pin DIPs. This is consistent with MuTron IIIs that I've seen the insides of, which all used common 4558 dual op-amps in plastic packages. I'm surprised you're not asking about that big black thing that resembles the nose-cone of a space ship.

1/23/1997 10:39 AM
Craig	Thanks for the reply. What's the deal on subbing op-amps? I went to my local electronics shop looking for 2N5088's that I need for a distortion circuit, and they didn't have any. I know that you can sub if you observe power and polarity, but what else should be considered? Also, I didn't see anything like the space ship nose cone you described. I did remember when I got home last night that there was one other mystery cap: - rectangular green, 100v, XX =/- 20%, located near the power switch. I can't read the 1st 2 numbers. It's not mine, or I'd just pull it and get out the meter.

1/23/1997 10:39 AM

Craig

Thanks for the reply. What's the deal on subbing op-amps? I went to my local electronics shop looking for 2N5088's that I need for a distortion circuit, and they didn't have any. I know that you can sub if you observe power and polarity, but what else should be considered?

Also, I didn't see anything like the space ship nose cone you described. I did remember when I got home last night that there was one other mystery cap:

- rectangular green, 100v, XX =/- 20%, located near the power switch. I can't read the 1st 2 numbers.

It's not mine, or I'd just pull it and get out the meter.

2/6/1997 7:19 AM
R.G. Keen	Op amp substitutions usually need to get the pinout correct, as the pinout for all modern unity gain stable ones has been standardized. But 2N5088 is a transistor, not an opamp. The 2N5088 is a pretty common device with a gain of about 250-350. You can substitute 2N3904, 2N4401, 2N4124, and possibly 2N5089 in many circuits. The 2N4124 is only a 20V device though. If you're building a 9V battery powered stomp box, especially if you're building a TS-x clone, any of them will work well. To answer what I think your question might have been, the other thing you need to consider is gain. There is no good way to tell what the mystery cap is without either reading the value or metering it.

2/6/1997 7:19 AM

R.G. Keen

Op amp substitutions usually need to get the pinout correct, as the pinout for all modern unity gain stable ones has been standardized. But 2N5088 is a transistor, not an opamp. The 2N5088 is a pretty common device with a gain of
about 250-350. You can substitute 2N3904, 2N4401, 2N4124, and possibly 2N5089 in
many circuits. The 2N4124 is only a 20V device though. If you're building a 9V battery powered stomp box, especially if you're building a TS-x clone, any of them will work well. To answer what I think your question might have been, the other thing you need to consider is gain.

There is no good way to tell what the mystery cap is without either reading the
value or metering it.

2/7/1997 8:47 AM
*NoCarrier*	Re: MuTron III schematic? Transistors?? I have a question about transistors,..... I'm just beginning in electronics and i was wondering if a transistor in a stomp box could be subsituted to offer more gain??,......what can i modify on a distortion to offer more gain???,.............. Thanks, Jeff

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