PT2399 Echo Delay Reverb Processor IC

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ruffrecords

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Nov 10, 2006
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I just  bought a couple of these on a whim for £1.59 including shipping. Looks like a nice little digital delay line, could be good for those 50s tape delay effects. Anyone used them?

Cheers

Ian
 
They are ubiquitous in guitar effects, DIY and commercial. There are also non-original parts around, your low price could suggest you have these. They generally perform the same but have been reported to have lower SNR sometimes.

This is a well designed project using the IC. Many others don't include the compander IC, which helps reducing the noise. But there are dozens of variations around, combining two or more ICs for longer delay, different filters to mimic particular analog delays, etc.
 
Honestly I don't know why anyone would bother with a chip like that anymore. The latest digital delay guitar pedal has amazing specs. It's just not that hard or expensive to put an ADC, DAC, pic and some RAM on a PCB and get near perfection.
 
I bought 10x PT2399 to do build the Echo Rocket found on this page http://musicfromouterspace.com/index.php?MAINTAB=SYNTHDIY&PROJARG=ALIENSCREAMER/ALIENSCREAMER.php&VPW=1670&VPH=790. 
I bought the pcb from a site to raise money for the designer Ray Wilsons treatment when he got cancer.    It is quite an "out there" effect.

Since I had a bunch of chips left over I built one of these https://shop.pedalparts.co.uk/Echo_Blue_Delay/p847124_8651062.aspx
That pedal is really good especially since it costs hardly anything.  You can get some great Duane Eddy type sounds.  It's not really hifi, but for guitar effects it's really good IMHO. 

SInce I still had a load of them left I bought this pcb https://www.ebay.co.uk/itm/Build-your-own-guitar-effects-pedal-ABDUCTOR-II-DELAY-PCB-Deadastronautfx/254220923143?hash=item3b30bf7107:g:3w4AAOSwaA5WjmPZ to use another 3 of them up, but currently haven't finished it.

There are plenty of other DIY prjects for it of varying complexity too.    It's a great chip & easy to implement, but not particularly hifi.
 
I’ve used them in various guitar delay pedals. My favorite would be the old “Echo Base” project which sounds a lot like a Deluxe Memory Man
 
I have also used them in guitar delay reverb applications. Installed one in a custom amp as well. I think my favorite design was 'ancestral apparition' at guitarpcb.  My violinist uses one in the set up I built for her with very light settings but I can't imagine not using it.
 
Rocinante said:
I have also used them in guitar delay reverb applications. Installed one in a custom amp as well. I think my favorite design was 'ancestral apparition' at guitarpcb.  My violinist uses one in the set up I built for her with very light settings but I can't imagine not using it.
Whilst exploring the the ancestral apparition at guitarPCB I discovered it also uses an Accu Bell digital reverb module. A quick trip to the Accu Bell web site revealed a US patent number US08204240. Browsing through the figures of the patent you eventially discover a schematic which uses three PT2399 chips!!

The patent looks pretty smart to me. Anyone have any experience of these modules for reverb?

Cheers

Ian
 
ruffrecords said:
Whilst exploring the the ancestral apparition at guitarPCB I discovered it also uses an Accu Bell digital reverb module. A quick trip to the Accu Bell web site revealed a US patent number US08204240. Browsing through the figures of the patent you eventially discover a schematic which uses three PT2399 chips!!

The patent looks pretty smart to me. Anyone have any experience of these modules for reverb?

Cheers

Ian
I’ve used Belton Bricks. The reverb has modulation which I don’t like. It sounds like reverb and chorus
 
ruffrecords said:
Whilst exploring the the ancestral apparition at guitarPCB I discovered it also uses an Accu Bell digital reverb module. A quick trip to the Accu Bell web site revealed a US patent number US08204240. Browsing through the figures of the patent you eventially discover a schematic which uses three PT2399 chips!!

The USPTO does not recognize that number but does recognize this... US8204240B2

The maths to make reverb are well studied and it seems remarkable that somebody could patent this in this century but the more "ifs and ands" in the claim the easier it is to argue novelty.

The classic work IIRC was by Schroder(?) who wrote a paper called "colorless reverberation(?)"  where he described the benefit of combining mulitple discrete delays in feed forward and feedback combinations.  I was surprised (or not) to not see it referenced by the patent.  ::)

OK, you made me look... https://ccrma.stanford.edu/~jos/pasp/Schroeder_Reverberators.html

The original Schroeder paper was apparently published in 1961...

JR
The patent looks pretty smart to me. Anyone have any experience of these modules for reverb?

Cheers

Ian
 
JohnRoberts said:
Um that is what I just said?? 

Maybe fix the patent number in your earlier post that was not found because it lacked the B2?

I already found it.

JR

OK. The number I quoted was just the US Pat number printed on the device (no B2). I just searched for the number and the link I quoted was  the first hit and included the B2. Apologies if that confused anyone.

Cheers

Ian
 
Fuzz Face said:
Isn’t it what you’re talking about?

http://www.accutronicsreverb.com/main/?skin=sub01_05_1.html

Yes, you are right. I thought of them as Accutronics  the one I was looking at had that on the front but it seems they also put Beltron on the front instead on some models. Duh?

Cheers

Ian
 
ruffrecords said:
Yes, you are right. I thought of them as Accutronics  the one I was looking at had that on the front but it seems they also put Beltron on the front instead on some models. Duh?

Cheers

Ian
It’s odd that they have multiple names. I’ve just always known them as “Belton bricks” on the forums

At any rate, I don’t think the sound quality is up to the standard of your mixers. The modulation really gives it an unnatural sound. It is great for some things but not an every day reverb for me

I would rather use a Spin FV-1 personally, but I don’t know what newer parts are out there these days
 
Belton bought Accutronics a while back. They use both brands as they see fit.

The PT2399 is a simple one-chip solution for reverb in Karaoke machines. Better reverb is certainly possible, but the users are all drunk, who cares? The guitarists use them but it isn't such a good fit.
 
Fuzz Face said:
It’s odd that they have multiple names. I’ve just always known them as “Belton bricks” on the forums

At any rate, I don’t think the sound quality is up to the standard of your mixers. The modulation really gives it an unnatural sound. It is great for some things but not an every day reverb for me

I would rather use a Spin FV-1 personally, but I don’t know what newer parts are out there these days
Yes, I have ba spin FV-1 waiting for me to get round to it also.

Cheers

Ian
 
PRR said:
Belton bought Accutronics a while back. They use both brands as they see fit.

The PT2399 is a simple one-chip solution for reverb in Karaoke machines. Better reverb is certainly possible, but the users are all drunk, who cares? The guitarists use them but it isn't such a good fit.
To be fair the PT2399 itself tends to sound pretty good. Not really for reverb but for echo/delay. The delayed signal is dark and lofi, which works well to keep repeats from obscuring the dry signal

To me it sounds more like BBD delay than tape delay
 
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