Chameleon Labs 7720 Stereo Compressor vs GSSL Clone?

rajprods said:

Has anyone compared the two?  If so, what did you think?   Are they basically the same or are they different?  If different, in what way?  Sound or performance?

Also, did the clone have That Corp VCA's or by chance have the DBX 202C VCA's?   Just wondering if using the old DBX VCA's would make the unit sound any different and/or better than the Chameleon.   The reason I'm asking is because I just got a Chameleon Labs 7720 to test out, and I haven't heard a GSSL clone.   I have the DBX 202C VCA's if I have a clone built, but wondering if it would really make that much of a difference.   If it's a big difference, I definitely would like to know.  Any thought or opinions would be greatly appreciated.   Thanks.

Click to expand...

This is off the subject a bit, but has anyone seen the TK Audio BC1?  http://www.tkaudio.se

It's a new stereo compressor that uses "That Corp" VCA's....

[edit] talking about TK Audio BC1 here:

another GSSL clone it seems. with some mods. some easier than others.

1. It has more attack range. Look at the GSSL schematic and find out just how easy it is to stick more values in there.
2. It has a switchable dual sidechain ie. "turbo" mode (this is closer to how a real SSL 4000 series bus comp behaves). some call it oxford mode.
3. It has wet/dry control. search "crush and blend" here on the forum.
4. Less featured, but likely quite similar sidechain filter to the Chameleon labs one.

Not sure about that "hard" ratio. Rest assured it can't be anything too fancy. Another simple mod.

Kingston said:

another GSSL clone it seems. with some mods. some easier than others.

1. It has more attack range. Look at the GSSL schematic and find out just how easy it is to stick more values in there.
2. It has a switchable dual sidechain ie. "turbo" mode (this is closer to how a real SSL 4000 series bus comp behaves). some call it oxford mode.
3. It has wet/dry control. search "crush and blend" here on the forum.
4. Less featured, but likely quite similar sidechain to the Chameleon labs one.

Not sure about that "hard" ratio. Rest assured it can't be anything too fancy. Another simple mod.

Click to expand...

Thanks.... FYI.... The current cost in US dollars is $1,250.00.

@Kingston - replacing 553's def. takes away their signature from circuits. I haven't built the gssl, but judging from other swapping and tweaks I have done, a lot can be accomplished with I/O sections improvements (f.e. beefier opamps @output and diff. topology) and some simple tweaks @553's within the existing circuit.

Pimping the gssl's PSU can be done on the existing pcb afaik.

Kingston said:

another GSSL clone it seems. with some mods. some easier than others.
...
2. It has a switchable dual sidechain ie. "turbo" mode (this is closer to how a real SSL 4000 series bus comp behaves). some call it oxford mode.

Click to expand...

Are you talking about the Chameleon, as pictured in the above 'guts' photo?

If so, there's no turbo mode... To do a 'turbo' requires a total of FOUR VCAs; one for each chanel and one for each channel sidechain. -The Chameleon has three VCAs, -same as a GSSL with NO turbo.

My last build used a demounted rectifier and a C/R/C/R/C reservoir board, which removed the ripple and improved noise significantly (a measured 17dB noise improvement). -Other than that, I wasn't able to noticeably or measurably improve upon the 7815/7915 regulator combination, so I'd take slight issue that there are improvements to be made in that area.

The chameleon is DEFINITELY developed from the GSSL. -You can see it in the layout, and how closely it mimics the GSSL. -Jakob's little 'module' for replacing the can VCAs is essentially transplanted right into the layout. The TL074 and TL072 remain unchanged (instead of 3xTL072's for example... and the division between the 072 and the 074 looks the same... the ORIGINAL SSL version did not use ANY 074's, so that's another big clue!)

Another clue is the apparent use of 5532's for the outputs and 5534's for the inputs... the original SSL used 5532's ONLY, with no 5532's anywhere.

So I can only conclude that it's plainly "inspired" by (i.e. a pretty much direct copy of) the GSSL, which has been 'expanded' by the inclusion of the sidechain filter. -It cannot do 'turbo' mode, which means that it can't do what the real SSL does. -Looking at the expat audio YouTube demonstration, should make it pretty clear that you NEED the fourth VCA in order to do what the real SSL buss compressor does.

Improvements: -The power supply looks better, and the sidechain filter gives options. -However, the sidechain filter was only EVER developed to address the GSSL's tendency to 'overcompress' low-frequency, center-panned instruments. -the original SSL buss compressor NEVER needed this, because it DIDN'T 'suffer' from the same traits... As a result, this further reinforces my view that this is a copy of a GSSL including the attempt to reduce the inherent "misbehavior", and a further improvement in supply noise reduction.

A GSSL with a sidechain filter will do the same thing, and if you include the remote bridge rectifier and C/R/C/R/C mod (which is a $5 mod) then you will match its performance. -The apparent choice of inexpensive ceramic capacitors suggests that there have been some corners cut in terms of component cost.

That's by full "analysis"... I do think that the conversation is better held in the forum ina thread rather than over PMs or emails, so that everyone can share in what's discussed.

Keith

SSLtech said:

Kingston said:

another GSSL clone it seems. with some mods. some easier than others.
...
2. It has a switchable dual sidechain ie. "turbo" mode (this is closer to how a real SSL 4000 series bus comp behaves). some call it oxford mode.

Click to expand...

Are you talking about the Chameleon, as pictured in the above 'guts' photo?

Click to expand...

No, this is that TK Audio BC1 clone, explicitly mentioning dual sidechain on their website.

I "broke down" the chameleon clone on the last page already.

copy of a GSSL including the attempt to reduce the inherent "misbehavior", and a further improvement in supply noise reduction.

Click to expand...

the PSU unit of the CL7720 shows signs that steps were taken into this direction.

I mentioned also that very simple steps could be taken to "pimp" the existing 78xx-based gssl psu (google "bugle power supply" and fetch the pdf), could be soldered on copper side..

Now, there is a question: if there are designs obviously based on gssl, wouldn't it be logical to sum these up and come up with a streamlined, upgraded "gssl v.2" project?

I mentioned what poked my eye...

tv said:

copy of a GSSL including the attempt to reduce the inherent "misbehavior", and a further improvement in supply noise reduction.

Click to expand...

the PSU unit of the CL7720 shows signs that steps were taken into this direction.

I mentioned also that very simple steps could be taken to "pimp" the existing 78xx-based gssl psu (google "bugle power supply" and fetch the pdf), could be soldered on copper side..

Now, there is a question: if there are designs obviously based on gssl, wouldn't it be logical to sum these up and come up with a streamlined, upgraded "gssl v.2" project?

I mentioned what poked my eye...

Click to expand...

The only point I can add in terms of the power supply, is that the internal power supply is a bit noisy..... It's a weird "space sounding" noise when the unit is on.... The noise oscillates a bit, if that makes any sense.  It's my understanding the external power supply unit eliminates the noise. 

Ah.. TK-audio version. -I see.

Looks much better than the Chameleon. interesting that they make specific mention of the dual sidechain...

Also, they've built a "crush-n-blend" into it... -Well, they do say that 'imitation is the sincerest form of flattery'!

Keith

SSLtech said:

Ah.. TK-audio version. -I see.

Looks much better than the Chameleon. interesting that they make specific mention of the dual sidechain...

Also, they've built a "crush-n-blend" into it... -Well, they do say that 'imitation is the sincerest form of flattery'!

Keith

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What do you think about the price?  I would say it's about twice the cost as the parts for a clone with a decent case and Sifam meter. 

The price? -Are you suggesting it should be less money?

At that price, I wouldn't be able to make and sell one with those features on. -You won't find anything better.

Keith

SSLtech said:

The price? -Are you suggesting it should be less money?

At that price, I wouldn't be able to make and sell one with those features on. -You won't find anything better.

Keith

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No, I wasn't suggesting it should be less.  As you know, the SSL stuff is in the mid $3,000's.... Alan Smart units are $2,000 to $3,000.   I was just wondering if the price on the TK Audio BC1 is considered to be a decent price for the features.  I guess I answered my own question, but just wanted to know what some real "tech" people thought since I'm not familiar with the advantages/disadvantages of the technical aspects for this type of gear.  Thanks.

Hrrr they have boeing 737 knobs on. Methinks is non-sequitur with shiny metal panel. Mewants
developers to visit opencockpits.com.

Well the chinese thing to do would be
buy it as a grp buy !
who wants their name on it ?

rajprods said:

Has anyone compared the two?  If so, what did you think?  Are they basically the same or are they different?  If different, in what way?  Sound or performance?

Click to expand...

I've had the CL7720 for about a year now and I liked it for the cost and what it did.  I just finished building my first GSSL clone and when I compared the two, the GSSL clone blew the CL7720 out of the water.  I built the GSSL without any mods and still the 7720 didn't compare.  I'm building my second GSSL now with a turbo "Oxford" mod.

Any one wanna buy a CL7720?