chrissugar
Well-known member
"I left out the 68k / 10k resistors and the distortion trim"
I supose you want to say 68 ohm.
chrissugar
I supose you want to say 68 ohm.
chrissugar
SSL Clone compressor ratio measurements
- Thread starter SSLtech
- Start date
Help Support GroupDIY Audio Forum:
martthie_08
Well-known member
Yes, of course, that was a typo: 68R and not 68k !
Did you do any adjustments to the threshold range? I measured the makeup gain on my unit, and it is 16,6 dB, what are you getting? Does the compression ratio modification have any effect on this?
cheers, mart
Did you do any adjustments to the threshold range? I measured the makeup gain on my unit, and it is 16,6 dB, what are you getting? Does the compression ratio modification have any effect on this?
cheers, mart
chrissugar
Well-known member
I will have to check this next week. Today I have to do some tube tests and I also have two mastering jobs to finish to next week.
chrissugar
chrissugar
gar381
Well-known member
Hi drpat
Try emailing... [email protected]
They have THAT 2180la for $8.95 each.
A bit much but they have them.
GARY
Try emailing... [email protected]
They have THAT 2180la for $8.95 each.
A bit much but they have them.
GARY
chrissugar
Well-known member
I can confirm that they are fast and helpfull. I bought a tube of 2180LB from CEDOS. The only problem is that they are in Germany.
For the US members probably it is not the best solution.
chrissugar
For the US members probably it is not the best solution.
chrissugar
bcarso
Well-known member
Is there a drafting error in the GSSL schematic? I've simulated the rectifier and compression ratio adjust section and it's not showing much change at all for different settings of the switch. But clearly the circuit works, subject to the various aformentioned tweaks, as you all have built any number of them successfully.
My guess is that the wiper of SW1 really goes directly to the inverting input of the TL074 section and not to the 10k/20k/1N4148 cathode junction.
EDIT: Yes, comparing to an old SSL schematic just now kindly provided, the wiper does indeed go to the inv input.
My guess is that the wiper of SW1 really goes directly to the inverting input of the TL074 section and not to the 10k/20k/1N4148 cathode junction.
EDIT: Yes, comparing to an old SSL schematic just now kindly provided, the wiper does indeed go to the inv input.
idylldon
Well-known member
[quote author="Steffen"]I did it another way by increasing the 100k resistor feeding the gain-make-up-mixer, rsulting in less audio VCA tracking
127k was the perfect value but I used 120K...was close enough for me....[/quote]
Would this be the one connected to pin 6 of the TL072?
Thanks,
--
Don
127k was the perfect value but I used 120K...was close enough for me....[/quote]
Would this be the one connected to pin 6 of the TL072?
Thanks,
--
Don
yes, there's an error in the schematic (around rectifier opamp out), but not in the layout.. So I haven't gotten around to fix it yet, sorry..
chrissugar
Well-known member
[quote author="bcarso"]
My guess is that the wiper of SW1 really goes directly to the inverting input of the TL074 section and not to the 10k/20k/1N4148 cathode junction.[/quote]
I checked the two PCBs (main and control) against the schematic and you are right, the SW1 wiper goes directly to the inverting input of the opamp to pin13 ( 20k,10k,1M node).
chrissugar
My guess is that the wiper of SW1 really goes directly to the inverting input of the TL074 section and not to the 10k/20k/1N4148 cathode junction.[/quote]
I checked the two PCBs (main and control) against the schematic and you are right, the SW1 wiper goes directly to the inverting input of the opamp to pin13 ( 20k,10k,1M node).
chrissugar
chrissugar
Well-known member
[quote author="idylldon"]
Would this be the one connected to pin 6 of the TL072?
[/quote]
It is the 100K that is between pin8 of TL074 and pin2 of TL072 on the schematic. On the PCB is a bit different because Jakob swaped the two opamps in the TL072 and if you look at the board the resistor goes to pin8 of TL074 and pin6 of the TL072. A bit confusing if you don't know about this little error.
If you use That 2180 you can use 120K, and ratios will be fine.
Jakob, at the next REV you should swap the pins on the schematic for the two opamps fromTL072 and also connect the SW1 wiper to pin 13 of TL074.
chrissugar
Would this be the one connected to pin 6 of the TL072?
[/quote]
It is the 100K that is between pin8 of TL074 and pin2 of TL072 on the schematic. On the PCB is a bit different because Jakob swaped the two opamps in the TL072 and if you look at the board the resistor goes to pin8 of TL074 and pin6 of the TL072. A bit confusing if you don't know about this little error.
If you use That 2180 you can use 120K, and ratios will be fine.
Jakob, at the next REV you should swap the pins on the schematic for the two opamps fromTL072 and also connect the SW1 wiper to pin 13 of TL074.
chrissugar
chrissugar
Well-known member
Sorry Jakob, I didn't refresh the page and I didn't see you already responded.
chrissugar
chrissugar
I think I have a copy of the Al*n Sm8rt version of this schematic (the original, not the "crush" version). If any one is interested, I can try to dig it up, unless it's already up here somewhere (way too many pages here to plow through!).
Crusty,
That would be very interesting to see!!! :shock:
e_mail_: gyrafaudio (at) gmail (.) com
Jakob E.
That would be very interesting to see!!! :shock:
e_mail_: gyrafaudio (at) gmail (.) com
Jakob E.
chrissugar
Well-known member
matthias
Well-known member
I've never found any a-smart schematics in the web...
and would be really interested in that one..
would you please be so kind... and ... :grin:
matthias3000 (at) gmail.com
and would be really interested in that one..
would you please be so kind... and ... :grin:
matthias3000 (at) gmail.com
