SSL THRUST CIRCUIT

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wiz1der

Well-known member
Joined
Nov 11, 2004
Messages
120
Location
California, L.A. Area
Was intrigued by the thrust circuit in Silent:Arts SSL.

Is anyone going to make up boards for this? I have yet to build mt SSL (It's been about a year)... but I would like to include this.

Or, if anyone has some perfboards already stuffed with parts, that I can just wire into my SSL, that would be great too!!
 
[quote author="wiz1der"].....Or, if anyone has some perfboards already stuffed with parts, that I can just wire into my SSL, that would be great too!![/quote]

And what would you've learned after doing just THAT? :wink:
 
[quote author="radiance"][quote author="wiz1der"].....Or, if anyone has some perfboards already stuffed with parts, that I can just wire into my SSL, that would be great too!![/quote]

And what would you've learned after doing just THAT? :wink:[/quote]

Man, I knew that was coming.......
 
I recently read the A*P*I-box does normal/semi-thrust & full-thrust.

Hadn't realized that at first. FWIW...

http://www.soundonsound.com/sos/Oct01/articles/api2500.asp

The next button is labelled Thrust, and this controls a unique filter stage applied to the level sensing circuitry. This feature borrows patented technology from parent company ATI, where the Thrust circuit has been employed for many years in the Paragon series of live sound consoles. In the API 2500 compressor, the system inserts a filter in the sensing circuit which, it is claimed, results in "a chest-hitting low-end punch" and "puts the mix in your face". The three options are for no filtering at all (Norm), a 2dB/octave high-pass filter (Med), or the full 4dB/oct slope (Loud).
 
FWIW, Ive been using a 2500 for several years now and havent found that thrust feature to be very useful at all. Seems more like marketing to me more than anything else. It also doesnt do what you would expect something labeled thrust to do. It certainly doesnt push the low end forward as much as just limit the high end in a wierd way, all it is is a filter before the detector. Im sure someone might have a use for it, but I have never found a good way to use it mixing rock and believe me Ive tried. Great limiter though. Lotsa stupid features though...

dave
 
Soundguy, you partywrecker you ! :wink:

Hugh R. also wrote:
.. but the Thrust control came as something of a surprise. At its Loud setting, the extra punch created was impressive and seemed to work very well with a wide variety of material, lifting the attack and weight of rhythm instruments in a totally different way to conventional EQ.

So that sounded promising (haven't added it yet here), but then you wrote the previous message... :sad: :wink:

All fine, bye,

Peter
 
W.r.t. the tech-side of it, interestingly the A*P*I-patent proposes a +10dB/decade slope (+3dB/oct),
as realized by the filter-circuit we've seen here.
The 2500-unit has 2 of 4 dB/octave slopes, so actually a bit less & a bit more than that - who knows they fumble a bit with components in the input-circuit or likely better they switch between two incarnations of that input-circuit.

Even more interestingly, I'm writing a message here about +/-1 dB ! :grin: Enough ! :cool:
 
well, its just my opinion about it, dont mean to discourage you from trying it, you may love it. Their copy claims it thrusts the low end, my problem with it is that it just doesnt compress the low end as much, the sidechain reacts to stuff over where ever the cutoff is, for argument say 100hz, so you get compressed high end with less compressed low end. Supposed to help with pumping but the net effect I hear is that the HIGHs get thrusted forward since they contain the limited part of the signal while the low end is obviously open in comparison. If you are stuck having to run a limiter in series, I suppose it might save you in a pinch but for the market it was designed for (this was the buss limiter put in the legacy at some point) you'd imagine that mixers were doing cooler things using it in parallel. In the end, it kinda just seems like another feature thrown on there to market it more than anything else. I personally wouldnt miss it if it was gone, but then again I almost exclusively use a limiter in parallel. Im sure there are people out there that wouldnt buy it at all without that feature.

dave
 
[quote author="soundguy"]well, its just my opinion about it, dont mean to discourage you from trying it, you may love it. Their copy claims it thrusts the low end, my problem with it is that it just doesnt compress the low end as much, the sidechain reacts to stuff over where ever the cutoff is, for argument say 100hz, so you get compressed high end with less compressed low end. Supposed to help with pumping but the net effect I hear is that the HIGHs get thrusted forward since they contain the limited part of the signal while the low end is obviously open in comparison. If you are stuck having to run a limiter in series, I suppose it might save you in a pinch but for the market it was designed for (this was the buss limiter put in the legacy at some point) you'd imagine that mixers were doing cooler things using it in parallel. In the end, it kinda just seems like another feature thrown on there to market it more than anything else. I personally wouldnt miss it if it was gone, but then again I almost exclusively use a limiter in parallel. Im sure there are people out there that wouldnt buy it at all without that feature.

dave[/quote]

Thanks Dave,
It's just such a little circuit so it's easy to add while at it and then see what it does. 'Special gimmicks' can be fun but I fully agree with you, the job needs to get done and when something hardly ever is needed it just clutters the frontpanel and was better not added at all.

Im sure there are people out there that wouldnt buy it at all without that feature.
Could imagine that, aren't we all hoping for that magic button that does all the work for us... :wink: despite people should know better I can imagine marketing just keeps trying so the techs have to keep adding bells & whistles...
The patent-story does seem to make sense though, but that doesn't mean it'll always work or be required, as you know from experience.


Bye,

Peter
 
[quote author="wiz1der"][quote author="radiance"][quote author="wiz1der"].....Or, if anyone has some perfboards already stuffed with parts, that I can just wire into my SSL, that would be great too!![/quote]

And what would you've learned after doing just THAT? :wink:[/quote]

Man, I knew that was coming.......[/quote]

Sorry, could not resist.....
 
Well Ill be trying the thrust idea next week in the gssl.

Ill let you know what I think.

Im hoping it will be useful.

Daves thoughts are very interesting, I would think the thrust thingy would perform slightly differently in different compressors, I hope anyway. :grin:

We shall see...
 
I think it would be useful to compare the thrust filter with a simple lowcut filter in the sidechain... then we can see, if it is really something special... or not...
 
[quote author="matthias"]I think it would be useful to compare the thrust filter with a simple lowcut filter in the sidechain... then we can see, if it is really something special... or not...[/quote]
It'll all come down to the corner frequency & the filter-slope below that frequency. Thrust does something like 1B/decade & a simple first order 2B/decade. It could both be interesting & over the top to have both parameters adjustable.
 
[quote author="Viitalahde"]Thrust me, a simple two-mode HPF in the sidechain, made of 2 capacitors after the two 47k resistors is plenty enough for signal spanking. :razz:[/quote]

We trust only features with fancy names or mysterious abbreviations - so that certain 'HPF'-thing you mentioned might be just the ticket ! :cool: :grin:
 
[quote author="Anonymous"]Thrust me, a simple two-mode HPF in the sidechain, made of 2 capacitors after the two 47k resistors is plenty enough for signal spanking. :razz:[/quote]

I'm in 3 minds as to whether to go with the Thrust filter, The other sidechain filter circuit that's knocking about here or now the idea given above when I put my GSSL's together. :roll:

Care to identify yourself Mr. 'guest' :wink: and suggest some values for these caps?

:?
 
You might be interested in this. Some test PCBs are getting fabbed right now. I've built this circuit on perfboard, and it works like a charm.

http://www.groupdiy.com/index.php?topic=11398
 
Yep, that' s the 'other' circuit I was referring to, I'm just not sure I want to put another 5 way switch on the front panel. I was thinking of a couple of toggle switches - one for filter in/out, the other for frequency. I guess I can do that with your circuit & choose 2 settings that I like best. :cool:
 
Exactly, when I implemented it I used a simple toggle with an off position and a 100Hz high pass, but since I was making the boards I figured I'd pull all the options. :green:
 
Ok, best put me down for a pair of pcb's then! :grin:

I'll post this in the appropriate thread too. :thumb:

PS, sorry, I meant Steffen's circuit & your PCB... :!:
 
[quote author="Greg"]Exactly, when I implemented it I used a simple toggle with an off position and a 100Hz high pass, but since I was making the boards I figured I'd pull all the options. :green:[/quote]
W.r.t. all options for the PCB, I guess that would mean doing both (1) the HPF-thing & (2) the Thrust & (3) drowning in too much possibilities :wink:
 

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