Aussie Compressor VERO LAYOUT *****testers/tweakers needed!***

[Toney]

 Here's Brett Robinson's simple , elegant compressor.
I haven't built it yet, but will in the next few days.
This got great reviews when it was released.

From Brett:
Possible mod: The resistor that parallels the cap at the MOSFET gate controls the "release" time.  Some people like to use a pot (linear) to control release time.  My personal preference is to keep things very very simple, and use a large resistor to make the release time long and slow.

R3 is right at the edge of the board. You can replace it with a pot if you wish.

Enjoy, Toney   

         



coming soon......ROG's Double D

[Xavier]

I'm going to try this one in place of the squeezer side in my "bi-comprossor". Looks like a simple build for sure. Thanks again Toney. The Double D will also be built.

Yo da man

[MartyMart]

"Toney" - strikes again !!

Nice, looks 95% like mine.
I never got it to perform as "smoothly" as my "Flatline" though  .. !!  :-(

MM.

[jrc4558]

Wow! I think I missed the schem for that one. Can anyone post a link?
Thanks!

[Toney]

 Constantin... here you go




Haven't had time .....
Any one have a go at this yet ?

[343 Salty Beans]

If I had a BS170, I would give it a go as soon as my bulk shipment of assorted sh*t gets here. Any suitable replacements for that particular tranny?

[Toney]

Yep, 2n7000

[343 Salty Beans]

dang, ain't got one of thems either.....

[RickL]

should pin 7 really be connected to V+? Nothing else I've seen using a 386 connects this pin to the supply and it's marked 'reset' on the datasheet.

Rick

[Toney]

Good point.
I read it that way from the above schem...
Anyone chime in on this ?

[SuperGeo]

very nice layout 

MartyMart
Is this compressor subtle like the OS?

[brett]

Hi.
Power to pin 6.  (unlike single op-amps where it usually goes to 7)
Output from pin 5 (it usually is 6).

Virtually any MOSFET will work in this.  MTP3055s are huge, but are commonly available, and only cost about $1. Note pinout.
I did partly develop a JFET version, but it was more complicated and not any better.

cheers

[Toney]

Excellent, thanks Brett.
Will take pin 7 out of the mix!

[Xavier]

very nice layout 

MartyMart
Is this compressor subtle like the OS?

Yeah I was wondering the same question.....

[MartyMart]

very nice layout 

MartyMart
Is this compressor subtle like the OS?

No, but then i don't think my OS is subtle at all !!
I liked it, but was just struggling with the "attack/decay" and the pumping.
I have it set up with an extra pot ( see original thread ) and have some control
but was never quite satisfied with it ....  sorry  !!

"Flatline compressor" or Craig Andertons compressor are great, the Flatline is on
my pedalboard at the moment.
They are a little more "complex" as builds though  ... CA comp is a +9/-9 volt circuit !

MM.

[rockgardenlove]

^Has the issue with this layout been fixed?  I think I'm going to build this if it has.

[Toney]

Yep, fixed same day.

Some love it some do not.

Remember, one variable can be the 386 chip used.

There are several differing types and may/may not yield different results.
Haven't tried, but this occurred to me after the varying reports.

[brett]

Hi.
I initially used the Aussie for short, fast, loud rock, so I didn't notice any "breathing" or ups and downs.  But I can see that it's a problem.

I've been thinking about the long release time.  In the Dyna compressor, which I really like for its sound, the resistance paralleling the "holding" 10uF capacitor ranges is about 10kohms (when the pull-down transistors are "on" enough to turn Q5 off and start compressing).  So the combined resistand and capacitance and release time is WAY shorter than in the original Aussie compressor.

So maybe a better value for the 1M resistor is around 22k ??  22k and 4.7uF gives a time constant, RC, of 0.1 seconds.  I *guess* that 0.1 seconds would be short enough to give a quick(ish) response to the envelope of a picked note, yet slow enough not to follow even the lowest frequencies (ie it is equal to 10 Hz).  Hmmm... probably too fast for even the fastest vibrato.

I'm up to my ears in a McTube at the moment (a really excellent project), so would someone else like to try 22k (and maybe 47k) in place of that whopping great 1M resistor?
 
cheers

[Toney]

Right.
So basically, when building remove R3 ...it's right on the edge of the board for this purpose....with a 50 or 100k pot for adjustable release time...
If anyone does this , please report how it goes.

[wampcat1]

Anyone built this yet? Seems like the 386 would sound sort of 'lo-fi' and fuzzy instead of bright and clear?
I'm guessing a tl072 could be subbed pretty easily (not pin for pin though), which may make it a little clearer.

bw