MOOG Moogerfooger MF-103 12-Stage Phaser  [schematic]

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djathey
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Post by djathey »

Actually, I've been working recently on other projects:

https://www.diystompboxes.com/smfforum/ ... ts;u=55604

Definitely need to move this project to the top of the list...

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Post by djathey »

A more or less complete front panel...
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MF phaser front panel.PNG

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Post by djathey »

Dry fit for front panel controls…
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70C869DE-B4FA-48A8-A730-FA948B76F74D.jpeg
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Post by mhogan »

djathey wrote: 28 Jun 2021, 17:54 Dry fit for front panel controls…
Any update? How's it sound?

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Post by djathey »

I haven’t completed this yet, so it’s an unproven effort, so far.

Definitely need to bump this project up, on list of things to-do…

I also probably should have used readily available 78xx/79xx regulators, instead of ldo’s.

I’d also like to add features used within this phaser (even/odd and buffered tap points):

https://www.birthofasynth.com/Scott_Sti ... _schem.jpg

Thanks for the interest.

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Post by bumblebee »

djathey wrote: 03 Mar 2022, 13:59 I haven’t completed this yet, so it’s an unproven effort, so far.

Definitely need to bump this project up, on list of things to-do…

I also probably should have used readily available 78xx/79xx regulators, instead of ldo’s.

I’d also like to add features used within this phaser (even/odd and buffered tap points):

https://www.birthofasynth.com/Scott_Sti ... _schem.jpg

Thanks for the interest.
It’s a big project…a very cool one though.

I’d like to get the EH Guitar Synthesizer 8000 (rack unit) up and running but that is a massive project for me. Still, I’m intent on doing it some time.

I currently have 6 projects going on (traces and builds) and I’m a procrastinator at the best of times. :mrgreen:
I so dislike the modern digital world that I need to use semi-digital effects to emulate the analog world of cassette, VHS, and vinyl.

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Post by Scruffie »

bumblebee wrote: 04 Mar 2022, 02:23 I’d like to get the EH Guitar Synthesizer 8000 (rack unit) up and running but that is a massive project for me. Still, I’m intent on doing it some time.
Have you seen this thread? https://www.diystompboxes.com/smfforum/ ... msg1240673

I'm quite familiar with the unit if you need a hand...

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Post by bumblebee »

Scruffie wrote: 04 Mar 2022, 13:00
bumblebee wrote: 04 Mar 2022, 02:23 I’d like to get the EH Guitar Synthesizer 8000 (rack unit) up and running but that is a massive project for me. Still, I’m intent on doing it some time.
Have you seen this thread? https://www.diystompboxes.com/smfforum/ ... msg1240673

I'm quite familiar with the unit if you need a hand...
Yes, Scruffie….that’s what prompted me to want to do it. :mrgreen:

Thanks for the redrawn schematics, too!

I will likely need a hand, lol. I’ll keep your offer in mind. Thanks!

What would be great is any gutshots of the 8000…if you have them. It seems it would be a modular type PCB system, yeah? That was my plan anyways.

There’s certainly no rush as it will be quite some time before I tackle such a large project as I have plenty of others on the list that take priority over it simply because of the complexity of the 8000 (to me).
I so dislike the modern digital world that I need to use semi-digital effects to emulate the analog world of cassette, VHS, and vinyl.

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Post by Scruffie »

bumblebee wrote: 04 Mar 2022, 22:18
Scruffie wrote: 04 Mar 2022, 13:00
bumblebee wrote: 04 Mar 2022, 02:23 I’d like to get the EH Guitar Synthesizer 8000 (rack unit) up and running but that is a massive project for me. Still, I’m intent on doing it some time.
Have you seen this thread? https://www.diystompboxes.com/smfforum/ ... msg1240673

I'm quite familiar with the unit if you need a hand...
Yes, Scruffie….that’s what prompted me to want to do it. :mrgreen:

Thanks for the redrawn schematics, too!

I will likely need a hand, lol. I’ll keep your offer in mind. Thanks!

What would be great is any gutshots of the 8000…if you have them. It seems it would be a modular type PCB system, yeah? That was my plan anyways.

There’s certainly no rush as it will be quite some time before I tackle such a large project as I have plenty of others on the list that take priority over it simply because of the complexity of the 8000 (to me).
Excellent, my plan to ensnare someone else in to helping working on it was successful :mrgreen:

Yup, got plenty of gutshots and access to two units through one I repaired and one I've been helping someone else repair.

There are indeed multiple PCB's, a master board with all the pots, switches and mixing and then 3 individual boards connected to that (the schematics are separated in to the individual boards) and a separate power supply board.

I'll try and remember to start a separate thread here with some shots tomorrow, if not, give me a poke.

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Post by bumblebee »

Scruffie wrote: 04 Mar 2022, 22:50
bumblebee wrote: 04 Mar 2022, 22:18
Scruffie wrote: 04 Mar 2022, 13:00
bumblebee wrote: 04 Mar 2022, 02:23 I’d like to get the EH Guitar Synthesizer 8000 (rack unit) up and running but that is a massive project for me. Still, I’m intent on doing it some time.
Have you seen this thread? https://www.diystompboxes.com/smfforum/ ... msg1240673

I'm quite familiar with the unit if you need a hand...
Yes, Scruffie….that’s what prompted me to want to do it. :mrgreen:

Thanks for the redrawn schematics, too!

I will likely need a hand, lol. I’ll keep your offer in mind. Thanks!

What would be great is any gutshots of the 8000…if you have them. It seems it would be a modular type PCB system, yeah? That was my plan anyways.

There’s certainly no rush as it will be quite some time before I tackle such a large project as I have plenty of others on the list that take priority over it simply because of the complexity of the 8000 (to me).
Excellent, my plan to ensnare someone else in to helping working on it was successful :mrgreen:

Yup, got plenty of gutshots and access to two units through one I repaired and one I've been helping someone else repair.

There are indeed multiple PCB's, a master board with all the pots, switches and mixing and then 3 individual boards connected to that (the schematics are separated in to the individual boards) and a separate power supply board.

I'll try and remember to start a separate thread here with some shots tomorrow, if not, give me a poke.
Cool :mrgreen: Your evil plan worked! Lol

I look forward to seeing inside this behemoth! (Will PM you in a couple of days if no images pop up)
I so dislike the modern digital world that I need to use semi-digital effects to emulate the analog world of cassette, VHS, and vinyl.

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Post by mhogan »

djathey wrote: 03 Mar 2022, 13:59 I haven’t completed this yet, so it’s an unproven effort, so far.

Definitely need to bump this project up, on list of things to-do…

I also probably should have used readily available 78xx/79xx regulators, instead of ldo’s.

I’d also like to add features used within this phaser (even/odd and buffered tap points):

https://www.birthofasynth.com/Scott_Sti ... _schem.jpg

Thanks for the interest.
Would you be able to post the Eagle files you used to order the pcb's? And is there a list of all the components needed anywhere? I'd be interested in working on it as well.

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Post by djathey »

Just looked at the dates of some my files: can't believe it's been a year since I've done any meaningful work on this...

Attached is what I've got so far...
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MF103.zip
(2.54 MiB) Downloaded 243 times

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Post by Jarno »

Pretty cool, might be interesting to convert it to SMD, thanks!

(also, if anyone needs a BOM, run the BOM ULP on the schematic and presto!)
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Post by djathey »

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Post by mictester »

There is a fundamental design flaw with this circuit - the LM13600 / 13700 is both noisy and distorted. Put a few of them after one another, and the problems will be multiplied!
"Why is it humming?" "Because it doesn't know the words!"

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Post by LaceSensor »

wen demo? wen release PCB for sale? :)

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Post by Whoismarykelly »

mictester wrote: 22 May 2023, 00:38 There is a fundamental design flaw with this circuit - the LM13600 / 13700 is both noisy and distorted. Put a few of them after one another, and the problems will be multiplied!
Is the Moog design not companded? 12 stages of phase shift have a pretty high noise floor regardless of architecture without companding.

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Post by orghead »

djathey wrote: 25 Mar 2022, 04:37 Just looked at the dates of some my files: can't believe it's been a year since I've done any meaningful work on this...

Attached is what I've got so far...
It is a very nice project.
But I have a concern with the schematic.
It looks like the output of the OTA buffer next to the input op amp is not connected anywhere.
Is the 10uF capacitor connected correctly?

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Post by djathey »

Is this the referenced connection?

I tried to follow the available ‘original’, but it seems this was missed…
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Screenshot 2023-08-07 at 11.59.32 AM.png

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Post by orghead »

That is correct.
I also assembled it from the same 'original' schematic using SMD. At first I got an abnormally distorted sound, so I compared several schematics for debugging and used your schematic as a reference.
In the end, the distorted sound was caused by a bad soldering...
Anyway, I am sure you will get the great phaser sound if you use the same schematic.

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