GSSL HELP THREAD!!!

[vertiges]

you're welcome ! :wink:

eD)))

 

[karl j]

I have some questions.

(1) On the control PCB, what goes in the 2 holes to the left of the attack and to the tight of to the "-" meter hole, and above the 0ABC holes for connecting to the main PCB? Is that a jumper?

(2) On the schematic it shows a 4k7 resistor for the meter cal, but the PCB has a 2k meter sensitivity. These are the same things, right? So which one/value is right?

(3) Also, the schematic shows a 330r strapped across the meter, do I need that on the B-style meter?

 

[vertiges]

[quote author="karl j"]I have some questions.

(1) On the control PCB, what goes in the 2 holes to the left of the attack and to the tight of to the "-" meter hole, and above the 0ABC holes for connecting to the main PCB? Is that a jumper?

(2) On the schematic it shows a 4k7 resistor for the meter cal, but the PCB has a 2k meter sensitivity. These are the same things, right? So which one/value is right?

(3) Also, the schematic shows a 330r strapped across the meter, do I need that on the B-style meter?[/quote]

Hi Karl,

1) It's a jumper. Don't forget it ! (Unless you want to have distortion :wink: )
2) You should use a 5k trim and calibrate it yourself. (The calibration procedure has been explained several times in this thread)
3) The 330R is for the case you would like to use a 1uA Meter (@ 20 dB scale). Forget about it, you don't need it with the B-Ringer whis is a 1mA FSD.

Cheers,

eD)))

 

[karl j]

Thanks Vertiges!!! I'm really close to having this thing all wired and ready to test/calibrate. Just got the last few pieces I needed for the side-chain. Just need some time to solder the board.

I have one more question:

What do I use to light the meter? I have the PTownKid meter. I believe it's the B-meter with a LED in it. I thought I read somewhere in this thread that you should light the meter right off the transformer secondaries . But, this is for a LED.

 

[crisotop]

take the positive output of the bridge rectifier and calculate a suitable drop-resistor. I powered a second led from the main power led connected to the control pcb.

best,
christoph

 

[karl j]

Thanks Christoph, but I have 3 LEDs I need to light. I was going to use the "power on" from the control PCB to light my power on and bypass LEDs, so I need to light the meter still. Why can't I light the meter from the same source? Also, what do I need to do to calculate the drop-resistor value if I need to light it off the bridge rectifier? And further, where should I connect the 2nd lead on the meter?

Sorry if these are kind of lame questions. I can solder like nobody's business and know what the parts I'm working with are (mostly) and what they kind of do, but I don't know jack about this stuff otherwise.

Just trying to learn!

 

[vertiges]

karl,

What power transformer did you use ? You have to be sure it's strong enough to handle 3 leds. You have to check the current the leds will draw.

For calculating the values of the resistors (and for learning a lot of things about the leds science), you can use this tool :
http://led.linear1.org/led.wiz

I used 3 leds on my first GSSL. I powered one from the control PCB. For the two others I used two wires with 5k trim resitors connected after the rectifier as crisotop said (and before the regulator).
The trim resistors are very useful if you want the 3 leds to have the same intensity. Depending of the colours and the led type, different voltages has to be applied.

About the second lead of the meter : the + and - are for the meter itself (connected to the control PCB "+" and "-") and the 2 others are for the led : apply the "voltage" on the long leg and connect the short leg to the ground (could be the chassis or the star ground).

eD)))

 

[karl j]

Vertiges,

I used the Amveco 62063 on Greg's BOM. It's a 15 volt 25 VA.

 

[vertiges]

[quote author="karl j"]Vertiges,

I used the Amveco 62063 on Greg's BOM. It's a 15 volt 25 VA.[/quote]

No problem at all with the 62063 ! (I used the 62053)

eD

 

[karl j]

Right on! Thanks for the help. I won't get to do much on my GSSL for a few days. I'll post again when I make my changes.

 

[karl j]

So far so good. Got the rest of my parts in and everything wired up. I ran all my LEDs off the "power on" spot on the control PCB. Everything powered up fine. LEDs were plenty bright. I ran some signal through it and it sounded okay. I could here it compress and hear a difference in the ratios, threshold level, attack and release times, and checked that the bypass worked too.

But no meter.

It lights up, but doesn't do anything, even when there is obvious compression happening.

Thanks for all the help.

I've got some calibrating and troubleshooting to do still, but at least it seems to work.

 

[KMB-AUDIO]

I've been searching and I can't find info about this problem: My SSL works as it should, except for a high end roll-off on both channels. Voltages are good, I'm wondering if my VCA's are bad...I'm using DBX 260. Any thoughts?

 

[MartyMart]

Just wondering what the best way to wire TRS balanced jacks is.
I have neutriks which have the sleeve connected to ground at the case...so
I need to ground the inputs to case for a "circuit" ground, will there be a
problem with the outputs like this, or should I leave the out's connected only
at the board end and heat-shrink the shield at the output sockets ??
Should I find "insulated" output jacks to solve the problem ?

MM.

 

[Harpo]

[quote author="KMB-AUDIO"]I've been searching and I can't find info about this problem: My SSL works as it should, except for a high end roll-off on both channels. Voltages are good, I'm wondering if my VCA's are bad...I'm using DBX 260. Any thoughts?[/quote]
Check compensation cap values (22pF) for 5534 input buffer and caps across the feedback resistors (33pF for 5534 input buffer and 100pF for 5532 output stages).
Whatever a DBX260 is, in case a substitution circuit is required to make this chip behave similar to a DBX202, the compensation caps (100pF) and bandwidth limiting caps (100pF for a 1k feedback resistor) for the 5534 are only for stable operation of control voltage, not for audio.

 

[vertiges]

[quote author="karl j"]But no meter.

It lights up, but doesn't do anything, even when there is obvious compression happening.

[/quote]

From the page 40 of this thread :

"Look at the schematic. The meter is driven from 1/4 TL074, through a 2K resistor. Check that voltage is changing with compression at the output pin of the TL074. Check resistor value. Check continuity all the way to the meter. Check your panelmeter with your ohmmeter (it should move when ohm'ed in the 200Ohms range)

Jakob E."

eD))) :wink:
_________________

 

[karl j]

Thanks for the tip Vertiges! I'm at work right now reading up on all the stuff I need to calibrate and adjust to get things working right. This help thread is great! Very thorough, but also very long, which makes finding the right info difficult sometimes.

So, thanks for the tip on the meter. :thumb:

 

[karl j]

[quote author="RogerFoote"]With 2180s you don't use a symmetry trimpot. With 2181, you do.

The way I learned to measure distortion from old dbx literature is to feed a 100 Hz signal at nominal level into the compressor and look for the 2nd harmonic component on a sectrum analyzer. So, look for a peak at around 200Hz, and trim until it is at the lowest amplitude you can get.
If you go past the "ideal" spot, you will notice the 200Hz harmonic start to rise again and you then know to go the other way with the trim pot.

I don't have a hardware spectrum analyzer anymore, so I use a plug in called "Periscope" from AudioEase on my DAW to measure with.

It is probably best to use a 24 bit system for this. Mine is a "typical" MOTU setup with a Lucid AD9624 for input. Nothin fancy, but very usable.

Hope that helps (a little)[/quote]


Is this a good method for setting the 50k dist trimmers? I don't have a scope, only a VOM.

So, besides the dist. trimmers, I still have to calibrate the side-chain (Th med & Th loud), and the meter. I think I have the info for those.

Guess one of these days I'll have to buy a meter for better calibration.

 

[vertiges]

[quote author="karl j"]

Is this a good method for setting the 50k dist trimmers? I don't have a scope, only a VOM.

So, besides the dist. trimmers, I still have to calibrate the side-chain (Th med & Th loud), and the meter. I think I have the info for those.

Guess one of these days I'll have to buy a meter for better calibration.[/quote]

Yes, you can use the Roger method or you can find someone who has a distortion meter. (You can also let the trimmers in the center position for the moment. Actually by ears, it's quite hard to tell.)

Concerning the calibration of the Th. modes : adjust VR2 et VR3 for no threshold re-adjustment when switching to other switch positions.

Ah yes, about the Super Sidechain, R14 has to be increased. Look at this thread : http://www.groupdiy.com/index.php?topic=16113&postdays=0&postorder=asc&start=75&sid=72550e5477ce2d5f04b711f998b069ef


eD)))

 

[Stagefright13]

Just use 2180's and this chart and it works great! Altho a high pass adjustment may or may not help depending on source material... But that is a separate idea and board. But the Gyraf design is great and sounds great without any kind of fuss. Why you think there are so many pages!!???

The distortion trim is kinda mute audibly anyway. You may want to induce some distortion purposely. Depends on the sound you want. But in the middle as said is perfectly fine.

http://diy.fischerworks.com/gssl_vca.shtml

And thanks so much Matt made my SSL so easy!

 

[karl j]

John,

Thanks for the link. But, I'm using the DBX202c vca, so think I just have to adjust the 50k trimmer.