GSSL Turbo board complete!

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Keith - since you have built both the Ultimate SSL using 2 full boards - (differential signal paths) and the slimmed down version(ala turbo) - is there any discernable difference between the 2 models? I might expect the fully differential beast to be quieter(lower noise floor) and less distortion, but is it worth the extra effort to do a full differential unit - or is the turbo just as or nearly as good?

Cheers and beers in advance
 
I welcome any comments about what other people think of the difference in character with this mod. -I have to say that I was VERY surprised at what a positive improvement it has made.

I just got my board hooked up this weekend (Thanks Keith!!) and it is a night and day difference. I only had a small amount of time to mess with it so far, but I like it!

Not that the GSSL is bad by any means, but the Oxford mode is much less touchy on the center transients like snare, kick, bass, etc. It seems to be a much more open sounding compression, if that makes sense.

I can see both modes being useful in the right app. Mine is going to stay switchable!!

mm
 
Marshman,

Any feedback? -Instructions not too confusing? Construction okay?

Congrats on the install... colossal difference in character, huh? -It
surprised the HECK outta me when I first did it!

MikeyB,

As I eventually deiscribed in the 'ultimate' thread, I anticipated the biggest difference with the 'ultimate' to be the differential performance, and the second sidechain to be of secondary significance, in terms of appreciable difference...

What I eventually found -after building it and lving with it for a while- was that the differential is a SLIGHT improvement, but not all that greatly significant, whereas the second sidechain is MIGHTILY important.

If I had to put a numeric value to the significance I'd say that the turbo sidechain is 80% as good as the 'complete' ultimate... and I'm sure that people will agree that the turbo is about a tenth of the aggravation in terms of figuring out the wiring... -I don't think that ANYONE put an 'ultimate' together without some serious head-scratching... whereas of the several 'Turbos' that have been intalled so far, nobody seems to have complained of a difficult install to date... taking Marshman and dagoose as typical examples.

Cheers,
Keith
 
Thanks for that Keith - yes, and what a headache it was building an ultimate with sidechain filters as well!! I'm testing it at the moment and if it becomes too much of an mare - i'll mod it to use the turbo and use the spare pcb to make another.
 
Nice! :thumb: I knew it was possible, would like to do the same trick. I can't really follow your drawing though, any chance of an "officaial" schem with added changes? Please? :wink: :sam:

[quote author="dagoose"]I just modded my second GSSL with another turbo board and made this one switchable with just one hp filter board.
This hp filter board is just 4x hp freq and a external out so a 6 pos switch.
I never used the external sidechain so that position is now the turbo position :cool:
To make it work i added a relay based system, otherwise it wasn't possible.
When i switch to the EXT position the relay gets 12v and switches to turbo. :green:
When in off it's just like a no modded SSL and then i still have 4 positions with hipass in regular mode as well.

I made a simple drawing the way i connected things.
The rest is connected as it should be according to the turbo drawings.

This way you save one sidechainbaord in case you want to use it anyway (in turbo mode you don't really need it) and still have GSSL mode with sidechain.
If you use a 2 deck switch you can use pos 11 or what ever on the second deck to power the turbo mode relay.
[/quote]
 
Any feedback? -Instructions not too confusing? Construction okay?

Congrats on the install... colossal difference in character, huh? -It
surprised the HECK outta me when I first did it!

Instructions were great! This is such a clean and simple add on. If I can figure it out, anybody should be able too!! One very minor suggestion, maybe a page with all the connections together? I found myself flipping pages back and forth to get the turbo board pin outs and the GSSL board pin outs to make sure all was right.

Thanks for your hard work on this. The board was beautiful, dropped right in!

Yeah, character, that is the word... literally two different compressors when you are done. Both rock in their own way!

mm
 
Had some questions about this 'mod' and i will try to make a more readable schem for it, i allways tend to do this kind of stuff out of my mind and i'm baaad when it come to drawing stuff.
It is indeed possible and it works great i must say.
But sometimes you want the SSL to be more like a pumping compressor and then the GSSL mode is a must with sidechain filtering, if you want nice, smooth but pumping compression you want turbo. :cool:

I was also thinking of another mod some time ago to make it even pump more, kinda like a reverse thrust circuit, boosting bass, cutting mid/high so that it just reacts to low end.
So a bit like an external sidechain but the internal.
Will that be interresting? :roll:


[quote author="ask"]Nice! :thumb: I knew it was possible, would like to do the same trick. I can't really follow your drawing though, any chance of an "officaial" schem with added changes? Please? :wink: :sam:

[quote author="dagoose"]I just modded my second GSSL with another turbo board and made this one switchable with just one hp filter board.
This hp filter board is just 4x hp freq and a external out so a 6 pos switch.
I never used the external sidechain so that position is now the turbo position :cool:
To make it work i added a relay based system, otherwise it wasn't possible.
When i switch to the EXT position the relay gets 12v and switches to turbo. :green:
When in off it's just like a no modded SSL and then i still have 4 positions with hipass in regular mode as well.

I made a simple drawing the way i connected things.
The rest is connected as it should be according to the turbo drawings.

This way you save one sidechainbaord in case you want to use it anyway (in turbo mode you don't really need it) and still have GSSL mode with sidechain.
If you use a 2 deck switch you can use pos 11 or what ever on the second deck to power the turbo mode relay.
[/quote][/quote]
 
morning.
so i'm building up my turbo board and was about to order a That 2181lb for it when i found a draw of various dbx 21** chips.
Theres some dbx 2151's, one dbx 2150A and several half height dbx 2150A, marked 912K Singapore.
Are the half height ones inferior to the full sized ones?
I'd prefer to use the 2151's as theres more of them, has anyone tried them yet?
thanks
paul

found the answer here:
http://www.groupdiy.com/index.php?topic=12881&highlight=dbx+2151
 
Finished adding my turbo board.
Sounds great. Went with the dbx 2150a's for the sidechains.
Will be very useful with the two side chain modes.
Might have to build another one!
Luckily i managed to make it switchable with a push switched make up pot, which was nice.

http://twin-x.com/groupdiy/displayimage.php?pos=-2303
http://twin-x.com/groupdiy/displayimage.php?pos=-2304
 
I was just about to ask if there were any known issues with using the pre-trimmed 2180 instead of 2181, but I see in Keith's first picture he used an 2180.

So I'll shut up now.

:?

:thumb:
 
I finished the turbo mod on my G last night and jumped in my car to head out to the studio to see how it sounded. I have to say it is a really great addition to the original design. I only have two stereo compressors including the G(DBX 162 is the other). Until now I was very wary of using either on my 2 buss but with this addition I am very happy. I did not expect as much of a difference in the sonic difference between non-turbo and turbofied! It really seemed to let the mix breathe more than without turbo.

If you havent turbo accelerated your G yet you would be very happy if you did. The build is simple, 16 resistors 5 caps 5 diodes 10 interconnects ... and wham. HOMERUN.

Like many have said before me, I want a second G at this point. Unfortunatley I still have to finish an eq3d, pm 660, 1176, la2a...

Great stuff Kieth :guinness: :green:
 
Just finished one with THAT 2181LB & a SC filter set. I had to remove the 47 ohm resistor from pin 4 to ground on both sidechain VCAs to get the distortion near acceptable. I also had to reduce the value of the 12 feed resistors to supply the increased current demand.
 
hi,

i'm currently making a GSSL w/ turbo with THAT 2181LA.

1/ correct me if i'm wrong :
on the Turbo board
> i have to remove 10K resistor next to VCA (beetween pin 3 & 5)
> i have to also remove 47R from pin 4 to ground

is there other changes to do on the turbo board for That 2181LA ?

i'm not sure :
i have changed the 3K9 to 5K1 for the audio VCA.
do i have to change 3K9 (to pin 5) to 5K1 in the sidechain circuit ?
and so on the turbo board ?



Nielsk >
I also had to reduce the value of the 12 feed resistors to supply the increased current demand
you mean the 10R before the 7912/7812 ?
if not, which resistors ?
what value work best ?

thanks
 
I think that Niels' build draws more than what you're proposing, because he's also included two complete multi-pole sidechain filter boards also, in addition to the turbo board.

If you're just building a GSSL + Turbo, you'll be fine for current demand.

Keith
 
1/ thanks for answering so fast.

and thanks A LOT for all your contributions !

i also have 2 sidechain boards w/ t"h*r"u*s"t filter.
so i'm intersted in getting infos ;)

2/ for people reading my previous post :
3K9 to pin 5 is fine on the sidechain VCA (it's a voltage drop resistor, and sidechain is fed w/ 12V, as signal VCA is fed w/ 15V. that's why there's different values)

Anyone on the turboboard with That 2181LA ?
 
Hello, I am new in this forum and I'd like to know how to contact "Expat Audio" to buy a Turbo PCB.
Thank you
 
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