Tube comp/limiter under development

[analag]

[quote author="NewYorkDave"]I did use plate resistors on my GR stage. (As I mentioned earlier, it's similar to that of the UA175--not identical, but similar). The plate resistors are small enough that, in concert with the regulated B+, the plate voltage variations are small compared to something like an Altec 436. As a result, the knee is harder--but as Larry points out, series resistance can be introduced deliberately when a softer knee is desired.[/quote]

I took the plate resistors out of both the GR and sidechain amp circuit for a fully transformer coupled setup. I followed Dave's reasoning and shunted the primaries with some resistance. The exact value was derived through simulation and it's a whole new sound again. I'm leaving it like this.

analag

 

[pstamler]

Welcome back, Winston.

Peace,
Paul

 

[SSLtech]

[quote author="pstamler"]Welcome back, Winston.[/quote]
+1.

Don't be a stranger. -We've been concerned for you and yours.

Keith

 

[NewYorkDave]

Rowan, I'm gonna give that a try, myself. (In the GR amp, anyway--my sidechain amp is quite different). I'm on vacation this week and have little in the way of test equipment at home. But I can always evaluate it for sound and, if I like what I hear, take some measurements when I go back next week.

 

[StephenGiles]

[quote author="PRR"]> Hmmm. bit of overshoot on the GR,

So get a few THAT Corp chips. Or build a Fairchild.

This is a 3-bottle limiter. You don't get perfection in 3 bottles.

He's getting 20+dB GR in 0.5mS. You won't hear 0.5mS of tape/ADC clipping. If you have ribbon-shutter film-sound, or trouble with the FCC, you put a clipper after this limiter to whack the overage.

20dB in 0.5mS is fabulous performance for such a simple sidechain built in hollow-state.

It undershoots 1dB but so what?[/quote]


que......meeester fawlty?????

 

[SSLtech]

Meeester Fawlty... -I no want work here no more!!!
:green:

 

[Larrchild]

Don't mention the War!

 

[SSLtech]

(I mentioned it once... I THINK I got away with it...)

 

[analag]

[quote author="NewYorkDave"]Rowan, I'm gonna give that a try, myself. (In the GR amp, anyway--my sidechain amp is quite different). I'm on vacation this week and have little in the way of test equipment at home. But I can always evaluate it for sound and, if I like what I hear, take some measurements when I go back next week.[/quote]

I had 10K plate resistors on the 6BZ8's goining into a 4:1 output ratio, after loosing the 10k's the output swing was still the same, but I noticed I lost some sweetness to the sound, after clapping the resistance across the plates, things changed. Noise performance is also much better.

http://groupdiy.twin-x.com/albums/userpics/10049/Spectrum.JPG

Spectrum analysis of the 660 and the mixing board with all faders set to unity (660 going into channel #24 and the analyser connected to the main outs of the board)
so a little noise is being added by the desk.

analag

 

[NewYorkDave]

I had X/2 plate resistors and a X:X interstage terminated with X across the secondary. I just ran a jumper between the B+ feed side of the plate resistors to the primary CT. So the two resistors are still there to define the source impedance, but the DC is flowing through the primary now, essentially bypassing the plate resistors. This connection could be broken with a SPST switch for a "soft knee" setting.

The result? Well, after only a few minutes of putzing around with it... I like it, I like it a lot :thumb:

(Edit: I removed the specific values of the resistors for perverse reasons known only to me. Suffice to say that X = X) :razz:

 

[analag]

[quote author="NewYorkDave"]This connection could be broken with a SPST switch for a "soft knee" setting.[/quote]
Putting that on my to do list. It's a great idea.

analag

 

[Winston OBoogie]

[quote author="NewYorkDave"]
(Edit: I removed the specific values of the resistors for perverse reasons known only to me.[/quote]

I don't think that's perverse at all. It's YOUR design to do with as you please my friend.
F.W.I.W. If you choose to post a complete schem at some point down the line, I will probably build it eventually.
If you choose not to post one, it's enough already that you've presented the ideas.

Thanks :thumb:

 

[analag]

[quote author="NewYorkDave"]I had X/2 plate resistors and a X:X interstage terminated with X across the secondary. I just ran a jumper between the B+ feed side of the plate resistors to the primary CT. So the two resistors are still there to define the source impedance, but the DC is flowing through the primary now, essentially bypassing the plate resistors. This connection could be broken with a SPST switch for a "soft knee" setting.

The result? Well, after only a few minutes of putzing around with it... I like it, I like it a lot :thumb:

(Edit: I removed the specific values of the resistors for perverse reasons known only to me. Suffice to say that X = X) :razz:[/quote]

It's a vari-mu thing.....yah man.

analag

 

[NewYorkDave]

Tube comp in action on bass and vocals:

http://www.groupdiy.com/index.php?topic=208577&highlight=#208577

 

[analag]

Dave I like the way the compressor does it's thing...very transparent. Thats a money piece right there, are you really gonna release the schemo?

analag

 

[mik]

yea! very nice compression !

NYD as always, your poject rocks !

:thumb:

 

[NewYorkDave]

Thanks. I was compressing the vox and bass tracks pretty heavily, more so than I would usually tend to do. But that's what happens when you've got a new toy in your rack--it's too tempting to over-use it. Still, I'm pretty pleased with how the breadboard performs and even though there's more work to be done, I feel I'm on the right track.

For "those what care", the bass signal chain was bass direct into the Hi-Z input of the MILA-1 preamp, then the compressor, then the passive EQ and into the soundcard line input. (The soundcard is just a run-of-the-mill Soundcrapper). The vocal chain was mic into low-Z input of the MILA-1, and then as above. Guitars were via booster pedal, amp, power attenuator, 10" speaker and mic into MILA-1, then soundcard. I never compress distorted guitars--what's the point?

BTW, if you think you hear an acoustic guitar down in the mix, that's just a happy accident. I was tracking the guitars at very low volume and playing only about three feet away from the amp, so the mic was picking up a fair amount of direct pick/string noise along with the amp sound.

 

[mik]

I 'd like to ear your baby, on piano or a classic guitar..
that's the trouble I've got, to find right tune of compression on this acoustic instruments.. your baby should be the solution.. i hope.

M.

 

[louder]

alo NYD
great sound,and great voice.
your voice remembers me frank zappa.
now i gotta make this compressor,and the MILA.
best regards
pedro

 

[solder_city]

more an old style baritone crooner than a zappa type- i think. its an interesting contrast to hear that kind of vocal over a punk backing track. you hear those opening bars and you expect to hear some guy yelling at you or something.