MXR - Micro Chorus

Post by **GodSaveMetal** » 19 Jan 2011, 15:53

Please man a layout with the mod using the MN3007 o the MN3207!!!!! thanks for your efford your are great!!!

Fender3D · Post by **Fender3D** » 19 Jan 2011, 17:40

Dirk_Hendrik wrote:...
2) In the current application the supply voltage for the BBD and the BBD bias is the same as the overall supply voltage. This means that when this voltage rises or lowers suddenly your BBD output signal can start to distort or fall away since the bias voltage changes as well. Add a resistor and a 8v2 zener and be on the safe side.

Looking at the Vbias vs Vdd graphic, you have an almost linear curve, meaning that when Vdd decreases, Vbias should decrease in a similar manner thus avoiding distortion rising (in an acceptable way) when DC supply gets lower and lower.

It's different with phasers where the zener will provide a proper FET biasing.
I used a different approach to achieve Vbias and Vdd in my MXR flanger replica:

Dirk_Hendrik · Post by **Dirk_Hendrik** » 20 Jan 2011, 16:51

Unfortunately it doesn't work that way.... which I found out after spending half an afternoon trying to find out why my box did work on the bench (delayed signal) and did not in the living room (no delayed signal). Bench supply was set at 9 volts. Living room was a "standard" Ibanez adapter which when I finally figuered out the problem happened to be a 10 volts type used for tubekings.

Dirk_Hendrik · Post by **Dirk_Hendrik** » 20 Jan 2011, 16:53

Fender3D wrote:I used a different approach to achieve Vbias and Vdd in my MXR flanger replica:

Charming piece of economy use of that trimmer!

DimebuGG · Post by **DimebuGG** » 22 Jan 2011, 06:42

jbgron wrote:I just built Dime's layout and it doesn't work, the signal just passes straight through unaffected. I've tweaked the trimpots and audio probed to no avail. Has anyone successfully built Dime's layout?

The layout's is as per schematic (the corrected one) by mictester's. I'm pretty sure there are no mistakes assuming the schematic is working.

Fender3D · Post by **Fender3D** » 25 Jan 2011, 17:43

Just updated MXR micro chorus' .jpg and .pdf schematic files.
Corrected R8 value (was 2K7)

Post by **GodSaveMetal** » 26 Jan 2011, 03:05

Fender3D wrote:Just updated MXR micro chorus' .jpg and .pdf schematic files.
Corrected R8 value (was 2K7)

Please were I found taht schem or PCB it´s any???

Post by **GodSaveMetal** » 26 Jan 2011, 03:11

I got it!!! but how to make a doubler withut the MAX1044 or the ICL3660 or other!!! there are nothing of these in my country!!! please another form to do a conversion for 9V to 18V???

Fender3D · Post by **Fender3D** » 26 Jan 2011, 17:25

the MXR micro chorus works with 9V.
I don't know if the MN3007 adaption works with 9V, my MXR flanger wouldn't work properly with 9V, so I guess an MN3207 might be a better choice...

Doubling voltages with MAXs or ICLs, always leads to boring noises here and there, whether the battery isn't an option, you'd better build a proper power supply or adapt the schematic for MN3207.

Barcode · Post by **Barcode** » 10 Feb 2011, 21:38

You can also use analogguru's schematic for voltage doubling with a 555 timer chip, a common part.

odgeuk · Post by **odgeuk** » 27 Feb 2011, 15:53

Hi guys

I notice that MXR still sell a Micro Chorus pedal. What are they using if SAD512D chips are no longer in production?

sinner · Post by **sinner** » 27 Feb 2011, 18:14

odgeuk wrote:Hi guys

I notice that MXR still sell a Micro Chorus pedal. What are they using if SAD512D chips are no longer in production?

My guess is MN3207

Post by **GodSaveMetal** » 27 Feb 2011, 19:38

Barcode wrote:You can also use analogguru's schematic for voltage doubling with a 555 timer chip, a common part.

Please you have the link????

sinner · Post by **sinner** » 27 Feb 2011, 19:49

GodSaveMetal wrote:
Barcode wrote:You can also use analogguru's schematic for voltage doubling with a 555 timer chip, a common part.
Please you have the link????

Here or http://www.justfuckinggoogleit.com/

ny_racer_xxx · Post by **ny_racer_xxx** » 09 Mar 2011, 02:39

Has anybody built one from the PCB layout?

Thanks,
CR

jbgron · Post by **jbgron** » 09 Mar 2011, 09:10

I did and it didn't work. If you get it working please let me know.

odgeuk · Post by **odgeuk** » 18 Mar 2011, 10:45

sinner wrote:
odgeuk wrote:Hi guys

I notice that MXR still sell a Micro Chorus pedal. What are they using if SAD512D chips are no longer in production?

My guess is MN3207

I read that the 80's Micro-Chorus used an R5106.

For the Micro-Flanger, MXR substituted the SAD512 with what they described as a "512-stage delay line similar to the MN3204".

ivanmarch · Post by **ivanmarch** » 21 Mar 2011, 10:48

The NEW micro chorus (Reissue) uses a V3204D. This is a 512 BBD stages made in china for Dunlop. It is a copy of the old MN3204.

ivan.

ny_racer_xxx · Post by **ny_racer_xxx** » 24 Mar 2011, 01:05

Question, the trouble seems to be in the timing circuit, would it work better if you used a MN3101 timing chip like the CE2 clone, instead of the discrete components?
Would that change the sound?

CR

Speeddemon · Post by **Speeddemon** » 24 Mar 2011, 17:34

I just received a brand new reissue Micro Flanger;

I also have an original, which has the Reticon 5106 IIRC (though I have seen them with the SAD 512 as well), but the reissue has the V3204D chip.
Footswitch is an Alpha DPDT by the way, and I've read a few times that new MXR pedals that say 'True Hardwire Bypass' have in fact a true bypass switching method, using the Millenium bypass for the LED.
In the reissue Micro Flanger I also spotted a TI 4069UBM.

MXR - Micro Chorus [schematic]