CLX-VU Build Thread (DBX 160VU ) UPDATE: REV 3

[jplebre]

Hi your options are:
- screw standoffs to front panel
- use longer pots
- cut the metal bracket with something (angle grinder will do) and glue it. Hibrid based (epoxy) will do and will not go anywhere. Majestyc12 suggested it to me and indeed it's strong!
Also, you may need to trim the bottom of the case. The L shaped lid was touching the inside metal. Most likely because I didn't line up the metal bit exactly.

J

 

[plektra]

Thanks for the suggestions. I think I'll go with the solution of cutting the metalpiece in half so that it will only attach the switches and glue it with epoxy. If that won't do it, I can always go with the hole & screw alternative.

 

[jplebre]

on both mine and majestic's units, those switches are not going anywhere

 

[berkleystudios]

so this is the 1st build where i sourced all the parts myself... and as soon as I submit my mouser order i realize.... I FORGOT STANDOFFS!! lol. they wheren't in the BOM, so my real question is metal or plastic? ... i hope the rest of my parts are right haha

 

[tfp]

Hi Abe,

It is a silver can! When I bought it I did not know that there were also black cans, but it sounds great! Today i did a new measurement for what about the noise and RMS level is -84dB and maybe noise is a little bit higher than hum I think. But it is now connected with a maudio soundcard with cinch, so maybe gonna be better when fully balanced.

Now I have the correct 3k (shop didn't gave me 3k3) for the meter and went trough the calibration, there is one strange thing, for the input or output mode the meter goes below the scale, when measuring the voltages I noticed that the voltage for the meter is negative (no input signal). Any idea?

grtz,

RJ

 

[nuclues]

The BOM says that the resistors should be 1%- can I use  5% instead ?
Best from Nick

 

[jplebre]

should be fine but test them. you might be lucky enough to get them within tolerances.
the original schematic says 5% unless where specified so check there

 

[nuclues]

Cool JPlebre ,and thanks one more time

 

[eparg]

Now I have the correct 3k (shop didn't gave me 3k3) for the meter and went trough the calibration, there is one strange thing, for the input or output mode the meter goes below the scale, when measuring the voltages I noticed that the voltage for the meter is negative (no input signal). Any idea?

grtz,

RJ

If you mean it goes below the scale to the left with no input signal then the meter is functioning properly in that regard. No input signal = no input level = no output level. The meter should rest on zero when you have it in GR mode with no input signal.

 

[tfp]

Hi Eparg,

Thanks for your reaction but what I meant is that the meter goes below the normal rest postion (eg the position where the meter is when power is down) because of the negative voltage it then receives. The meter is pulled down instead of pushed up and I do not know how long the meter will like this before burning. I was experimenting with a diode on the plus side of the meter and this solves the problem, only I have to caliberate the whole meter again including finding the right resistor. Also with the diode I do not know if the working of the meter is less accuarate?

RJ

 

[nuclues]

Does someone know if it is possible to use DBX 260 vca's in this project?
Best from Nick

 

[jplebre]

TFP you sure you don't have the leads the wrong way around?
is it a vu meter or an ma meter?

 

[tfp]

It the hairball 8027-WF 1mA Meter

I double checked it, it is working perfect in all modes except when there is no signal the base volt is not equal to zero volt more like -0,111 volts and thats why the meter goes below its normal rest position. I do not know if the meter will like this for a long time. Tommorow I am going to try other resistors in the pad maybe it gets to much voltage.

 

[ilfungo]

Hi
R30 is omitted?
thanks

 

[tfp]

For the That chip build you do not need it. For vca200 build you need the 200R.

 

[tfp]

Hi Abe,

Solved my issue with the meter with a schottky diode works perfectly. Now minimum is -40dB with no signal present.

The numbers:

distortion minimum 0.40% (silver can vca) is this OK?

Level calibration lowest possible 0.000VDC, is this a big problem?

Noise with balanced connnection -91.5dB peak, -103.5 RMS

Hum none (barely noticeble with 60dB extra gain and dynaudio's full open). I use the expat audio crc board for rectification and smoothing off board. works great!

RJ

 

[nuclues]

Does someone know if it is possible to use DBX 260 vca's in this project?
Best from Nick

 

[berkleystudios]

okay couple Qs


do i need Panasonic's in the film spots C9, C11, C17 C18, C19, C10,C20, will WIMAs sound good?


where is R125??? i can not fin it on the board....

... thats really all for right now while i finish populating...

 

[jplebre]

do i need Panasonic's in the film spots C9, C11, C17 C18, C19, C10,C20, will WIMAs sound good?

I assume when you say panasonic's you mean e-lytics.
This can be polyester, but I prefer polypropylene as some of those are in the audio path (yeah, film, like Wimas)


R125 is on top of the board, next to the 1:4 ratio trimmer and TL082

 

[berkleystudios]

do i need Panasonic's in the film spots C9, C11, C17 C18, C19, C10,C20, will WIMAs sound good?

I assume when you say panasonic's you mean e-lytics.
This can be polyester, but I prefer polypropylene as some of those are in the audio path (yeah, film, like Wimas)


R125 is on top of the board, next to the 1:4 ratio trimmer and TL082

so i can leave the wimas in and be okay? i have panasonic polyesters in C12 and C21 did know how different it would sound with the Wima filsm in the other positions

ahh never mind i had already done it, must have been reading a different BOM