Skip to content

a blog on effects

Menu
  • Home
  • collection (486)
  • Ibanez (111)
  • Danelectro (53)
  • DOD, Digitech (51)
  • Electro-Harmonix (40)
  • Boss (54)
  • Other Brands (177)
Menu

DOD 280 Compressor

Posted on 15/03/2015 by mirosol

DOD-280-Comp

What is it?
DOD 280 Compressor. Made in USA, 1979.

Late 70’s DOD classic. This particulat unit had mean pumping sound that made it pretty much unusable. So the previous owner had it modded by me. Instead of doing something permanent and killing the heart of the tone with extensive modding, i simply solved the pumping by other means. The box itself, by appearance, would definitely make you think about MXR Dyna Compressor and its big sister, the Ross Compressor. But this assumption would be completely wrong. Even though the box layout is the same, the guts are nothing alike. Dyna and Ross both rely on the OTA, while 280 is an optical design. The schematic can be found by using any internet search engine and there are number of slightly different versions around. You should check them out for yourself, if you’re interested.

Back to the mod. Like i said, the effect was just way too steep to call it even remotely usable. The LDR simply attenuated the attack too much, even when the compression control was set at minimum. The opamp was taking the LDR’s control too heavily, so i figured that the best way to make this more usable was to add a trimmer pot in series with the LED that controls the LDR inside the VTL5C2 Vactrol. I added the trimmer after the 4k7 resistor, leaving this resistor in place. So that once the trimmer was set at minimum, the effect would be exactly like it was before this mod. This simple procedure made the controls a lot better. Maxing the controls can still be too much for most compressor users, but this solved most of the issue. In this session i also swapped a new battery snap to replace the broken one and added a modern standard power jack. After all, it did fit.

DOD-280-Comp-guts

Looking at the guts, this is definitely a beauty. Real heart warming old school manufacturing. The design itself is something that may have been influenced by older Ibanez optical compressors of the seventies. Meaning that the main amplifier takes care of the compression with gain modulation controlled by the output signal. The trigger for the Vactrol is taken care by two transistors and half of a opamp. I’m not convinced that the design is completely copied fromĀ  elsewhere. Knobs on mine do not look like the original ones, but they do look reasonably good here.

Working units of this age always make me feel good. Like everything wasn’t already lost.

How does it sound?
Big and fat. Capable of boosting even the hottest pickups with clean, almost hi-fi definition. While the mod described above makes the attack time range (or depth) of the effect way more usable, the word here would still be – a classic. I think it may have been due to wide availability of OTA chips that killed the optical designs, but nowadays there are several manufacturers doing Vactrol controlled devices again.The OTAs may have been cheaper, but they never did quite catch the behavior of a light controlled circuits. So in all. Amazing box by its design, manufacturing and most important of all – the sound.

There is 2014 released reissue out. I may need to get one someday and compare.

Leave a Reply Cancel reply

Your email address will not be published. Required fields are marked *

/usr/bin/locate

/usr/bin/whoami

here used to be a short description of me. however, it wasn't exactly accurate anymore. so i'm replacing it with this placeholder for now. and yes. it's been a long time since my last post. but let me assure you. i'm very much still alive.

Found an error? One of my assumptions is dead wrong? Something else is just not right? Let me know! Leave a comment to a post, or drop a line to mirosol at kapsi dot fi.

I do mods, repairs and custom builds too. For inquiries, use the email address above.

/var/lib/collection

  • Electro-Harmonix (40)
  • DOD, Digitech (51)
  • Other Brands (177)
  • Boss (54)
  • Danelectro (53)
  • Ibanez (111)

/var/lib/tags

Amp Autowah Bass Boost Booster Chorus Compressor Delay Distortion Echo Envelope Filter EQ Filter Flanger Fuzz Harmony Loop Modulation Noise Gate Octave Overdrive Phaser Pitch Power Preamp Reverb Special/Multi Synthesizer Tremolo Tuner Utility Vibe Vibrato Wah

/usr/lib/comments_recent

  • zix on DOD FX55-B Supra Distortion
  • Ali Imran on Ibanez MF5 Modern Fusion
  • Ali Imran on Ibanez MF5 Modern Fusion
  • Schlunzo on Ibanez MS10 Metal Charger
  • Jefferson on Ibanez MS10 Metal Charger

/var/lib/archives

  • August 2016
  • July 2016
  • June 2016
  • September 2015
  • June 2015
  • May 2015
  • April 2015
  • March 2015
  • February 2015
  • January 2015
  • December 2014
  • November 2014
  • October 2014
  • September 2014
  • August 2014
  • July 2014
  • June 2014
  • May 2014
  • April 2014
  • March 2014
  • February 2014
  • January 2014
  • December 2013
  • November 2013
  • October 2013
  • September 2013
  • August 2013
  • July 2013
© 2025 | Powered by Superbs Personal Blog theme