Anaolgue Delays

[gilgad2000]

I have been looking for ages for a circuit diagram for an analogue delay suitable for use as a guitar fx pedal that doesn't use delay IC's other than the old bog standard op amp I have looked every where with no luck.

Thanks,

Matt.

[cbarrow7625]

Why?

[gilgad2000]

So i can work out how many more fx's work and design my own.

Matt.

[Alex/Tubewonder]

Analog delay ICs are, well...analog

[cbarrow7625]

I'm just not sure what you mean by "analogue delay". As Alex pointed out, the analog delay IC's are analog. What is it that you have in mind? Is there a particular pedal that you know of that you are looking for a schematic of? If you name one I'll bet somebody here has one.

Do you want to create your own discrete component bucket brigade delay circuit? Is that what you are looking for? Again, I would ask why? What is is about that type of circuit that you think is better than the analog bucket brigade chips? How much delay do you want / expect out of the circuit?

I understand it is all about learning how to do it. If you give up some more details with a little more explanation you might be surprised by some of the info other guys here give up that might be useful in your search.

[gilgad2000]

Yes a bucket brigade delay thats what I need to build.

Thanks,
Matt

[Alex/Tubewonder]

Yes a bucket brigade delay thats what I need to build.

Thanks,
Matt

Are you saying you want to build the bucket brigade itself with discrete components, opamps and switches?

A 128 delay cell bucket brigade in its simplest rudimentary form will need at least 256 opamps (2 per cell), 512 switches and a handful of other stuff for clocking, input & output filters etc. You'll need at least 512 cells to get reasonable delay times and signal bandwidth. Well over 1000 opamps.
Even if you build it your chances of success are extremely small, you'll have to battle with switching noise, clocks leaking onto signal, cumulative opamp noise and signal degradation along the line. Not to mention size of the whole thing and current consumption. Assuming money is no object ......

If this is really what you're setting out to accomplish then I'm getting an impression you don't really know what you're getting into.
To get a taste of what is involved try building a high performance Sample & Hold circuit, connect two or three in series and clock them sequencially to achieve delay function.

All of the above doesn't apply if it is an integrated circuit bucket brigade you want use as the heart of an audio delay.

[gilgad2000]

Ok thanks for that it was more of a how do I do this rather than an I am going to do this so now know that maybe using an echo IC would be a better option.

Matt.

[Enzo]

That is why specialized chips like that are designed in the first place. The bucket brigade chip IS a row of stages, they all just are in one package.

[Mark Hammer]

Your smartest move is to use one of the Princeton Technologies digital-delay chips. The Rebote, Rebote 2, and PT-80 delay projects found at the Tonepad and generalguitargadgets websites are time-tested designs that deliver good delay at low cost. More prudent still is to buy yourself a Fab Echo pedal for $20 and mod it to provide variable delay time (stock unit comes with a fixed delay).

Once upon a time there was every reason to want to use BBD chips instead of digital, but in recent years the sound quality of digital all-in-one chips has improved dramatically, as the cost and rarity of analog chips has shot up. The so-called "warmth" of analog delays is, in my view, largely a byproduct of the filtering usually found in them. The same filtering applied to a digital copy of the input signal manages to sound every bit as warm to most ears, and for only a fraction of the cost and heartache.

Go digital. You won't regret it.

[cjlectronics]

With the size of components getting smaller everyday, I'm sure it's possible to put 1024 stages of JFETs and capacitors on a 3"x 3" piece of double sided FR4 to make your own BBD. At least 512 stages...???

CJ

[Alex/Tubewonder]

With the size of components getting smaller everyday, I'm sure it's possible to put 1024 stages of JFETs and capacitors on a 3"x 3" piece of double sided FR4 to make your own BBD. At least 512 stages...???

CJ

Anything is possible if money is no object

[coxster]

the Analog IC you need

I'm with ya on this one. Why buy the digital stuff and try to turn it into analog ( kinda like buying Line 6 modeling stuff to get 'that tube sound' ) I had a DOD analog delay back in 1982 that was THE BEST, and wish I still had it. It used a Reticon SAD 1024 bucket Brigade IC, which is really two 512 stages. It is the IC of all ICs for analog delay. Back then they were $3.99 at Radio Shack. Here's a link to someone else using them

http://mysite.du.edu/~etuttle/electron/elect39.htm

I have an old Ibanez AD80 that I will never part with. For the under 30 crowd, the clean crisp repeats are great for an 'effect' of the non-musical nature if used rarely, but good ol' analog delay is the only way to go for general rock guitar sounds. The lack of hi fidelity is actually welcome, so you're not bombarded with so many crispy repeats. In a stadium, the echos would be lo-fi as well. The first van halen album doesn't have any digital effects, hmmmm.

But on the other hand, a dano fab echo with a 100k pot added will get you a long way, and put a 25k pot from signal out to a .22 mfd cap to ground, and you get a tone control that will load the hi freq out of the delay line and get you that dark tone, but it will darken your guitar too depending on where you us it

Good luck

Coxster
myspace.com/howawesome