MXR Flanger redone

[Fender3D]

Hello guys,
I've redone the MXR Flanger 117 following the schematic from Shredaholic.
I've adapted the schematic to mount TDA2107 (MN3007), since a found a bunch of them in a trower in my lab, and it works indeed.
My question:
does anybody know what's the specific procedure for adjusting the trimmers?
Distortion and level trimming is not an issue, but I really don't know how adjust the clock trimmer.
I've reduced the value of the C21 cap 'cause the different BBD yet, but it was formerly selected at final test so there should be an optimal clock to achieve.

Or, should anyone have one of this pedals:
could you please measure the clock freq on 4013 (U3) pins 1 or 2, with "Width" fully CCW and "Manual" both fully CW and CCW and post them here?

Thank you in advance

[oldschoolanalog]

I have a bunch of the old SAD1024 based 117's. I grabbed 2 at random and here's what I got.
READINGS TAKEN AT THE BBD. Readings taken at the BBD. READINGS TAKEN AT THE BBD. Readings taken at the BBD.One measured ~29KHz to ~960KHz. The other measured ~32KHz to ~965KHz. Give or take a couple of 100 Hz.
IIRC, the SAD1024 has its 2 sections hooked up in series (1024 stages). The MN3007 is a 1024 stage BBD. There shouldn't be a need to change much. Nice to hear that Shreadaholic project is confirmed working. Been wondering about that one for a while.
Let us know how things turn out!
Dave

[Fender3D]

Thanks Dave, 

I'll try your settings, I'll post results here (and some pics if I manage to enclose it in a box properly  )

[shadowmaster]

Took a stab a this to keep the current flanger-mania going. I did not really change anything that much. Just the usual retrofit for the SAD1024 and integrated a 15V regulator with filtering caps on-board. Sounds good to me although I don't have an original at hand that I can compare with.

Based on the schematic at Shredaholic, I was able to get clock frequencies of 32KHz-996KHz using a 62pF for C21. A bit close to what oldschoolanalog have measured from his MXR flangers. But for some reason and with my limited knowledge of electronics, at the slowest speed setting, the sweep did not sound good which I cannot explain. At the start/end of the sweep, I get this slow rubbery-bounce-type of sound which I did not like at all. So I used my ear instead for cap and clock trim adjustments. For C21, I ended up with 47pF and with proper clock trim adjustment, I was able to hear a good sweep transitions at slow speed settings. I measured the clock and got frequencies from 42Khz to 1.2MHz. I am by no means an expert at this so I'm not sure if I did get an optimal clock setting. I just adjusted it based on what is good to my ear.

This build is quite picky about opamps on the oscillator. The LM358 and RC4558 did not work for me. As far as I remember, the LM358 did not produce any oscillations and for the RC4558, it did oscillate but there was no modulation at all. To this date I still don't know the reason so I guess I need more reading and studying. TL082 and LM1458 both worked but I settled on the latter. And yeah by the way, no major noise issues encountered on this one.

Big thanks to the people involved in the references I used below!

Shredaholic MXR Flanger Project page
http://www.shredaholic.com/mxrflanger.html

Fender3D's MXR Flanger MN3007 retrofit schematic and board
http://www.diystompboxes.com/smfforum/index.php?topic=79154.msg652910#msg652910

9V Electric Mistress MN3007 retrofit thread
http://www.diystompboxes.com/smfforum/index.php?topic=78270.0

Below are some of the pics of my build:









This project has been mentioned as a possible candidate in one of those TZF threads here so hopefully this project can grow.

[Scruffie]

Very nice, I was considering taking a stab at doing that myself soon, nice to know it works well with the retrofit.

How does it sound? From all the demos I thought it seemed it had a much deeper sweep than the Electric Mistress.

Now where's Jorge R to put it all on one PCB for us... (Or Fender 3D to find his pnp File).

[StephenGiles]

"since a found a bunch of them in a trower in my lab, and it works indeed."

Was that a Robin Trower??

[Fender3D]

lol
I had my fingers drunk while writing that...
I meant "since I found a bunch of them in a drawer..." 

[Gordo]

But for some reason and with my limited knowledge of electronics, at the slowest speed setting, the sweep did not sound good which I cannot explain. At the start/end of the sweep, I get this slow rubbery-bounce-type of sound which I did not like at all.

It's been a while since I've played one but I seem to recall the 117 had a metallic/fast delay sound at the bottom of the sweep that was drastic enough to wipe out the audio signal fed into it.  It should get a lot more tame if you back off the regen.  I'm stoked.  If you get a chance post a few sound clips.  I'm not a big fan of the newer Dunlop versions/EVH, so it would be cool to have one again.

[shadowmaster]

Very nice, I was considering taking a stab at doing that myself soon, nice to know it works well with the retrofit.

How does it sound? From all the demos I thought it seemed it had a much deeper sweep than the Electric Mistress.

Now where's Jorge R to put it all on one PCB for us... (Or Fender 3D to find his pnp File).

I don't know. My memory of how deep the sweep of Electric Mistress already flew out of my mind. All I can say is that the 117 is "more of a flanger" than the Electric Mistress. Hmmm... I'll try to A/B my retrofit Electric Mistress and my retrofit 117 flanger one of these days.

But for some reason and with my limited knowledge of electronics, at the slowest speed setting, the sweep did not sound good which I cannot explain. At the start/end of the sweep, I get this slow rubbery-bounce-type of sound which I did not like at all.

It's been a while since I've played one but I seem to recall the 117 had a metallic/fast delay sound at the bottom of the sweep that was drastic enough to wipe out the audio signal fed into it.  It should get a lot more tame if you back off the regen.  I'm stoked.  If you get a chance post a few sound clips.  I'm not a big fan of the newer Dunlop versions/EVH, so it would be cool to have one again.

I haven't played a real one so I don't know what non-musical extreme sounds should be normally present and what are not aside from those I hear on those youtube demos.

Well, my primary goal in setting the trimpot is to get that even jet flange with the slowest speed setting and every other pots maxxed-out. So far I was not disappointed. It swooshed.... I hope I can find time to record some sound clips.

[oldschoolanalog]

But for some reason and with my limited knowledge of electronics, at the slowest speed setting, the sweep did not sound good which I cannot explain. At the start/end of the sweep, I get this slow rubbery-bounce-type of sound which I did not like at all.

I finally got a chance to take out some of my vintage 117's and really have a good listen. At extreme settings eg: man. control full CCW [slow clock/long delay], range full CW [max LFO] & high regen, things do get a bit noisy & "messy" [for lack of a better term] at the bottom of the sweep. Seems you got that fixed w/the cap change. If it sounds good/"right" then it is. Your ears are the ones that count...
I'm going to try 47pF on one of mine. Nice build, BTW!

It's been a while since I've played one but I seem to recall the 117 had a metallic/fast delay sound at the bottom of the sweep that was drastic enough to wipe out the audio signal fed into it.  It should get a lot more tame if you back off the regen.

Agreed. IMHO, it's clocked a bit too low. Back off regen, turn man. more CW [shorter delay], back off range [CCW]. The controls are very interactive. The thing I always liked about the MXR is once you get a feel for the controls adjusting them "on the fly' becomes very intuitive/comfortable.
Purchased my first one in '78. Still works & sounds great.

[Fender3D]

...Agreed. IMHO, it's clocked a bit too low. Back off regen, turn man. more CW [shorter delay], back off range [CCW]. The controls are very interactive. The thing I always liked about the MXR is once you get a feel for the controls adjusting them "on the fly' becomes very intuitive/comfortable.
Purchased my first one in '78. Still works & sounds great.

+1
I ended up with a 15pF and 54MHz min freq. (the clock trimmer range is so huge you can achieve 28-34MHz min even with 15 pF)
Again, in '78 I was 14, and could only afford the micro flanger 'cause 117 was too much expensive... so I can't recall its sound (VH aside), maybe the micro's shortest delay line is the reason for my "treble sweep quest" when building this clone...

@shadowmaster
tried with BC548 npns and RC4558, no hearable difference so far.

[jorge r]

Now where's Jorge R to put it all on one PCB for us... (Or Fender 3D to find his pnp File).

My God!!!!

[aeroguitar]

hello guys, someone would have the board layout that flanger thermal transfer, to give me? I would do it, but I do not know how to make the pcb from the wiring diagram!
If someone can help me be grateful!

Greetings!

[jdub]

Welcome!

The layout and PCB transfer image can be found here:
http://www.shredaholic.com/mxrflanger.html

A few things:  The PCB image will have to be resized to get proper spacing; the parts list is incomplete, but the layout uses the same part numbers as the schematic (also on this page), so you can figure out the missing values; lugs 1 & 3 on the "Manual" pot will need to be reversed for proper adjustment; finally, if you choose to use BC549C transistors (as the layout suggests), they will need to be turned 180 dgrees from how they are shown on the layout. Other possible subs, like 2N3904 or 2N5088, should be oriented as shown.

Hope this helps! 

[oldschoolanalog]

I believe what "aeroguitar" (welcome to the forum, BTW!) and others really want is a layout w/the MN3007 retrofit on the PCB so a daughterboard is not necessary. Trying to get an SAD1024 has become a very difficult and expensive proposition nowadays. MN3007's are still cheap & abundant.
Good luck to all involved!

[aeroguitar]

Hello guys, thanks for the great reception, I feel honored to be participating in this great forum, and please excuse my English because I am Brazilian, so curl up sometimes!
I think I expressed myself wrong, I wanted the layout of the pcb in order to use MN3007, the SAD1024 is very difficult and very expensive to achieve, even being here in Brazil, and what is not seen how to use the layout posted on Shredaholic because SAD1024 has 16 pins, while the Mn3007 has 8 pins, so I'm here asking for your help, I really like this effect and would love to build it, but without having to spend a big money for a IC ! If someone can help me would be much appreciated!

thanks!

[jdub]

Doh! Considering that I did the MN3007 retrofit on my build, and was looking for that very kind of layout, you'd think I would have understood that    Sorry! AFAIK, a PCB layout for the M117 with the retrofit hasn't been done by anyone yet; however, I did start making one based on the Shredaholic layout but never had time to complete it and just used the daughterboard.  If I get some time in the near future, I'll see if I can finish it.

[oldschoolanalog]

A daughterboard board really wouldn't take up that much space. See shadowmaster's nice work above. It would be great to have it all on one PCB though.
Fender3D posted a nice verified schematic & component layout for the MN3007 retrofit "all on one board" MXR117 (see above). No "copper side artwork" however.
Any chance of that happening Federico?
Please?

[Fender3D]

I have no more the etching PCB files 'cause the prototype pictured here http://www.diystompboxes.com/smfforum/index.php?topic=36392.msg655757#msg655757 was just that: a prototype,
I started modding and tweaking it as soon as I built it, so I redrawn pratically everything. [If you look carefully at the comp. picture you'll see there are pads for other parts not used (according to schematic), but since I was etching the board and I had to sell the pedal I wouldn't have any concern in case of missing components or misbiasing (I didn't breadborded it at the time, I did it few months ago, testing with different LFOs and dual BBDs)]. I build other units with other tweaks (such as a 3 transistors control for 4013 and just 2 knobs or a 4046 clock gen.), but all PCBs "on the fly".

There's a picture here http://www.diystompboxes.com/smfforum/index.php?topic=79154.msg652910#msg652910 of the schematic and comp. layout,
here you can find guts picture, you may trace it down eventually
.

[oldschoolanalog]

^ Thanks! Now, who is going to give this a whirl?