MXR MICRO FLANGER ! NEED HELP!

[wizard]

Hello everyone,
A friend of mine gave me a MXR micro flanger whose BBD chip was missing. I don't know what BBD chip to use, can anyone tell me?
Or if it's not a BBD chip that micro flanger uses, please tell me what chip it is.
Thanks for help.

[MartyMart]

Well I searched  A LOT and could only find the "Large" flanger schematic
which uses a SAD1024 chip .....
Sorry, perhaps someone else will chip in  !

Marty.

[stm]

Well this may be also an opportunity to trace the micro flanger as well.

I shouldn't be too difficult to tell which BBD to use. If the IC has 8 pins, it is likely to be a MN3007 or a member of this family.  If it has 16 pins, first option would be the SAD1024.  If you could post some pictures of the board (both sides) it might be possible to follow the clock lines from the oscillator and see in which pins on the BBD IC they get into.  This would serve as a double check for the BBD identity.  The same for the audio path.

[George Giblet]

http://www.modezero.com/mxr-micro-flanger.htm

Note:   "bbd: reticon r51xx"

I'm pretty sure this is the reticon family that followed the SAD512 - IIRC Mark Hammer has the data sheets on is site (although I could be mistaken).

[hank reynolds 3rd]

if it's the same as this one
http://www.modezero.com/mxr-micro-flanger.htm

it says a reticon  51xxxx (512?? )

[hank reynolds 3rd]

snap!!!!

[wizard]

It seems like I will never have the chance to repair it.

[Mark Hammer]

Depends on what type of SAD512 it was.  One of them is essentially an SAD1024 (same # of pins) with only one set of 512 stages working.  The other one (with a D-suffix I think) is an 8-pin DIP that has an on-board complementary clock pulse circuit (i.e., you only need to provide it with a single phase clock, rather than complementary clock signals as with the MN3xxx chips).  The first type you could probably fake with an SAD1024 from Small Bear.  The other....not so much.

In theory, one could rig up a daughter board with an MN3004 or something similar to sub for the SAD512, but it would involve more than just something to shift pins around in order to plug into the mainboard socket.  Worth it forthe tone?  Not likely.  Save your heartache and headache.  Save your shekels.  Get a Flanger Hoax or Liqui-Flange.  Then save rock and roll!!

[A.S.P.]

R5106 ? from smallbear

[R.G.]

Mark is absolutely correct on this one. If it's an eight pin set of holes, it was for the SAD512D. There are no more SAD512Ds. I have never found any in about 20 years of looking, and I found a lot of other stuff along that path.

The only real hope for that flanger is to replace the SAD512 by a daughter card holding an SAD1024 plus clock drive circuits or alternatively an MN3207 and MN3102 BBD/clock generator pair. There are no more SAD512s, and I'm generally not one to give up hope on rare parts.

Mark is right - save your money, get a newer flanger with better sound.

[Mark Hammer]

Not so fast, brother Keen....we might both be wrong

Pinouts for SAD512D (first) and R5106 (second)

1 - Clock in, clock in (both do complementary clock pulse conversion internally)
2 - Gnd, Gnd
3 - Out 1 ("Odd"), No Connection
4 - Out 2 ("Even"), Output
5 - Vbb, Vbb (I don't understand what this is, but related to bias)
6 - Input, Input
7 - Sync, Sync (generally grounded in both instances)
8 - V+, V+ ("Vdd")

With the exception of pin 3, the two chips are remarkably similar, and pin 3 would seem not to be that big of a problem.  Keep in mind the R5106 has 256 stages, where the SAD512 has, surprise!, 512 stages.  That means that achieving the same delay range requires you to cut the clock rate/range in half in order to mimic the delay time of an SAD512.  A better choice might be to score an R5108, which has the same pinout and everything else the R5106 has, except with 1024 stages.  This would require you to double the clock rate.

Why is one "better" than the other?  Every BBD device includes some minimal degree of lowpass filtering of the delay path to keep clock noise out of the audio output. The cutoff/rolloff frequency selected is based on assumptions about the lowest frequency the clock will be operated at.  If you drop the clock by half, the filtering may still be enough to keep noise to a minimum...or it may not.  If you double the frequency, you are assured that the onboard filtering will be more than sufficient to keep clock noise and aliasing out of the audio signal.

In contrast to my earlier assumptions (and thanks to A.S.P. for the tip!), you may still be able to pull this one back from the brink.  And once you're celebrating, THEN go a buy a Flanger Hoax or Liqui-Flange.

However, before you do anything, take a good hard look at the datasheets for the two chips (harder than I did) and verify they are compatible enough.

[A.S.P.]

or PM this guy,
who doesn`t come here often anymore,
but rather dwells here,
and ask Colin whether he got some Reticons left...


relevant datasheets

[A.S.P.]

or use the search button, and type: " R5106 " 

[wizard]

Thank you for these informations.I think it's not worth to fix it.
But I still have learned a lot from you guys. That's good for me.
Thanks again.