ruckus328
Well-known member
Thx, that really clears it up. Basically with this scheme I wouldn't even need to bring my LED12V supply anywhere near the meter, just my dirty ground path. Awesome.
New GSSL Layout Proposal - Anyone Interested?
- Thread starter ruckus328
- Start date
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livingnote
Well-known member
Haha yeah lookat that guess who was just synched with my reaction 
Thanks T, makes sense.
Thanks T, makes sense.
ruckus328
Well-known member
T, I do have 1 question - I'm guessing you're only pulling a few milliamps across each of your LED's? Otherwise since your driving your 5V reg directly off of your main supply (in my case +15V), I'd be bogging down my 15V reg if I try pulling anything significant (what we had previously talked about as being bad).
Next (and I hope final question) - Does anyone think there's any benefit to keeping Audio and Sidechain Ground planes segregated? And only tied together at the power input point? This was originally my plan, but don't know if this'll buy anything and possibly even introduce some unforseen issue.
Next (and I hope final question) - Does anyone think there's any benefit to keeping Audio and Sidechain Ground planes segregated? And only tied together at the power input point? This was originally my plan, but don't know if this'll buy anything and possibly even introduce some unforseen issue.
livingnote
Well-known member
Haha I just gave a QSOP 8 legs and bent it to look like a spider so now every time I reach for the beer I get a jolt.
Yah, no dangling LEDs off audio supply in cascade at least in the SSL - but re SC ground plane, me intuition sez that's chasing weasels.
SC VCA and Texas Lightnings don't suck worth a (bedtime now).
Yah, no dangling LEDs off audio supply in cascade at least in the SSL - but re SC ground plane, me intuition sez that's chasing weasels.
SC VCA and Texas Lightnings don't suck worth a (bedtime now).
ruckus328
Well-known member
livingnote said:
GO TO BED.
LOL
This was not my schematic, it's from pico compressor:
http://www.picocompressor.com/PicoComp/PCB-Kits/Documents/GR_Meter_10/GR_Meter_10.htm
Used as an easy example how to wire the ground-sensing.. roll your own.
I said how I would wire the LED supply earlier.
(a pair of 1N4007 taken directly from trafo into LED regulators, and ground "dirty" taken before or at the FIRST reservoir cap junction) This way you don't task the "audio" ground with hash from led drivers/meters.
http://www.picocompressor.com/PicoComp/PCB-Kits/Documents/GR_Meter_10/GR_Meter_10.htm
Used as an easy example how to wire the ground-sensing.. roll your own.
I said how I would wire the LED supply earlier.
(a pair of 1N4007 taken directly from trafo into LED regulators, and ground "dirty" taken before or at the FIRST reservoir cap junction) This way you don't task the "audio" ground with hash from led drivers/meters.
livingnote
Well-known member
Aha ok of course makes sense to merge the two ground planes at the reservoir cap junction
despite having two distinct regulators, it'll be quiet back there if my thinking is right. My thing
in the mean time has become "how do I brutalize two of these meter driver chips into the already
full panel"...but who knows, just might work.
despite having two distinct regulators, it'll be quiet back there if my thinking is right. My thing
in the mean time has become "how do I brutalize two of these meter driver chips into the already
full panel"...but who knows, just might work.
livingnote
Well-known member
http://www.youtube.com/watch?v=Rqte5w257C4
livingnote
Well-known member
Spidey says it's gonna work
7 Legs actually, guess that's close enough. But how in the world am
I gonna pull that off...hm...maybe spidey wasn't having his day after
all...
7 Legs actually, guess that's close enough. But how in the world am
I gonna pull that off...hm...maybe spidey wasn't having his day after
all...
livingnote
Well-known member
Absolutely I had a whole batch of those things for an AD thermocouple
amplifier but here I just had impatience getting the better of me so I did
the hedgehog. Deciding that was pretty stupid it went Vero next which was
pretty rigid, but now that you mention it, might as well make some right now.
amplifier but here I just had impatience getting the better of me so I did
the hedgehog. Deciding that was pretty stupid it went Vero next which was
pretty rigid, but now that you mention it, might as well make some right now.
ruckus328
Well-known member
Well.....I think I'm good with the whole LED driver now. Got everything to fit, thx again guys.
Back to changing the sidechain voltage to +/-15V. If the original 2150's could handle it, then why the change to 12V to begin with? Just curious.
Now, if I change it over to 15V, then 12V will only be used for control voltage, and all circuitry will now run off of 15V, so back to the original design for the sidechains. One thing I'm unsure of - is if any of the values around the SC VCA need to be adjusted if running it at 15V. All of the orginal schematics I have have 2150/2151/or202's in the sidechain - so doesn't help me much there since new design will be using 2180/81's. Anyone done any experimenting with this?
Back to changing the sidechain voltage to +/-15V. If the original 2150's could handle it, then why the change to 12V to begin with? Just curious.
Now, if I change it over to 15V, then 12V will only be used for control voltage, and all circuitry will now run off of 15V, so back to the original design for the sidechains. One thing I'm unsure of - is if any of the values around the SC VCA need to be adjusted if running it at 15V. All of the orginal schematics I have have 2150/2151/or202's in the sidechain - so doesn't help me much there since new design will be using 2180/81's. Anyone done any experimenting with this?
livingnote
Well-known member
In vino veritas et in vero virilitas!
ruckus328
Well-known member
Yea, I know about those changes for the Audio VCA's - but the Sidechain configuration is slightly different (seems as though it's pretty much retained the values that were there for a 2150 more or less) - so you're saying the sidechain VCA's should be configured exactly the same as the audio VCA's? That would make sense, since you would want them to behave the same, which is the reason for changing voltage back to 15V to begin with.
So kill the 10K between 3 & 5? CV coming into Pin 3 of the SC VCA still going through a 470R with a 47R dropdown to ground I would think would remain unchanged. Also, what about Pin 4 - still grounded through a 47R in the case of a 2181 or lifted like in the Audio VCA configuration? And pin 4 lifted still for a 2180 obviously. I had thought about putting a jumper there on pin 4 for the audio VCA but figure lifting a pin is quick and easy, and one less part to install.
Sorry for the 50 million questions. I realize some of them are "no-duh's", I've made so many changes at this point though I'm second guessing myself at every turn and just trying to avoid excess troubleshooting with my proto as the result of a boneheaded mistake.
So kill the 10K between 3 & 5? CV coming into Pin 3 of the SC VCA still going through a 470R with a 47R dropdown to ground I would think would remain unchanged. Also, what about Pin 4 - still grounded through a 47R in the case of a 2181 or lifted like in the Audio VCA configuration? And pin 4 lifted still for a 2180 obviously. I had thought about putting a jumper there on pin 4 for the audio VCA but figure lifting a pin is quick and easy, and one less part to install.
Sorry for the 50 million questions. I realize some of them are "no-duh's", I've made so many changes at this point though I'm second guessing myself at every turn and just trying to avoid excess troubleshooting with my proto as the result of a boneheaded mistake.
Disclaimer: that's what 2180 appnotes say - use a single 5K1 to V-. Try to ask for the "second opinion" from people who have devices configured this way or the "old way".
Also, regarding rail voltage, appnotes say that the VCAs are current-in/current-out devices and in this regard less dependant on actual rail voltage compared to voltage-out devices.
The sidechain VCA should not be as critical regarding distortion, so the "dist-trim" could be left as-is or possibly even completelly left out.
Also, regarding rail voltage, appnotes say that the VCAs are current-in/current-out devices and in this regard less dependant on actual rail voltage compared to voltage-out devices.
The sidechain VCA should not be as critical regarding distortion, so the "dist-trim" could be left as-is or possibly even completelly left out.
Attachments
Kingston
Well-known member
tv said:ruckus328 said:
from:
http://homepage.mac.com/marten.thielges/gssl/calibration.html
Also in 2180/1 appnotes.. the 5K1 to V-
Just a sidenote to anyone reading the page linked above:
do NOT replace the 100pF VCA input buffer feedback cap with a 100nF, no matter what the webpage says. It completely ruins the sharp and accurate and controlled VCA behaviour.
Say hello to wobbly and inconsistent (incontinent?) attack. There are so many GSSL units in the world some people actually mistake that flubbery crap as the "SSL sound".
Don't say I didn't warn you.
