GSSL HELP THREAD!!!

[Gustav]

3.  Meter calibration? Its hard to tell if you're being  super picky, or if there is a huge discrepancy. Ive never felt the need to trim the meter, so it may be

A: a case of expecting too much of it.
B:different metering scale from you DAW
C:an actual error.
D:?

Are we talking 0,5dB differences or 5dB differences within 10dB of compression?

Hi Gustav, I will redo proper measurement but there was something between 3 and 8 dB difference depending on how much GR was going on. I am monitoring all of this in a Protools HD with a scale in dB FS.

Try compressing 20dB with a slow release and dial the release from slow to fast, and see how much the analogue metering range changes.

This may give you a clue if there is a real problem or not.

Edit:And as a side note - very accurate meters cost money. If you're using the little round meter, you can only use it to verify the needle is moving a little or a lot.  I have never had problems using the edgewise meter with the 20dB scale, but I am not the type of person that obsesses about these things. For a much faster meter, I dont know if theres anything better than the actual Sifam within reasonable sense.

In case you are measuring with sine wave inputs, I have no idea whats going on getting 8dB discrepancies, sorry.

Gustav

 

[thomasdf]

The meter is behaving fine. It's the 8027B from Hairball and indeed it is not up to the SIFAM in terms of build quality, speed and acuracy but not the same price also. Anyway,  it seemed like I had some problem with my output gain pot and my meter trimpot. I fixed it all and now the meter is showing the right amount of GR up to 12dB and that's absolutely fine with me. After 12dB it drifts by around 2dBs but I don't care.

My 7815 regulator is going wrong from time to time, you were right. Very strange! I will change it ASAP.

 

[rosestudios]

Hey guys,

I have a turbo and super sidechain board and I was wondering how to have them both switchable on a single GSSL board?  I have seen posts regarding this but they're sort've unclear to me and the diagram pdfs have all vanished, if anyone has these pdfs or could provide a clearer explanation of how these boards work off of a single SPDT switch that'd be great, thanks.

 

[gyraf]

The 8027-B meter is a "Class 10" type - at +/- 10% reading.

Definitely good enough for the GSSL for all realistic needs, but don't expect detailed and absolute readouts (you can't get precision readout anyway with an analogue meter because of the timing vs. the meter ballistics).

Jakob E.

 

[TheBassgasm]

Okay,
since I still wasn't able to find the instrunctions I searched I'm just going to measure every VCA and IC.
Do I best do this with them all in place or should I take them out for measuring purposes?

Cheers 

Edit: I just measured the obvious ones:

+15V: 14,99V
-15V: -15,02V

+12V: 12,7V
-12V: only 0,6V

The bridge rectifier puts out 47,6V

So my 79L12 is fried, right? Does this explain the behaivour of my GSSL, or is there something else wrong with it?

Also, would it make sence to up the amperage of those rectifiers to, say, 1A? Just to be shure to be albe to drive multiple button LEDs, meter lighting, turbo extensions etc. in the future?

 

[Harpo]

+12V: 12,7V
-12V: only 0,6V

double check sign. Most often the positive voltage regulator 78L12 is hanging on startup, not the negative one.

So my 79L12 is fried, right? Does this explain the behaivour of my GSSL, or is there something else wrong with it?

Latching, not fried. See previous sentence.

Also would it make sence to up the amperage of those rectifiers to, say, 1A?

Look up your parts datasheet in order to know the continuous current value. Your part might already be OK.

Just to be shure to be albe to drive multiple button LEDs, meter lighting, turbo extensions etc. in the future?

whatever 'multiple button LEDs' might be (maybe illuminated switches)...

 

[Mazieresantoine]

Hi,

my GSSL from Gustav is finish, but i have a little problem
In 2:1 the comp is ok, but the behavior in 4:1 and 10:1 is the same, and it seems to be more a 10:1 reaction.
I check the resistor 1M8 and the 3M9 out of the circuit and their good, i check also the 510k before the 1M8 and it's good too
So if you have an idea of what i can check...

Thanks

 

[TheBassgasm]

double check sign. Most often the positive voltage regulator 78L12 is hanging on startup, not the negative one.

Okay, so I measured it again and certainly the 79L12 is "latching" (what does that mean btw.?). Measured -0,65V this time. The +12 supply is fine, though.

[...] whatever 'multiple button LEDs' might be (maybe illuminated switches)...

Yep exactly. I read a lot about the current beeing too limited to safely run illuminated switches, addon PCBs etc. - is that even the case?

Cheers!

 

[Gustav]

Hi,

my GSSL from Gustav is finish, but i have a little problem
In 2:1 the comp is ok, but the behavior in 4:1 and 10:1 is the same, and it seems to be more a 10:1 reaction.
I check the resistor 1M8 and the 3M9 out of the circuit and their good, i check also the 510k before the 1M8 and it's good too
So if you have an idea of what i can check...

Thanks

I started by looking for a short between 510K and 270K on the side of the switch to see if you're running these in parallel in both positions on the switch side, but it seems unlikely they should be shorted, when I check with the PCB.

510K shorted to 68K?

Just try clearing up the area in the schematic blind, and if you find a short, check back with what was going on, maybe!? (What I would do )

Edit:Or, realizing I reversed the switch looking at it - between 1M2 and 1M8 on the side of the switch(could be a good candidate checking with the board layout).

Gustav

 

[frazzman]

Just a quick idiot check here - I've got a couple of rev 12s working nicely here...

Just a question in regards to the HPF connector on this revision:

I wired up a rotary switch with selectable caps to make use of the new onboard side chain HPF connector.  I wired switch pole to pin 1 and end of the cap chain to pin 3.

All appears to work but the difference between different values seems negligible at least sonically...

Is it that subtle and did I wire it up right? What's the middle pin on this connector for?

Thanks guys

 

[Harpo]

..a rotary switch with selectable caps ... and end of the cap chain...

Might be a series connection of whatever caps values for whatever desired cutoff frequency, or not.

All appears to work but the difference between different values seems negligible at least sonically...

What values. Only the sidechain is listening to reduced bandwidth in order to lesser compress out of frequency range signals.

Is it that subtle and did I wire it up right? What's the middle pin on this connector for?

Subtleness depends on program and your kept a secret parts values and connection.  Not knowing how you wired it, no idea if you wired it up right. Either the 1st. and center pin is used for a 2-pin connector with 0.1" pin spacing, or the outer pins are used for a 2-pin connector with 0.2" pin spacing. A 3-pin connector with 0.1" pin spacing leaves one pin unused.

 

[frazzman]

..a rotary switch with selectable caps ... and end of the cap chain...

Might be a series connection of whatever caps values for whatever desired cutoff frequency, or not.

All appears to work but the difference between different values seems negligible at least sonically...

What values. Only the sidechain is listening to reduced bandwidth in order to lesser compress out of frequency range signals.

Is it that subtle and did I wire it up right? What's the middle pin on this connector for?

Subtleness depends on program and your kept a secret parts values and connection.  Not knowing how you wired it, no idea if you wired it up right. Either the 1st. and center pin is used for a 2-pin connector with 0.1" pin spacing, or the outer pins are used for a 2-pin connector with 0.2" pin spacing. A 3-pin connector with 0.1" pin spacing leaves one pin unused.

Pretty sure I'm ok then....

I went with the values Jakob posted a while back except I added in 40hz as well - from memory I used :
40hz = 390nf, 80hz = 220nf, 160hz = 100nf, 300hz = 68nf

Wired up on a 2 pole 12 pos switch - 1 leg of each cap to respective rotary pin leg, other leg wired in series with all other caps

Pin 1 is no cap but just a link so as to provide SC bypass

If I stick my DMM meter prongs with 1 end at the end of the caps series and the other on the switch pole I'm reading the  correct capacitance at each position.

Switch pole wired to HPF connector pin 1, end of caps series connected to pin 3

I think I just made the mistake of expecting the effect to be more pronounced.

The switch seems to be substituting the respective cap value into the circuit - so provided I didn't misinterpret anything I think it should be working as expected.

Any obvious way for measuring affect of side chain HPF in each pos?

 

[kante1603]

Harpo already explained it well,the hpf filtered signal is in the sidechain,not your normal audio.
Best to test is use your ears.
So here's a quick test.You need a wide range signal,for example a drum set.This will contain all frequencies from low to high.Best to have an uncompressed set,e.g. a pure untreated recording or to take a jazz recording.
Run it through your compressor with hpf set to lowest or off position and set it to a high ratio and low threshold so it impacts the signal in a heavy way.
Mainly the bass drum will make the compressor work and affects the complete signal,if there is ambience you can now clearly hear it to become louder.
Now start to check the various hpf switch positions:The higher you go in frequency the less compression you will have on your signal.This is because you now start to cut off the low frequencies in your sidechain.Remember low frequencies contain the most energy,so once they miss in the sidechain the compressor will not work so hard anymore.
Hope that makes sense to you,


best,


Udo.

 

[turk sanchez]

...just finished mine (had to wait for IEC to come in).

Powered it on ~ VU meter lights worked for a couple seconds, then they went dark (8027-b 1ma).

The compression is not working...the only knob that does anything is makeup gain, and that only works when the unit is in bypass.

First thing I am going to do is check the wiring for the bypass switch. I am red/green colorblind ~ had to get a friend to look at the pics from the build guide (PCB Grinder SC Ed). I will double check this first (when I can get a friend over to help w/the colors). The color thing is always the hardest part for me w/DIY.

PS...page 17 in the gssl sc assembly guide...really hard to tell what the dark colored wires are (for me).

At least it's passing audio, no smoke, powers up, sounds clean and quiet and I like the sound of the makeup gain.

 

[gyraf]

.the only knob that does anything is makeup gain, and that only works when the unit is in bypass.

Then bypass switch is wired wrong. Re-check.

Jakob E.

 

[Mazieresantoine]

Hi,

my GSSL from Gustav is finish, but i have a little problem
In 2:1 the comp is ok, but the behavior in 4:1 and 10:1 is the same, and it seems to be more a 10:1 reaction.
I check the resistor 1M8 and the 3M9 out of the circuit and their good, i check also the 510k before the 1M8 and it's good too
So if you have an idea of what i can check...

Thanks

I started by looking for a short between 510K and 270K on the side of the switch to see if you're running these in parallel in both positions on the switch side, but it seems unlikely they should be shorted, when I check with the PCB.

510K shorted to 68K?

Just try clearing up the area in the schematic blind, and if you find a short, check back with what was going on, maybe!? (What I would do )

Edit:Or, realizing I reversed the switch looking at it - between 1M2 and 1M8 on the side of the switch(could be a good candidate checking with the board layout).

Gustav

Hi Gustav

I check, there is no short cut in this section.

I check the resistor value and it's ok.

Do you think there is another thing i can check?

Thanks for your help

 

[Gustav]

Hi,

my GSSL from Gustav is finish, but i have a little problem
In 2:1 the comp is ok, but the behavior in 4:1 and 10:1 is the same, and it seems to be more a 10:1 reaction.
I check the resistor 1M8 and the 3M9 out of the circuit and their good, i check also the 510k before the 1M8 and it's good too
So if you have an idea of what i can check...

Thanks

I started by looking for a short between 510K and 270K on the side of the switch to see if you're running these in parallel in both positions on the switch side, but it seems unlikely they should be shorted, when I check with the PCB.

510K shorted to 68K?

Just try clearing up the area in the schematic blind, and if you find a short, check back with what was going on, maybe!? (What I would do )

Edit:Or, realizing I reversed the switch looking at it - between 1M2 and 1M8 on the side of the switch(could be a good candidate checking with the board layout).

Gustav

Hi Gustav

I check, there is no short cut in this section.

I check the resistor value and it's ok.

Do you think there is another thing i can check?

Thanks for your help

Sorry, but I won't be able to help further. Thats the only placeI would know to look specifically. Two ratios are the same, so my logic says it must be a short causing the value to stay the same, even when you are switching. If I had understood the ratio switching right (which it seems I hadn't), a short between 1M2 and 1M8 on the switch side would have made the value the same at position two and three.

Gustav

 

[Graph]

Hi, sorry that i couldnt read or find much information, my package from PCBgrinder arrived yesterday, and there are some resistors and trimpots which arent in the kit(the ones marked as % in the PCB), i havent finished soldering yet anyways.

My doubt is what should i do about these resistors and trimpots, what resistors should be used using 2180B. I only found this picture i dont know if it is accurate.

http://diy.fischerworks.com/diy_pictures/ssl_overlay_web.png

Thanks and sorry if this is a questioned before, couldnt find anything besides this.

 

[Gustav]

Hi, sorry that i couldnt read or find much information, my package from PCBgrinder arrived yesterday, and there are some resistors and trimpots which arent in the kit(the ones marked as % in the PCB), i havent finished soldering yet anyways.

My doubt is what should i do about these resistors and trimpots, what resistors should be used using 2180B. I only found this picture i dont know if it is accurate.

http://diy.fischerworks.com/diy_pictures/ssl_overlay_web.png

Thanks and sorry if this is a questioned before, couldnt find anything besides this.

Components marked with % should not be mounted when using the pre-trimmed VCAs included.

If you have doubts of this manner, refer to the assembly guide on the site. If theres no mention of something puzzling you, it may help to take a look at the pictures for reference when proceeding.

Hope that helps

Gustav

 

[Graph]

Great Thanks Gustav, i was about going to buy those resistors, i will only need to buy pots, chassis and all mounting stuff.

I didnt saw there was an assembly guide, right now i figured out.