MXR - M-163 - Sustain (Commande Series)  [schematic]

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Re: MXR - M-163 - Sustain (Commande Series)

Postby Tonetweaker » 01 Mar 2011, 04:38

Dirk_Hendrik wrote:it was the worst distortion I've ever encountered...

Here it is in the way I did handdrawings in 1995. There is some stuff which I would like to recheck though...


Interesting. I'm far from an expert on these things, but it doesn't look like a horrible design at first glance. Nothing special, by any means, but nothing sticks out as a blatant clinker design-wise. You have a lot more experience with a wide range of pedals than I do... What do you think made it so bad? Was it the component choices, or something in the design itself that caused a problem?

Also, I don't think you mentioned what was so bad about it specifically... Was it noisy or just not a good sound overall? I'm really curious about your take on this.

I've certainly plugged in my fair share of pedals that I wasn't particularly impressed with (including a couple I got in mail this week), but it's rare that I get one I just outright dislike completely. When I get a new pedal in, I tend to find myself associating them with what I can use them for. Sometimes, I'll get one that will probably be good for a certain song or vibe, but really doesn't seem to have the flexibility to do much else. Those don't usually get much playtime unless I'm looking for a certain sound and can't seem to dial it in otherwise. It's only the rare pedal that I can't think of any song/sound it would work with that hits the bottom of the foot locker.

Cheers...
Steve


PS ~ I decided to take one for the team and ordered the schem for the Sustain circuit. I couldn't think of any other way to easily ID those transistors short of ripping the pedal to shreds, since there's not even any guarantee that they're all the same type. Hopefully, the schem will come in handy for someone. Stay tuned.
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Re: MXR - M-163 - Sustain (Commande Series)  [schematic]

Postby Tonetweaker » 06 Mar 2011, 06:15

Hey folks...

The schematic is finally done...

MXR Sustain.jpg


I have also compiled the Bill of Materials with component tolerances and values...

M-163 Sustain.xls



I had finished tracing it out a couple of weeks ago, but had to buy a copy of the schematic to find out what the hell those transistors were. I verified my schematic against the purchased copy, but if you happen to see anything that looks out of whack, just let me know and I'll double-check it.


Cheers...
Steve
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Re: MXR - M-163 - Sustain (Commande Series)

Postby roseblood11 » 06 Mar 2011, 16:15

I wonder if the 2n4126 can be substituted with a 2n4402 or a 2n3906?
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Re: MXR - M-163 - Sustain (Commande Series)

Postby roseblood11 » 07 Mar 2011, 00:05

I found a document from Phillips that lists the 2n3906 as the replacement part for the 2n4126.

The zetex 109 is still available, I just ordered some at ebay. But probably any similar npn silicon will work...
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Re: MXR - M-163 - Sustain (Commande Series)

Postby mictester » 07 Mar 2011, 00:38

roseblood11 wrote:Maybe they used discrete FET stages where the Morley has opamps?


No. The transistors are all normal bipolar transistors. I've got the circuit diagram here somewhere, and will post it when I find it!
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Re: MXR - M-163 - Sustain (Commande Series)

Postby roseblood11 » 07 Mar 2011, 00:43

Good morning, mictester! :lol:

Tonetweaker posted the schematic yesterday...
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Re: MXR - M-163 - Sustain (Commande Series)

Postby mictester » 07 Mar 2011, 00:51

mictester wrote:
roseblood11 wrote:Maybe they used discrete FET stages where the Morley has opamps?


No. The transistors are all normal bipolar transistors. I've got the circuit diagram here somewhere, and will post it when I find it!


The diagram posted a few posts above is much better than the original MXR drawing!

As you can all see - MXR put the 3080 in the negative feedback loop of an op-amp. One thing I saw - my unit had a TL072 instead of a 4558.

In use, it's a low distortion, very quiet, very usable sustain unit. If behaves more as a limiter than a compressor - onset is quite abrupt. It sounds quite different to the usual Dynacomp and its clones. It has a smaller range of control than a Dynacomp, but sounds more "natural" because of that. Notes really hang on, and it's wonderful to drive a dirt box with a consistent level. You know the problem - the dirt box has a particularly sweet spot where it's just exactly right, but playing too loudly or too quietly spoils that magic sound. This box will go a long way to mitigating that problem.

I'll do a Vero and a PCB for this one in the next few days. It's truly worthwhile.
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Re: MXR - M-163 - Sustain (Commande Series)

Postby Tonetweaker » 07 Mar 2011, 04:41

mictester wrote:The diagram posted a few posts above is much better than the original MXR drawing!


Thank you, sir. This was my first attempt at tracing out a circuit from scratch, and my first drawing with ExpressSCH.

My version was traced out before I had the MXR schematic available. When it came in, I noticed that I had placed some of the circuitry differently than they did, but I verified everything against both their schematic and the PCB itself, so I thought it would still do the trick.


mictester wrote:In use, it's a low distortion, very quiet, very usable sustain unit. If behaves more as a limiter than a compressor - onset is quite abrupt. It sounds quite different to the usual Dynacomp and its clones. It has a smaller range of control than a Dynacomp, but sounds more "natural" because of that. Notes really hang on, and it's wonderful to drive a dirt box with a consistent level. You know the problem - the dirt box has a particularly sweet spot where it's just exactly right, but playing too loudly or too quietly spoils that magic sound. This box will go a long way to mitigating that problem.


I agree with you completely. When I first plugged this in, I immediately thought this would be a good circuit to trace and get a better understanding of. I barely knew it was there until I let some notes ring... It doesn't seem to alter the tone much or give an overly-compressed sound, as you mentioned. I'm not a big fan of compression-type circuits in general, but this one was very easy to dial in to get a nice sweet sustain when you let your notes ring without completely smashing all the dynamics out of your tone. I liked the Philosopher's Tone I bought recently for the same reason. Compression and sustain without squashing all the life out of your tone.

Because of it's relative simplicity, I was thinking that this would probably be a good design to incorporate in with another circuit. Obviously, you wouldn't want to put this in front of something where playing dynamics are critical to the effect (like a FF), but coupling an effect like this together with a nice OD or distortion inside the same box could make for an excellent little project. I was thinking of trying to design a sort of "Lead Box" kind of effect, which would couple an OD for a sweet lead tone along with the long sustain this circuit provides. :hmmm:


Cheers...
Steve
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Re: MXR - M-163 - Sustain (Commande Series)

Postby mictester » 07 Mar 2011, 11:43

Tonetweaker wrote:
Because of it's relative simplicity, I was thinking that this would probably be a good design to incorporate in with another circuit. Obviously, you wouldn't want to put this in front of something where playing dynamics are critical to the effect (like a FF), but coupling an effect like this together with a nice OD or distortion inside the same box could make for an excellent little project. I was thinking of trying to design a sort of "Lead Box" kind of effect, which would couple an OD for a sweet lead tone along with the long sustain this circuit provides. :hmmm:

Cheers...
Steve


That's a fine idea! I started work on the PCB layout for the sustain on its own. It should end up quite small, and is an ideal candidate for a dual-effect box. I was considering changing the input and output circuits a bit - using an op-amp instead of the input transistor buffer, and another at the output after the level control, to give low output impedance (it'll drive anything then). Also, I have issues with the 3080 - not my favourite device, and getting rare (and therefore expensive). I was contemplating using half of a 13700. The other half could be used for a Dynacomp... Two differing compressors in the same box! Just thinking out loud... :)

:hmmm: :hmmm:
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Re: MXR - M-163 - Sustain (Commande Series)

Postby Tonetweaker » 08 Mar 2011, 05:13

mictester wrote:That's a fine idea! I started work on the PCB layout for the sustain on its own. It should end up quite small, and is an ideal candidate for a dual-effect box. I was considering changing the input and output circuits a bit - using an op-amp instead of the input transistor buffer, and another at the output after the level control, to give low output impedance (it'll drive anything then). Also, I have issues with the 3080 - not my favourite device, and getting rare (and therefore expensive). I was contemplating using half of a 13700. The other half could be used for a Dynacomp... Two differing compressors in the same box! Just thinking out loud... :)

:hmmm: :hmmm:


The DynaComp/Sustain idea sounds like a great idea too! It would be cool to be able to flip between the two as needed. You could use the DynaComp side for rhythm, and then switch to the Sustain for the extra oomph needed for leads.

I wonder if changing the input and output circuitry to an op-amp architecture will have any effect on the overall characteristics though? I realize that it shouldn't, but this circuit struck me as a little quirky design-wise, so I wonder if tinkering with it too much will cause it to behave more like a flat compressor? It sounds like a great idea, but it might be worth breadboarding it first to make sure it doesn't alter the characteristics too much.

Incidentally, I tried this thing out in front of several ODs and distortions when it first came in. I've got a ton of them laying around... Most sounded pretty good, with the exception of some of the "metal" distortions (MT-2, Metal Muff, etc.), which get too feedbacky and unmanageable. It's pretty sweet with a nice OD, though... I tried several of mine. The TS9, Fulltone OCD and ToadWorks John Bull were particularly good. However, it really stood out when I put it in front of that AMT Tube Magnum I threaded about awhile back. I'm not sure I fully understand why it sounded so awesome feeding a tube OD specifically, but I could barely bring myself to unplug it. I guess the tube is just better for clipping the signal without getting too harsh. I already love the sound of that AMT... but with the Sustain in front, I was getting all kinds of really sweet lead tones, even at very low volumes.

Makes me wish I had been more careful about the battery clip on the Sustain when I took it apart. All of my soldering equipment is packed up pending my move, and it'll be awhile before I get a chance to fix it up. I'll have to check to see if I have the right adapter for the AC jack. This thing has been in pieces since I started this thread while I traced it all out... I hope I didn't lose any of the parts. :slap:

:lol:


Cheers...
Steve
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Re: MXR - M-163 - Sustain (Commande Series)

Postby Tonetweaker » 05 Apr 2011, 03:28

Hey all... I was just curious if anyone had tried building anything based upon this circuit. If so, I'd like to hear what you thought of it.

I find myself using this thing quite a bit in front of an OD, so once I get settled in my new place, I plan on building one of these with some sort of OD in one box.


Cheers...
Steve
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Re: MXR - M-163 - Sustain (Commande Series)

Postby ishred » 16 Apr 2011, 07:32

MXR-M-163-SUSTIAN was a cool circuit but the lexan box the switch and circuit mount jacks all prone to fail. When you hit the switch the board flexes causing breaks in solder. Best thing to do is Rehouse it to a metal box, change to real stomp switch change to standard Switchcraft jacks witch I have done SWEET.
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Re: MXR - M-163 - Sustain (Commande Series)

Postby Tonetweaker » 21 Apr 2011, 01:54

ishred wrote:MXR-M-163-SUSTIAN was a cool circuit but the lexan box the switch and circuit mount jacks all prone to fail. When you hit the switch the board flexes causing breaks in solder. Best thing to do is Rehouse it to a metal box, change to real stomp switch change to standard Switchcraft jacks witch I have done SWEET.


Agreed. I'm sort of a purist in that regard, but if I was to seriously consider rehousing a pedal, this one would be at the top of the list... especially considering how often I use it.
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Re: MXR - M-163 - Sustain (Commande Series)

Postby ishred » 25 Apr 2011, 07:07

ishred wrote:MXR-M-163-SUSTIAN was a cool circuit but the lexan box the switch and circuit mount jacks all prone to fail. When you hit the switch the board flexes causing breaks in solder, No shielding,etc.. Best thing to do is Rehouse it to a metal box, change to real stomp switch change to standard Switchcraft jacks witch I have done SWEET.
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Re: MXR - M-163 - Sustain (Commande Series)

Postby roseblood11 » 07 Sep 2018, 13:26

Has anybody made a veroboard layout for this?
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