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Joyo - JF-10 Dyna Compressor (Ross compressor) [schematic]
Posted: 04 Sep 2021, 22:26
by Bernardduur
Hi all!
Got this pedal cheap as it 'didn't work' ==> turned out that the LED resistor was loose. The pedal works fine, just the LED didn't work.
The schematic:
As you can spot it is a Ross Compressor clone; as I marked in RED the changes they made to the schematic. These changes don't sound really good...... my unit was really bright and 'Boring' sounding!!
EnjoY!
Re: Joyo - JF-10 Dyna Compressor (Ross compressor)
Posted: 04 Feb 2024, 14:50
by rsasgtr
I got one of those in order to mod it. There is one significant change that's not marked explicitly in the schematic. The 'attack' pot is only 100k (92k in mine, when measured), while the original Ross/Dyna has a 150k resistor there.
Anyways, I replaced C44 with a 1nF cap, R72 with a 15k resistor, and I pulled one of the legs of 'attack' up and put a 68k resistor between it and the PCB. After the changes, the compressor sounds nice and squishy, similar to Dyna and Ross samples e.g. on YouTube.
IMO if you can get this compressor for cheap (e.g. I got mine for ~25 EUR/USD), it's totally worth it. It has true bypass, and it's easy to mod, since it's not SMT. In addition, unlike the one above, mine has a DIP8 socket, so I might try different chips at some point.
Re: Joyo - JF-10 Dyna Compressor (Ross compressor)
Posted: 20 Mar 2024, 14:39
by SwedishWings
rsasgtr wrote: ↑04 Feb 2024, 14:50
I got one of those in order to mod it. There is one significant change that's not marked explicitly in the schematic. The 'attack' pot is only 100k (92k in mine, when measured), while the original Ross/Dyna has a 150k resistor there.
Anyways, I replaced C44 with a 1nF cap, R72 with a 15k resistor, and I pulled one of the legs of 'attack' up and put a 68k resistor between it and the PCB. After the changes, the compressor sounds nice and squishy, similar to Dyna and Ross samples e.g. on YouTube.
IMO if you can get this compressor for cheap (e.g. I got mine for ~25 EUR/USD), it's totally worth it. It has true bypass, and it's easy to mod, since it's not SMT. In addition, unlike the one above, mine has a DIP8 socket, so I might try different chips at some point.
Just tried this mods and it was a huge improvement! This pedal used to be in the box because it was too lame, but after this its like a new pedal that sounds awesome.