BBD differences between chorus and flanger

[Mark Hammer]

1024-stage chips have been used for slapback, back when we had fewer choices, but are not necessarily a preferred way to get there.  The challenge is that a slow-enough clock rate for something like 100msec requires either compandng or some serious lowpass filtering, or both, in order to get a sound that is acceptable, both in terms of noise and tone.

I suspect most folks would recommend a 3208 chip instead, so as to be able to exploit a faster clock rate for less noise, greater bandwidth, and better resolution.

[anotherjim]

PT2399 rules for things like slapback.
With BBD, I say embrace the grot. It's  got a certain character, that works so long as it's doing something interesting - plenty of feedback and sweep the delay time a long way, maybe best with an expression pedal. Not something you can use a lot maybe, but nothing else will sound quite like it.
Simplest might be based on the Hollis Chorus/Flange designs using CD4046 VCO BBD clock. Delete the LFO and use the expression for VCO CV input.

[StephenGiles]

PT2399 rules for things like slapback.
With BBD, I say embrace the grot. It's  got a certain character, that works so long as it's doing something interesting - plenty of feedback and sweep the delay time a long way, maybe best with an expression pedal. Not something you can use a lot maybe, but nothing else will sound quite like it.
Simplest might be based on the Hollis Chorus/Flange designs using CD4046 VCO BBD clock. Delete the LFO and use the expression for VCO CV input.

Or the humble 4047 BBD clock used in a number of EH designs.

[thermionix]

PT2399 rules for things like slapback.

Any particular circuit you recommend?  Ideally something I can get a PCB for since I don't etch my own.  All of my 'scratch' builds so far have been ptp with discretes.  Analog delay is probably the biggest gap in my current selection, but most commercial ones are quite pricey and I won't touch digital with a 10-foot dung fork.

[anotherjim]

hmmm... PT2399 is digital.
So was that an incomplete quote, or do you want something to slap the 3007 in?
Search for MN3007 chorus should find examples, currently available  pcb's for them might take a little more finding. Zombie chorus was my first thought, there are some more complex ones due to better signal filtering.

[StephenGiles]

Doesn't the EH Flanger Hoax use 2 clocks? What was the trick in that?

[thermionix]

hmmm... PT2399 is digital.
So was that an incomplete quote, or do you want something to slap the 3007 in?
Search for MN3007 chorus should find examples, currently available  pcb's for them might take a little more finding. Zombie chorus was my first thought, there are some more complex ones due to better signal filtering.

I have no idea.  You said "rules" so I assumed analog.  MN3007 is analog, right?  As I said earlier, I know virtually nothing about this stuff.  And I don't care for chorus.  Mr. Hammer has made the point that the MN3007 is probably not a good choice for a delay, even a short one.  I'm going with that, but would like some opinions about a simple, low(ish) cost analog delay, using whatever chips, if anyone has any recommendations.  Long delay would be nice, but I'm open to a quick slapback if it's considerably cheaper to build, easier to find components for.  And an available PCB would be nice.  I looked at Aion and didn't see any delays at all.

[StephenGiles]

Any reason why you can't build on "brexit board"? 

[Mark Hammer]

hmmm... PT2399 is digital.
So was that an incomplete quote, or do you want something to slap the 3007 in?
Search for MN3007 chorus should find examples, currently available  pcb's for them might take a little more finding. Zombie chorus was my first thought, there are some more complex ones due to better signal filtering.

I have no idea.  You said "rules" so I assumed analog.  MN3007 is analog, right?  As I said earlier, I know virtually nothing about this stuff.  And I don't care for chorus.  Mr. Hammer has made the point that the MN3007 is probably not a good choice for a delay, even a short one. I'm going with that, but would like some opinions about a simple, low(ish) cost analog delay, using whatever chips, if anyone has any recommendations.  Long delay would be nice, but I'm open to a quick slapback if it's considerably cheaper to build, easier to find components for.  And an available PCB would be nice.  I looked at Aion and didn't see any delays at all.

It's gonna depend on how many you have, won't it?  Maxon went with an octet of them for their AD-999.    But yeah, a single MN3007/MN3207 can be forced to produce audible delay, but at serious cost to aural quality.

[anotherjim]

Personally, I don't think the PT2399 sounds particularly digital - it can get pretty close to tape with the right surroundings. Nothing like BBD though, and yes, BBD is what most people mean by analog. I think that if you had a PT2399 and followed it with the 3007, the BBD sound quality could dominate. I think the BBD clock could be derived from the PT2399 clock out ( after a divider counter). I don't know if such a design already exists, but it's coincidentally something I've been thinking about PT2399 delay begins at a minimum about 30ms and a single one can go up to short, but useful, looping territory.

I do have a 1024 stage BBD delay that can go down to definite repeats, I think about 80ms. Of course it sounds very grungy & it has no fancy noise reduction or companding. After I built it, it dawned on me that I could have simply modded an old cheap MN based chorus pedal I have laying around.

[thermionix]

I see a lot of PT2399-based kits and PCBs out there, but I have an aversion to digital, even if it's "close" to analog sounding.  I do have a TU-2, but I unplug from it as soon as I'm done tuning up.  That might be more because of the buffering though.

There is the BYOC analog delay kit, but it is pretty expensive, more delay time than I need, and won't run on a battery.  (I also have an aversion to wall warts.)  If they offerered a "short"-only version with just one 4096 BBD, battery capability, and a much lower price, I might be into that.

[StephenGiles]

I see a lot of PT2399-based kits and PCBs out there, but I have an aversion to digital, even if it's "close" to analog sounding.  I do have a TU-2, but I unplug from it as soon as I'm done tuning up.  That might be more because of the buffering though.

There is the BYOC analog delay kit, but it is pretty expensive, more delay time than I need, and won't run on a battery.  (I also have an aversion to wall warts.)  If they offerered a "short"-only version with just one 4096 BBD, battery capability, and a much lower price, I might be into that.

Christ there's no pleasing you, just get soldering and be done with it!!

[slacker]

Whilst the PT2399 is digital, it's got far more in common with a BBD than it has with what people are typically referring to when they say digital. A BBD ain't really anologue anyway, not compared to tape or springs or plates, a better term would be "not digital". At the end of the day why does it matter anyway, use your ears, if it sounds good it is good.

[Mark Hammer]

It's analog in the sense that it has no fixed resolution or "coding".  Where it differs from what we normally think of as "analog" is that it is not continuous with respect to signal transmission.

[thermionix]

if it sounds good it is good.

I agree, but I don't have one in hand to try out.  Maybe I should just fork out the buck fifty for a Carbon Copy.

[slacker]

It's analog in the sense that it has no fixed resolution or "coding".  Where it differs from what we normally think of as "analog" is that it is not continuous with respect to signal transmission.

Exactly what I was getting at.