GDIY passive 'Mojo' box

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I built a prototype of something similar a short while ago. Spent many happy hours listening to diodes...

The final results were really good but it needs a PCB to bring build time down to a reasonable level

https://www.bn1studio.co.uk/shop/compressors/stereo/grasshopper-valley-yellowhammer/

Nick Froome
 
pvision said:
I built a prototype of something similar a short while ago. Spent many happy hours listening to diodes...

The final results were really good but it needs a PCB to bring build time down to a reasonable level

https://www.bn1studio.co.uk/shop/compressors/stereo/grasshopper-valley-yellowhammer/

Nick Froome

if you are happy to release the schematic then  I am happy to create a PCB.

Cheers

Ian
 
pvision said:
I built a prototype of something similar a short while ago. Spent many happy hours listening to diodes...

The final results were really good but it needs a PCB to bring build time down to a reasonable level

https://www.bn1studio.co.uk/shop/compressors/stereo/grasshopper-valley-yellowhammer/

Nick Froome

It's looking good.
 
Here are my two cents...
I copied the "Mojo Maestro" with some small adjustments.
I added 2 rotary switches for a diode selection and a rotary switch for the Mojo mode which allows you to switch through different caps.



Found a nice solution to hook up different diodes:
http://diy-fever.com/misc/flexi-clip/
And a listening test to different types:
https://m.youtube.com/watch?v=bifKfe04TBc
 

Attachments

  • GDYMojo.pdf
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gyraf said:
..for experimentation (and yes, this requires massive amounts of experimentation), it's probably easier just to solder directly to the switches?

Yes, for sure. Breadboard and some cables are absolutely fine for beginning.
I only made the board because it was fast and to get a feeling for the size and layout.
 
Great idea, Ian!

As for the linear approach, I really like the DIYRE 15 IPS Tape Saturation Colour: Clipping germanium diodes and a low end roll-off/bump meant to mimic the sound of analog tape. I use it all the time... not sure it actually does sound like tape but I'm a sucker for germanium diode distortion...  ;D

As for transformer saturation, the Neve Silk stuff is amazing. There's an intersting analysis here: http://koo.corpus.cam.ac.uk/rnd-portico-schematic/

/Rasmus
 
rbuskov said:
Great idea, Ian!

As for the linear approach, I really like the DIYRE 15 IPS Tape Saturation Colour: Clipping germanium diodes and a low end roll-off/bump meant to mimic the sound of analog tape. I use it all the time... not sure it actually does sound like tape but I'm a sucker for germanium diode distortion...  ;D

I really like the 15 IPS module myself. I think it's the most usable one. But I like the older one better than the latest newest design.
 
Ricardus said:
I really like the 15 IPS module myself. I think it's the most usable one.

Agree.

Here's a demo of all the Colour modules from DIY RE:

https://www.youtube.com/watch?v=nbrqXS5VjTA&feature=emb_rel_end

Some are definitely more usable than others.
 
rbuskov said:
Agree.

Here's a demo of all the Colour modules from DIY RE:

https://www.youtube.com/watch?v=nbrqXS5VjTA&feature=emb_rel_end

Some are definitely more usable than others.

Indeed, the DIY RE stuff looking really good.
But in this case it’s not a passive circuit for passive box.
 
wlinart said:
Mammoth cave audio did some things like that. Here is the description, maybe there's some inspiration to get there: https://web.archive.org/web/20160219215310/http://mammothcaveaudio.com/passive-aggressive-series/

That one is an active box. I have built quite a few of these in the last decade. Basically one of my standard tube amps with input and output controls so you can set the amount of tube/transformer overdrive and then tame the output level.

I was hoping we could do a passive only device - saves loads of problems with power supplies and so on.

Cheers

Ian
 
ruffrecords said:
That one is an active box. I have built quite a few of these in the last decade. Basically one of my standard tube amps with input and output controls so you can set the amount of tube/transformer overdrive and then tame the output level.

I was hoping we could do a passive only device - saves loads of problems with power supplies and so on.

Cheers

Ian

The device got a misleading name then  ;D I would prefer a passive device too, so i'll watch this thread with much interest
 
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