Another diode bridge compressor

[richiyobs]

Great build!
Are you using the same meter driver for diode comp?

Edit_ sorry i confused it with the vari mu!

 

[Heikki]

Here’s a sound sample. pumpkineaterdiode.flac has been processed with the diode compressor and pumpkineater.flac has not.

https://drive.google.com/drive/folders/1-BXke8NqWyzh0HN2DIFcmSa_m98N8sZH

 

[scott2000]

Sounds cool!
Some kind of imaging thing happening. Can't quite put my finger on it...almost L/R swap ish in places?.Wearing headphones though..

 

[richiyobs]

Here’s a sound sample. pumpkineaterdiode.flac has been processed with the diode compressor and pumpkineater.flac has not.

https://drive.google.com/drive/folders/1-BXke8NqWyzh0HN2DIFcmSa_m98N8sZH

Great sound!
i like details coming up, nice snap on snare, the bass take some extra growl and better fitted in the mix without loosing presence....
are you pushing it heavy?
best
richi

 

[TwentyTrees]

Oh, that's nice. Lovely density and weight added there. Scott's right that the L/R is flipped in the processed version from the unprocessed, easy enough to sort out in the DAW though.

Colour me interested!

Here’s a sound sample. pumpkineaterdiode.flac has been processed with the diode compressor and pumpkineater.flac has not.

https://drive.google.com/drive/folders/1-BXke8NqWyzh0HN2DIFcmSa_m98N8sZH

 

[Heikki]

I accidentally flipped the channels by having my L/R cables crossed

edit: I uploaded corrected version to the folder.

 

[TwentyTrees]

I accidentally flipped the channels by having my L/R cables crossed

edit: I uploaded corrected version to the folder.

I've done that more times than I can count...

 

[Heikki]

are you pushing it heavy?

I had the attack and release at fastest position, ratio at low and the compression meter needles were barely moving. Since the compression knee is fairly sharp and ratio pretty high even at lowest ratio pushing it heavy will quickly end up sounding way too compressed.

 

[richiyobs]

One thing I noticed in common with my proto is the ability to excite details in the upper range... But I m still using it in mono so can t really judge... Even at faster setting is not destroying the sound... Also not compressing the output is better than the original source... Better transients
Best
Richi

 

[Heikki]

Almost done building another one. I made few minor changes to this one. I also decided to try Monacor LTR-110 transformers at the output. LTR-110 seems to be surprisingly good transformer for the price.
http://www.ghr.fi/proaudio/diodecomp/comp1.pdf

 

[Heikki]

Couple pictures of the finished build.

 

[Script]

Always big cases, so spacious, just like nature in Finland, awe

Is that LEDs behind those VUs?

 

[Heikki]

I glued LEDs behind the meters to make them glow.

 

[Script]

What does the Monacor LTR-110 add to the output sonically ? FQ response of that transformer looks quite flat on paper. Picked up a pair for cheap, but not sure worth implementing.

Also, pins 4 and 5 of that xfmr would be unused. Good for hooking up an LED indicator...? Any other use ?

And would hooking pin2 and / or pin7 to ground make much of a difference?

 

[abbey road d enfer]

What does the Monacor LTR-110 add to the output sonically ? FQ response of that transformer looks quite flat on paper.

It's a quite small core, so it will probably start to saturate early; you can expect some 3rd-order THD.

Also, pins 4 and 5 of that xfmr would be unused. Good for hooking up an LED indicator...? Any other use ?

It's a secondary output. You may use it as such or hook it to anything, as long as you don't load it unduly.

And would hooking pin2 and / or pin7 to ground make much of a difference?

Compared to what? Certainly you can't drive the primary between 1 and 3 and ground pin 2. You could drive the primary between 2 and 3, for 6dB additional gain, but the frequency response may suffer because of the reduced coupling. Grounding pin 7 should make very little difference, but you would ruin CMRR.

 

[Script]

Quite small xfmr (core) indeed. Not a huge fan of 3rd-order THD. Might still give it a try.

Sure don't need a secondary output for LED indicator. Any other hint what it could be used for ?

 

[Heikki]

At high output levels there will be significant distortion at low frequencies with LTR-110. If I remember correctly I think I measured several % THD at 20 Hz at +20 dBu output level. When playing music through the compressor I can't hear a difference with or without the transformer.

 

[Script]

Can the standalone diode bridge be retrofitted with this DC balancing ? Would different resistor values be needed ?

 

[Bo Deadly]

Also, pins 4 and 5 of that xfmr would be unused. Good for hooking up an LED indicator...? Any other use ?

The extra winding might be used to make a negative impedance converter driver. That could improve the thd and bandwidth by quite a bit. But NIC drivers are very sensitive so a lot of experimenting and testing would be necessary to even see if it would work correctly and be stable. And even though it would only be a few parts, one would have to be a trimmer I think.

Or it could just be used for feedback which should also improve thd and bandwidth.

 

[abbey road d enfer]

Can the standalone diode bridge be retrofitted with this DC balancing ? Would different resistor values be needed ?

Do you suggest driving the bridge control current from two inverted sources?
If you do that, you have to remember that GR is directly related to the DC current, so if you use balanced control voltage sources, you have either to halve the voltage or (roughly) double the series resistors.