GSSL Turbo problem ! FIXED :-)

[SSLtech]

[quote author="MartyMart"]One observation though, I/O op-amps read -15v pins 4 and +12.8v pins 8 ?[/quote]
You talking about the 5534's instead of the 5532's? 5534's positive pin is seven, not eight...

Thus the INPUT 5534's will have some random voltage on pin 8 (it's a compensation/offset trim pin, I think) whereas the output 5532s should indeed have the full +15V on pin 8.

Do you have a scope?

I'm beginning to think that it's something to do with the board...

SO if you reconnect EVERYTHING except pin 8, does the GR still peg?

I'm getting close to swapping you my turbo board... :?

Keith

 

[marshman]

Not meaning to butt in...

I have the other board that Keith built and for what it is worth, it worked right out of the gate. I did make sure to triple check all the connections before powering up.

How about a picture or two?? Might be something another pair of eyes could spot right off??

mm

 

[MartyMart]

Shit, sorry Keith - mixing up 5532/5534 whilst looking for a problem which
isn't there.
Work got in the way for a bit, It's stock right now and working fine.
I'll get the Turbo back in when I can and let you know what happens, may be
after the weekend now.
Unless my "removal" fixed an issue, then it looks like the Turbo board may have
a problem.
I'm generally careful and accurate when soldering etc, but we all make mistakes.
Fingers crossed !!
Marty.

 

[MartyMart]

Hi Keith, about to get this re-wired and came across something in the
instructions.
The photo of the "lifted" 47k is the lower one nearer to the 12v regulators
and this is what I used last time, however the "text" says the one nearest to the
letter "L" of LeftVCA on the board.
Is it the lower one as pictured or the higher one nearest the letter "L" ??

Ta,
Marty.

 

[SSLtech]

Marty, the two 47ks are completely interchangeable; either works fine.

-You need me to send you a board? -I'll see if I can get hold of some connectors to send to you also.

-You've tried swapping the TL074, just in case something silly happened like it getting 'zapped'?

Keith

 

[MartyMart]

Hi Keith, give me 'til the morrow, to get it re-fitted "exactly" as you describe
in the PDF and let me see what happens.....
Have changed the TL074 but not the 2150A but neither got any nasty zaps or
incorrect voltages.
I have a feeling that it may have been my switch soldering being a little
rushed and perhaps a cold joint at the original GSSL sub board point.

MM.

 

[SSLtech]

Cool. -as and when you're ready, then.

-I just want you to make sure you know that whatever it takes to get it all happ'nin for you, I'm down for that.

:thumb:

Keith

 

[zebra50]

It's so good to see The Lab delivering the usual top quality customer support!
:thumb: :thumb:

Looking forward to getting my turbo board. The GSSL doesn't see much action, and I'm hoping this mod will make it a little more usable.

 

[MartyMart]

[quote author="SSLtech"]Cool. -as and when you're ready, then.

-I just want you to make sure you know that whatever it takes to get it all happ'nin for you, I'm down for that.

:thumb:

Keith[/quote]

Your help and expertise is VERY much appreciated
( In case you didn't know !! )

AAlright ... caalm down caalm down !
( Harry Enfield scouser in black curly wig, for those who don't know )

Marty.

 

[SSLtech]

:twisted:

Keef

 

[MartyMart]

HOUSTON .... WE HAVE LIFT OFF !!!!



Yet to test audio but the meter does NOT peg now and voltage readings are
looking good, put the chips back in and all looking good also
Keith,
I don't know for sure what it was, either my "DIY" connections caused a problem
or the soldering to the ratio switch was "duff"
This time, I followed your instructions "to the letter" and made all fresh connections
to good de-soldered points on the bottom of the board ( main board )
For anyone else doing this, take your time and make GOOD connections as described
by Keith in the PDF.

Cheers, off to fire her up across the main mixer buss ......

MM.

 

[MartyMart]

Sounds FANTASTIC !! :green:

I'm very happy with it and will leave it as "Turbo only" - why make the unit
less accurate to mono and bass end stuff ?

Wonderful stuff, thanks a bunch Keith and Rochey for doing this.

Marty.

 

[SSLtech]

Yay!

:thumb:

:guinness:

[quote author="MartyMart"]I'm very happy with it and will leave it as "Turbo only" - why make the unit less accurate to mono and bass end stuff ?[/quote]
Well, even as the original advocate of dual-sidechain stuff, I still maintain that for submix application (drum buss within a larger mix etc,) there's an excellent argument to be made for the compression being sensitive to center material, since that may have more apparent loudness WITHIN a mix sometimes...

-But by all means keep it one way or the other if you don't want to drill another hole in a finished case. -Personally I reckon that for a NEW build, the turbo is a MUST, and front panel switch provision should be made.

...Now... get some heatshrink on those pin connections, before I send the boys round! :twisted:

:wink:

Keef

 

[MartyMart]

[quote author="SSLtech"]Yay!

...Now... get some heatshrink on those pin connections, before I send the boys round! :twisted:

:wink:

Keef[/quote]

Ha - knew you would say that :wink:
It's very stiff almost solid core wire, so it will NOT move a mm !!

You mean that the GSSL "mode" may be useful across a drum buss ?
I have a spare "hole" that was ready for a side chain pot, so could install
the required switch !
No room for side chain boards in this GSSL but another will come along quite
soon.

MM

 

[amorris]

semantics police!!!!

almost solid core

is that not like "almost pregnant"?

 

[MartyMart]

[quote author="amorris"]semantics police!!!!

almost solid core

is that not like "almost pregnant"?[/quote]

OK, it's stranded solid core AND pregnant :green:

 

[SSLtech]

[quote author="MartyMart"]You mean that the GSSL "mode" may be useful across a drum buss ?[/quote]
Yessindeedie!

[quote author="MartyMart"]I have a spare "hole" that was ready for a side chain pot, so could install the required switch ![/quote]
Do it, man!!!

Seriously, I in no way wish to condemn the unmodified GSSL, -just that the CHANGES which Jakob built into the design do -in my opinion- make it much LESS suitable to overall buss compression, which is what the original was designed specifically for, and what so many people expect it to do once built.

-The changes which Jakob built in DO -in my opinion- make it MUCH better at drum buss compression.

Having TWO units would make it fantastic in terms of the ability to 'crush' a drum buss with one in GSSL mode AND run a second unit in 'Turbo' mode, thereby getting the best of both worlds!

However, I do encourage people to discover for themselves the new 'character' of the units, and where they think either mode works well for them, or for their typical style of project. -Not ALL projects respond the same after all.

Keith

 

[Rochey]

thrilled to hear you got it working.

/R

 

[diylan]

Sorry for reviving this old thread, but I'm having very very similar issues and I'm looking for some help!

When the turbo board is connected, and ICs socketed, the meter pegs when taken out of bypass. If I set the ratio @ 2:1, attack @ 30ms, and release @ .1s I can get the meter to show somewhere around 16db of reduction. A little more "gain reduction" at .3s release, but those are the only settings that don't max out the meter.

I've taken voltage readings on the TL074 socket and they don't seem normal:
1: 3.18
2: 3.41
3: 0
4: 12
5: 0
6: 0
7: 2.8x (drops slowly in .01 increments when taking reading)
8: -.04
9: -.04
10: -.01
11: -12
12: 0
13: 3.41
14: 3.71

Also, my point "C" reads 0vdc when engaged, .05 when in bypass. And I've got very similar low resistance readings across R6.

Sorry for the info dump, but I tried this thing connected every appropriate way I could imagine. Switched turbo and hardwired turbo, I've lifted and tested all the resistors and diodes, and still it persists. Without the turbo connected the GSSL works as normal.

Any thoughts? ???

 

[diylan]

Bump