Monday 15 May 2023

DOD Compressor 280

 Yet another compressor, this time an optical one. The specified vactrol is quite expensive and hard to get hold of nowadays but you can roll your own using a LDR with 1M dark resistance and green diffused LED.

Demo by Ian!

 



20 comments:

  1. Please add the Demeter Compulator. I think it's based on the DOD 280, but better

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    1. I tried building the Demeter on the Tag blog. The circuit seems to insist upon a specific vactrol that I don't have. I tried lots of combinations but never got it right. You might have more luck than I did. Check out the layout on TagboardFX.

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    2. I built it on a self etched pcb. But I don't remember, where the layout came from and what vactrol U used. I sold the pedal years ago, but regretted it later.

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    3. I think that was the one that Gilmour was using most recently, right? I liked the simplicity of it. I tend to prefer the optical compressors. There are a lot of nice ones.

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  2. We want a Fat General! We want a Fat General! .... c'mon guys feel free to join in ...

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    1. #Orion Tonehunt: I remembered that you were interested in the Thorpyfx compressor. It looked interesting to me too. Stumbled upon a layout from a sister site today. I haven't gotten a chance to try it yet but I thought you might be interested.
      https://vero-p2p.blogspot.com/search?q=fat+general

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    2. Good looking out, Tom! Many thanks. I'll definitely give this a shot!

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  3. +100 for the ThorpyFX Fat General!!! Schematic: PedalPCB, General Tso’s Compressor

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  4. T-t-t-tag it!!! Made my vactrol with a juried engineer gl5516 and after a little trial, I settled on a 5mm blue diffused LED. I like c500k better for the comp. Nice and squishy at high settings, different flavor from a dynacomp. Pretty good for a low part count comp.

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  5. Ok...I'm keen to make a working compressor... quick question on the orientation of the LED...which column is plus and minus (sorry
    - I should probably be able to read the symbol)

    Also, Mr tonehunt, what transistors did you use because I see 2n3904 as a mid gain transistor (around 350) and 2n5088 as a high gain transistor (usually around 500 to 600 which I usually substitute for mpsa18) due to difficulty sourcing 2n5088. Any advice is gladly appreciated

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    1. https://commons.m.wikimedia.org/wiki/File:LED_symbol.svg

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    2. Positive leg to top column. I made mine with 3904s from Tayda, but I'm not sure if their hfe. The gl5516 photo resistor I'm using is only 500k dark, so I ordered a batch of gl5528 for the appropriate 1M dark. I'm probably leaving a little action on the table which might be why the c500k was more pleasing.

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  6. That's great. Thank you. I have the right ldr from the magnavibe.

    Cheers

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  7. Here it is!

    https://youtu.be/S3eDC9Bcqtg

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  8. I built this pedal and I really liked the result

    LDR 5528 + green diffused LED 5mm.

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