What is it?

SPB-2xPT2399 is a stereo reverberation sound effects board. It supports stereo analog signal input/output and can adjust reverberation parameters.
SPB is a standardized stereo analog audio signal processing card designed by me. I usually use some retro sound effect chips to make this kind of sound effect processing card, such as TDA1524, YSS247, PT2399, NJM2150 and so on. The design style is based on the RE:Birth series of modular sound cards.
The SPB series sound boards usually need to be used with a sound motherboard, because many retro chips require ±12V power supply.

Why did you make it?

Many open source synthesizer projects use PT2399 as a reverb chip, which is low-cost but very effective. However, PT2399 only supports mono reverb, so I use two PT2399s for stereo reverb, which works very well.

What makes it special?

I included two potentiometers to adjust the reverb time and self-feedback depth.
Note that the reverb board will make the sound blurry, so it needs to be placed at the front of the serial audio bus, which is the SB1 position on the SEB motherboard.