Electronics Lab Philippines

PT2399 Reverb Kit Build

Offline Super zHero

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PT2399 Reverb Kit Build
« on: April 14, 2020, 01:54:22 AM »
My last night's boredom buster was building a kit that I ordered from eBay last December.  I've had it in my parts drawer since it arrived and was just waiting for the right time to waste on it.  It so happened that last night was the occasion and it was a relaxing moment.

The kit was a digital audio Echo/Reverb based on the PT2399 IC by Princeton Technology Corp.  The IC had been around since the '90s and is presently very popular on eBay and other online electronics boutiques and shops, by itself (IC), as a kit or as a finished unit.

Here's what it looks like:



Offline Super zHero

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Re: PT2399 Reverb Kit Build
« Reply #1 on: April 14, 2020, 01:59:16 AM »
Everything came in in a zip-lock bag.  No paperwork other than the QR sticker.



I scanned the QR code with my phone and it showed a webpage in Chinese.

Offline Super zHero

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Re: PT2399 Reverb Kit Build
« Reply #2 on: April 14, 2020, 02:11:09 AM »
Dimensions and specs:



It has a pre-amp on the Input which uses an NE5532 op-amp.

Offline Super zHero

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Re: PT2399 Reverb Kit Build
« Reply #3 on: April 14, 2020, 09:02:43 PM »
Assembling the kit was easy.  I mentioned that there was no instruction or any paperwork included, most kits now coming from China are like this.  But they make it so simple by printing the values of the components on the PCB instead of designators.  This makes populating the PCB faster.



Offline Ikasamoko

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Re: PT2399 Reverb Kit Build
« Reply #4 on: April 22, 2020, 06:48:42 PM »
how's the sound?

Offline Super zHero

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Re: PT2399 Reverb Kit Build
« Reply #5 on: April 22, 2020, 10:43:16 PM »
All I could say for now is it works from zero to full echo on a small guitar amp.  Kasi I don't have a PA amp to test it at the moment.

Offline Super zHero

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Re: PT2399 Reverb Kit Build
« Reply #6 on: May 03, 2020, 04:18:18 PM »
Time to get back to it.  I found some time today to trace the circuit from scans of the top and bottom of the PCB.


I mirrored the image of the PCB bottom so it will look like an X-ray view from the top.  Much easier to correlate it with the component side.

Offline Super zHero

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Re: PT2399 Reverb Kit Build
« Reply #7 on: May 03, 2020, 06:20:11 PM »
Let's start with the Input section.  It's an NE5532 Op-Amp which voltage comes from a 78L09, TO-92 regulator.  There is a reverse polarity protection diode, the 1N4007.  The supply voltage can be from 12-24Vdc.



So the Op-amp is supplied with 9Vdc.  Please note that in this diagram, the L7809 pins are 3-2-1, pin 3 being the left end with the flat side of the TO-92 facing you.

Offline Super zHero

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Re: PT2399 Reverb Kit Build
« Reply #8 on: May 03, 2020, 06:42:58 PM »
Here is the Input stage of the NE5532:



The Op-amp is single-supplied with 9V and GND.  Pin 3 has half the voltage (4.5V) coming from the 5K6 voltage divider network.  There are two Mic inputs summed up by the 2K2 input resistors to the front of the 10uF capacitor, with 5K6 resistor to GND.

I noticed that there are 10K pull-up resistors (R1 & R2) on each of the Mic inputs which you don't need if you will be using Dynamic Mics.  These will give 5.1Vdc on the Mics if you leave these in the circuit.  I supposed they designed these for "phantom power".

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Re: PT2399 Reverb Kit Build
« Reply #9 on: May 03, 2020, 06:47:47 PM »

Offline Super zHero

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Re: PT2399 Reverb Kit Build
« Reply #10 on: May 03, 2020, 07:48:28 PM »
Here's the rest of the NE5523 circuit, the PT2399 to follow: