geetar_king said:Posted another revision. Realized I put C3 inline on the 48V input instead of one leg going to ground. C3 could probably be left out anyways but I'm going to keep it on I think. Dunno I have some nice 3u3 caps lying around. OR should I just leave out C3?
Another anomaly between the board and the schematic is C16 which is actually another 10uF/35V cap instead of 100uF thats on the schematic. 100uF might not be a bad idea there though anyways, but I put 10uF in my schemo
geetar_king said:Yes the production boards actually have 470nF caps there for both talkback amps! Strange there is a discrepancy on the SSL schematic.
geetar_king said:Yes Whoops! Working on a first proto right now. Working with Livingnote on getting a CnB board combined with the talkback board... Hopefully will have something assembled and powered up in the next few weeks.
edit: and by "Yes Whoops!" i don't mean "Yes Oops!" haha
fucanay said:This thread was great reading and then it just stopped. Any updates on this?
Matt
geetar_king said:wired up a channel last night but didn't have much time to play around with it. it's passing audio! phew! still some work to do with the blend board. man this thing really compresses though when it kicks in! i put it on a snare track and i could almost here my neighbor's microwave coming through in the background
anyone know what the best way is to set the bias trimpot for the FET?
SSLtech said:This way instead:
Keith
jdiamantis said:Looking on the schematic, you would remove jump 2 so that when you apply a test audio signal the side chain is not trying to compress.geetar_king said:wired up a channel last night but didn't have much time to play around with it. it's passing audio! phew! still some work to do with the blend board. man this thing really compresses though when it kicks in! i put it on a snare track and i could almost here my neighbor's microwave coming through in the background
anyone know what the best way is to set the bias trimpot for the FET?
When I made this post, I now realize that the first sentence may be misleading; I was using a mental shorthand when I wrote, it the instructions may not be clear...
Clarifications are underlined and in italics;
On most FET type compressor/limiters, you first want to adjust the trimpot so the gain through the circuit is at maximum i.e. no reduction in gain from the fet.
apply a tone signal to the input (1kHZ will do), and monitor the output with a device that can read dB out. adjust the gain of the signal so it high enough to read on the output of U1B, but not high enough to distort.
Adjust the bias pot so you have maximum gain through the circuit. Turning it one way will reduce it; the other will increase. Wait for the gain to settle. Make sure you can't get any more gain turning the pot.
NOW, slowly turn the bias trim pot until the output of U1B drops by 1dB. This may take a little effort as the bias circuit has a long time constant in this circuit. What this does, is turn the FET channel on so it's always conducting whether you are compressing or not. This reduces distortion.
return the jump 2 to it's place, remove the test signal and apply audio.
Compress and enjoy.
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