GSSL SuperSC board

[SaMpLeGoD]

Hey Peter... yes I' using it the NE5532AP... I'll try to increase the trim to one of 20k that I have on my parts bin, so I'll have "extra room" to increase the Supere SC output stage, insted of changing the R14! I'm using the 47K resistor on the + leg of the Threshold pot! What you said appears to be right to me Marten!
Thanks Marten for charing your experience! you both helped me a lot, I really apretiate that!
Just one more question: how can I test if I'm loosing or not gain reduction/ threshold sensivity on the SC PCB without removing the SC and putting the 2x 47K back again? What´s suppose to happen? is there any easy way to verify that?

Thanks!

Cheers :guinness:

Eddie :thumb:

 

[Harpo]

[quote author="SaMpLeGoD"]Just one more question: how can I test if I'm loosing or not gain reduction/ threshold sensivity on the SC PCB without removing the SC and putting the 2x 47K back again? What´s suppose to happen? is there any easy way to verify that?[/quote]

Switch the SC to bypass mode and feed the SC at both inputs (left side of R12/R13) with a signal. Adjust the trimmer VR1 that way, so the left side of R18 (close to SC out) measures the same.

Increase R14 to 6.8K (or any other value between 2K and 12K, but 6.8K keeps the wiper of the trimmer more in it's center position.) With R19=12K, the sum of R14+VR1 should also measure 12K, so it can be replaced by this fixed value, avoiding the hassle of adjusting this gain stage to set the voltage gain of this inverting op-amp to -1.
If you don't use the compressor as a stereo bus unit, but only for a single canal, eighter increase R15 from 10K to 20K or increase the sum of R14+VR1 to 24K.

-Harpo

edited for clarity

 

[SaMpLeGoD]

Thanks Harpo!

Is there any problem if I only change VR1 with a 20k trim and regulate it to VR1+R14 to 12k?

Cheers :guinness:

Eddie :thumb:

 

[Harpo]

[quote author="SaMpLeGoD"]Is there any problem if I only change VR1 with a 20k trim and regulate it to VR1+R14 to 12k?[/quote]
no, but I would probably take the trimmer as spare for another project where it may be more useful. :wink: :green:

 

[SaMpLeGoD]

Hehehe... thanks Harpo, but the trim is already from my "parts bin" so... no problem in change it! I'm leaving the 10k trim from another project instead :wink:
Thanks for all the support you guys gave me... apretiate that!

Cheers :guinness:

Eddie :thumb:

 

[SaMpLeGoD]

It's working! it's working! hehehe thanks guys!

Cheers :guinness: :guinness: :guinness:

Eddie :thumb:

 

[clintrubber]

Hello,

Kind but serious request.

Please note I've pulled the schematic in which I gave an emulation-circuit of the two Thrust-modes.

As I consequence I ask you to remove/take back/change any copies of
the circuit-diagram that you might know about and have made available on-line. This holds as well for documentation with an added PCB-layout: please remove the schematic.

No further distribution either please; this circuit cannot longer be made available online.

Thank you for your cooperation.

 

[12afael]

:shock: Done

any issue with api?

 

[clintrubber]

[quote author="12afael"]:shock: Done

any issue with api?[/quote]
Thanks, much appreciated!

Regards,

Peter

 

[vertiges]

Hi,

I'd like to addthe superSC to my second GSSl and I'm wondering if my the Amveco 62053 will be strong enough. (It's a 15VA-500mA)

Please enlight me,

eD)))

 

[crisotop]

Switch the SC to bypass mode and feed the SC at both inputs (left side of R12/R13) with a signal. Adjust the trimmer VR1 that way, so the left side of R18 (close to SC out) measures the same.

I just tried to do exactly that, but as soon as i turn the power supply (the whole ssl clone) on, I can't see any signal on the output of the sidechain board? If I turn the power off, there's at least a slightly distorted sine to see?

EDIT: Alrigth, my fault, the voltage on the output was way to high?! Seems like the circuit amplifies the signal a lot, I can't even get near the same input voltage, even with the trimput fully down? But the compressor is working as it should, got good threshold range, adjusted the pot per ears with a 1k Sine Wave.

Any ideas?
Thanks, Christoph

 

[Harpo]

[quote author="crisotop"]I just tried to do exactly that, ....[/quote]
Hi Christoph,

try again, but don't measure at the output of the sc-board (this is current, not voltage, so called virtual ground, the summing node at pin 1 of the sc-VCA). ...so the left side of R18 (close to SC out)... , or measure at the output of ic-1 (pin 1) on your sc-board.

-Harpo

 

[crisotop]

Thanks Harpo,

This is where I measured, left side of R18 ist Sidechain Out, or am i missing something?

regards
christoph

 

[Harpo]

measure there

-Harpo

 

[crisotop]

allright thanks - but isn't that the right side of R18 then? because the left side of R12/R13 is the input?

Thanks Harpo
Christoph

 

[Harpo]

R12/R13 is the input of the summing amp x3. The sidechain-vca need its own input resistor (R18=47k), as the 2 original 47k's on the gssl-board have been taken out to get comfortable soldering lugs for send/return to/from the sidechain-board. see non restricted part of the schematic here

-Harpo

 

[vertiges]

Hello,

I'm trying to make the B.O.M. for the Super SC.
It's almost finished but I need confirmation for :

1)Do the C14, C18 (on the 06.07.2007 Rev A. PCB) use the same components of tje 4x Cbypass ? Can I use : Panasonic CAP .1UF 50V POLY B SERIES / Digikey : P4593-ND ?

2)Do the C21, C22 use the same components of the 2x Cpsu ? Can I use : Nichicon CAP 47UF 35V ELECT PW RADIAL / Digikey : 493-1858-ND ?

3) For the little values capacitors, I'm talking about the :

22p C1, C3, C11, C13, C23, C24
1n5 C5, C6
4n7 C9
15n C10
22n C4
47n C8
56n C20*
68n C2, C12
82n C19*

I've read that it was better to use ceramic C0G, NP0 instead of X7R.
The C0G, NP0 are VERY expensive !!! Is there an alternative ? What do you use ?

Thank you very much,

eD

 

[barclaycon]

COG ceramics, or indeed NPO (same thing really) should be used for the 22p capacitors.
Over here they are normally very cheap (about 5p).
Nothing to be gained by using NPO for things like the 0.1uF caps
The other capacitors can be polyester.

I used 22uF for the bypass caps.

 

[vertiges]

barclaycon,

Thank you for answering !

For the 22pF, I found the 478-4204-1-ND from Digikey. (cheap)
For the other, I took polyester.

By the way why did you use .22uF instead .1 uF for the bypass caps ?

eD

 

[sonicwarrior]

[quote author="vertiges"]
By the way why did you use .22uF instead .1 uF for the bypass caps ?
[/quote]

I think he meant the electrolytic capacitors (47 uF in my BOM).
Instead of the 100nF (Cbypass) you could e.g. also use 150nF if you already have lots of them. I would just use a cheap ceramic type (I buyed lots of them to get them really cheap as you need much 100nF caps for bypass purposes, e.g. I have 1109PHCT-ND from Digikey which is an axial type).

The sidechain is AFAIK not in the audio path therefore the capacitors are not that critical.

But it is always a good idea to use better electrolytics for their longer lifetime.