GSSL HELP THREAD!!!

[Harpo]

but what about 5% or 1% tolerance? Can I have any problem using non precision resistors?

Any problem using carbon resistor with the same especification?

For best CMRR you want the 22K resistor values at the balanced line receivers close matched (for same value, not absolute value). Maybe read http://www.thatcorp.com/datashts/THAT_1240-Series_Datasheet.pdf for a specialized part on the same subject, using better than 0.005% tolerance resistor values to archive this. Other resistor values are a lot less critical (in some spots a jumper or omitting it seems the better part). Besides higher or comparable cost of carbon comp Rs over here, the GSSL is not a tube/high supply rail circuit where carbon comp might be an improvement over metal film Rs in specific spots. YMMV.

 

[thomasdf]

Can you kindly direct me as to where the 0V reference is on the PCB please?

echo answer "the center pin of the aux.12VDC connector might come handy, or any spot at the big filled pcb traces"

And what do you mean exactly by the aux. 12VDC?

The auxiliary 12VDC supply rail, coming from the 7812 voltage regulator, maybe useful for supplying relais, incandescent lamps, LEDs,..., as you don't want any additional load at the 78L12. This additional/optional on board +12V supply rail goes to a 3-pin connector. The center pin of this 3-pin connector that connects to 0V reference voltage is the pin in the middle. The pcb silkscreen has this connector labled "+12V 0V NC, RELAY AND LIGHT POWER"

Why do some people add another PSU for the relays and light? Can this one alter the sound of the unit (groud loops or such?) or was the external PSU for older PCBs?

By the way, I received mine yesterday... Thanks Gustav! Fast as usual

edit: for the PSU, do I need 100uF or 1000uF caps? Gustav's BOM says 100 and the PCB and GSSL schematics says 1000. Thanks

 

[ctechdx]

Hello my friends,

I´m building the GSSL based on Gyraf´s project. Some of my components just arrived and now I realized some things seems to be wrong on the gyraf´s component list. Then I need some help here to be sure...

About the elektrolytic capacitors... that´s what it is on the list:

4pcs RADIAL ELEKTROLYTIC 100µF-25V
14pcs RADIAL ELEKTROLYTic 22µF-25V

I did check the the mic and mod build tread, and I see he uses 100up/35v and 22up/6.3v. I bought both 25v as it is on the list.

My question is... can I use those 25v capacitor? These values are right or not? Should I change for 100up/35v and 22up/6.3v?

thanks,

 

[weiss]

I used 4x 1000µF 63V and 14x 22µF 63V in my GSSL. The voltage rating on a capacitor is the maximum amount of voltage that it can safely be exposed to and can store. It is normally recommended to give a good amount of room when choosing the voltage rating.

 

[ctechdx]

I used 4x 1000µF 63V and 14x 22µF 63V in my GSSL. The voltage rating on a capacitor is the maximum amount of voltage that it can safely be exposed to and can store. It is normally recommended to give a good amount of room when choosing the voltage rating.

Thanks Weiss,

And what you say about the capicitors I already bought? The 1000uF I got 35v and the 100uF and 22uF I got 25v. Those values are ok for this project? The toroidal provides 15v to the board... I might be wrong, but I supose nothing is happening with more than 15v on this GSSL PCB, is that right?

 

[weiss]

Thanks Weiss,

And what you say about the capicitors I already bought? The 1000uF I got 35v and the 100uF and 22uF I got 25v. Those values are ok for this project? The toroidal provides 15v to the board... I might be wrong, but I supose nothing is happening with more than 15v on this GSSL PCB, is that right?

important is the voltage of the 1000µF capacitors (which is marked as 35V on the pcb)

 

[thomasdf]

So their value do not matter that much? (100uF vs 1000uF?)

Does anybody have a Frontpanel design file with a 8028B meter cutout? the Front Panel website offers front panel drilled for that meter but I can't find any editable files...

 

[gyraf]

Look at original schematic, pcb layout and partslist.

You need 1000uF/35V for power supplies, and 100uF/min.25V for output caps.

Jakob E.

 

[Gustav]

So their value do not matter that much? (100uF vs 1000uF?)

Does anybody have a Frontpanel design file with a 8028B meter cutout? the Front Panel website offers front panel drilled for that meter but I can't find any editable files...

https://pcbgrinder.com/download/FPD/GssL1RU.fpd

Gustav

 

[Gustav]

I supose nothing is happening with more than 15v on this GSSL PCB, is that right?

+15 and -15 = 30V span on the supply.

Gustav

 

[thomasdf]

So their value do not matter that much? (100uF vs 1000uF?)

Does anybody have a Frontpanel design file with a 8028B meter cutout? the Front Panel website offers front panel drilled for that meter but I can't find any editable files...

https://pcbgrinder.com/download/FPD/GssL1RU.fpd

Gustav

Thanks, I've already toyed with this one, but it doesn't have the 8027B meter cutout... This is what I am looking for. I will probably end up do it myself I guess.

 

[Gustav]

it doesn't have the 8027B meter cutout...

Do you realize how lazy that sounds?

You asked for a file to go by, and I posted a link to a full FPD file with the correct dimensions for the control cutouts, so all you have to do it modify it to your own taste/add the meter cut out instead of the current one.

1. Delete cut-out in current FPD file.
2. Find the meter (I managed to find by typing your model reference into google) - http://www.hairballaudio.com/shop/product_info.php?cPath=25&products_id=61
3. Check "cutout and dimensional info"http://www.hairballaudio.com/docs/meters/8027-B.pdf
4. Modify file accordingly (and if you are worried about the screw mounting holes, just omit them and drill them when you have the meter and panel in hand).

8)

(pst - You can even do your own scales http://stiftsbogtrykkeriet.dk/~mcs/Scale.html )

Gustav

 

[thomasdf]

That is what I did, I am not that lazy Gustav...
It's just that I am sure somebody here already did that so I was just asking. I am not a pro at using FrontPanel designer but I am a maniac about alignment so I need to take a huge care bout drawing and then drilling these holes for the VU otherwise it won't be parallel to the sides... Damn...
I will share my cutout when I'm done, because I'm that cool

 

[ctechdx]

Hey guys...

I would like to have some tips about the THAT VCA. I´m in doubt about the THAT 2180 or 2181 + trimpot. The 2181 with the trimpot gives more sound possibility adding more harmonic distortion? Any one have experiences with both types? What you guys suggested me? Any considerable diference?

Thanks,

 

[Gustav]

Hey guys...

I would like to have some tips about the THAT VCA. I´m in doubt about the THAT 2180 or 2181 + trimpot. The 2181 with the trimpot gives more sound possibility adding more harmonic distortion? Any one have experiences with both types? What you guys suggested me? Any considerable diference?

Thanks,

Use the pre-trimmed type, and dont hesitate to use the search function!

Gustav

 

[ctechdx]

Hey guys...

I would like to have some tips about the THAT VCA. I´m in doubt about the THAT 2180 or 2181 + trimpot. The 2181 with the trimpot gives more sound possibility adding more harmonic distortion? Any one have experiences with both types? What you guys suggested me? Any considerable diference?

Thanks,

Use the pre-trimmed type, and dont hesitate to use the search function!

Gustav

Thanks Gustav... then I go with the 2180... what do you mean with the search funcion? To search the topics before post?

 

[Gustav]

Hey guys...

I would like to have some tips about the THAT VCA. I´m in doubt about the THAT 2180 or 2181 + trimpot. The 2181 with the trimpot gives more sound possibility adding more harmonic distortion? Any one have experiences with both types? What you guys suggested me? Any considerable diference?

Thanks,

Use the pre-trimmed type, and dont hesitate to use the search function!

Gustav

What do you mean with the search funcion? To search the topics before post?

Yes!

It seems like you are posting every time you get to a new type of component on the BOM. Since those questions have been covered  numerous times, it would save you some time to use the search function.

Gustav

 

[rearturo]

The auxiliary 12VDC supply rail, coming from the 7812 voltage regulator, maybe useful for supplying relais, incandescent lamps, LEDs,..., as you don't want any additional load at the 78L12. This additional/optional on board +12V supply rail goes to a 3-pin connector. The center pin of this 3-pin connector that connects to 0V reference voltage is the pin in the middle. The pcb silkscreen has this connector labled "+12V 0V NC, RELAY AND LIGHT POWER"

Thanks Harpo. Just to make sure... i don't have anything connected to the 3-pin connector on the PCB, so i should just place my black com lead to the middle hole?

 

[ctechdx]

Guys,

I did check the search engine looking for the wattage value for the resistors. I found 1/4w. My dout is... is there any problem if use higher wattage? I didn´t find all resistors 1/4w... some of them are 1/2w or 1w... is there any problem? I suspose this is not a problem... but just checking!  ;D

Thanks,

 

[thomasdf]

The only problem you may have is the size of the resistors. Other than that it izzz fine