check for shorts, components and breaks, then check again. If you read back through this thread, you'll find that the problems comes in these categories.
Jakob E.
Jakob E.
GSSL HELP THREAD!!!
- Thread starter hairyandy
- Start date
Help Support GroupDIY Audio Forum:
I don't have a unit to check against.
Use logic: you feed the IC +/-12V (from the threshold pot) into the inverting input through a 220K resistor. You have 56K feedback resistor. The gain should be 56/220=0.25x - giving you some +/-2-3V at opamp output when the unit is in bypass. If it's not bypassed, there will probably be a lot of interaction due to feedback through the control circuit.
Check that you have -12 to +12V at one end of the 220K resistor when varying threshold. Check that you have approx. 0V at the other end of said resistor (as it's a virtual-ground coupling).
Jakob E.
Use logic: you feed the IC +/-12V (from the threshold pot) into the inverting input through a 220K resistor. You have 56K feedback resistor. The gain should be 56/220=0.25x - giving you some +/-2-3V at opamp output when the unit is in bypass. If it's not bypassed, there will probably be a lot of interaction due to feedback through the control circuit.
Check that you have -12 to +12V at one end of the 220K resistor when varying threshold. Check that you have approx. 0V at the other end of said resistor (as it's a virtual-ground coupling).
Jakob E.
..check all four powersupply lines for correct voltage and noise..
So after having read the whole thread twice... (my eyes hurt now) i am wondering abou tthe voltages i observed.
All voltages measured without IC installed. all voltages above Millivolts are listed. i didnt write the mV measurements. all grounds/earths do seem ok though.
i do wonder why the voltages for pin 6 on the SC VCA was 3.3v and falling and why Pin 6 of TL074 was 3.9 and falling
All voltages measured without IC installed. all voltages above Millivolts are listed. i didnt write the mV measurements. all grounds/earths do seem ok though.
i do wonder why the voltages for pin 6 on the SC VCA was 3.3v and falling and why Pin 6 of TL074 was 3.9 and falling
discobloud
Well-known member
hey all. i wish there was a forum for newbie's to forums and spelling for that matter. so yes total newbie. of course questions about the SSL.
Which wires from the transformer go where? does it matter blue/red. I'm looking at other peoples photo's and posts and figured where the leads going to the pcb connection are. i have a multimeter and will use it if forced. i'm in north america if that helps. which autobot can transform?
some photo's ground pin 1 on xlr in. must i ground? what about the output?
next question anyone have: part numbers for mounting hardware and xlr screws, hole sizes for standard neutrik fare, tips and tricks?
much appreciated.
disco
Which wires from the transformer go where? does it matter blue/red. I'm looking at other peoples photo's and posts and figured where the leads going to the pcb connection are. i have a multimeter and will use it if forced. i'm in north america if that helps. which autobot can transform?
some photo's ground pin 1 on xlr in. must i ground? what about the output?
next question anyone have: part numbers for mounting hardware and xlr screws, hole sizes for standard neutrik fare, tips and tricks?
much appreciated.
disco
welcome disco
hardware mounting and for xlr jacks i use #4-40 (that is a width and threading standard) a various lengths and typs. Slotted head usually, but i get brass, black and silver ones these can be obtaiend at local hardware stores, Home Depot or through some catalog parts companies like Digikey, Mouser, and Newark
which transformer do you have?? part number
the hole size for the typical neutric XLRs is 15/16 inch the greenlee hole punch of that size is rather nifty
are you in Canada or the US?
hardware mounting and for xlr jacks i use #4-40 (that is a width and threading standard) a various lengths and typs. Slotted head usually, but i get brass, black and silver ones these can be obtaiend at local hardware stores, Home Depot or through some catalog parts companies like Digikey, Mouser, and Newark
which transformer do you have?? part number
the hole size for the typical neutric XLRs is 15/16 inch the greenlee hole punch of that size is rather nifty
are you in Canada or the US?
Quad,
Pin6 on the SC vca is grounded, surely you mean pin8 -
22u Capacitor discharging. Look at the schematic.
Disco,
As quad implies, transformer colour coding depends entirely on what exact make and model transformer we're talking about. There is no standard notation for this, you need to know your transformer AND your circuit. Search the archives for examples of how to find the odds and ends on power transformers - it's been described several times.
And btw: If you post your location in your profile, it is often much easier to help, as many questions are area-specific..
Jakob E.
This is only good for initial check, tells us only little about circuit intergety
Pin6 on the SC vca is grounded, surely you mean pin8 -
22u Capacitor discharging. Look at the schematic.
Disco,
As quad implies, transformer colour coding depends entirely on what exact make and model transformer we're talking about. There is no standard notation for this, you need to know your transformer AND your circuit. Search the archives for examples of how to find the odds and ends on power transformers - it's been described several times.
And btw: If you post your location in your profile, it is often much easier to help, as many questions are area-specific..
Jakob E.
discobloud
Well-known member
thanks guys. i'm in canada, montreal to be exact. ok i think i'm getting this whole internet/messageboard/diy/research thing after reading till my eyes bled. i'll check the data/spec sheet for the info on the primary... i'll check the home depot today. thanks again guys, i'll let you know when i test this bad boy out. letters to tape-op.
disco
disco
Jakob. as usual you are right.
Yes, it is pin 8 of the SCVCA and pin 6 and pin 7 of the TL074. so is this ok that the vltage is discharging?
also I was testing without ICs in becasue i dont want to fry any. so if its all good I will put them in and retest.
Yes, it is pin 8 of the SCVCA and pin 6 and pin 7 of the TL074. so is this ok that the vltage is discharging?
also I was testing without ICs in becasue i dont want to fry any. so if its all good I will put them in and retest.
..all looks good, I think..
IT works!!! .......... Sorta
without the control board it sounds great. granted its just like bypass....
there is No hum at all though... and thats without grounding anything.. just the pcbs, xlrs and xformer meter and pots on my bench. So thats a happy thing.
With the control pcb attached..... hings get FUN.,
the meter is SLAMMED/ Pinned all the way up with the slightest amount of programme material.
for this unit i am using a Be*****er meter. i didnt put the 2K nor the 330.
around the meter. but then i experimented with the 2K in aand the 330 in and other combinations. Still nothing Pinned meter.
makeup gain works well....
when control PCB is attached. and on (not bypass mode) everything is really really compressed like and 1176 in NUKE... but this is at all ratios, and the threshold seems to not work, har dto tell as the levels are SOOOOO LOW the release and attack seem fine though.
i will keep poking around, but wonder if i will find the problems...
:?
without the control board it sounds great. granted its just like bypass....
there is No hum at all though... and thats without grounding anything.. just the pcbs, xlrs and xformer meter and pots on my bench. So thats a happy thing.
With the control pcb attached..... hings get FUN.,
the meter is SLAMMED/ Pinned all the way up with the slightest amount of programme material.
for this unit i am using a Be*****er meter. i didnt put the 2K nor the 330.
around the meter. but then i experimented with the 2K in aand the 330 in and other combinations. Still nothing Pinned meter.
makeup gain works well....
when control PCB is attached. and on (not bypass mode) everything is really really compressed like and 1176 in NUKE... but this is at all ratios, and the threshold seems to not work, har dto tell as the levels are SOOOOO LOW the release and attack seem fine though.
i will keep poking around, but wonder if i will find the problems...
:?
discobloud
Well-known member
hello. more newness. first off, i turned this thing on and no smoke or white bubbles(yes for me and for you for making this thing available to regular dudes with hair) that burst. secondly, i want to use a DPDT(the big metal ones that say: "ON/OFF") type switch instead of the rotary type. how the heck do you wire this thing. if you wire it wrong will it do strange things? so far all i got is strange things, some no brainer wiring love is needed.
disco
disco
discobloud
Well-known member
hello. more newness. first off, i turned this thing on and no smoke or white bubbles(yes for me and for you for making this thing available to regular dudes with hair) that burst. secondly, i want to use a DPDT(the big metal ones that say: "ON/OFF") type switch instead of the rotary type. how the heck do you wire this thing. if you wire it wrong will it do strange things? so far all i got is strange things, some no brainer wiring love is needed.
disco
disco
discobloud
Well-known member
hello. more newness. first off, i turned this thing on and no smoke or white bubbles(yes for me and for you for making this thing available to regular dudes with hair) that burst. secondly, i want to use a DPDT(the big metal ones that say: "ON/OFF") type switch instead of the rotary type. how the heck do you wire this thing. if you wire it wrong will it do strange things? so far all i got is strange things, some no brainer wiring love is needed.
disco
disco
discobloud
Well-known member
hello. more newness. first off, i turned this thing on and no smoke or white bubbles(yes for me and for you for making this thing available to regular dudes with hair) that burst. secondly, i want to use a DPDT(the big metal ones that say: "ON/OFF") type switch instead of the rotary type. how the heck do you wire this thing. if you wire it wrong will it do strange things? so far all i got is strange things, some no brainer wiring love is needed.
disco
disco
discobloud
Well-known member
shit just posted four times. newbie's rule.
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