DOD - 670 Flanger  [schematic]

All about modern commercial stompbox circuits from Electro Harmonix over MXR, Boss and Ibanez into the nineties.
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GERG
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Post by GERG »

The output on my DOD 670 is distorting slightly. Almost as if I'm driving the input to hard. But when I turn my guitar input down the distortion is still slightly there. The distortion seems to follow the sweep pattern as the lower frequencies are ehanced by the flanging effect but when I strike my strings with more effort is more noticeable. Playing lightly cleans it up somewhat but not totally. I'm considering replacing the filter cap in the power supply in case I'm getting some sag and that is creating my problem. Any ideas or suggestions would be helpful.

Thank you

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Govmnt_Lacky
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Post by Govmnt_Lacky »

Hello all...

Just got done repairing one of these and I figured I would share a CORRECT schematic of an actual unit. The one from Harman has so many changes, errors, and mark-ups that it is almost unusable.

Since there is little to no information on this fantastic unit, I figured this would come in handy! :thumbsup

ENJOY!!!

P.S. Feel free to attempt an MN3007 conversion OR PCB layout!!
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DOD 640 ACTUAL Redraw.pdf
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Intripped
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Post by Intripped »

thanks for sharing!
...is harman and hartman the same thing? because i see harman international and DOD are the same group, but hartman flanger is an electric mistress clone ...and this is not (?)

well, a bit of confusion

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Govmnt_Lacky
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Post by Govmnt_Lacky »

Harman is who owns DOD

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Govmnt_Lacky
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Post by Govmnt_Lacky »

If anyone needs them, I could provide voltages from the working unit as well. :horsey:

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Post by Govmnt_Lacky »

Almost 10 to 1 download to thanks quota..

Better than nothing I suppose :applause:

Still no requests for voltages so I am going to let that go!!

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Fender3D
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Post by Fender3D »

Greg,

please if you can take some measurements, add clock frequencies.
Please read here viewtopic.php?f=28&t=22623

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larsjm
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Post by larsjm »

Thanks for the schematic, great job. This confirms what I suspected though, the SAD1024 is being run in parallel-multiplex in this case, just like the Electric Mistress. Therefore an MN3007 is a poor choice as a substitute, as it cannot be run in parallel-multiplex. It would change the pedal from a 512-stage to a 1024-stage and go more into chorus territory than flange.
A better substitute for a clone would be the often-overlooked MN3001, a dual-512 stage BBD just like the SAD1024. Or you could use two MN3204s.

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Scruffie
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Post by Scruffie »

larsjm wrote:Thanks for the schematic, great job. This confirms what I suspected though, the SAD1024 is being run in parallel-multiplex in this case, just like the Electric Mistress. Therefore an MN3007 is a poor choice as a substitute, as it cannot be run in parallel-multiplex. It would change the pedal from a 512-stage to a 1024-stage and go more into chorus territory than flange.
A better substitute for a clone would be the often-overlooked MN3001, a dual-512 stage BBD just like the SAD1024. Or you could use two MN3204s.
Which is why we use clock buffers to over come the 3007s clock input capacitance and allow us to clock it in to the same territory as the SAD1024.

The MN3204 and MN3001 (which has poorer noise specs than most of the MN line and also much higher losses) are both in short supply and as hard to come by as SAD1024s almost, that's why they're overlooked where as the 3007 is much more plentiful. The 3207 is better than the 3007 in some respects as it can be clocked further than a 3007.

Either way we can use a 3007 or 3207 here just fine.

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Post by Dirk_Hendrik »

How nice! And you signed up to spam it!! What a great guy you are! [smilie=a_huh.gif]
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Post by mictester »

Govmnt_Lacky wrote:Hello all...

Just got done repairing one of these and I figured I would share a CORRECT schematic of an actual unit. The one from Harman has so many changes, errors, and mark-ups that it is almost unusable.

Since there is little to no information on this fantastic unit, I figured this would come in handy! :thumbsup

ENJOY!!!

P.S. Feel free to attempt an MN3007 conversion OR PCB layout!!

I was toying with the idea of a 3007 version of this. What are the pot values? Some of them are missing from your drawing.
"Why is it humming?" "Because it doesn't know the words!"

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Post by TheKoala »

Five years later, here are the pot values :
Accent - B100k (lin)
Width - B100k (lin)
Speed - C500k (antilog, measures 650k here but the pot says 500k on its back)
Manual - B100k (lin)
I love this flanger so much, it is so versatile but takes too much space. I'm designing a 3207 version to get the same sound somewhat, in a smaller package.

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