Something I've been meaning to do for a long time, but forgot 'till just now...

[Skreddy]

I want to 'speriment with a cheap-ass, tiny little audio transformer (you know, the RadioShack kind) in a PT2399 delay to see if it does anything like a tape-head emulator.  I'll report back with results later tonight.

That is all.

[John Lyons]

Should cut the bottom and the top off the signal. Might sound cool!
John

[tommy.genes]

I've been thinking about putting my Boss DD-2 and/or my Ibanez DML-20 into bigger boxes to give myself more room for all the delay mod ideas I've collected. I was thinking of combining a gain stage, a diode soft clipper and a variable low or band pass filter to try to emulate tape. I'd be very interested to see if the transformer gives similar results with fewer components. Although I'm guessing you would still need a gain stage to saturate the transformer.

Please do keep us posted.

-- T. G. --

[zachomega]

I'd love to know about this...I have a couple of pt2399's that I haven't done anything with since I couldn't decide which effect I was going to build.  That reminds me, anybody know of any none IC based echo's with the pt2399?  Yes I realize the PT2399 is an IC itself.  Here's to hypocrisy!

-Zach Omega

[Skreddy]

I've been thinking about putting my Boss DD-2 and/or my Ibanez DML-20 into bigger boxes to give myself more room for all the delay mod ideas I've collected. I was thinking of combining a gain stage, a diode soft clipper and a variable low or band pass filter to try to emulate tape. I'd be very interested to see if the transformer gives similar results with fewer components. Although I'm guessing you would still need a gain stage to saturate the transformer.

Please do keep us posted.

-- T. G. --

We'll see.  My layout is plenty spacious at this point, and it won't be that hard to add in a transistor if need be.  Since the digital chip only runs on 5v, I can see how adding a transistor might be needful if I want a huge signal swing going into the transformer.  I'm not necessarily looking to saturate it--just curious how it sounds in linear mode, though.  I just want to "soften" the sound a little, make it blurry, squishy, less distinct.  The tiny transformer I'm thinking about may just do too good a job, though.  Might be a good candidate for a dpdt switch (capacitor/transformer coupling) in that case...

[Skreddy]

I'd love to know about this...I have a couple of pt2399's that I haven't done anything with since I couldn't decide which effect I was going to build.  That reminds me, anybody know of any none IC based echo's with the pt2399?  Yes I realize the PT2399 is an IC itself.  Here's to hypocrisy!

-Zach Omega

The only thing the other IC does (leaving out the compressor/expander versions) is buffer the signal.  Just substitute your favorite discrete transistor buffer where you see the input and output IC stages in a schematic.

[zachomega]

Here is the thing though...I have heard some people complain about the noise of the pt2399...Do you think that amplifying the signal a small amount could help with the signal to noise issues people are having? 

-Zach Omega

I'd love to know about this...I have a couple of pt2399's that I haven't done anything with since I couldn't decide which effect I was going to build.  That reminds me, anybody know of any none IC based echo's with the pt2399?  Yes I realize the PT2399 is an IC itself.  Here's to hypocrisy!

-Zach Omega

The only thing the other IC does (leaving out the compressor/expander versions) is buffer the signal.  Just substitute your favorite discrete transistor buffer where you see the input and output IC stages in a schematic.

[Skreddy]

Here is the thing though...I have heard some people complain about the noise of the pt2399...Do you think that amplifying the signal a small amount could help with the signal to noise issues people are having? 

-Zach Omega

No.

First of all, the chip is not noisy.  It distorts when you try to get more than ~330ms out of it.  Not the same thing at all. 

Boosting the signal into something with such low headroom isn't the best solution.  You only have two ways to go: either use it for short delays only or else add an extra pole or two of filtering at the output to deal with the distortion--which sounds a lot like "hiss" but isn't noise per se.

[zachomega]

Other than for the sake of the battery, what is to stop somebody from chaining two or more of these things together to achieve a longer delay and yet relatively distortion free signal? 

Skreddy, thanks for bearing with me here.  I'm not only an IC noob, but and echo noob to boot. 

-Zach Omega

Here is the thing though...I have heard some people complain about the noise of the pt2399...Do you think that amplifying the signal a small amount could help with the signal to noise issues people are having? 

-Zach Omega

No.

First of all, the chip is not noisy.  It distorts when you try to get more than ~330ms out of it.  Not the same thing at all. 

Boosting the signal into something with such low headroom isn't the best solution.  You only have two ways to go: either use it for short delays only or else add an extra pole or two of filtering at the output to deal with the distortion--which sounds a lot like "hiss" but isn't noise per se.

[Skreddy]

Other than for the sake of the battery, what is to stop somebody from chaining two or more of these things together to achieve a longer delay and yet relatively distortion free signal? 

Skreddy, thanks for bearing with me here.  I'm not only an IC noob, but and echo noob to boot. 

-Zach Omega

Here is the thing though...I have heard some people complain about the noise of the pt2399...Do you think that amplifying the signal a small amount could help with the signal to noise issues people are having? 

-Zach Omega

No.

First of all, the chip is not noisy.  It distorts when you try to get more than ~330ms out of it.  Not the same thing at all. 

Boosting the signal into something with such low headroom isn't the best solution.  You only have two ways to go: either use it for short delays only or else add an extra pole or two of filtering at the output to deal with the distortion--which sounds a lot like "hiss" but isn't noise per se.

It's a fine idea, actually and one I've considered myself.  But I think I'd probably rather just go over to the older, bigger version, the PT2395, which uses an external dram chip (preferably 256k, not 64k or why bother), for 800ms of clean delay.

[zachomega]

I saw those chips but they looked considerably more complex to work with.

Also I had the idea of chaining the two chips and then tapping them for example:

Chip 1 feeds Chip 2 and it loops back into itself.

Chip 2 is the output and it loops back into itself and back into chip 1. 

It would be a complex signal, but might make the echo come closer to a reverb if the two delay times were set differently.  I don't know how practical this is as an idea, but it is just something I pondered.

-Zach Omega

Other than for the sake of the battery, what is to stop somebody from chaining two or more of these things together to achieve a longer delay and yet relatively distortion free signal? 

Skreddy, thanks for bearing with me here.  I'm not only an IC noob, but and echo noob to boot. 

-Zach Omega

Here is the thing though...I have heard some people complain about the noise of the pt2399...Do you think that amplifying the signal a small amount could help with the signal to noise issues people are having? 

-Zach Omega

No.

First of all, the chip is not noisy.  It distorts when you try to get more than ~330ms out of it.  Not the same thing at all. 

Boosting the signal into something with such low headroom isn't the best solution.  You only have two ways to go: either use it for short delays only or else add an extra pole or two of filtering at the output to deal with the distortion--which sounds a lot like "hiss" but isn't noise per se.

It's a fine idea, actually and one I've considered myself.  But I think I'd probably rather just go over to the older, bigger version, the PT2395, which uses an external dram chip (preferably 256k, not 64k or why bother), for 800ms of clean delay.

[Skreddy]

I saw those chips but they looked considerably more complex to work with.

Also I had the idea of chaining the two chips and then tapping them for example:

Chip 1 feeds Chip 2 and it loops back into itself.

Chip 2 is the output and it loops back into itself and back into chip 1. 

It would be a complex signal, but might make the echo come closer to a reverb if the two delay times were set differently.  I don't know how practical this is as an idea, but it is just something I pondered.

-Zach Omega

It's a great idea.  You should run with it.  Sure there'll be a lot of knobs, unless you hard-wire some of the paths or whatever.  But it sounds perfectly feasible.

Maybe you should start with a single version and get to know it and tweek it to your liking, then deal with the dual, multitap version.  And forget about battery power. 

[zachomega]

haha...It is a great idea if it works.  I'm hoping somebody will chime in on this thread and "steal" the idea...as long as they share the schematic with me.    

-Zach Omega

I saw those chips but they looked considerably more complex to work with.

Also I had the idea of chaining the two chips and then tapping them for example:

Chip 1 feeds Chip 2 and it loops back into itself.

Chip 2 is the output and it loops back into itself and back into chip 1. 

It would be a complex signal, but might make the echo come closer to a reverb if the two delay times were set differently.  I don't know how practical this is as an idea, but it is just something I pondered.

-Zach Omega

It's a great idea.  You should run with it.  Sure there'll be a lot of knobs, unless you hard-wire some of the paths or whatever.  But it sounds perfectly feasible.

Maybe you should start with a single version and get to know it and tweek it to your liking, then deal with the dual, multitap version.  And forget about battery power. 

[Processaurus]

Skreddy, very cool.  I love the idea of combining space age technology with the 1930s.

Hey, how would it sound to make a tapeless delay with a walkman and one of those CD player tape adaptors?  

tommy genes, I popped the hood on my DD2 and did some things to it, one was to add a jack for an effects loop, but the trick was that not just the wet, but the regeneration has to cycle through the loop.  I've been getting some outstanding sounds with different pedals in the loop, you can get a normal to ridiculous caricature of tape delay with a EQ or wah (my fav is my mu-tron knockoff, with the dry guitar hooked into the envelope follower, the delay will start to self oscillate on the peak frequency when you're playing, and then when you stop it sweeps down and kills the regeneration!)here's partly how to do it if there's interest I could write up a little thing, its easy to figure out though, looking at the schematic.  

[tommy.genes]

tommy genes, I popped the hood on my DD2 and did some things to it...

I've already done the hi-cut on the regen path, added the external regen loop, and tried to add a "tails" switch similar to the Line 6 Echo Park. That didn't work the first time, but I think I know how to do it now. I am also interested in the stutter mod you came up with on the other thread. Beyond that, I want to try something like the "slam" switch of the SIB Mr. Echo. And I want an expression pedal jack for just about every knob, and an LFO to modulate the delay time and...

You can see why I'm starting to need more space.

-- T. G. --

[Skreddy]

I couldn't find the transformer I was thinking about using.  So I used an inductor from a bag I picked up the other day on a whim.  It's a little 15uH inductor--looks kinda like a resistor.  Anyhow I put it into the path after a resistor between the chip's delay out (pin 12) and the input the the chip's LPF2 (pin 13).  The low-passed signal from pin 14 then continues on to the regen and mix pots (along with a couple extra poles of low-pass filtering on the way).

The inductor worked perfectly; it got rid of that last bit of "hiss" without killing any needful treble.  So I can clock this PT2399 chip all the way down to almost half a second delay and still sound decent.  It's taken me like a couple of months of trial and error to get the filters and levels just right so it sounds as close to a tape delay as possible.  Not as dark as an analog delay and not as bright as a typical digi delay.  Plus I added modulation for tape warble.  Nothing sounds as good as adding a bit of tremolo-bar modulation to clean chord going into a longish repeating echo for a spacious chorus sound, but the tape-warble function can be set to a decent frequency and subtlety to get something kind of close.

[runmikeyrun]

Skreddy, very cool.  I love the idea of combining space age technology with the 1930s.

Hey, how would it sound to make a tapeless delay with a walkman and one of those CD player tape adaptors? 

tommy genes, I popped the hood on my DD2 and did some things to it, one was to add a jack for an effects loop, but the trick was that not just the wet, but the regeneration has to cycle through the loop.  I've been getting some outstanding sounds with different pedals in the loop, you can get a normal to ridiculous caricature of tape delay with a EQ or wah (my fav is my mu-tron knockoff, with the dry guitar hooked into the envelope follower, the delay will start to self oscillate on the peak frequency when you're playing, and then when you stop it sweeps down and kills the regeneration!)here's partly how to do it if there's interest I could write up a little thing, its easy to figure out though, looking at the schematic. 

I have a pt-80 that i built and am always looking for ways to make some insane noises.  IF you could could outline how to put this effects loop into my pt-80 that would be AWESOME!!!

[tommy.genes]

I did it on a DD-2, but looking at the PT-80 schem shows that the same idea will work there.

Notice how the delayed signal comes off pins 6 & 7 of the compander (SA571), through the 50k REPEATS knob, through some RC filtering and then back into the other half of the compander on pins 12, 14 & 15. That is the feedback path. You just need to place a "switching" or "normally closed" JACK, like in Aron's store, in that path. When nothing is plugged into that jack, the feedback flows normally. When a stereo insert cable is plugged into the jack, you can rout the feedback through other effects on its way back into the delay.

You could also do this with two mono jacks if you don't want to mess with a stereo "Y" cable. Just use a normally closed jack on the return.

My family is waiting for me to come upstairs, but if you still have questions, maybe I could draw a little diagram in the next day or two.

-- T. G. --

[runmikeyrun]

ok, i think i got it, i'll print it out and see what happens... if you don't get a PM from me then i have figured it out!!  Thanks so much this sounds like an awesome mod.