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

[Jase_Sanderson]

Trying to remember back, lol. I think in the end I have a 207 RMS on one side and a 208 RMS on the other side. So, in the end I got the 208 working and must have been happy with it. I know I bought another 208 can afterwards and planned to replace the 207 with it eventually, but haven't gotten around to it.

I haven't used the CLX in awhile (long story short, had first child this year and have had no time), but my recollection is that both the 207 and 208 sounded good. I think the low end response was slightly different between them, but that is probably more due to an error in calibration than anything else.

Like I said, I bought another 208 can after I finished the CLX, so I must have wanted to replace the remaining 207 with it. So, I think you are good with 208 cans if you have them.

Edit: If you are using vintage cans, I would look at the original DBX schematic. I think I posted it somewhere in this thread. There are a few values that are different than the CLX schematic. I think I also posted somewhere all or most of the different values I found between them FYI.

Great, thanks mate. I have been referencing those posts with the differences. Appreciate you

 

[Freq Band]

Got a couple of boards online (bay).
Getting parts together. Soldered-in machined sockets for DIPs and an SIP for the THAT vca.
I got a hold of some Motorola CeramicDIP LM301's, but I may use vintage 301AH metal cans - and those are from Signetics and AD.
I noticed on the original Cal doc, that it says " *OA6 to be Signetics only" ....and I'm not sure why ?
Since the single 22uf tantalum cap seems important (for timing), I'm going hermetic glass-sealed military-grade here, for optimum shock-&-awe.

I've never used an original 160vu, so I am really not knowing what to listen for, or what to compare it to.
I imagine much of any uniqueness prob comes from the vintage DBX vca's, which I'm not using.
I don't even know if the 301's add or subtract from the final sound.

Interesting, here is (was) Jim Williams commenting on what he typically has done to the vintage 160's that came through his shop.....

As to old 160/161's, yes they have really poor psu's and lot's of noise. All of them benefit from 5000 uf mains caps in place of the 470 uf's they used. Many are also out of calibration as well.

As for the opamps and their sonics, I do install machine sockets in these and the old opamps are returned (to the customer). It's as simple as plugging in the original chips to duplicate the old noise and dirt. You have the choice, but once folks hear the parts I use, none have elected to return to the older parts. We're talking LM301's folks, the 1967 designed original monolythic opamp!

Jim Williams
Audio Upgrades

https://gearspace.com/board/showpost.php?p=4584003&postcount=9

 

[Freq Band]

Getting closer...stuffing the case, almost.
But first I need to order the meters (Hairball site). I want to get the correct ones, prob the 1mA ones (w/3.3k resistor on the board)
These two fit the cut-outs for the "Collective Cases" case......
(links below)

8027-WF 1mA Meter​

and/or

8027-WF VU Meter​

I am guessing it is the first choice above, because "1mA" is in the name. But the second choice does not mention it's "mA" at all.
Nobody has listed a part# or direct link to the correct meters in this thread.

 

[JMan]

The second one is a VU meter. I'm pretty sure this build is intended for a 1mA meter.

 

[Spencerleehorton]

I’m hunting down some gremlins in one channel, it seems the output gain doesn’t do anything really but the 133k resistor shouldn’t measure as 133k and go from about 1k to 7k but doesn’t?
All pots are wired correctly must be a wrong resistor somewhere but haven’t found it yet?

 

[Spencerleehorton]

Got the pots working again and sorted the gain issue but chA not compressing now!!

 

[Spencerleehorton]

Pretty sure my problem is to do with the switch wiring as I’m using a lorlin 4p3t for input/output/GR

 

[Spencerleehorton]

got some horrible noise on chA within the RMS unit, it could be a bad CA3083 but ive tried the other channel one in there and get the same noise?
will check all caps and resistors and hopefully find a wrong one!!!

 

[Spencerleehorton]

When I probed on pins 16, 1, 2, 3 on the CA3083 they were down to gnd!!!!?
Turns out the c15 22uf tantalum capacitor was bad, replaced with electrolytic and now unit setups fine.
Will order a new 22uf tantalum and replace.
Now to try and find a stereo link diagram.
Seems it’s a simple SPST switch in between the two CAP pads and then set the controls on both as close as you can.

 

[Spencerleehorton]

Going to repost schematic and pdf for everyone as links have been broken.
Original dbx schematic

 

[Spencerleehorton]

Manual pdf

 

[Spencerleehorton]

Clx 160 schematic

 

[blackart777]

Great project...great sound...thanks very much.

 

[Waadka]

Hi guys
I am building this unit just having difficulty to find 3.02k 1/4 resistors so can this be replaced with different value ?

 

[SmokeyJoe]

Hi guys
I am building this unit just having difficulty to find 3.02k 1/4 resistors so can this be replaced with different value ?

That’s within a 1% tolerance of a 3k resistor, so can you buy a bunch of those and pick the ones that measure close to 3.02k?

 

[EarthTone]

Great project...great sound...thanks very much.

Man incredible looking build- Where did you acquire that case from? I may do a pair of these soon. Did you make it custom? Or find an old broken unit to salvage the case from? Thanks!

 

[blackart777]

Man incredible looking build- Where did you acquire that case from? I may do a pair of these soon. Did you make it custom? Or find an old broken unit to salvage the case from? Thanks!

Hi Earthtone,
Thanks!!! for the case I took this
https://collectivecases.com/?product=dbx-160-vu-stereoIt sounds really good, be careful during the build, errors seem very difficult to find according to what I read in this thread.
The calibration is very important too, so take your time! The build guide explains everything very well.
I haven't compared it with the original directly, but to my taste it has the same characteristics as the dbx160 I've seen!
good build!
hugh.

 

[Waadka]

Hi guys
I need help with calibration,
There are few calibration forms and steps I am Lost here don’t really know which one should I fallow? Please if someone can help i’ll appreciate

 

[matthieu68]

Hello everyone.
I would like your help please.

I have just finished a double clx vu, I calibrated it as indicated, but at the last step (VU meter calibration) once the r109 resistor is installed I notice that the vu meter of each unit is working backwards. (i.e. the needle goes up instead of down and vice versa)

whether for the gain reduction the line and the out.

-I checked the potentiometer wiring, OK
-I checked the switch wiring, OK
-I checked the correct polarity of the VU meter, OK
- The LEDs work as they should
- I measured the output level, it normally varies depending on the action of the potentiometers.

So only the VU meter works backwards.

The VU meter is a Sifam AL19WF

Do you have any idea what could be causing this?

Thanking you

 

[HerbertR]

Hi, you need to replace the VU meter scale with the DBX scale. The needle moves anti-clockwise when compressing. This is a very critical job not to destroy the needle. You will find the file anywhere at the first posts of this thread Congratulations, I think you did your setup right, but you have to do it again with this scale. Sorry, but I do not have any better news for you. Greez H