SSL (Or Similar) Console Saturator/Distortion

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The 4000 starts to distort gradually wheras the 9000 series has more overall headroom, but once you reach the clipping amplitude, distortion sets in hard and sounds nasty.

Are the mix bus amps significantly different on the 4000 and 9000? Would be interesting to pinpoint the more gradual overload of the 4000. The newer designs also eliminated a lot of coupling caps in the signal path.
 
I seem to recall the 9000 used a discrete summing circuit similar to the 990 discrete op amp. And yes, they eliminated the caps and used DC servos.

Ironically, many complained that the 9000 sounds bland compared to the 4000.
 
Hi All,

I've digging around a bit more and came across these:

Solid State Line Archives | HRK

I'm leaning towards getting a Driver and Console module.

There are some disadvantages to going down this path because they're designed for the Colour format so modifying them is probably going to be tricky (I suspect I'll want to increase or decrease some characteristics). I wish they made the schematics of these things available!!!

I also discovered that schematics for some of the other Colour modules are available. I've attached them for those interested.

Cheers!
 

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Hi All,

I've digging around a bit more and came across these:

Solid State Line Archives | HRK

I'm leaning towards getting a Driver and Console module.

There are some disadvantages to going down this path because they're designed for the Colour format so modifying them is probably going to be tricky (I suspect I'll want to increase or decrease some characteristics). I wish they made the schematics of these things available!!!

I also discovered that schematics for some of the other Colour modules are available. I've attached them for those interested.

Cheers!


The Colour format is totally open for anybody to develop and add to the system. The Louder than Lift-off guys just close their modules. Whereas most Colour modules are kits, the LTLO products are all pre-built. If you hop out to the DIYRE site, you can get full schematics and documentation of the Colour Pallet that will give you everything you need to be able to incorporate the Colour modules into your own designs.

https://www.diyrecordingequipment.com/pages/colour-designer-s-toolkit
 
The Colour format is totally open for anybody to develop and add to the system. The Louder than Lift-off guys just close their modules. Whereas most Colour modules are kits, the LTLO products are all pre-built. If you hop out to the DIYRE site, you can get full schematics and documentation of the Colour Pallet that will give you everything you need to be able to incorporate the Colour modules into your own designs.

https://www.diyrecordingequipment.com/pages/colour-designer-s-toolkit

Thanks, yes I'm aware of that. Not sure I want to tie myself to the Colour platform when I'm prototyping and not even really sure where I'm going 😀 One thing about the Colour modules that puts me off a bit is that the only parameter that's variable is the input gain - other options need to be jumpered on the boards.
 
Apparently SSL's VHD is patented:

The VHD circuit is actually derived from an early SSL experimental mic-pre project that was shelved at the time because the distortion was too high! Unusually though it produced 2nd harmonic distortion rather than the 3rd harmonic distortion normally associated with solid state technology. This is why it was re-visited later on when SSL engineers were looking for a musical way to add distortion back into our SuperAnalogue designs. The core circuit was patented, and we added the mix pot to balance 2nd and 3rd order harmonics for even more flexibility.

I've had a look for the patent but haven't been able to track it down as I don't really know what I'm looking for and the naming can be quite obscure. Any ideas about what I should be looking for here (or if anyone could find it that would be a big help!)?

Cheers!
 
Apparently SSL's VHD is patented:



I've had a look for the patent but haven't been able to track it down as I don't really know what I'm looking for and the naming can be quite obscure. Any ideas about what I should be looking for here (or if anyone could find it that would be a big help!)?

Cheers!
I note that it's the "core circuit" that it says is patented.
Also it doesn't state where any patent applies ? eg EU / USA etc.
 
(p.7) High-frequency distortion
It says input resistor should be kept to 10k or above as asking for too much gain will lead to high-frequency distortion.
Actually, gain is not the issue, it's current. THD in Blackmer VCA is related to the sum of the input and output currents.
(p.10) Stray signal pickup
The VCA produces second harmonic distortion if the audio signal is present at the control port.
That is a common characteristic of all VCA's. Since a VCA is a multiplier, if you have signal in both inputs, the result is the signal squared.
Also, for THAT215x, I think, some designs have a 22M or so in parallel from VCA in to VCA out for small-signal integrity. Opposite of bad design (possibly) for older THAT VCAs.
That was a long time ago. The problem was fixed in subsequent chips.
 
I note that it's the "core circuit" that it says is patented.
Also it doesn't state where any patent applies ? eg EU / USA etc.
It's probably patented as something like a "novel microphone preamp". There's no indication of where the patent applies - I'd assume it would at least apply to the U.K.?
 
Are the mix bus amps significantly different on the 4000 and 9000? Would be interesting to pinpoint the more gradual overload of the 4000. The newer designs also eliminated a lot of coupling caps in the signal path.
I'd have to search for the specific diagrams, but the 9k is basically a 4k designed 20 years later. Balanced buses, different electronic switches (no discrete fet switching any more), crazy overengineering (the maybe 20 cm cable to the fader carries an electronically balanced signal, both ways if I remember right), the total numbers of opamps the untreated signal passes through the channel is mental. The large fader VCAs don't exist, they use moving faders. The main bus amps should be similiar to the 4k in the basic approach, discrete transistors (maybe 1 or 2 pairs) into opamps. I'd have to look that up, but I don't recall anything like a discrete opamp anywhere in the console. The channels run so hot, that chemical reactions destroy the cabeling on the channels. And of course the few remaining electrolytics get cooked. In order to buy a 9k you had to prove that your room had sufficient air conditioning, otherwise the console wouldn't be delivered. This makes sense, warranty claims would have killed SSL if the console wasn't cooled sufficiently.

I liked the sound of the console a lot, it was cleaner than a 4k, but had more grip than a Neve VR.

I do remember the 9k being very clean until the clipping point, but I also don't recall the 4k to 'overload gradually'. Maybe the VCAs contributed a bit to that feeling, but the whole console is opamp based and - in my opinion - doesn't have a particular gradual overload.

Are there no 9k schematics around here? It would be interesting to bust some myths ;-)
 
Are there no 9k schematics around here? It would be interesting to bust some myths ;-)
There's a track mix amp schematic availible at this very location:

https://groupdiy.com/attachments/9ktrackmixamp-pdf.38479/
It uses an AD829 (video op amp). Interesting...

I tried better op amps than the 5534 in the summing position of my console but I and the company's designer agreed that the 5534 sounds best. I also prefered it in my other console over lot's of fancy discrete and monolytic op amps. Go figure...
 
For another approach maybe OP could build some 4000 style EQs and compressors? Now that I think about simply inserting the 4000 black style EQ gives a decent amount of "that sound". I've compared the black vs silver EQs a lot and there was quite a contrast just inserting them and everything set flat.
 
To perfect patent protection you need to clearly identify the IP and where used by printing the patent number on the product somewhere.

JR
I was thinking that the patent might be mentioned in the manual (one page) but unfortunately not.

I heard back from SSL and they're going to look into it for me so hopefully they'll be able to tell me the patent number.
 
It's probably patented as something like a "novel microphone preamp". There's no indication of where the patent applies - I'd assume it would at least apply to the U.K.?

Yes and I think that would means it applies throughout EU.
*Please don't ask me how UK leaving EU affects this ! - the introduction of UKCA rather than CE in UK will be enough for me to deal with :)
I wondered about it in general mainly due to past brief involvement with patent application.
Not my invention but I was the 'bridge' between the third party inventor and the patent agent that my employer was using. While the European side of things went smoothly the USA application got pushed back to us several times citing prior art that clearly did not apply and had already been addressed in the initial submission. The patent agent had said that this sort of thing was not unusual with USA applications.

In the end the company I was working for decided that the cost / benefit equation of the patent process and upkeep didn't work out and declined to pursue it further. Leaving one very annoyed third party inventor.
 
Back last century I routinely argued with Hartley that the cost benefit of so many foreign patents he pursued just were not justified. Patents only give you the right to sue and foreign patents give you the right to sue only in that foreign country. But he collected them like trophies (expensive wallpaper).

The primary business benefit of a patent is to prevent competition in your major market(s). Last century the EU was moving toward a harmonized single english language patent for the entire EU... prior to that it was a tower of babel exercise to secure patents in every EU country in different languages, not to mention incredibly expensive. If you secure protection in US and EU it makes it less attractive for an international competitor to make a product that they can only sell elsewhere.

Lastly large companies accumulate patents that they can trade with each other like chips, to settle minor patent conflicts. (I don't think Peavey ever did that, but they probably weren't big enough).

JR

PS: I am very much a supporter of the concept of patents, sharing the technology to expand the world's knowledge. In my life experience I haven't seen much payback personally from that sharing and subsequent protection.
 

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