2166 quick and dirty vs Engineer's thumb compressors

[blackieNYC]

Moving this to start a new thread. 2216 [edit - oh, whatever!] Q&D II vs. engineer's thumb preliminary comparison (because I'm not sure I'm finished tweaking yet.)  And I could use some advice with both.  I have a MXR custom comp to compare with also.
Two very different compressors.
The engineer's thumb is as quiet as Merlin told us it would be.  I'm having some trouble getting it to sound the way I want.  I have the 4 control pots going, so there is a lot of interaction between them.  Setting attack and release to the fixed resistances, the release is very very long. I'll get a little pop-attack on the first note, and then all notes are compressed until you have been silent for a release time of what could be two seconds (the max release time of the d1176 and dbx160x compressors is 1.1sec and 400ms, respectively.) I'm not sure how to compare what I'm hearing to the measured specs, so this is not very scientific.  Rolling the release time back with a 1M pot (and you have to stay above 250K or so) will help, but it still seems long to me.   And the con of reducing the release resistance is something I'd really like to get rid of - play a chord, or a pair of notes, and the beat frequencies play with the compressor.  The result is a very noticeable tremolo. (Change your tuning a little, or bend one of the two notes, and you'll hear the beat/tremolo speed change.  I can see this happening at perhaps just the right threshold, but it happens at almost any threshold settings.  I can't get the Q&D or the C.C. to do this at any setting.  But like I said, I'm not convinced I've tried everything to get rid of this effect.  suggestions welcome.
The Q&D II is certainly easy.  It sounds exactly like I want a compressor to sound.  The noise gate is very useful, and Jack at AMZ has made this chip sound like it was made for guitar.  I have not tried it end-of-chain.  I'll be interested to see if higher input levels cause a problem.  But this guy has a problem too. Noise.  Now, I have not boxed this up, so maybe this will not be a problem, and maybe someone can tell be how much quieter it became in a box.  As the note trails off, the noise level swells in a lot higher than I would like.  I don't think it's completely fair to compare it to the ET, given the different usage of VCAs.  The gate adjustment controls the time spent listening to this noise.  I think the chip's specs state that it is a 15(?)dB expander, but it sounds like a gate to me.  I don't mean that in a bad way.
I'm not done with these two.  If you've built either, please chime in on the above.  Additionally, the bright mod for either circuit - I can't hear it.  Not a big deal.  Certainly not a deal breaker.  No change in the nature of any hiss, or perceived brightness of the notes.  What caps did you guys use?
I should point out that I'm looking for a compressor as effect pedal, not as a means of reducing the output vs input by a ratio of yadayada.  You know what I mean.  Country chicken picking', dire straight-ish, and added sustain for dirt

[Mark Hammer]

It's a 2166, Alan...2166.

Just making sure that you don't inadvertently end up with a Mouser package that leaves you wondering what the hell you're going to be able to do with those chips. 

I have an Engineer's Thumb board populated and almost completely wired up, and still have a pair of 2166 chips left to whip up a replacement for the compressor I sold a guy.  I'll let you know when I have both to do a shootout with.

[blackieNYC]

Doh!  Ha ha!  Did I mention there's also a loud tone at the output? I got a 2206 oscillator chip in the same order!  No, I've got the right chip. 2166.  Thanks Mark. Others may think I'm an idiot but you know. Better, that is...

[merlinb]

Moving this to start a new thread. 2216 [edit - oh, whatever!] Q&D II vs. engineer's thumb preliminary comparison (because I'm not sure I'm finished tweaking yet.)  And I could use some advice with both.  I have a MXR custom comp to compare with also.
Two very different compressors.
and then all notes are compressed until you have been silent for a release time of what could be two seconds (the max release time of the d1176 and dbx160x compressors is 1.1sec and 400ms, respectively.) suggestions welcome.

Reduce one or both of the 1uF side chain capacitors to 470nF. This should shrink all the attack/release times to something closer to what you appear to prefer.

[blackieNYC]

Thanks Merlin. I'll report back.

[blackieNYC]

I've cut those cap values in half as suggested, but not much changed.  I've rolled back no the threshold and the ratio, to where one can still hear compression, but the release still seems long to me.  If I'm talking about the right thing. a picked note with a nice little attack, but then following notes are still within the release period for what seems to be too long compared to other compressors.  And as I listen to the note trailing, before recovery from release, the compressor is slightly fumbling around trying to figure out how much to amplify the circuit. And again, any beat frequencies turn into a tremolo effect.  I realize this behavior is within the realm of compressor operation, but I just can't get this to sound like my other compressors, or get them to behave like my ET.  I don't think I could easily whip up a demo that would illustrate this. I'd really like to stick with the ET because it is such a low noise compressor.

[blackieNYC]

The sound of the compressor "hunting around" for the right level does correspond to the DC on control pin 1.  Play one note and let it ring, and the DC level rises, and initially falls smoothly but then bounces around.  On my scope (digital, and a little slow) the DC level goes up 200mv, falls smoothly to 60-75mv, and then wavers around there.  That's what it sounds like too.  Any thoughts? Can that voltage decline be stabilized?  My attack and release pots are not altering this.
I'm not saying there is something wrong with the design of the ET, but my voltages are right, I've checked my parts over, and this seems like something to fix rather than give up.

[merlinb]

The sound of the compressor "hunting around" for the right level does correspond to the DC on control pin 1.  Play one note and let it ring, and the DC level rises, and initially falls smoothly but then bounces around.

The control voltage on pin-1 of U2A (the base of the transistor) should fall when a note is played, then slowly rise back up.
Or if you mean pin-1 of the LM13700 then I would not expect to see such a large increase in voltage. Sounds like something is built wrong to me...

Schem for reference:
http://valvewizard.co.uk/engineersthumb.pdf

[blackieNYC]

I haven't given up on the ET yet.
I've boxed up the Quick and Dirty 2.  The compression sounds very nice - just what I like really, even though there is no attack nor release.  The gate is very good.  With the pot over one way it kills pickup noise, and spun the other way it manages my noisiest noise just fine.  But it is noisy.  Briefly, an only as the note trails off.
Not a deal breaker though. The gate cannot be completely turned off by its pot (now I know why) and it gets rid of this noise at it's lowest gate threshold.  Very noticeable with the compression all the way up, but I don't think I'd use anything over 12 o'clock on the comp ratio pot.  At that setting, the noise is tolerable.  I might end up choosing the Q&D II.  Going to try the optical compressor as well.