Bought this old yamaha LI-01 compression limter. anyone know anything.

[Nyklus]

Bought this old compression for $35 in Cambodia.
yamaha LI-01 compression
it has quite a pop when it's pressed on, figured that could be fixed with a resistor across the switch.
and also.
If you know anything about compressors, based on the chip shown here, maybe you have some sentiments.

[armdnrdy]

The LM358 and the LM4558 shown in the photos are op amps. The compression is created with the LM13600 which is a dual OTA.

So...without seeing a schematic...I would imagine that this would be similar to a CA3080 based compressor.

[armdnrdy]

This Korg LIM-1 looks very similar component wise.

It uses half of the LM13600 which puts it in the class of a 3080 circuit.

[aron]

Nice looking pedal! Good score!

[noisette]

This circuit looks really nice!
With the OTA as ´VC ground´ is it still as noisy as in OTA as VCA circuit? There´s no attenuation before the
compressor...
And could it be used as VCF (for example)? It actually is a vcf.

[noisette]

Did you try a 1M from point A to ground? re:switch pop

OTAs in compressors are usually not your choice for hifi sound, because when they are used as VCA you have to attenuate the signal a lot before them, just to pump it up after the VCA. that kills signal to noise ratio. But in this pedal the OTA is used in another way that I hadn´t noticed before so would be very interested in how it sounds!

Typical OTA compressor, description german, schematics international
http://www.elektronik-kompendium.de/public/schaerer/otalim.htm

[zombiwoof]

First time I've ever seen a JRC 4558"V" opamp, wonder what the "V" denotes as the suffix?.  Usually it's D or DD.  Just something I noticed.  I guess it probably would say in a data sheet, though.

Al

[Mark Hammer]

Larry had the same reflex I did.  You will note that Korg printed circuit boards generally have the prefix "KLM" on this.  Chorus and flanger pedals in the same pedal line, that were made under the Yamaha brand name, were also essentially Korg pedals.  I gather the relationship is a bit like that between MXR and Ross pedals - a near-clone with a tweak here and there.

[Nyklus]

thanks for all the response guys. I'll make a video with the sound of my compresser, with and without a boost.