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

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There is a need of 3X LM301, labeled LM301A, LM301B, LM301H
I guess these are all just LM301?

The only one I found is the:
LM301AH-NOPB

https://www.mouser.be/ProductDetail/Texas-Instruments/LM301AH-NOPB?qs=X1J7HmVL2ZGmBxYIZrEViA==

Will this one just be fine?
 
BerndVP said:
There is a need of 3X LM301, labeled LM301A, LM301B, LM301H
I guess these are all just LM301?

The only one I found is the:
LM301AH-NOPB

https://www.mouser.be/ProductDetail/Texas-Instruments/LM301AH-NOPB?qs=X1J7HmVL2ZGmBxYIZrEViA==

Will this one just be fine?

Ouch...spensive.... Should work nice but if the pcb is for PDIP, just be mindful of the orientation etc....

Maybe an online seller has good feedback and some pdip versions.... I'm still hesitant to buy from thee bay but have had good success more times than not if everything seems in line...
 
So,

There is no need for C1? Between the two big alu caps?

And for the power supply, I have one with two Secundairy 18V, how do I need to connect it ?
 
BerndVP said:
So,

There is no need for C1? Between the two big alu caps?

And for the power supply, I have one with two Secundairy 18V, how do I need to connect it ?

I think you do need C1, although maybe someone knows something I don't.  Did you see/read somewhere that it wasn't necessary?  That's in the power supply section, if I'm remembering correctly.  I have it installed -- it's a rather tight space, so just make sure you don't buy one of those fat Wimas or something, which may not fit.  (Also, as I mentioned before, my unit has been sitting on the sidelines for awhile and still needs the final steps completed, so there may still be some surprises in store for me.  I want to be helpful, but there's always the possibility that I am wrong).
 
So, I re-read the whole topic.
C1 needs to be installed.
Just on the photo’s in the manual it isn’t soldered.

I went for KEMET ones, those are small enough.

The transfo is ok now 😊
The PSU is now trimmed to +/- 15V so Ican start putting other components in it.

Just the 24V rail was giving me  around 55V.
But I guess it has something to do with no ‘grounding’ yet
 
Hi all

I just finished my built of the CLX (stereo) but it doesn't seem to work as it should. I get sound through but no compression. The meters are not responding either.
I get +15VDC on the rails and +54V on the second connection where it states +24V. Possibly this has got something to do with the PSU (toroidal 50VA 18-0-18). I tried grounding and ungrouding but this didn't make any difference (@BerndVP: I read your comments too... :) ).
When I want to set the RMS the trimmer seems not to be responding though when I measure it (power off mode) it seems fine (resistance wise). The response I get on the oscilloscope is a very symmetrical waveform though. Also when I take the output I can read the response from the sinewave (on SMAART). So sound is going trough.
My panpots are somewhat responding (gain and threshold is, ratio doesn't seem to be responding but I'm not sure of this). The LED's (above and below) is only responding on the above side. And as I said no meters whatsoever...
Both PCB's do the same thing and I measure on both the same values...

I built the VCA kind, not the discrete one...

There will be quite a few problems instead of just one and I am aware that this might be over my head. But I've built other beautifull compressors before without any issues like these (LA2A, 1176...). I also found a few errors in the 'manual' like most of you did I suppose but anyway I'll give them once again.
C1 is not mentioned though it should be in there (this forum says so). What about C13? I've put it in anyway (don't know if it does make a difference for now). I also suppose they just were forgotten in the BOM-list.
There is no mention of grounding except for the XLR and even that I find hard to grasp (because of the 'chassis' for me is the case and instead they speak of the XLR itself). I tried without grounding and with grounding everything that says 'G' or 'GND'. I hope I'm not making groundloops... But I tried them one by one and untill now it doesn't make any difference on my measurements which I can do.
A few of the trimmers are not mentioned anymore further on in the manual, if they need to be trimmed and how (or what value it should read)?
The LM317's get quite hot too...

I also found an addendum where it says that Q8 is misprinted on the board and that you have to change C14 (from 22 pF to 150 pF) if you use a THAT chip, but this is from REV2? So maybe in REV3 this is corrected? Does anyone know?

I also don't know where to start looking for the error(s)...
I tried the web but this is the most I found (like any of you I suppose).

I think I have all the info there is to find (manual rev3 and a picture from someone here years ago)
Is there anyone out there who got his working (with this kind of buildtype: stereo AC CLX-VU)?

I'll post some pictures too and hope someone can help me here... I also post the addendum I found (I can't remember where so maybe it is from somewhere around here but hey there you have it...)

 
 

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Hi Roel,

I haven't finished the project yet, I ordered too few of the 'POLYPROPYLENE FILM CAPACITOR' 1nF.
So 1 board isn't finished yet and I ordered a bi-polar for C21 but going to put an POLYPROPYLENE in it.

I see we used the same PP film caps I see on you're pictures.

I don't have the case, switches and VU yet for further finishing of the project.

I see you got some LM301 on DIP8, I had to go with an other type of LM301: 926-LM301AH/NOPB

An for C13, that's a good question, at this point, I haven't solder it, but the manual is not telling you need to, but that was the same for C1....
 

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Hi Bernd

I got the rest from Collective cases, Hairball and Don audio...

Btw, I'm from Belgium too, Heusden-Zolder.
 
Roel said:
Hi all

I just finished my built of the CLX (stereo) but it doesn't seem to work as it should. I get sound through but no compression. The meters are not responding either.
I get +15VDC on the rails and +54V on the second connection where it states +24V. Possibly this has got something to do with the PSU (toroidal 50VA 18-0-18).
You should be hitting the brakes right there and resolving that basic issue before letting the unit run for any additional testing of the audio. You can fry components if your voltages aren't in the ballpark, then troubleshooting becomes a real nightmare.
 
I know... That's something I had to be aware of...
But I stopped now  :-\

Problem is that the manual only speaks of the 15V rail and not of the 24V as if it isn't used. There are more things left unused and I assumed that the 24V was for that purpose (or not...).
But I think I didn't burn anything yet and hope to keep it that way. Now my next problem is what makes the 24V rail be so high?

I'm gonna find it and I hope someone here can help with the troubleshooting. I'm good with the solder and can read a good plan but I'm not an electronic engineer, just a thing I really love to do. But if the manual is poorly made...
 
Hy Roel
You have pcb for rev 3.
Read manual for rev 3. In rev 3 is more explain.
Check the wiring for switch. Maybe you have switch gr and out switch.
Also first make sure without chips that your power rail is +15 and -15 v
Check your c11 c12 and c21 of je polarization good is
I have 2 ca chips and 3 lm301 burned for one board. Troubleshooting is nightmare
 
Hi

I do have the manual and by now I almost know it by heart... ;D

I did the wiring of the switches accordingly to the manual. Isn't this correct?
power rail is perfectly +15V. There is no -15V as far I can tell. Where should I measure -15V?
Only the +24V side of the power rail is about 54V...

C11, 12 and 21 are non polarized or bipolar, not?

I'm trying to check each IC individual now but I'm learning...

Thanks for the reply though
 
Okay, thank you very much . Indeed I was measuring between + and - ...  Now it's fine. On the 24V rail I get 25V but that's ok I think (no IC's inserted and so).

I'll start again from here
 
Yes 25v is ok
You set black probe from mm to G and rode probe first to - you must see -15v at your mm
Then rode probe to + you must see +15v at your mm
This is very important

Rail for 24v is not so important
 

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