GSSL HELP THREAD!!!

[gyraf]

There's several places where resistor tolerance could affect channel balance if you need extreme-precise L/R-tracking

The resistors feeding the VCA's are just the easiest place to adjust.

Use a small trimmer in series with one (or both) of these these resistors for gain trim.

Jakob E.

 

[somsay]

hello,

how does my transformer wiring look now?

anyone? thanks in advance.

 

[Barbera Media]

Well I'm finally glad to say I've got my SSL up and running. I finally found what was causing the 10 ohm resister to fry, and unfortunately it was a stupid (but hard to find) error on my part.

The 2 smaller 12v regulators were installed opposite of how they were supposed to. (9 in the 8 and vice versa) and this caused one to fail and short, so I removed them and replaced them with new ones along with a new 10 ohm resistor and VOILA!! I gotta say this thing sounds amazing. Once I get the case finished and the turbo boards wired and working I'll post pics. It looks like no other I've seen on here. I CAN'T WAIT!!!

 

[guavatone]

somsay, your primary is right now. I am not sure of the voltage of your secondary. I have mine wired to the 3 connectors in the lower right corner of the GSSL board. You will want to bring a wire from chassis to the primary center tap where it meets 0V on the GSSL.

 

[somsay]

[quote author="guavatone"]somsay, your primary is right now. I am not sure of the voltage of your secondary. I have mine wired to the 3 connectors in the lower right corner of the GSSL board. You will want to bring a wire from chassis to the primary center tap where it meets 0V on the GSSL.[/quote]



thanks Guavtone,

i don't know whats the difference if i wire the secondary winds to the top left or the center?

thanks everyone

im close the the finally...

 

[somsay]

Here is my revised secondary winds.

does it matter what voltages go on one side or the other side?

center taps get wired together and put into the center tap input right?

thanks allot...cant wait!

 

[guavatone]

Somsay, what voltage rating is your power transformer?

Almost there.

I would also find a way to bring Chassis ground point to the center pin on the PCB.

 

[somsay]

my transformer is the 15v




the grounds...where my next question.

you mean i have to connect all grounds to goto the iec ground right?

thanks for guavatone! helping me...i really appreciate it!

 

[guavatone]

Is it 15-0-15 eg, 15 VCT? both would be 30V in series which is what you need.

 

[somsay]

my transformer is the 15V-0-15V, 0.832A -- 25VA

TRANSFRMR 15V 1.664A WITH WIRES


Technical/Catalog Information 62063
Vendor Amveco
Category Transformers
Mounting Type Through Hole
Type Toroidal
Primary Winding(s) Dual
Secondary Winding(s) Dual, No Center Tap
Series Output Voltage 30.0 VAC @ 832.000 mA
Parallel Output Voltage 15.0 VAC @ 1.664 A
Output Power 25.0 VA [Max]
Input Voltage Typical 115, 230 VAC
Input Voltage Typical 120, 240 VAC
Input Voltage Typical 117, 234 VAC
Contact Type Wire Lead
Packaging Bulk
Diameter 58.0000 mm [Typ]
Height 34.500 mm [Typ]
Standard UL
Weight 388.0000 g [Nom]
Wire Length 150.00 mm [Typ]
Efficiency 84.0 % [Typ]
Frequency 50.000 Hz [Min]
Frequency 60.000 Hz [Max]
Inner Diameter 13.800 mm [Typ]
H 34.500 mm [Typ]
Lead Free Status Lead Free
RoHS Status RoHS Compliant

this is what the north american BOM list said to order. so is my wiring ok for secondary winds? and how do i go about grounding everything?

thanks allot...i am a beginner.

 

[guavatone]

somsay, just bring Chassis ground bolt to CT/0V on the GSSL. Then you'll be all set.


Then for bring pin 1's on XLR to that bolt too.

see how it interfaces with your studio, how it sounds etc.

 

[SIXTYNINER]

I HAVE
same doubts about gssl psu configuration (i have to set it in 220volts)
nobody have examples in jpg format about?
or better post a new topic in the lab?

2
there is much difference between
polyester capacitors
and
stack metal film
capacitors?

thanks in advance to any guy give helps about.

 

[guavatone]

[quote author="SIXTYNINER"]I HAVE
same doubts about gssl psu configuration (i have to set it in 220volts)
nobody have examples in jpg format about?
or better post a new topic in the lab?[/quote]

-The XFMR manufacturer should have the diagram.

2

A bit of difference. There's tons posted here in elsewhere about the differences. I would use polyester for Power area and polypro for audio bypass caps.

 

[geetar_king]

I read somewhere that you should use a 330 ohm resistor across the +/- terminals of the gauge. Everyone else do this?

I just built a clone and I can't get any compression at all. Audio passes through cleanly but there is no difference between bypass and 'in' state, except that makeup gain works when compressor is "in."

I'm guessing that the meter wont have any effect on that at all. I will troubleshoot using the forum until I run out of ideas before I start asking anyone.

Guess this means sidechain problem though..?

 

[geetar_king]

Well, I couldnt resolve my problem. Still no compression.

I think its a problem in the sidechain. I have checked all resistors they are good. I have swapped TL074 and still same problem. I also have a turbo board built up, so I hooked it up and still the same thing. No compression, but clean signal going through.

Here are some measurements I have taken:

TL074: Pin 14
Ratio at 2:1, 0.22Vdc
Ratio at 4:1, 0.34Vdc
Ratio at 10:1, 0.37Vdc

TL074: Pin 2
threshold at max c.c.w position, 6 mAdc
threshold at max c.w. position, 0mA dc

TL074: Pin 1
threshold at max c.c.w position, 0 mAdc
threshold at max c.w. position, 120 mA dc

I'm using the THAT2180A vca's in all three positions. I have removed pin 4 now to to see if that helped, but it didnt. I have also done the resistor modifications and left out the components as described on Matt's DIY site.

Any other suggestions? Bypass switch looks like its wired properly. I have tested all the wire connections and they appear okay. I have 12V at the threshold pot.

hmm....

 

[guavatone]

geetar, are all your opamps getting the correct power? I had some problems only to find my opamps weren't getting the right voltages.

 

[geetar_king]

I will double check. Another thing is that the operation doesn't change with the sidechain VCA removed. I will double check voltages.

I was fairly meticulous in adding all the components. I will be surprised if I have a wrong resistor, but its gotta be something!

How can I check my opamp voltages? just by going by what the datasheets specify?

 

[guavatone]

yes, follow the datasheets. i had to tweek mine a bunch to get it to compress at the correct threshold. Did you try inputting a high signal?

 

[geetar_king]

yeah, I tried with a high signal and nothing. i will look at the specs on the opamps. thanks for the tips, appreciate it.

 

[geetar_king]

This is what I'm using for TL074: http://www.fairchildsemi.com/ds/LF/LF347.pdf

On Pin 4 I get +12.21 Vdc which the data shows as Vcc.
+12.14Vdc on pin 11 which the data sheet shows as Vee

Data sheet says supply voltage (Vcc) should be 18V is that the problem you think? or should i be checking a different pin



----

Similar thing for TL072.
http://www.fairchildsemi.com/ds/LF/LF353.pdf

I have about +12.21 Vdc on Pin 8 which is Vcc. And about +12.38 on pin 4.

The Gyraf schematic shows +12V /-12V supply to TL074, and +12V/-12V to TL072.