GSSL HELP THREAD!!!

[gyraf]

Hi Mich,

Yes, the two halves of the TL072 are switched between schematic and PCB.

Is your timing circuit working right, giving relatively slow changing DC with signal?

There is a small jumper on the front panel pcb (near the centre where the incoming wires attach) that will prevent timing from working if it is left out by error. check that this jumper/wire link is mounted correctly. This has been a known error before.

Jakob E.

 

[mich]

timing circuit works, and the jumper is mounted correctly...

 

[mich]

another question...

the bypass switch can easily be replaced by a toggle switch like a simple dpdt (double pole double throw) right?
maybe i have it conected wrong?

on com off
* * *
-- -- --

-- -- --
* * bypass - (or this conection or jumper on control pcb)
make up
thats the way to conect the bypass-right?

 

[tmbg]

For the 5534s, I can't seem to get the N or AN! Mouser suggests the NJM5534D as a replacement... or I can get the TI NE5534D or AD....

whats the difference here?

 

[tmbg]

Also, can the 0.1uF poly caps be 63V instead of 100V? the 100V ones are backorder only :/

 

[mich]

i dont think you will find voltages greater then 24v in the circuit..

the threshold pot is going from -12v to +12 for feeding the sc and the sc compreses more or less depending on this voltage.(if i understand corectly :roll: )

 

[ChrisA]

thanks jakob for pointing me in the right direction with my last question...I resolved that problem, but have another one.

This ssl is extremely loud... more than the others I made by about 6 db....All of the resistirs look right...It also has a hum problem which my others didn't using the same ground scheme....when I power it on the first time after being off for a while it doesn't compress at all...If I switch it off really quick, then turn it back on it starts compressing...ratios, attack and release all seem right, etc...still loud though....if I turn it off and let it sit and then turn it back on a few minutes later....no compression again...its completely repeatable...weird, right?...I'm wondering what this kind of behavior could possibly be.


any suspects come to mind for this? could it be a cap somewhere?

thanks!

btw- when I first powered up this ssl I forgot to put the jumper that goes behind the 7915 and 7185....I then put it in and have been having problems...could I have hurt something over there by doing that?

 

[mich]

found it! :grin:
like most of my debuging,it comes down to the pcb....
a veeery small piece of sh*ti coper in the main board-conecting points G and D- and freaking out the tl074(it created feedback between the out and the non inverting input of the stage that drives the meter).

it took me the whole freaking day,but the sound of the unit now-is worth it.....thank u jakob - great project!-and thanks everyone else for helping.

ill post some pics when ill get it looking sharp....

cheers

 

[BladeSG]

Hi Guys. I'm nearing completetion of this project and got a question before I power up and test this thing.

On the control PCB (to the right) next to the 750K Resistor there are two points between 'A' + 'A2', there is a line joining them. Is this a small jumper?

These 2 points connect to the BYPASS Rotary switch and to me there is no reason they could not have been joined on the trace side of the PCB, that's why I'm asking.

Thanks in advance.

 

[Mendelt]

Hi, this is my first post here, so just ignore me if I sound stupid

I'm just starting building one of these compressors and there's one thing i'd like to do different.
I usually like rows of leds better for metering than normal meters (and it's a lot cheaper). Is it possible to replace the meter with for example a LM3916 and a couple of leds?
I understood the LM3916 works like a VU meter and i read the meter used in the SSL is different but I'm not really sure about how it's different. Is it possible to build some stuff around the LM3916 chip to emulate a meter for the SSL or are there other chips that could be used for this?

Thank you.

 

[gyraf]

Mendelt,

Welcome to "The Lab"..!

[quote author="Mendelt"]Is it possible to replace the meter with for example a LM3916 and a couple of leds? [/quote]

Yes - no problem. You will need a linear-scale LED driver circuit, not a dB scale one. This because the VCA control voltage (and thus the meter indication voltage) is linear dB/V.

[quote author="BladeSG"]On the control PCB (to the right) next to the 750K Resistor there are two points between 'A' + 'A2', there is a line joining them. Is this a small jumper?

These 2 points connect to the BYPASS Rotary switch and to me there is no reason they could not have been joined on the trace side of the PCB, that's why I'm asking.
[/quote]

This is the optional makeupgain-bypass. If the jumper is installed, you will have constant makeup. If it is wired to the switch, you will have makeup only when compressor is "IN"

Jakob E.

 

[BladeSG]

Thank you Jakob again for your help.

I 've finished soldering the boards and powered it up earlier today. Not good so far, BUT I think I know why....

The 15+15V toroid is supposed to be wired in series to provide the board with 30V.

Is this correct?

Thanks again.

Steve.

 

[gyraf]

Yes, the board needs 15-0-15V AC - which is 30V AC between outer connections.

Jakob E.

 

[BladeSG]

Thanks again Jakob, it's much appreciated.

 

[EEMO1]

does monacor have a meter that would suit the ssl comp? i have easy access to those, so...

-eero

 

[gyraf]

[quote author="EEMO1"]does monacor have a meter that would suit the ssl comp? i have easy access to those, so...[/quote]

They surely have some that will work - but IMHO not anyone that looks good.

Jakob E.

 

[EEMO1]

http://www.monacor.com/int/en/produktseite_monacor.php?artid=1763&spr=EN&typ=u


like this one? i think it doesn't look that bad... with a black face it could be alright...

 

[gyraf]

Yes, it would definitely look better with a black face (you would have to paint the needle white then). But I don't think it'll fit a 1U frontplate.

Jakob E.

 

[radiance]

One thing that is not clear to me is:

Are the outputs off the SSL clone ?pseudo balanced? or are they a so-called ?cross coupled output stage??

I'm asking because I'm making insert cables and a came accros some terms I did not understand.

 

[BuzAllen]

Are the outputs off the SSL clone ?pseudo balanced? or are they a so-called ?cross coupled output stage??

From looking at these schematics http://www.gyraf.dk/gy_pd/ssl/ssl_sch.gif the outputs are differentially driven and impedance balanced outputs. They are not cross-coupled, nor (depending on what they mean) psuedo-balanced. That is if by psuedo balanced they mean matching ouput impedances but only the hot leg driven.

Brian