Kicking The Bucket The Hard Way--

Not a theremin? :)

analogue Bucket Brigde delay line

chances are it's obsolete, I didn't find any alternatives either, look for more recent plans.

--
?? 100% natural

My recollection is that those analog delay lines gave fairly low quality audio. Their big virtue was that they were also fairly simple to use.

If you don't mind more work, there is another way to approach chorus effects using a "phaser/flanger" design. You can make one of these using "all pass" filter stages, where you modulate the (phase) corner frequency. For each stage, you get a moveable notch in the frequency response when the total output is summed with the input. (A true delay gives a whole series of notches at multiples of the delay time reciprocal.)

Since each stage requires some modulateable component, the trick is to find something cheap and available. When I did this many years ago, I used CD4016 quad analog switches. The idea (from Don Lancaster's "Active Filter Cookbook"... highly recommended!) is that you drive all the switches with a single PWM oscillator. Each switch is in series with a resistor that determines the stage frequency. When the duty cycle is high (close to 100%), the effective total resistance is obviously pretty much that of the resistor alone. When the duty cycle is (say) 50%, current can only flow half the time, so the effective resistance doubles. And so on. You need to make the PWM oscillator run at a high frequency (preferably above 20 kHz) that can be easily filtered from the output.

Once you have the basic PWM controller, adding more notch stages is dead simple: Just add another all-pass stage (one op-amp, plus a couple Rs and Cs) and put one 4016 switch in series with the tuning R. All stages are basically identical except for the tuning. Because all stages are controlled by the same PWM oscillator, perfect tracking is built in.

Best regards,

Bob Masta DAQARTA v6.02 Data AcQuisition And Real-Time Analysis

Scope, Spectrum, Spectrogram, Sound Level Meter Frequency Counter, FREE Signal Generator Pitch Track, Pitch-to-MIDI Science with your sound card!

"Ron Hubbard"

** They all seem to live in Hong Kong and sell via eBay.

But you already knew that - didn't you ?

.... Phil

ADC --> memory --> DAC

The memory will come in the microcontroller you choose. You probably don't even need a DSP to do this, and may be able to shoe-horn it into a PIC, if you just use it for audio delay and not the whole application.

There's a _reason_ that analog delay lines went obsolete.

A better way to skin the cat is to put the whole chorus signal processing chain into digital. This may need a modest DSP, but your external circuitry will be at a minimum.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" was written for you.
See details at http://www.wescottdesign.com/actfes/actfes.html

eBay. $5 for a set (Mn3007 + MN3001), $75 for 50.

The circuit I found is a very simple one that uses a CD4046 in conjunction with MN3007; a very simple and elegant design. :-)

Ron

"Michael Black"

But you're not listening.

** And you are not thinking.

Analog shift registers were a temporary thing, a need at a certain point in time, but made obsolete as digital took over. The analog shift registers could be noisy (from the clock) and I seem to recal suffered from bad dynamic range. But back then it was easier than going digital.

** None of which has the SLIGHTEST thing to do with the OP's DIY project.

Now it's different. Not only are analog shift registers expensive because nobody is making them anymore, but digital has become really simple and cheap. Yes, the number of parts may be greater, but it's a relatively straightforward wiring.

** So writing and installing a program for a chorus effect in a SP is trivial job for anyone is it ?

And working with SMD is piss simple too ?

The OP does not want to have to learn new skills or make 100,000 units - he merely wants to make ONE unit using a long proven, dedicated analogue IC.

There is an old saying that when all you have is a hammer, EVERYTHING looks like a nail.

..... Phil

But there's a reason why digital designs don't thrill me: I like simplistic designs I can knock together on a piece of perf-board some evening--- not some ultra-sophiticate digital mess that'll take a complicated PCB that I would probably have to have somebody make for me plus some program that'll have to be entered into a chip . This is a simple project with emphasis on the word "simple." Sound quality may never be great, but this isn;t a high-fidelity project to begin with. And excpt for that damn MN3007 IC, eveything else can be gotten from Mouser for five bucks or less-- what more can you ask for? :-)

Ron

Are you saying you're looking for an analog delay line? Why not make one, with a handful of ferrite beads, some magnet wire, and a few capacitors?

Good Luck! Rich

"Michael Black"

The analog shift registers could be noisy (from the clock) and I seem to recal suffered from bad dynamic range.

** Clock frequency residual is small and at frequencies above the audible range.

The dynamic range of the MN3007 is quoted as 80dB by Panasonic.

THD is low as is current drain - and although the data makes no mention, it can operate from a 9 volt battery.

.... Phil

Or a spring, a speaker coil, and a microphone. _That_ should be a project and a half!

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" was written for you.
See details at http://www.wescottdesign.com/actfes/actfes.html

yeah, Like the old ones used in cars years ago, hit a bump or rock the car :), you'd really get some extra effects.

Jamie

Actually, "Elementary Electronics" did it in the seventies with a garden hose, a speaker of some sort at one end, a microphone at the other end.

Michael

Ron Hubbard wrote in news: snipped-for-privacy@bl1g2000vbb.googlegr oups.com:

This is how simple a digital delay can be. Probably better fidelity than BBD. Cheap common chips though higher parts count than BBD design. No uP so no software.

Thanks, Geoff; as Mr. Spock would say, there are always possibilities. More work than a lazy person like me usually wants to do, but it probably beats waiting to get a MN3007 from who-knows-where.

Ron

I run the group for folks with ESP (

epaths_empaths_scanners/ )and I saw it coming; I just desperately hoped I was wrong for once... ;-)

Ron

__________________ "There are special people in this world. We don't ask to be special. We're just born this way. We pass you on the streets every day, unnoticed by most. "

-- Cassie Holmes (Push) --

Ron Hubbard wrote in news: snipped-for-privacy@l28g2000yqc.googlegr oups.com:

I do have some MN3001 in my garage, do you know the going rate for these?