I need some BBD advice...

[smoguzbenjamin]

Hey all

I want to make a small device that creates a small 30-50ms delay. Dry signal through one channel, wet signal trhough the other, with only one repeat. Sort of like a simulated stereo but not quite. I normally do this with my boss DD-2 but I want nice time delays and a nice spacious sound! I use two amps, one of which I've borrowed but when I build my own amp I think I'll put this between the preamp/tonestack/reverb and power stage...
But which BBD is best suited for this? I'd like to keep costs down but if it's necessary I don't mind paying a little more. Will a 512 stage BBD work, or should I go for 1024 stages or more. Or less? I donno :?

Suggestions very much appreciated

[ExpAnonColin]

Go for 1024 stages.  Get a MN3207 and a 3102. A 3207 has about 50ms max.  I warn you that this effect will be very weak, and moderately useless-but good luck to you, and if you have any questions I"d be more than willing to help.

-Colin

[smoguzbenjamin]

Well the idea is to take the dry signal, then delay it slightly and play it through the other channel. I do this with my DD-2 all the time, but when I take the direct plug out, yes you're right, it's useless. But not when you have signal A hitting its amp slightly earlier than signal B. I'll record a soundclip in a while when I get my hands on some recording gear (cables ) so you can tell what I'm trying to do... Hang on a sec I'll draw a pic

[puretube]

NO ! don`t use a 3101 when chosing a 3207!!

rather use a 3102 for clocking....

[smoguzbenjamin]

Here's the link:
www.geocities.com/smoguzbenjamin/stereo.html

By the way I have some 555's. Would they do?

[ExpAnonColin]

Well the idea is to take the dry signal, then delay it slightly and play it through the other channel. I do this with my DD-2 all the time, but when I take the direct plug out, yes you're right, it's useless. But not when you have signal A hitting its amp slightly earlier than signal B. I'll record a soundclip in a while when I get my hands on some recording gear (cables ) so you can tell what I'm trying to do... Hang on a sec I'll draw a pic

Don't worry, I totally understand what you're trying to do, it just seems sort of boring.  No offense or anything.  On the diagram you'd want to have the input going directly to the dry output, so that it's not effected by the low pass filter set at 10k you're going to need to have.

You could do this basically with the MN3102, a 3207, and a low pass filter (preferably op amp active).  Have the MN3102 as follows:
Pin 1-9v
Pin 2-To MN3207 pin 2
Pin 3-Gnd
Pin 4-To MN3207 Pin 6
Pin 8-To MN3207 Pin 4
Pin 7 connected to the end of a 22pf capacitor connected to pin 5
Pin 6 connected to the end of a 5k resistor connected to a 10k pot connected to pin 5

Wire the MN3207 as follows:
Pin 3-Guitar
Pin 1-Gnd
Pin 5-9v
Pin 7 or 8-To the 10k lowpass filter.

Good luck!

-Colin

[ExpAnonColin]

By the way I have some 555's. Would they do?

Yes, but badly.  Use a 3102, they're more simple and work much better with MN3207's.

-Colin

[smoguzbenjamin]

Thanks Colin! My guess is the lowpass filter goes to the delayed output Whats the lpf for, to get rid of clock noise? Oh and the 10k pot etc, is that wired as a series resistor?

I wasn't really going for a stunning effect, just something that I could use instead of my boss delay to simulate stereo, so I could use the dd-2 for looooooong delay sounds Right, now I've also justified a SBE order Cheers!

[Maneco]

Instead of using a mn3102,you can also use a cd4047,take a look at the small clone schematic,and you don´t need to modulate it...hey,you can even build the bbd clock around a single hex inverter...

[ExpAnonColin]

Thanks Colin! My guess is the lowpass filter goes to the delayed output Whats the lpf for, to get rid of clock noise? Oh and the 10k pot etc, is that wired as a series resistor?

I wasn't really going for a stunning effect, just something that I could use instead of my boss delay to simulate stereo, so I could use the dd-2 for looooooong delay sounds Right, now I've also justified a SBE order Cheers!

Yes, yes, and yes.

Let me know how it ends up sounding.

-Colin

[Maneco]

...and what about a  pt2399 wired like the datasheet?you solve everything with a single chip,and you save that mn3207 for a nice vb2 clone

[ExpAnonColin]

...and what about a  pt2399 wired like the datasheet?you solve everything with a single chip,and you save that mn3207 for a nice vb2 clone

He asked for BBD

-Colin

[smoguzbenjamin]

As long as it delays and it seemed suitable Plus smallbear stocks MN3207s :mrgreen: K, in a weeks time its my B-day so I will hopefully be rich and be able to buy all the stuff I need Sweet!

[ExpAnonColin]

As long as it delays and it seemed suitable Plus smallbear stocks MN3207s :mrgreen: K, in a weeks time its my B-day so I will hopefully be rich and be able to buy all the stuff I need Sweet!

Come on man, it's only like 10 bucks.  You can pull that one off, no?  Or is shipping to big?

I recently ordered a large lot of PT2399's, which I should be able to offer for pretty cheap if you decide to go that route.

-colin

[Zero the hero]

If you already have a DD-2 or something similar, you should try Craig Anderton's Retro Stereo. Well... I forgot where's the schematic... If I remember well it was a very easy project.

[smoguzbenjamin]

I might just order both from SBE, he ships both... I have a breadboard, I'll just see what works the best. Sounds like the BBD option has alower parts count though. Shipping from Steve isn't bad, to ship a US pound it cost â,¬7,60. I need some other stuff from SB, mostly knobs which NO-ONE here supplies so I'll see. Oh as a matter of curiosity, can I put this before a power amp stage without any problems? 'cause that's the idea

[ExpAnonColin]

Can I put this before a power amp stage without any problems? 'cause that's the idea

Yep.

-Colin

[smoguzbenjamin]

Thanks Colin, you help is much appreciated

[Chico]

I am just starting to get into BBD devices, so alot of folks around here are much more qualified than I to answer your question, but I see exactly where you are going.  I have done this delay trick powering two combos, one on each side of the stage, and my tone really opened up, esp. when playing with a three piece.

Here is what I would do.

Input into op-amp buffer, split two signals out from there.  Take a first signal, the dry signal, to an output.

The second output would be the delay signal.

I think for BBD devices, you should really filter pre and post.  So I would pass the second output through an low pass filter, to the bbd, then another low pass filter to remove clock noise, then buffer the delayed signal to the second output.

I think someone above suggested you try the small clone as an example for using a bbd.  I think this would work well with a few modifications. Using the Small Clone as a starting point, I think you can simply eliminate the mixer, and optionally the modulation section and you would have a pretty good start.  (although I might leave the modulation section in and tweak it for a slower and more subtle sweep of the delay time - that may be cool.)

If you get rid off the modulation, I think you can get rid of the oscillator circuit based on the 358 op-amp and corresponding components up to the point where the diode and capacitor connect on the CD 4047, i.e., from the 39k on.  Replace the diode with a series resistor and a pot for manual control of the delay time.  Now, your delay can be manually set by the combination of the series fixed resistor and pot, and the timing capacitor.

Also, I would consider replacing the low pass filter on the output of the delay chip with a higher order filter.  I have cranked a small clone into slap back delay range, and when I have done so, I got audible noise and clock bleed.  At 25ms, you may likely be fine with the Small Clone circuit as is.  If you want much higher delay however, I'd seriously consider a better post delay filter.  

As I noted above, I am quite a beginner at this, so I hope someone else chimes in here.



I would be interested to know how it turns out.

[smoguzbenjamin]

I drew up a schematic based on Colin's suggestions, if you hang on a sec I'll draw it on paint and post it at my site. Hold on a sec... :?