Echodeck - Quad PT2399 delay/reverb/chorus

[~arph]

This thread is here to keep all information on my latest delay project in one place. There is already some information spread out over various topics. (if you search for binson or look in the pictures thread)
I will be happy to answer all questions here. I'm not sure if I will be releasing a full schematic, because basically, I don't have that yet.

I'll try to do a short write up during the course of this day.

A small preview on what it sounds like:

http://www.youtube.com/watch?v=26lLAmFi5t0

And this is what it looks like.

[Jarno]

Wow! I would be interested to see the schematic, to see how it works.


Heftig ding, Arnoud!

[Zero]

Let me say it sgain in this thread:  Awesome job, man!

I just watched the video.. It sounds really, really cool! 

Dare I make a small cosmetic suggestion? I think you should get some nicer screws arround the rubber buttons--  either black screws or at least some nicer screw-heads. 

[~arph]

Dare I make a small cosmetic suggestion? I think you should get some nicer screws arround the rubber buttons--  either black screws or at least some nicer screw-heads. 

Yes, I plan to do that. I'm still looking for M3 black imbus bolts.. ~25 mm long. Anyone?

[~arph]

Delay section

This is the right hand print you see in the gutshots. This print contains four PT2399 ic's and four quad JFET input opamps
Each delay section is based on the rebote 2.5 except that I dropped all filtering at first and made them allpass stages.
You can see this in the image below. I decided that the delay sections should be in series, to enable individual delay time control.
The other option would be parallel. This would be less noisy, but gives you a shorter max delay time. Now the max delay time is the sum of the max delay times of four stages. Plus it ise easy to get the four quick equally spaced repeats by just setting all head time pots to the minimum.



This turned out to be too noisy, so I added the (rebote) MFB filter at the output of each stage. (in the red square)
You can see them in the pic. They are the four small perfboards hovering over the print
If you look at the rebote 2.5 pdf from tonepad you can see a schematic of the opamp section of the pt2399.
I'm speaking of the filtering after the delay-out node. So the image above is just an indication.

The direct_out line is connected to the input of each subsequent stage. Except of course the first stage taking its input from the clean/feedback mixer.
In the last stage direct_out is not used.

For each delay section there is a buffered output for both playback and feedback. These outputs are fed to the MAX395 analog switch IC and from there to the mixer circuitry

The feedback is mixed in at the input of the first delay stage after some filtering and level control.

The playback signals are mixed and filtered, then fed into a SM2166 set up as a downward expander only (it can compress too, but I set the ratio to 1:1).
This is to surpress all noise when there is no delayed sound present.

I have tried companding around the delay stages too, but that did not improve things much.
The noise I heard sounds more like white noise then high hissing. So any suggestions in this area are welcome.

The left hand print has all signal mixing. The small print stuck to the side is the (sine)modulation LFO (modulating only the first delay stage, interesting options possible here)

The large perf board inside has the arduino on it and a CD4015 SIPO shift register for the LED's. Plus it contains the button detection circuitry (simple voltage divider )

That's it for now. A bit of a messy walkthrough, but I hope it makes sense.

I will start making an improved version. Especially focusing on the delay stages and the power supply. As you can see I have voltage dividers for each delay stage as wel as a 78L05 for each delay stage. I should be able to use the 5V regulated as a Vref there and only use one 78L05 for two PT2399's
This will reduce current consumption a bit ( currently around 160mA !! ).

[soggybag]

Excellent idea, great work. Very inspiring.

[aziltz]

what size box is that?

[KazooMan]

Wow!  Really great pedal.  I have three vintage Echolette tape echos, and the sound of your pedal is pretty darn close to the sound of the '60s machines.

Is this a labor of love, or a potential for profit venture to sell them?  If it's the former I too would love to see a schematic and layout to have a crack at a build.

[jkokura]

what size box is that?

10 bucks says 1590DD. I've used them for projects, and it looks identical in shape and size.

Jacob

[mth5044]

what size box is that?

10 bucks says 1590DD. I've used them for projects, and it looks identical in shape and size.

Jacob

Looks a little deep to be a 1590DD doesn't it? Looks more like a 1590D, similar dimensions but 2" deep.

[Brymus]

Yeah thanks Arph for th erun down.
I hope too you post a final version when you get a chance.

Thats the same vid from the Binson thread isnt it ?
I was expecting a short bit of "Lucifer Sam" 
But yeah sounds very promising,for all us Floyd fanatics. (and time travelers)

[~arph]

The box is the hammond D indeed. I'm still planning on a good PCB design so I can fit it inside a DD.
I listened to that first floyd album for the first time in my life ..erm.. thursday.  It still has to grow on me I guess  
I'll check lucifer sam and see if it can do that sound too.
My favorite band is interpol and they are very delay/reverby too.

[~arph]

This one is for Brymus

http://www.youtube.com/watch?v=qD9kGnulGrw

[Pierre]

man that sounds awesome !!!
...I really need to build this one ! (but I just don't know how )

Please post the pcb and layout (please ! please! please!!!)

Pierre

[quarara]

This is definitely the best effect I've seen on this site in the last year or so.
Great job, ~arph!!

And if you're willing to share... dank je wel! 

[Brymus]

This one is for Brymus

http://www.youtube.com/watch?v=qD9kGnulGrw

Nice !!!
That made my day,thanks Arph !!

[Galego]

I really hope you find the time and will to do a full schematic. I'd really appreciate it 

Great job.

[~arph]

Hi guys,

Yes I'm seriously considering doing a full schem and PCB release. Also I might do a batch of PCB's and sell them here if there is enough interest. Please give me some time as this is the most complex PCB I ever did. Right now the two separate pcbs are single sided with some jumpers, but I'd like to make this double sided so I can fit in the led driver and the lfo.

I will release the schematic first because I also like this boards professional members to have a look at it and point out errors and improvements. It is rather thrown together.

[AudioMime]

I'd buy one! 

[Ry]

I would certainly be up for this build.  I honestly had dreams about it all night  .  Congratulations, you've rekindled my love of diy pedals  .