sr1200
Well-known member
Just an update on my diagram above. Just finished building it (the thing in the drawing). Works perfectly!! CCW is INPUT. CENTER is GR. CW is OUTPUT.
CLX-VU Build Thread (DBX 160VU ) UPDATE: REV 3
- Thread starter abechap024
- Start date
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sr1200
Well-known member
Dumb questions: The ground from the IEC.... wheres that supposed to be hooked up?
Part kits still available? (wanting to build ch2 soon)
Part kits still available? (wanting to build ch2 soon)
abechap024
Well-known member
sr1200 said:
Awesome, and good diagram in case anyone else wants to use a rotary switch.
sr1200 said:Dumb questions: The ground from the IEC.... wheres that supposed to be hooked up?
Part kits still available? (wanting to build ch2 soon)
The ground should be attached to the chassis somewhere, for safety reasons. You may or may not then choose to attach your Analog power ground to the ground of the chassis. I think its common to find the Analog ground attached to power ground with a 10ohm resistor bypassed with a 100n capacitor. But I my CLX I just leave them separate.
And yep there sure are kits left! Not many boards though, I need to get rev 3 cooking. There is about a week lead time,on some of the more expensive parts i didn't buy in bulk (That chips and some other chips) But I'm getting another batch in soon, so order whenever you want.
Rob Flinn said:
The original takes the +/- 24v after the diode rectification smoothing capacitors. Probably the best bet.
Cheers,
Abe
OK so I got both units passing a signal, & compressing but they don't calibrate properly at the mement.
First off I have a few questions about the build pdf.
Should C16 the lower tant cap be fitted.
Should R25 22R omitted, on the page in the pdf titled CLX-VU part designations for the that 2180 build, it shows it as fitted, but it says omit for that build on the pcb ?
I'm noticing that in the level calibration info on the pdf it say to get -0.11v on the top end of R79, on page 3 of the DBX calibration information it says to set it to -0.011v
First off I have a few questions about the build pdf.
Should C16 the lower tant cap be fitted.
Should R25 22R omitted, on the page in the pdf titled CLX-VU part designations for the that 2180 build, it shows it as fitted, but it says omit for that build on the pcb ?
I'm noticing that in the level calibration info on the pdf it say to get -0.11v on the top end of R79, on page 3 of the DBX calibration information it says to set it to -0.011v
More questions
1:4 ratio calibration...... what position should the make gain control be ??
How does one adjust R56 & R59 ? I can't seem to find any info on this ?
1:4 ratio calibration...... what position should the make gain control be ??
How does one adjust R56 & R59 ? I can't seem to find any info on this ?
sr1200
Well-known member
I was going to question this as well... my meter was reading in mv not v which i assume is correct. Also, on the symmetry calibration... the trim pot does nothing (or seems to do nothing at all) but the waveform looks damn good anyway, and the unit doesnt sound distorted.
sr1200 said:
I'm pretty sure it should be -0.011v or 11mV, since I can't actually set it to -0.11v since it's out of the range of the trimmer.
I'd like to know more about R56 & R59 since at the moment my meter shows -40dB GR when in reality the maximum actual GR I'm getting os only getting around -6dB
abechap024
Well-known member
Rob Flinn said:
Nope that is there just to trim the installed timing capacitor (as the DBX schematic)
That is my mistake, I only fixed it on the low res PDF, sorry for the confusion. you want to omit it.
Ah! Good catch
Thanks I'll get that sorted too.Cheers,
Abe
abechap024
Well-known member
I'll have to research some more on the gain 1:4 ratio some more.
I do know that the r59 trim pot controls how much the bass moves the meter as compared to the highs.
and r56 is the meter tracking, making sure the meter is acuate throughout the whole scale.
The calibration section has some holes in it that I need to get more in depth with...eventually
http://www.dbxpro.com/product_downloads/Calibration_Procedure/160-161%20Calibration%20Procedure.pdf
Cheers
Abe
I do know that the r59 trim pot controls how much the bass moves the meter as compared to the highs.
and r56 is the meter tracking, making sure the meter is acuate throughout the whole scale.
The calibration section has some holes in it that I need to get more in depth with...eventually
http://www.dbxpro.com/product_downloads/Calibration_Procedure/160-161%20Calibration%20Procedure.pdf
Cheers
Abe
One other thing I noticed in the DBX cal info is that on page 1 it says
"Note :On model 160, tie " - " terminals to Gnd, for normal testing"
Having just read the DBX alignment info in full, it seems there is a lot to calibrating the 160, think I'll have to sleep on it & take a look tomorrow. I think that perhaps it is better to follow the calibration procedure in the DBX document.
"Note :On model 160, tie " - " terminals to Gnd, for normal testing"
Having just read the DBX alignment info in full, it seems there is a lot to calibrating the 160, think I'll have to sleep on it & take a look tomorrow. I think that perhaps it is better to follow the calibration procedure in the DBX document.
Winetree
Well-known member
Looks like you need a resistor sub box for calibration. Any leads?
abechap024
Well-known member
Nope, thats what the trim pots are for
The resistor sub box was used to calibrate the voltage regulator, on the CLX the voltages are changed with trimpots
The resistor sub box was also used to trim the RMS unit (probably the most important calibration as far as the sound of the unit and it relies on the calibrated voltages) and that is replaced with a trim pot on the CLX.
See how easy I tried to make it!??! ;D
Also the rms symetry trims out distortion, and for reasons beyond my understanding it worked on the prototype but on rev 2 it has no effect. Very strange indeed. But that being said on the prototype, the distortion you could trim out got it around the same levels I'm seeing on the rev 2.
AC
The resistor sub box was used to calibrate the voltage regulator, on the CLX the voltages are changed with trimpots
The resistor sub box was also used to trim the RMS unit (probably the most important calibration as far as the sound of the unit and it relies on the calibrated voltages) and that is replaced with a trim pot on the CLX.
See how easy I tried to make it!??! ;D
Also the rms symetry trims out distortion, and for reasons beyond my understanding it worked on the prototype but on rev 2 it has no effect. Very strange indeed. But that being said on the prototype, the distortion you could trim out got it around the same levels I'm seeing on the rev 2.
AC
Ok so I have things working a bit better now on one channel. the reason I was getting hardly any compression was that I had R30 installed. In the pdf coloured overlay it indicates to install it, but it difficult to read that it says omit it for that's builds on the overlay.
I'm thinking that it might be good to have a checklist of parts to OMIT on the pdf.
The channel I have working seems to behave quite well although the tracking on the meter needs some trimming since it's showing -30dB when I only actually have -10dB.
Also step 2 of the DBX calibration procedure "connect the sub box betweeen the 2 trim pins of the rms unit .....
Is this relevant to the that's build ? If so i can only see 1 trim pin ?
I can only get to -0.004v before I run out of trim ?
I'm thinking that it might be good to have a checklist of parts to OMIT on the pdf.
The channel I have working seems to behave quite well although the tracking on the meter needs some trimming since it's showing -30dB when I only actually have -10dB.
Also step 2 of the DBX calibration procedure "connect the sub box betweeen the 2 trim pins of the rms unit .....
Is this relevant to the that's build ? If so i can only see 1 trim pin ?
I can only get to -0.004v before I run out of trim ?
abechap024
Well-known member
Rob Flinn said:
Good idea, when I get some time I'll do that
This is outlined in the CLX build manual. It is important to do as it affects the timing/calibration of the rest of the unit.
I've had enough variation on all of my units. Try adjusting the RMS first... probably something simple.
Cheers!
abechap024
Well-known member
Rob Flinn said:
Yes! it is the most in depth calibration of any unit I've made thus far. I though 1176's were tricky
But really the only calibration that really affects the sound is R36...the others are just for levels and meters...Got manual corrected and uploaded. Waiting till tonight to upload the HQ version as it takes a lot of bandwidth and time...
Thanks
Ac
sr1200
Well-known member
It's ALIVE!!!!
Gonna try and cram 2 of these into a 1U.
I have mine working now, but I still can't get the scaling on the meter to work properly. I would be interested to know from anyone else whether this lines up properly for them ? R56 & R59 trimmers seem to do nothing. Is anyone else experiencing this ?
Apart from that it's great, thanks Abe for a nice project, I appreciate the amount of work you have put in on this.
Apart from that it's great, thanks Abe for a nice project, I appreciate the amount of work you have put in on this.
abechap024
Well-known member
sr1200 lovin the one rack space idea man!
Rob - keep trying I got mine to line up...you might have to mess with the meter emulation pot to get it in a working range of the other pots.
Rob - keep trying I got mine to line up...you might have to mess with the meter emulation pot to get it in a working range of the other pots.
Songguy
Well-known member
Hi Abe,
Why can C-14 be populated with a 22pf or 150pf ceramic capacitor?
Why can C-14 be populated with a 22pf or 150pf ceramic capacitor?
abechap024
Well-known member
Hello,
We change the 22pf to 150pf because the original impedance with the discrete vca was 100k and we lower it 20k for the that build and that means we need to increase the capacitance to about ~ 150pf. At least that's what I found had to be done to get Rev 2 to function optimally.
We change the 22pf to 150pf because the original impedance with the discrete vca was 100k and we lower it 20k for the that build and that means we need to increase the capacitance to about ~ 150pf. At least that's what I found had to be done to get Rev 2 to function optimally.
