Mark, this is absolutely interesting.
I have compared my second build twice to original 33609, metal knobs, from 1981 IIRC.
The original was never maintained or re-caped, had more thermal noise and one channel was -2 db down.
Test setup - Apogee Rosetta and Big Ben; my CRM, ATC/Adam S3a; good acoustics room (about 40m^2, built in 1984 by English folks).
I mean, enough resolution.
Neither me nor guys from this studio had no any remarks about clone's sound and feel. It was close enough for our poor ears.
Yes, the original was a bit "darker" and somewhat "slower", ohh shit, hate this "audiotalk" language.
PLEASE, I am out of punchy crispy descriptions... Even not in free time with the hands down the blanket.
Sound can't be expressed in volts/db's/percents of distortion. Neither in punch and oumgh.
It is personal experience and can be related to Zen Buddhism experience gaining way, kidding again.
However, I can clearly hear the difference between opa627 and tl071 in...say, 4x10k +2x10pf line balanced receiver circuit.
This makes me feel strange about your post/revelations.
Yes and yes.
My extensive research when I built my 33609 did result in a shockingly better sounding compressor.
Photos? It can be great if you share your knowledge with another guys.
It actually made Igor's original sound like a plugin version.
Strange, again. Anyway, it is your personal taste.
Try to take both on analyzer, maybe, you will find a mistake or wrong placed component.
For Igor's compressor: I assume, diode matching, no mistakes, original iron, all is uptospecs, yes?
Plugin, well... inside pics hi-res is necessary to see what is going on.
This knowledge was hard earned and I feel somewhat uncompelled to give it out freely.
You can offer the service for remaking Igor's 33609 into real 33609.
I am the first customer, if the price is OK for my pocket.
About a month ago, had long phone discussion with one guy, who building tube amps, from Beer Sheva.
He needed from me pair of 1:1.5+1.5 input trannies on DU-1, superperm, pri ind 40Hy at least.
After a long discussion about how he replaced the capacitors in his speaker crossovers and other funny stuff,
he statred to talk about cables, battery powered single ended FET amps, etc.
Finally, I run out of patience and asked him just for a joke how much he will take for modding my Adam S3a,
or can we close barter trannies vs modding. He said yes, show me the speakers. I said, cool, come visit for coffee.
The rest was a great source of amusement, aye.
Anyway, don't take personally.
If your mods worth to hear it, I am not kidding now, I am your customer for a years.
A close look at the schematics for both compressors will begin to reveal some, not all of the details.
33609 is copy-pasted from rev. J manual; with the use of original transformers, bit aged capacitors, NOS transistors
and carbon crtacked (if went deep into audiofullery) resistors for audiopath, some have to be matched, it will sound 100% same.
I used bit different layout for makeup amp; however, it is 100% close to BA441....
Some notes for 33609. You can easy find all this on build support thread.
http://www.groupdiy.com/index.php?topic=26218
Carenhill iron sounds different than origins, and it is known.
6k8 at one of. recoverys has to be 24k, ma bad, it was posted on support thread.
Some guys had a prob with limiter section; if you scroll all the thread,
most of people had no this issue; I spent half a day to compare my 33609 to original and haven't found any
prob with limiter section, however, maybe I missing something?
For instance, there's a huge hole in the Igor's 2254 sidechain design.
He'll undoubtedly call it feature. :
Nope. Mostly used thing is compressor section.
Needed space at front for sidechain hi-pass sidechain filters, than, limiter section gone.
IMHO, 2254C is more usefull and easyer to build.
Anyway, just my $0.25. People and tastes are different.
My apologies for a long post, but Igor's comp sounded as plugin is what I understood using Google translator.
If I got this wrong, please, my apologies again.
