GssL 20th Anniversary edition

[Gustav]

Personally I don't care about anything but more ratio's (limit), attack/release times....Hpf, bypass and Mix/Blend. I don't care about colour option, I don't even know what it is. I'm kinda scared of it having too many 'options'. Just please, simple board with good features, good sound....no mistakes.

The whole point of doing this layout is to gather up the most common mods and do a layout. Also, for the board, we dont pay as much per square inch of PCB as we used to, so hopefully, we can space things out nicely, maybe even have a dedicated supply layer, and not end up paying more than the old board used to cost to make.

In doing so, I thought of including the color board as a fun way to introduce a new layer of DIY to the project. Maybe it can open up something interesting. It might also turn out, no-one uses it. You won't have to populate or use it.

Based on my experience, I dont believe there is a huge demand for blend. Most just parallel it in the DAW. You won't have to populate it or use it.

HPF - extremely common and useful feature, especially the filter posted by Magnus, which I included. You dont have to populate or use it.

Setting up the att/rel/ratio switches to utilize all steps. For the ratio, the added values are extremely useful, but for the att/rel, its just to make sure the board is set up to drop in values to use all steps, and also to show that thats all it is - Dont have a 680K resistor? Just put in 750K, right? Most builders dont think that way, and this is an attempt at a nudge to make them learn and realize, "oh, is thats all that resistor does".

As you see, I am getting requests to add more features, and requests to remove them all in the same thread, but I think what I have drawn up now is a good base.

I would remove the NE5532 footprints for in- and output if I wasn't aware that the costs and even availability of the THAT chips could leave some people out, I would remove the DOA footprint if I didnt see people actually doing it, and I would remove the blend if I didnt decide to bow to popular demand.

If you just want to do the basic version, the easiest thing would be to build a unit using the basic GssL board

Gustav

 

[Gustav]

If anyone has input on the schematic as is, that would be wonderful.

We will leave it for a bit, come back to it to read through it/check for errors again, and then start laying out a board!

Gustav

 

[Script]

Polarity of IC14A inputs is correct? Forget it. I think it is, cos of flip at buffer after VCA.

 

[Script]

Am looking at schematics only on phone... which might explain it...

Can't seem to find IC11B and IC12B ? The A's are on the outputs.

 

[wlinart]

If anyone has input on the schematic as is, that would be wonderful.

We will leave it for a bit, come back to it to read through it/check for errors again, and then start laying out a board!

Gustav

Is there also a DOA on the output? I see one on the input of the schematic, but not on the output. Am i just overlooking it?

 

[Script]

Audio signal after VCA is handled by IC15A, while IC15B handles CV (E drive port).

Not sure but often see channel separation mentioned in this context.

LM833 states amp-to-amp isolation as -120dB (the right thing to look at?). So not an issue, as long as 833 are used, I assume.

 

[Gustav]

Gustav

Polarity of IC14A inputs is correct? Forget it. I think it is, cos of flip at buffer after VCA.

Correct.

I was scratching my head over why the crush n blend schems I looked up did not take this into account, so maybe its me who overlooked something. The way I set it up looks right to me (I usually just go over it and mark + and - in the path, then add them up to see where Im at. If I didnt revese 14A, the clean would be flipped).

Gustav

 

[Gustav]

Am looking at schematics only on phone... which might explain it...

Can't seem to find IC11B and IC12B ? The A's are on the outputs.

Nope, just forgot to unhide them - will get this sorted.

 

[Gustav]

Is there also a DOA on the output? I see one on the input of the schematic, but not on the output. Am i just overlooking it?

There is no DOA on the output - to do the cavendish mod, you would add a transformer on the output. Ive planned to mark the single ended output on the PCB, so you can wire one up, but have had no plans to add a footprins for any specific transformer.

 

[Gustav]

Audio signal after VCA is handled by IC15A, while IC15B handles CV (E drive port).

Not sure but often see channel separation mentioned in this context.

LM833 states amp-to-amp isolation as -120dB (the right thing to look at?). So not an issue, as long as 833 are used, I assume.

I dont see how opamp crosstalk would ever be an issue here.

Gustav

 

[wlinart]

There is no DOA on the output - to do the cavendish mod, you would add a transformer on the output. Ive planned to mark the single ended output on the PCB, so you can wire one up, but have had no plans to add a footprins for any specific transformer.

But the cavendish mod also includes a DOA, not only the transformers. Would it also be possible to add the footprint for the DOA, and then indeed the output which connects to the transformer?

 

[Gustav]

But the cavendish mod also includes a DOA, not only the transformers. Would it also be possible to add the footprint for the DOA, and then indeed the output which connects to the transformer?

The opamp for the VCA stage, which also drives the output, is indeed replaced in the cavendish mod - I decided to stick to the input replacement footprint.

With the colour footprint implemented, it would not be the opamp driving the output anyway, and if you really want a DOA there, you can bypass the attenuator and put a colourmodule with a DOA in there

Again, walking the tight rope of trying to get everything in there, but not just throwing the kitchen sink at it.

Gustav

 

[Script]

+/- to ratio ladder hidden. Again, only looking at it on phone...

 

[Script]

I dont see how opamp crosstalk would ever be an issue here.

I guess I was thinking A bleeding into B. Stray signal pickup (2180 datasheet p. 9).

 

[Gustav]

I guess I was thinking A bleeding into B. Stray signal pickup (2180 datasheet p. 9).

I think were at a level of concern where we would also start looking into cooling of the system, but fair enough - Ill seperate the opamps.

Gustav

 

[Gustav]

+/- to ratio ladder hidden. Again, only looking at it on phone...

Ill add the tags on the schematic.

 

[Script]

I think were at a level of concern where we would also start looking into cooling of the system [...]

I hear you

 

[Script]

Noticed that, as is now, K1 and K3 hard bypass relays sit only on THAT output, not on standard gssl output.

(ATST, no bypass switch in SC -- never liked it anyway.)

 

[Gustav]

Noticed that, as is now, K1 and K3 hard bypass relays sit only on THAT output, not on standard gssl output.

(ATST, no bypass switch in SC -- never liked it anyway.)

Nice catch - most of those would probably stand out while routing, but great to get them sorted.

Its a hard bypass, so not bothering to add the old type.

Gustav

 

[desol]

The whole point of doing this layout is to gather up the most common mods and do a layout. Also, for the board, we dont pay as much per square inch of PCB as we used to, so hopefully, we can space things out nicely, maybe even have a dedicated supply layer, and not end up paying more than the old board used to cost to make.

In doing so, I thought of including the color board as a fun way to introduce a new layer of DIY to the project. Maybe it can open up something interesting. It might also turn out, no-one uses it. You won't have to populate or use it.

Based on my experience, I dont believe there is a huge demand for blend. Most just parallel it in the DAW. You won't have to populate it or use it.

HPF - extremely common and useful feature, especially the filter posted by Magnus, which I included. You dont have to populate or use it.

Setting up the att/rel/ratio switches to utilize all steps. For the ratio, the added values are extremely useful, but for the att/rel, its just to make sure the board is set up to drop in values to use all steps, and also to show that thats all it is - Dont have a 680K resistor? Just put in 750K, right? Most builders dont think that way, and this is an attempt at a nudge to make them learn and realize, "oh, is thats all that resistor does".

As you see, I am getting requests to add more features, and requests to remove them all in the same thread, but I think what I have drawn up now is a good base.

I would remove the NE5532 footprints for in- and output if I wasn't aware that the costs and even availability of the THAT chips could leave some people out, I would remove the DOA footprint if I didnt see people actually doing it, and I would remove the blend if I didnt decide to bow to popular demand.

If you just want to do the basic version, the easiest thing would be to build a unit using the basic GssL board

Gustav

Hi Gustav. Thanks for the message! No I do NOT want to build the regular version. I've been posting hopefully that someone 'would do' an UPDATED version with all the fixes and good mod's included. Making it so that a feature can be populated or not is a good solution I think. The blend is nice imo. It saves faders on my analog console and it's something I use all the time on plugins. I've seen it on a few stereo mix compressors and it's a good feature I think.