Author Topic: Mutron Flanger dissection.  (Read 102301 times)

digi2t

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Mutron Flanger dissection.
« on: July 16, 2013, 10:37:48 AM »
I've started to trace the Mutron Flanger for cloning. Here's a demo video to kick start things.



I want to start by redrawing the schematic, since the one on the net is really not that clear. I'll be in the shop tracing, if anyone is looking for me. :icon_mrgreen:
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Govmnt_Lacky

Re: Mutron Flanger dissection.
« Reply #1 on: July 16, 2013, 10:41:26 AM »
YES!!!!  :o
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Dave W

Re: Mutron Flanger dissection.
« Reply #2 on: July 16, 2013, 10:58:54 AM »
Nice! Thank you Dino!  8)
That's where it's at.

Mark Hammer

Re: Mutron Flanger dissection.
« Reply #3 on: July 16, 2013, 11:10:59 AM »
Why is Youtube telling me "This video is private"?

armdnrdy

Re: Mutron Flanger dissection.
« Reply #4 on: July 16, 2013, 11:20:23 AM »
Why is Youtube telling me "This video is private"?

Same for me.
I guess were not part of the "cool kids" club.  :icon_wink:
I just designed a new fuzz circuit! It almost sounds a little different than the last fifty fuzz circuits I designed! ;)

digi2t

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Re: Mutron Flanger dissection.
« Reply #5 on: July 16, 2013, 12:09:45 PM »
Why is Youtube telling me "This video is private"?

Same for me.
I guess were not part of the "cool kids" club.  :icon_wink:

Sorry folks, it's the new (ultra annoying) Youtube layout. Every time I upload, it's automatically sets to "Private", until I tell it otherwise after the upload. I keep forgetting to set it to "Public". I've even tried setting it to "Public" during the upload, but to no avail. :icon_mad:

Works now.
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Mark Hammer

Re: Mutron Flanger dissection.
« Reply #6 on: July 16, 2013, 12:39:29 PM »
Works for me too.  And it sounds one heckuva lot more inspiring than it did on Sunday!  Nice tweaking.  :icon_lol:  Worth the reputed $1k-$1.5k they supposedly sell for?  Nah.  But a damn fine-sounding flanger nonetheless.

The Stop and Start thing is essentially all about the min and max delays that it sweeps between.  There are probably trimpots inside to set the clock freq range, such that you may be able to get something much closer to thru-zero than you can at present.  Not QUITE thru-zero, but short enough to compare favourably with an A/DA.  I mean, after all, it's packing an SAD1024.

Of course, even if you can't, you'll still be able to play the return-from-solo on "And the Cradle Will Rock"...properly.

armdnrdy

Re: Mutron Flanger dissection.
« Reply #7 on: July 16, 2013, 12:44:47 PM »
This one's a keeper!

Musitronics really designed great sounding effects!

I also like the start /stop thang! I'll have to take a look at how that was implemented.
I just designed a new fuzz circuit! It almost sounds a little different than the last fifty fuzz circuits I designed! ;)

digi2t

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Re: Mutron Flanger dissection.
« Reply #8 on: July 16, 2013, 11:52:12 PM »
OK. I didn't feel like redrawing the entire schematic, so I used the original hi-rez one that I had, and tidied it up. I know it's huge, but it's best for clarity. Download it onto you computer, and then play with it.

I traced everything to my unit, and corrected what needed correcting. I've made my own notes on it, but if you have questions, fire away.



OK, Greg... how can we work around the SAD1024 now?
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Dave W

Re: Mutron Flanger dissection.
« Reply #9 on: July 17, 2013, 12:03:42 AM »
This SAD1024 to MN3007 conversion should be easy. The 2 sections of the SAD are in series. Won't have to tamper with the clock f. Have a look/see at the SAD to MN conversions done with the A/DA and EM...
That's where it's at.

armdnrdy

Re: Mutron Flanger dissection.
« Reply #10 on: July 17, 2013, 01:27:34 AM »
Great job!

Gut shots when you get the time?? And you know what would be very useful.....I don't believe I've ever seen any documentation of the foot pedal shutter and surrounding mechanics. A drawing with dimensions would be great!

I like things that go woosh!  ;D
« Last Edit: July 17, 2013, 02:02:36 AM by armdnrdy »
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Fender3D

Re: Mutron Flanger dissection.
« Reply #11 on: July 17, 2013, 05:12:41 AM »
Please digi2t,

I asked this on the other site also...
Please check the min and max. VCO frequencies...

If anyone would try and clone or just align the unit will need this 2 values more than any voltage...

thanks
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digi2t

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Re: Mutron Flanger dissection.
« Reply #12 on: July 17, 2013, 06:26:36 AM »
Please digi2t,

I asked this on the other site also...
Please check the min and max. VCO frequencies...

If anyone would try and clone or just align the unit will need this 2 values more than any voltage...

thanks

OK, I'm not that bright when it come to some of this stuff, so if you could tell me where I would have to plug my o-scope in I would appreciate it.

Just want to be sure that I get the right info out.
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12Bass

Re: Mutron Flanger dissection.
« Reply #13 on: July 17, 2013, 08:07:34 AM »
The demo video sounds great!  The Start/Stop controls are an interesting departure from the normal Manual/Width controls.

...There are probably trimpots inside to set the clock freq range, such that you may be able to get something much closer to thru-zero than you can at present.  Not QUITE thru-zero, but short enough to compare favourably with an A/DA.  I mean, after all, it's packing an SAD1024.

With the SAD1024A wired in series, it is not likely to match the upper sweep of the A/DA.  From the sound of the demo, however, it goes up high enough for most purposes.
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Mark Hammer

Re: Mutron Flanger dissection.
« Reply #14 on: July 17, 2013, 09:14:19 AM »
With the SAD1024A wired in series, it is not likely to match the upper sweep of the A/DA.  From the sound of the demo, however, it goes up high enough for most purposes.

You'd be surprised.  In theory, you are correct in asserting that a pair of 512-stage devices in parallel will provide a shorter delay than two cascaded 512-stage sections, for the same clock frequency.  However, folks have been able to get some pretty impressive sweeps from a humble MN3007 within the A/DA context. using suitably buffered clock signals.  Maybe I was just remembering things wrong, but the Mu-tron, both on the bench and in the video, seemed like it could be nudged up juuuusssssttt a little higher.

I see that the SAD1-24, when used in dual-parallel mode inthe PAiA Hyperflange, is spec'd to yield delay times as short as 170usec.  Double that and you have 340usec, which is still an octave and a half "higher" than a Boss BF-2.

12Bass

Re: Mutron Flanger dissection.
« Reply #15 on: July 17, 2013, 09:22:48 AM »
As mentioned in another recent thread, BBD signal gain decreases as the clock frequency goes up.  From the graphs, it would appear that the gain loss is not a linear function.  So, that means that even if the series-mode BBD were provided with buffered clock signals at double the frequency (to match parallel-multiplex), there would be a increased loss of BBD signal as the sweep nears the top, resulting in less dramatic signal cancellation. 
It is far better to grasp the universe as it really is than to persist in delusion, however satisfying and reassuring. - Carl Sagan

Fender3D

Re: Mutron Flanger dissection.
« Reply #16 on: July 17, 2013, 10:16:23 AM »
...so if you could tell me where I would have to plug my o-scope in I would appreciate it.

Probe should go to SAD's pins 3-14 or 8-10.
Set pedal control and write down the max. and the min. clock frequencies,
if you have 5 more minutes, please, set LFO control, start fully CW and stop fully CCW, rate at minimum and report min. and max.

Thank you so much

« Last Edit: July 17, 2013, 10:23:32 AM by Fender3D »
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Mark Hammer

Re: Mutron Flanger dissection.
« Reply #17 on: July 17, 2013, 11:04:01 AM »
As mentioned in another recent thread, BBD signal gain decreases as the clock frequency goes up.  From the graphs, it would appear that the gain loss is not a linear function.  So, that means that even if the series-mode BBD were provided with buffered clock signals at double the frequency (to match parallel-multiplex), there would be a increased loss of BBD signal as the sweep nears the top, resulting in less dramatic signal cancellation. 

Yes and no.  In truth, many, if not most, of the notches created at the "top" of the sweep (i.e., at shortest delay) are inaudible, largely because they are beyond the range of the guitar and most guitar-amp speakers.  So whether they are compromised because the BBD output drops a db or two or even three, once it heads for the <.4msec range, can often be timbrally moot.  I suppose one would likely notice it if playing white noise or something with similarly wide bandwidth through a wide bandwidth system (e.g., studio monitors), but not likely with the typical bass or guitar rig.

The expected question here is: so why the heck aim for delays that short?  And the answer is that dramatic slow sweeps have to feel like watchng slow-mo video of a car airbag inflating.  One moment there's absolutely no trace, and all of a sudden the car cabin is filling right up.  The transition from no audible notches to notches absolutely everywhere is a big part of the "drama" of flanging.  That nothing-to-everywhere traisition is a result of the overall sweep ratio (max delay divided by min), so both "start" and "stop" frequencies/delays play a role.  But the more critical one seems to be the minimum delay.  All other things being equal,  a flanger that seeeps from .5msec to 10msec will seem more "dramatic" than one that sweeps from 1msec to 20msec.

Dave W

Re: Mutron Flanger dissection.
« Reply #18 on: July 17, 2013, 11:39:02 AM »
Just want to add this for thought....
IMHO; a big part of the "drama" in the upper part of the sweep of the A/DA; aside from all the points that have been mentioned; is due to it's bare bones minimal post BBD low pass filtering. You can go up, up, up; but if you filter out too much sonic information those short delays are just not going to sound the way one would want them to.
Just my 2 cents from a hack with a soldering iron and a 'scope....
That's where it's at.

Mark Hammer

Re: Mutron Flanger dissection.
« Reply #19 on: July 17, 2013, 11:49:39 AM »
Absolutely.  If the onboard LPF kills everything above, say 8khz, then there's not much point sweeping up to those ultra-short delays.