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

late said:

Yes the silver cans are little bit more noisier. I have both silver and black. I like more black cans and they sound more like an original 160vu. I have two silver and one black (unpotted) they work well. But those two potted black cans not work. Sound is so distorted, is it possible that dbx have made different sorts of black cans for different units. Or are they just broken?

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hmm I would think they are broken?

Hey there- got my kits and everything in the build, I am wondering which meter I got, the 1mA or the .1mA???? I ordered the one recommended from the AC site links on abe's page. I just need to know which resistor to pop in the board!

Curran said:

Hey there- got my kits and everything in the build, I am wondering which meter I got, the 1mA or the .1mA???? I ordered the one recommended from the AC site links on abe's page. I just need to know which resistor to pop in the board!

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Hi!
10k is for 0.1ma deflection meters (it soaks up more current) and the 3k3 is for the 1ma (soaks up less current leaving more for the meter)
Hairball meters are all 1ma.
Happy building!

sweet!!! And I am also assuming that the components on the board with (T) are for the THAT build which is what I am doing correct!

Thanks For that Abe!  I have asked some silly questions :-[

I am at the same thing as well. its not on the BOM, soooooooooo I am ignoring it until further instruction!!!

abechap024 said:

late said:

Yes the silver cans are little bit more noisier. I have both silver and black. I like more black cans and they sound more like an original 160vu. I have two silver and one black (unpotted) they work well. But those two potted black cans not work. Sound is so distorted, is it possible that dbx have made different sorts of black cans for different units. Or are they just broken?

Click to expand...

hmm I would think they are broken?

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Yeps it sounds like a broken. I would like to do it to your pcb. Do you know is it possible to use BC263C like in original. So replacing BC550/BC560 with BC263C. Anyone have black can schematic?

dumb question (as usual) whats the value of R125 supposed to be with a "THAT" build?  My original unit has something different than what the board says... cant remember if there was a reason for that i over looked in the build manual or what.  Thanks

sr1200 said:

dumb question (as usual) whats the value of R125 supposed to be with a "THAT" build?  My original unit has something different than what the board says... cant remember if there was a reason for that i over looked in the build manual or what.  Thanks

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Thats the current limiting resistor for the LEDs in the meters, 4k7 is the value that is on the Rev3s

And that answers that, cool.  I only have a couple hundred of those resistors layin around. lol

OK! missing a couple of resistors and capacitors form my kits. NOT a real problem if they are not needed. C11, C1, C4, C16, C13. I also need to know if I have installed my 103 C18 in the correct holes on the PCB. I have the leads in holes 1 and 3 if you are looking at the C18 box silkscreen from the top of the PCB and the holes are left to right like all of the pix in the build guide. Is this fine?

Maybe it is easier to use bc550 and bc560. But looks like that bc263c is pnp and bc109 npn in original black can build. Can someone tell something about that matching thing?

Can someone tell something about that matching thing?

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if it's just to match those PnP and NPN, you can use your multimeter's HFE function or get an Atlas Peak measurer.
Bear in mind they are temperature sensitive, including to the touch.

C16 is a trimmer so I can ignore that, but I have an extra capacitor in my kit so far and extra 1.8uf. should this actually go in the C11 .33uf spot like the C12 which has to two options?

Curran said:

C16 is a trimmer so I can ignore that, but I have an extra capacitor in my kit so far and extra 1.8uf. should this actually go in the C11 .33uf spot like the C12 which has to two options?

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C11 is 0.33uf.

C12
1.8uf for that chip
0.33uf for discrete vca

Hi Abe,
If I used 25 uA meter, how to calculate  R107?
I have mine working now, but Il can't get the scaling on the meter to work properly.
Regards Andrzej

the antek transformer has a purple lead coming off of the primary side. What do I do with it?

Curran said:

the antek transformer has a purple lead coming off of the primary side. What do I do with it?

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I believe that is connected to the chassis ground. That is what I did and my power rails are working perfectly.

On another note my compressor is not passing signal on both channels. I have triple checked everything and can't find anything wrong. I tracked the input with a scope and I'm getting signal into the rms circuit. After the rms circuit I'm unable to trace the signal. The above/below leds respond properly. Not sure about the meter, the resistor that needs calibrated is still out of circuit. Anyone have a guess as to what is wrong? I'm using the kit abe provided for the THAT chip build. I can post pictures later.

eparg said:

Curran said:

the antek transformer has a purple lead coming off of the primary side. What do I do with it?

Click to expand...

I believe that is connected to the chassis ground. That is what I did and my power rails are working perfectly.

On another note my compressor is not passing signal on both channels. I have triple checked everything and can't find anything wrong. I tracked the input with a scope and I'm getting signal into the rms circuit. After the rms circuit I'm unable to trace the signal. The above/below leds respond properly. Not sure about the meter, the resistor that needs calibrated is still out of circuit. Anyone have a guess as to what is wrong? I'm using the kit abe provided for the THAT chip build. I can post pictures later.

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In my case it was a dead IC TL082.

eparg said:

On another note my compressor is not passing signal on both channels. I have triple checked everything and can't find anything wrong. I tracked the input with a scope and I'm getting signal into the rms circuit. After the rms circuit I'm unable to trace the signal. The above/below leds respond properly. Not sure about the meter, the resistor that needs calibrated is still out of circuit. Anyone have a guess as to what is wrong? I'm using the kit abe provided for the THAT chip build. I can post pictures later.

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The signal flow goes into the VCA not the rms circuit, the rms circuit is the start of the sidechain and converts the audio into DC so thats why you cant trace it.

Follow your signal to the that 2180 chip. Search for the datasheet if you need to know the in/out pins. If audio is going in and out of your vca check the second Tl082 chip as that is the make-up/buffer for the output of the VCA. Then it goes to the output section LM301 and the output buffer stage (2 transistors)

Also since both your channels are not working that is suspect.

On a side note, I've had people putting in all their chips before calibrating their voltage rails!! If you do not calibrate your voltage rails to +15/-15 before inserting your chips, you will obviously and very likely BLOW your VCA and other chips.

Not saying this is what happened to you, but thought I would mention it.