GSSL SuperSC board

[Harpo]

one question.. if i want the external sidechain to be 2 mono 1/4 jacks.. should i plug 0v just in paralell from the board with 2 separate wires? one to each jack`s sleeve

As you like. Just make sure, you use isolated sockets, else this might cause a ground loop.

 

[ptron]

safe! thanks for that! isolated as in closed from inside yeah? ...

thanks man

 

[Harpo]

safe! thanks for that! isolated as in closed from inside yeah?

isolated as in -not conducting- to the case.

 

[ptron]

propa! thanks harpo i got some of those but they got metal where it makes contact with the case  ??? theyre probably wrong ones

i just got other questions ...

1 if i just plug it as it is meant to (1 TRS for in out and 0v) do i have to worry about the plug being insulated??

and

2 if i want to adapt 1/4 inch plugs to my design (for audio signal) should they be trs and i just go on paralell with the xlr`s? or should i use mono jacks? (if they are mono how do i connect them?)

i realize this one is not related to ssc topic but kinda had something to do with jacks sorry

cheers!!

 

[Harpo]

1 if i just plug it as it is meant to (1 TRS for in out and 0v) do i have to worry about the plug being insulated??

Yes.

2 if i want to adapt 1/4 inch plugs to my design (for audio signal) should they be trs and i just go on paralell with the xlr`s? or should i use mono jacks? (if they are mono how do i connect them?)

A little hookup drawing might illustrate it easier than my wording. Only left side chanel shown for simplicitys sake.
Here you can use your unisolated TRS sockets for inputs and outputs. The 'S' from TRS is then already connected to shield/case gnd, that is ALWAYS connected to safety ground. There is NO connection to 0V. If you use shielded cable for hookup, the shield of your cable inside the gssl only connects at one end, else use twisted wire for each pair.
Better don't use mono sockets for in/out, otherwise they must be isolated from case and require a non standard external wiring.

 

[ptron]

ok so let me see if i understand correctly.. the case is already grounded so i shouldnt connect the 0V to my trs plugs at all? and on the xlr i just plug from the pin number 4 (the one on top with no number) to the ground pin? not making contact with the 0v wire from the board at all??? (black cable in your draw)

and

for the TRS on the SSC ext. do i hook it up like i just described too?

thanks so much harpo as usual u rock !! i already ordered everything!!! damn shipments take a while tho but im trying to compile all my doubts before i start messin it up!

 

[Harpo]

ok so let me see if i understand correctly.. the case is already grounded so i shouldnt connect the 0V to my trs plugs at all? and on the xlr i just plug from the pin number 4 (the one on top with no number) to the ground pin? not making contact with the 0v wire from the board at all??? (black cable in your draw)

yepp. Your 'pin4' is connected to the XLR housing internally. If your XLR doesn't come with a 'pin4' (XLR with plastic/non-conductive housing), link XLR-pin1 to your shielding -maybe 19"- metal enclosure instead. For usual, linking pin1 to pin4 is the easier way, just make sure that the XLR to case is a zero-ohm connection, so a non-conductive coating applied to your case might need to be scrapped off in this spot to give safe contact. Using TRS sockets instead or in a parallel config to the XLR connectors should do exactly the same, so when using isolated TRS sockets, the 'S' solder lug needs a wire connection to your case.
The GSSL operates the voltage difference between XLR-pins2/3 or between T/R from a TRS connector and returns an electronically, not cross-coupled, balanced operated signal to XLR-pins2/3 or T/R. XLR-pin1 or 'S' from a TRS connector is only used for the cable shield.

for the TRS on the SSC ext. do i hook it up like i just described too?

No. This SSC stage is unbalanced, amplifying/filtering the potential difference between signal-pin and reference voltage 0V. That's why you use isolated TS or TRS sockets here. Preferably you use 2 separate TS sockets instead of a single TRS socket for external send/return in order to avoid a shorted out send stage when plugging in an external key signal by a TS plug.
Just keep case+safety ground and reference voltage 0V separate. You -not neccessarily- might link these two different potentials in exactly one spot, called star ground. You can make a -for whatever reason wanted- link not permanent by a ground-lift switch.

For a connection reference have a look at the Rane paper http://www.rane.com/note110.html

 

[ptron]

man thanks so much u are like oracle for us GSSL`rs and beyond

then for ssc i do need isolated no way round it : i get it now!

thanks also for the reference reading i apreciate all information i can get!!

im not sure there are lot of people that engrave pannels out here in mexico ... jeez i couldnt even find 19" enclosures anywhere!! any ideas on how to do it manually and end up lookin nice?

cheerios harpo u the best 8)

 

[ptron]

i got a question that belongs here i think...

the bypass on barclaycon's board.. is it bypassing the whole circuit or just the sidechain vca? .. and will it defeat makeup gain when its bypassed?

thanks !!

 

[Harpo]

Instead of rectified audio, the timing stage now is fed with 0V and the wiper from makeup pot gets disconnected. This way the meter sees 0V and stops moving and the audio-VCAs see 0V at their control port, which is the current-in=current-out  bypass condition for the VCAs.
Audio is still running thru the balanced line receivers, audio-VCAs and output driving stage, but now the VCAs don't change audio level, as makeup gain is defeated as well. Bypassing the whole circuit from XLRs in to XLRs out would require 4 DPDT relais.

 

[ptron]

thanks thats very helpful! im going to look into that hard bypass circuit

 

[barclaycon]

i got a question that belongs here i think...

the bypass on barclaycon's board.. is it bypassing the whole circuit or just the sidechain vca? .. and will it defeat makeup gain when its bypassed?

thanks !!

It's not a 'hard wire' bypass, it simply cuts the signal to the sidechain. It will defeat the makeup gain as well.

In fact there is a little mod that you can do which will improve the distortion figure when in 'bypass'.
Instead of just lifting the wiper from the Makeup gain pot, ground connection as well.

 

[ptron]

ah i think ive seen that mod around somewhere! will look around on my favourites im sure i dragged it there

thanks a lot for that mod man!!!

actually im in the middle of trying to draw a mod myself for the release... ill post when i do it in paint or sumfin more civilized

EDIT:

just posted it on the gssl help thread

 

[ptron]

good news!!! i got my boards on the post yesterday wohooo!!

started with the link and ic sockets and soldering resistors now!! double wohoooo!! will upload some pics when i got more beef about the subject .. well i got a slight problem tho.. i got my terminals here downtown mexico.. they seemed fine and they are the right pitch cus all the pins are where they should be 2.54mm.. BUT! they wont fit in the holes!!! they are too big. do i have to buy different terminals?? if so what sort of diameter should the pin be?  should i dremel these? to take lil bit off from the pins .. see if that works? ;D

thanks!!

btw my diodes didnt fit either.. what diameter lead should they be?
thanks a lot!!

 

[Harpo]

..BUT! they wont fit in the holes!!! they are too big. do i have to buy different terminals?? if so what sort of diameter should the pin be?  should i dremel these? to take lil bit off from the pins .. see if that works? ;D

btw my diodes didnt fit either.. what diameter lead should they be?

Brilliant plan.  : Sounds like turning the ceiling when a light bulb in your room needs exchange. ;D
The right tool for the job probably is a drill to get the diameter of your holes larger.
If the pcb has plated thru holes and the part in question connects to top and bottom side of the pcb thru this drill hole, just solder on top and bottom side.

 

[tomcat]

Hope this wasnt covered in the past

Im using Turbo board + dual SSC boards. Thinking about using just one external sidechain connector. Imho ist useless to have this seperate for both channels.

To do this im planing to mix both send signals via opamps and put it out to send. Input/Return other way round. Goes to two opamps (follower) and from there to the two sidechain return pads (to keep both channels isolated).

Is my thinking correct or do i miss something?

EDIT: I think i can skip the two opamps on the return, when not on "Ext" the two channels are isolated by the dual 8 pole rotary switch anyways

 

[Harpo]

Im using Turbo board + dual SSC boards. Thinking about using just one external sidechain connector. Imho ist useless to have this seperate for both channels.

To do this im planing to mix both send signals via opamps and put it out to send. Input/Return other way round...

The use of the Turbo is to compress both sides audio, no matter what signal polarity one side is related to the other. Inserting a mono/single processor/eq/whatever as described might sum up a signal to a signal with opposite polarity, giving 0V, abandoning the Turbo function.

 

[tomcat]

Yes i know. Was thinking about sidechaining with different signal (bass/...) - for this mono would be enough.

But youre right, i overlooked the fact to insert an eq into the sidechain, for this stereo would be usefull.

Thanks Harpo!

 

[ptron]

..BUT! they wont fit in the holes!!! they are too big. do i have to buy different terminals?? if so what sort of diameter should the pin be?  should i dremel these? to take lil bit off from the pins .. see if that works? ;D

btw my diodes didnt fit either.. what diameter lead should they be?

Brilliant plan.  : Sounds like turning the ceiling when a light bulb in your room needs exchange. ;D
The right tool for the job probably is a drill to get the diameter of your holes larger.
If the pcb has plated thru holes and the part in question connects to top and bottom side of the pcb thru this drill hole, just solder on top and bottom side.

hehe i know it seemed a bit backwards to me too! but thought the cost of ruining my SSC pcb over the cost of ruining a couple of 1n4001`s ... yet again your right..
altho... i was just wondering if the solder pad wont get pushed out from the pcb with the drill bit going thru...
the bigger holes would be the diodes and the 6 pin terminal that connects from GSSL.

what size holes should 1n4001 be?? i seen .34" sort of story so like 8mm kinda fing?

thanks !!!

 

[Harpo]

what size holes should 1n4001 be?? i seen .34" sort of story so like 8mm kinda fing?

The datasheet for parts lead diameter says 0.034" or 0.86mm for DO-204AL package, so use 1mm dia drill. Drilling from traceside should keep the solder pad on pcb.
Your 8mm kinda fing might look funny with the diode dropping thru  ;D