Anyone built a 'What Compressor'?

[tony dB]

start in Belgium?
Could be your European distributioncenter :guinness:

 

[Greg]

hey Fabio:

You could move to New Orleans... The bars never close here. But I will admit New Orleans is a black hole, and you never be able to leave.

 

[Bauman]

bars that never close? uuh, this is dangerous :twisted:

 

[Mendelt]

By the way. Is anyone familliar with this design?

http://www.geocities.com/m_natsume/what_compressor.html

It seems to be a variation on the what compressor but with 5532's in the audio path, an attack, release and ratio control and without the double release.

 

[clintrubber]

bars that never close? uuh, this is dangerous

Dangerous, tell us about it... I mean, what about this place ? :wink:

 

[matta]

By the way. Is anyone familiar with this design?

http://www.geocities.com/m_natsume/what_compressor.html

It seems to be a variation on the what compressor but with 5532's in the audio path, an attack, release and ratio control and without the double release.

I'm sure Mnats could enlighten us, from the sounds of it he once printed the boards for what as well.

I am sure Peter had a reason for using the Op-amps he did, maybe he will pipe in. I like Peters design because it is a not frills opto, and to be honest I kind of like the 'less is more approach'

Cheers

Matt

 

[Ptownkid]

I wanted to get some of Fabio's boards for this, anybody have any interest?

 

[peterc]

I used the components specified in the original design apart from the opto.

The MC33079 would sound good in there, I'm sure. EDITED (thanks Jakob)

Peter

 

[gyraf]

Make that MC33079.. :grin:

 

[Flatpicker]

[quote author="Mendelt"]By the way. Is anyone familliar with this design?[/quote]No, I have not seen this. Thanks for putting it up. Odd that no one thought of patenting the high pass filter before the sidechain thing before ATI.

 

[Mendelt]

[quote author="matta"]
I'm sure Mnats could enlighten us, from the sounds of it he once printed the boards for what as well.

I am sure Peter had a reason for using the Op-amps he did, maybe he will pipe in. I like Peters design because it is a not frills opto, and to be honest I kind of like the 'less is more approach'

Cheers
Matt[/quote]

I hadn't even noticed it was mnats's site.. I just had that link floating around in the linkbar on my browser.
I find both what-designs interesting. Seems to me the original what-compressor is designed especially for vocals with the "april resistor" for mixing in some dry signal and its fixed low ratio. While the mnats version is more flexible cause it has all the knobs you'd expect in a compressor.

 

[Michael Krusch]

I have also built the what compressor. At the moment it's my favourite vocal compressor.
I have changed some thing:
-symmetrical ins and outs
-additional output pot
-lower values of the feedback caps in the audiopaths, because it killed some highs
-different opamps in audiopath
-gain reduction metering
-no 'April' resistor

I like the two caps in the sidechain, wouldn't leave them out like nmat did. It fits nice on vocals.
I have tried this compressos on drums and it gives very unique sound, not camparable to other compressors.

 

[StephenGiles]

Just arrived back home from Argentina, via San Paulo on the worst transatlantic flight ever, on a British Airways 747-400 with new seat configuration. This means economy seats which are not only narrow, but very close to the row in front. Many passengers were very angry, especially as the air conditioning turned into heating! - no sleep and the breakfast was disgracefull. We will never fly British Airways to South America again, we'll probably try Varig next time.

Ah yes the What compressor, I have built 5 of these, all on Veroboard all with the April resistor, and I changed one resistor to increase the amount of compression on the last 2 I built - I'll look this up and post which one when I've had some sleep.
Stephen

 

[StephenGiles]

matta - would you please let me know about the side in and out - is this short for sidechain perhaps, or have I missed the point in your excellent explanation? I've also noticed that you have quoted BC327 for Q1, is this what you just happened to have or do you have a preference for this transistor?
Stephen

 

[matta]

Hi Stephen,

It wasn't me that posted that info.

I have yet to build a 'What', I am hoping to. I was looking for a simple, yet effective vocal comp and it seems the 'What' is very favorable for this. I was hoping to see what others thought of it, and the response so far has been great and I will be building 2. I am planning on getting 2 boards from Fabio, anyone else want? Post here and hopefully he can Fab a bunch. I am sure he wouldn't mind and confirm price.

His board looks great because as with all his other boards it gives you options, I however am not sure there is a sidechain option like in Mnats design, though I might be wrong.

Cheers

Matt

 

[StephenGiles]

matta - now I've caught up with lost sleep, I can see what you say! Where he says "Side" perhaps the more usual jargon is "Key". At least that is what I've seen in a number of circuits. Incidentally, changing R9 to 47k in the original circuit gives far more compression.
Stephen

 

[omeiko]

Intersting. Could you share more about the mods?

Well, it's nothing special. I just removed the tantalums from the release circuit. This way the attack and release is determined by the opto-element's behaviour (very fast in the case of the VTL5C9). Works well on vocals though the sound is not as "open" as with the original circuit. It sounds a little more "controlled".
It would be interesting to try how a slower acting vactrol (e.q vtl5-c2) would work here.

Okko

 

[evil grill]

i´ve been thinking about building the "what" for years but as with most cool diy electronics i never get the time.
here´s a mod that i think would be better for stereo use.
http://www.geocities.com/evilgrill/what_stereomod.gif
if the left channel is to be totally in control make sure to switch the right channel signal out of the right channel sidechain (at the same point). does this make sense to you? i´m really tired after cleaning up the studio instead of sleeping and i should go to bed but... i donno, eh. this thread is really interesting. makes me wanna build stuff.

 

[matta]

Hey Guys,

Fabio has offered to do a run of his 'What' boards, we need a group buy, details are here: http://www.groupdiy.com/index.php?topic=6812

Cheers

Matt

 

[StephenGiles]

I've altered up my What Compressor redraw as the Weak Joe, which I'll post tomorrow. There are more values changed than I originally thought.
Stephen