PT2399

Ahhh yes! 😎 The PT2399 — the little magic chip that makes echo, delay, and reverb pedals tick. If you’re into audio effects or DIY guitar pedals, this IC is basically the bread and butter of digital delay circuits 🎸✨

📦 PT2399 – Product Description

The PT2399 is a low-cost, digital echo/delay IC that uses a digital delay line to create:

Delay effects

Echo effects

Reverb-like sounds

It’s designed for consumer audio, guitar pedals, karaoke machines, and small audio processors.

Key thing: it digitally delays the input signal, then outputs it so you can mix it back with the original for that spacious, repeating effect.

✨ Key Features

✅ Digital delay IC for audio
✅ Adjustable delay time (~30ms – 340ms typical)
✅ Very low external component count
✅ Single +5V to +15V operation
✅ On-chip ADC and DAC
✅ Low cost & easy to use
✅ Good for DIY audio effects

📊 Electrical Specifications
Parameter Typical / Max Value
Supply voltage 4.5 – 5V (5V typical), some designs use 5–15V
Quiescent current ~10–15 mA
Delay time 30 ms – 340 ms (adjustable with external resistor/capacitor)
THD ~0.1–0.3% (clean enough for guitar)
SNR ~80 dB
Input level 0.5 – 2 Vpp
Output Buffered analog audio
Package DIP-16 or SOIC-16
Temp range 0°C – 70°C
🔌 Pinout (DIP-16)
PT2399
┌───────────┐
1 VSS VDD 16
2 GND C1 15
3 C2 VCO 14
4 RSET IN- 13
5 IN+ OUT 12
6 IBIAS AGND 11
7 VREF MIX 10
8 NC NC 9
└───────────┘

Pin functions in brief:

IN+ / IN- → audio input

OUT → audio output

RSET / C1 / C2 → control delay time

MIX / VREF → mix delayed and original signal

VDD / GND → power supply

⚙️ How it Works (Simple Concept)

Audio enters the IC

PT2399 converts it to digital

The digital delay line holds the audio for a set time

DAC converts it back to analog

Mix the delayed signal with the original → “echo/delay”

You can adjust delay time using resistors and capacitors connected to the timing pins.

🛠️ Typical Applications

Guitar delay pedals 🎸

Echo units & karaoke effects 🎤

Small audio processors

Reverb/echo in keyboards

DIY DIY sound effect boards

💡 Design Tips
✅ Power supply

Use clean 5V DC. Noise in power causes hum in output.

✅ Capacitors

Timing caps set delay — larger → longer delay.

✅ Output mixing

You usually mix delayed + dry signal with a resistor network.

✅ Low noise

Keep input short, ground well.

✅ Quick Summary

PT2399 = affordable digital delay IC for audio

Perfect for:
✔ DIY guitar pedals
✔ Echo/reverb effects
✔ Small audio processors