BBD, Clocks, LFOs (MN3007 for MN3207, CD4046, CD4047)

[Michael Allen]

I've built the FL301, CE-2, and Ultra Flanger and have had poor luck. Faulty BBD and Clock drivers coming out of Hong Kong, you know that whole scam.

I've gone over the datasheets and read post here, and have modded the FL301 and CE-2 to use an MN3207 and MN3102 instead since I ordered some for other projects. I'm still waiting for the parts but expect it should work fine. Now my problem comes with the Ultra flanger. It uses a CD4046 buffered by a CD4049 as a clock.

I've looked at other flanger clocks and there are examples of using a CD4007/CD4047, http://www.morleypedals.com/cfles.pdf and http://hammer.ampage.org/files/Device1-9.PDF
as well as using the CD4046 with an opamp to amplify input voltages, http://www.flickr.com/photos/loscha/2503124435/sizes/l/

That last example is for a MN3001 but it shows the two biphase outputs which could be used for other BBDs if the clock is adjusted right, correct? So my question is, can I sub in an MN3207 for an MN3007 in the Ultra flanger if I adjust the power and ground pins and give in a 5V supply, without needed to adjust the clock input pins. Will I need to switch the clock input pins? Will I need to change the clock components since the MN3207 and MN3007 have different clocking capabilities?

If it's not possible to use this CD4046 clock, can you point me in the direction of a CDXXXX clock I can use to control the MN3207?

In addition, with one MN3007(faulty and not real flanging) I was able to hear all the discussed LFO tick and have read of other members using alternative LFOs in place of the Hollis LFO. What LFOs would you all suggest?

Thanks all,
Michael

[Mark Hammer]

If you go to Charlie Barth's Moosapotamus page and lok at the scanned Stompboxology newsletters, somewhere in the Vibrato or Tremolo newsletter, there is a nice explanation of a little tweak you can do to the standard 2-opamp LFO to prevent audible ticking.  Well worth reading.  Note that this identical adjustment is used in a number of Boss modulation pedals for that very reason.  http://www.moosapotamus.net/IDEAS/stompboxology/stompboxology.html

[Michael Allen]

good find, I'll add the cap and resistor and see if that helps the ticking.

any ideas on clock information?

[Michael Allen]

Added that fix and so far have noticed no difference in noise. Again shoddy BBD chips so who knows what it'll sound like when I get a legit chip.

[StephenGiles]

Nothing wrong with the 4047/4007 buffered by 4049 clock. I have never bothered with MN clocks. It should be possible to use the 4046 clock.

[StephenGiles]

http://www.mojotronics.com/images/FL9.pdf

Found this but may not be new.

[Michael Allen]

Alright,

Successfully got the Boss CE-2 working with a BL3207/BL3102 substitution.

No luck with the Fl301 or the Ultra flanger.

In general, do the LFO and BBD need to be run at the same voltage? I've modded the FL301 to just use 9V since I don't need 12V for the MN3007. The LFO is run on 9V but the MN3207 wants ~5V. I've regulated the supply going to the BBD to 5V. Should I put the LFO at 5V as well or can it still run at full supply voltage?

How do I bias these circuits, the BBD, the Clock, the LFO, etc. All schematics I've looked at for different flangers and choruses all have different bias circuitry. What voltages am I trying to feed to these parts of the circuits in general for proper function. The datasheets don't give any info on biasing.

I've tried to use the MN3207 in the ultra flanger with no luck. I tried the circuit with the CD4046 pins 3/4 and 2 going to MN3207 pins 2 and 6 respectively through the CD404. Also tried it as it is in the schematic and no luck. I saw a schematic for the Zombie chorus adopted to use the MN3207 here, http://www.synthdiy.com/files/2007/zombie_chorus_mn3207_based.jpg. This runs CD4046 3/4 and 2 to MN3207 6 and 2, which is the opposite of the Ultra flanger. Do the pins really matter since the clock signal is just opposite phase between pins? In that zombie circuit the MN3207 is biased through the Vgg pin 4. Again I'm uncertain how I should bias all these cirucits.

Any other ideas about what needs to get what voltage and what bias?
Thanks for any help

[Michael Allen]

Stephen thanks for that link, I see in the FL9 that the LFO and clock and BBD are all run at 5V. I'll try that out here...

[Michael Allen]

Ok, successfully got the FL301 running with a BL3207/BL3102 combination.

The power supply is now +9V. I ran the LFO at +5V along with the Clock and BBD. I replaced some of the FL301 parts with the values from the FL9 schematic. For reference:
R149 - 200k
R148 - replace with 10uF capacitor
R147 - 220k
R146 - 150k
R144 - 8.2k
R143 - 10k
R142 - 27k

R114 - to ground

Very subtle flanger, its alright but not as intense as I want it to be.

Now to get the Ultra Flanger working....

[mike_a]

Hi,

I was also wanting to adapt the CE-2 to use the 3102/3207 combo.
I would be very interested in what you did exactly.
that is what is the new pin connection, and the bias.

Thanks,
Mike.

[Michael Allen]

It's pretty simple on the CE-2. Switch Pin 1 and 5 of the MN3207. The resistor from pin 7/8 needs to go to ground instead of V+. The 30R resistor in the power rail by the filter caps, up it to 100 or 150R and then put a 5V zener after it to ground. This gives you a 9V supply on the front of the resistor that goes to all the opamps, and then a 5V supply which goes to the BBD and the Clock. I just soldered this diode across C30.

That should be all, then adjust the trim until you get chorus.

[mike_a]

Thanks a lot Michael!

[Michael Allen]

Well I can't get the Ultra flanger to work with the MN3207. No flanging happening.

The LFO is working, and biased at 3.8V. The opamps are biased at 4.9V. The MN3207 is running on 5V and I installed a bias trimmer on input pin 3 as seen in other flanger schematics. I've tried the clock outputs on MN3207 pins 2 and 6, and flipping them but no change.

How do I tell if the clock is functioning? The voltage on pins 2 and 3/4 slightly oscillates from 4.30 - 4.35V. Does this mean my clock is working?

[mike_a]

You won't be able to tell if the clock is working with a regular DVM.
The frequency is too high.  You'll need a scope.

[johngreene]

MN3207s will work with a supply of 4-10V.

[johngreene]

Nothing wrong with the 4047/4007 buffered by 4049 clock. I have never bothered with MN clocks. It should be possible to use the 4046 clock.

I often wondered if the 'dead-time' between falling and rising clock edges the MN clock chip provides is necessary for the MN version of delay chip to work properly....
If you look at the two clocks you will see that the 'high' times are shorter and centered between the 'low' times.