Completed GSSL with turbo, 2 SSC and true bypass

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Matthew Jacobs

Well-known member
Joined
Mar 17, 2009
Messages
396
Location
London - UK
Hello Everyone

Just wanted to show some pictures of my latest GSSL and to thank all the people that made it a reality! (in no particular order)

- A big thanks to Gustav for the boards and being so cool and helpful about everything, especially in getting the boards to me as soon as possible despite all the problems with the Danish post office.

- A big thanks to Purusha for the case and suggesting the switches. Beautiful work, makes the GSSL look pro!

- A big thanks to Mike at Hairball for the Meters. Also a big thanks to all those involve in developing this meter (IIRC Stereokiller and Ptownkid)

- A big thanks to [silent:arts] for the bypass boards

- A big thanks to Rochey and SSLtech for their Turbo and CRC board from ExpatAudio and SSLTech for his post on calibrating ratios

- A big thanks to Pascal from Sibalco for helping me get the knobs

- A big thanks to Clintrubber's for the Super Side Chain

- And finally a big thanks to Kingston for his mods (trimmers) and Op-amp suggestions

I built this unit as a gift for a very good friend of mine who as permanently left the UK to return to Brazil. He is a musician/producer/engineer who has taught me so much about music, especially Jazz, engineering, mixing and producing. After hearing my GSSL he wanted one so bad that I decided to build him one.

This was my most intense DIY build as it had to be built quick and completely as my friend had a plane to catch. Normally DIY takes me ages and I usually start using the units in there incomplete state (like my GSSL (in the background in the first picture) hasn't had a meter for more than 1 year... hey, at least I've learnt how to use my ears... lol)

This GSSL has:
- Power switch for 110/220 V mains supply
- True Bypass, relay operated, separate 24V regulated supply
- Rafi switches from conrad.com with LEDs also running off the 24V supply
- Turbo board, switchable
- CRC board
- 2 Super Side Chains
- That 2080 VCAs
- OPA2604 and OPA604 op-amps
- Trimmer to set unity gain
- Trimmer to set ratio
- Trimmer to calibrate meter
- Panasonic FC caps
- No 100nF caps in signal path
- 1/2 W Metal Film resistors in signal path
- Made sure all the panels, including the front panel, are electronically connected (scraped off paint and used wire)

Any advice on how I could improve my future builds welcome.

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MyGSSLFront.jpg

MyGSSLMeter.jpg

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I didn't really get a chance to burn things in and use it a lot as I had to give it away but the calibrating process was cool and fun. I got the ratios spot on, actually just the 2:1 and the 10:1, the 4:1 was off by less than 0.5dB. I think it's impossible to get all three ratios spot on, so it's more an art of balancing all three... The turbo mod is great... at first I though what's all the fuss about? the original sounds better... then I realised I got the switch the wrong way round... ha ha ha. I actually left it like that cause I thought the compressor will probably mostly be used in the turbo mode so I didn't want there to be a extra light constantly on on the front panel. The SSC is such a cool feature and the THRUST mode is really cool. My friend likes to use a lot of makeup gain, he claims the compressor sounds better that way... so I calibrated the compressor using the trimmers to have 3dB less gain... that means that he can apply 3dB extra makeup gain. The true bypass is excellent. You can really tell what the circuit is adding to the signal. All in all a really cool and versitile compressor.

Thanks for looking
J


 
Oh wow, that's nice  :)

Isn't it funny how you come to this point where you almost don't understand your own cabling
anymore, and then just gawk in disbelief when it all works?
 
livingnote said:
Oh wow, that's nice  :)

Isn't it funny how you come to this point where you almost don't understand your own cabling
anymore, and then just gawk in disbelief when it all works?

Thanks!
Ha ha ha... that's so true... I sure was glad that it all worked when I switch it on... I only cabled tied everything right at the end just in case...

 
that is a very nice version, and now you give it away? wow he must mean a lot.

top work..

Pete
 
Grand Master Audio said:
that is a very nice version, and now you give it away? wow he must mean a lot.

top work..

Pete

Thanks,

yeah, he's a good friend and a very good jazz musician that normally charges £150 a hour and he must have given me over 100h lessons so I think building some DIY for about £350 is the least I could do.

BTW, I've also built one for me since it's easier to build two at the same time than two separately, kind of like cooking a meal. Anyway one of them didn't quite work straight away so it still needs a bit of work.

J
 
Congrats - that looks wicked.

Did that purusha case come ready for 3 pushbuttons? The pic on his site only has 2 pushbuttons on it.

Cheers
 
snipsnip said:
Congrats - that looks wicked.

Did that purusha case come ready for 3 pushbuttons? The pic on his site only has 2 pushbuttons on it.

Cheers

Yes, me too I was confused by the photo on his site but I emailed him to check first and it turned out to have spaces for 3 push buttons.

The case is not too big and it was very tight for all the boards to fit in, and I didn't get it right first time, so the bottom panel is riddled with holes... I guess it's not to bad for ventilation...  ;D
 
How did you wire the SSC switch? To use all the purusha faceplate values you need imho a 2 deck 8 pos switch. Did you leave out some positions or do i miss something?
 
stereokillah said:
check the pictures he simply bypass some position like external cause there isn't jack on rear and the highter frequency.

Well spotted stereokiller!

Yes I just used a Lorlin 2x6 switch with the first 6 positions on Purusha's case which are: TL, TM, Off, 60, 90, 130

For my second identical unit I was thinking of using a 1 x 12 controlling relays cause a 2 x 12 is so expensive.

I found this cheap switch from Banzai http://www.banzaimusic.com/Rotary-Switch-2-level-2x1x12.html but I am still considering each option as I have no experience with these types of switches.

I think relays will be fun to do...

J
 
Sometimes the most important thing is right in front of you that you don't even realize it...

My BIGGEST thanks goes to Gyraf cause without him there wouldn't even be some GSSLs sitting in my studio....

Gyraf... you Rock!!! I got a G9, a G-Pultec and a GSSL and for that I am extremely grateful...

J

 
CIAO
Matthew
great work!!
Can you tell us the values of trimpots

- Trimmer to Set unity gain
- Trimmer to Set ratio
- Trimmer meter calibrated to
and all the changes you made (where to find information)
thanks
 
ilfungo said:
CIAO
Matthew
great work!!
Can you tell us the values of trimpots

- Trimmer to Set unity gain
- Trimmer to Set ratio
- Trimmer meter calibrated to
and all the changes you made (where to find information)
thanks
??? ??? ??? ??? ???
 

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