Looking for flanger schematic using mn3204 512-stage BBD

[Kevin Mitchell]

I would like to dig into the flanger effect and I happen to have a heap of mn3204 chips. I've read that 512 stage BBD chips are ideal for flangers but I haven't been able to find a good schematic to go from. I was recently given a box of old parts and I was actually looking for a mn3007 for a Mutron flanger project. Thinking it was a long shot I happened to find a bag of mn3204.

What familiar chips are "workalikes" for the mn3204? I've read of flangers using these chips but I haven't found a schematic yet.

Here's a data sheet . Any help is very appreciated 

[Fender3D]

I don't know if you can find any schematic with 3204 inside, since the chip was originally manufactured for MXR only, then relatively new chip.
It will work on schematics for 32xx BBDs.
You may use it on a 3207 flanger and verify if the

512 stage BBD chips are ideal for flangers

statement is true...

Otherwise... ADA flanger used 512 stages BBDs and the same did EH with its flangers. you might arrange the schematic to use 1 or 2 BBD...

[Mark Hammer]

The 3204 is used on the Boss HF-2 Hi-Band Flanger, which is directed principally at bass players.  There is very little difference between the BF-2 and HF-2, apart from the specific BBD used (3207 for the BF-2, 3204 for the HF-2).  The long and the short of it is you can use a 3204 anywhere that you can use a 3207.  If you find the delay time is too short for your needs, you can always adjust the small-value cap that sets the clock range in the circuit.

[Kevin Mitchell]

The long and the short of it is you can use a 3204 anywhere that you can use a 3207.  If you find the delay time is too short for your needs, you can always adjust the small-value cap that sets the clock range in the circuit.

Thanks for sharing.

So would the mn3204 be a "drop in" for a mn3207? I'd only have to consider the range (delay time) due to using a 512 stage BBD instead of the 1024 stage BBD?

Seems worth a try after looking at the mn3207 data sheet

[Mark Hammer]

Yep, the difference is that the 3204 has half the delay time, if fed the same clock frequency.

In some respects, a 3204 is a somewhat better choice for flanger than a 3207, since a standard 3102/3207 combo has a hard time reaching the very short delays that great flanging relies on.  On the other hand, sound quality depends partly on the clock frequency.  HIgher sampling rates yield better quality sound and greater bandwidth.  A 3207 is capable of that, but one needs to use a different clock circuit than a 3102 to overcome the input capacitance of the clock pins on the BBD.

So, as a simple fix for the short-delay conundrum, a 3102/3204 combo is a great solution.

[Kevin Mitchell]

I found a gut shot of a boss HF-2 that uses a 3204 and a 3102 and I've read its a good driver for the combo. I'm having trouble sourcing the 3102 chips. From what I understand a good clock driver is a must here and the 3102 is pretty much made for the role.

Any suggestions?

[PRR]

> trouble sourcing the 3102 chips.

MN3102 is getting scarce.

V3102 is CoolAudio's copy. SmallBear, Mammoth, Banzai. (Bear's price is best.)

[Kevin Mitchell]

Thanks PRR!

I'm thankful I don't have to order a $10 IC (mn3007) and I get to experiment for a while 

In the Boss HF-2 schematic a 9022 dual opamp is used. Could one use any generic opamp such as a lm358 or a tl072? I assume so for IC1 and 2 but not sure for IC5.
I'm going to try to use the combo and adapt it to a more sought after flanger effect.

[Mark Hammer]

Generics like 1458, 4558 and TL072 are fine.  Do try to use a dual designated as "low-power" for the LFO to help avoid audible LFO ticking.  An LM358 there would be good.

[Kevin Mitchell]

Thank you Mark.

I believe armdnrdy sent me a PM about a Ibanez FL99 and it using a mn3210(2 512 stage BBD in one) Data sheet here   He mentioned his efforts to use 2 mn3204s but I can't find any info about it on the forums (unpublished project)  But now it is a MUST HAVE and I'm putting my efforts towards this one.

Found a schematic for the pedal here

I understand how easy it would be to implement 2 or even 1 mn3204s into this project just by looking at the data sheets. I could omit the "Intense" switch and use just 1 mn3204 - I think. I'm assuming the driver would work just as well with the substitute and wouldn't need adjusting. Need that thought verified. Though I'm curious why the 8V regulator is there for the mn chips when they could get +9v easy. Is it there for power protection for the mn chips in case v+ exceeds their 10V max?

I'm on my toes waiting for a reply from armdnrdy so I can throw together a BOM to start testing    I had my eyes on his Mutron in a Morely pedal for a while but now I'm onto the FL99. 

[armdnrdy]

Thank you Mark.

Found a schematic for the pedal here

Though I'm curious why the 8V regulator is there for the mn chips when they could get +9v easy. Is it there for power protection for the mn chips in case v+ exceeds their 10V max?

Dirks schematic has a few mistakes on it.

The original voltage regulator is a NJM2930. It is a low drop out regulator.
I used a TL750L08 which has the same specs as the NJM.

[Kevin Mitchell]

Smallbear only has 5v then 9v and so on. Ehh...

I'd like to know why is a voltage regulator necessary if those chips can get up to 10V? I'm not sure what you mean by low drop out regulator.

Also, shoot me a schematic 

[armdnrdy]

The low drop out regulator has a .6 volt drop out...that is to say that you can input 9 volts and output 8 volts.
A "regular" 8 volt regulator (L78L08) has a drop out of 1.7 volts.
You would need to input 10 volts to output 8 volts.

You asked why an 8 volt regulator when the BBDs supply is rated for 10 volts?

Without the regulator, you chance 'frying" the BBD.
Even though the user manual will say to only use an Ibanez wall adapter..how many times do you thing that other "9 volt" wall adapters get plugged into a manufacturers effect.

Wall adapters are generally not regulated. I have taken output readings of 9 volt wall adapters that have gone as high as 13.5 volts!

[armdnrdy]

After I had the thought to replace the unobtainable MN3210 in this circuit, I drew this up to confirm my thoughts.

[Kevin Mitchell]

Thank you kindly!

Would it be an issue if I omit the regulator for now and the entire circuit shared v+? I mean as long as I use 9v regulated DC supply (pedal power brick)
Possible noise issue? Is that another reason for the regulator?

Just trying to wrap my head around some things.

[armdnrdy]

Considering the fact that the regulated 8V (V+) is feeding the clock, LFO and well as the BBD...I would keep that "as is" in fear of the possible frequency change due to the extra volt.

What you can do for now is to acquire an easily sourced L78L08 and feed it with a higher voltage wall adapter.
Do you have a 12VDC adapter laying around?

[Kevin Mitchell]

My power brick can do 12VDC as well. 8 isolated power supplies. So I have work-arounds 

If anyone could tell me more about the mn3204 chips it would be helpful. I'm not sure of the age of these chips or where exactly they came from. I'm convinced they're genuine. I'll post a picture in a moment. I can only find them on a site like ebay for $10 - $25 USD each. That's crazy.

[armdnrdy]

My power brick can do 12VDC as well. 8 isolated power supplies. So I have work-arounds 

If anyone could tell me more about the mn3204 chips it would be helpful. I'm not sure of the age of these chips or where exactly they came from. I'm convinced they're genuine. I'll post a picture in a moment. I can only find them on a site like ebay for $10 - $25 USD each. That's crazy.

If you have any builds that use a socketed MN3207...you can pull out the 1024 stage BBD and test the 3204s.

Post an image of what you have....I have a pretty good eye for spotting relabeled BBDs.

[Kevin Mitchell]

Each one has a number and a letter pressed on the bottom. The surface looks a little frosty in the picture due to my desk lamp.

I don't believe I have anything that uses BBD chips...

[Kevin Mitchell]

Also regarding the power, I'll just put 8v isolated into the necessary part of the circuit for when I mess around on the breadboard. Thank you!