dbx 160vu clone

[abechap024]

Hello,
Yes, the Idea is that you jumper the two boards using the "alt power supply"  and install the extra caps on the second board.
The one set of lm317/337 should have more then enough current as long as they are properly heatsinked.

-Abe

 

[Rob Flinn]

I was looking at the PSU part last night. 

For C2 & C3 you're specifying 1000u 35v with a 24v x 2 mains transformer.    Once you have rectified 24 volts  (24 x 1.414) you may have 34v (depending on load)  across these caps, which is a bit too close for comfort.  Probably better to have 50v or 63v caps there.

Also it is common to have some 100n caps round the LM317/337 from "in to ground" & from "out to ground", close to the regs.    It can be difficult to dial up the right voltage without them.    I was suufering this probalem only yesterday when I inadvertantly forgot them myself on a 24v PSU.  What happened for me was that as I adjusted the volatage upwards it was fine until I got to about 23v then in an instant it would go straight to full voltage.  Adding these two 100n caps, stabilised the psu so that I could get me 24v.

 

[Biasrocks]

I was looking at the PSU part last night.  

For C2 & C3 you're specifying 1000u 35v with a 24v x 2 mains transformer.    Once you have rectified 24 volts  (24 x 1.414) you may have 34v (depending on load)  across these caps, which is a bit too close for comfort.  Probably better to have 50v or 63v caps there.

On a related note; I found that a 20V x 2 PT got the voltages where they needed to be. The output section is largely unregulated and wants to see ~24V. I also upped the caps to 50V for better headroom in the power supply.

Mark

 

[Rob Flinn]

I have 2 copies of the circuit diagram for the 160VU.  I noticed on one diagram R85/95 are 3k3 & R87/91 are 10k.  On the other diagram they are the same as is used on Abe's board. I'm trying to work out what difference this makes if any ?

 

[abechap024]

Yea that's a good point about the transformer...
I'll switch it on the BOM for 2x20v transformer.
Just for the record I have mine working with a 24V transformer with about rectified 33v powering the output stage and it works fine.

Also Yes I was looking over the lm317/lm337 circuit last night and realizing that I could've put the trimmer resistors closer to the regulators, along with adding some 100n caps. As I also had trouble recently adjusting a new chip regulated power supply. But we won't know till we power one up. Hopefully it will work fine.

I have 2 copies of the circuit diagram for the 160VU.   I noticed on one diagram R85/95 are 3k3 & R87/91 are 10k.  On the other diagram they are the same as is used on Abe's board. I'm trying to work out what difference this makes if any ?

hmmm interesting....Just from glancing at the board, It changes how much voltage/current the output stage sees....It probably doesn't end up making that much of a difference...but I am curious also. do you have a link to the schematic with 3.3k /10k? I 'm wondering if there are other differences.


Abe

 

[damnyankee]

I was looking at the PSU part last night. 

For C2 & C3 you're specifying 1000u 35v with a 24v x 2 mains transformer.    Once you have rectified 24 volts  (24 x 1.414) you may have 34v (depending on load)  across these caps, which is a bit too close for comfort.  Probably better to have 50v or 63v caps there...

I am using 25v x 2 mains and you're exactly right: I'm hitting 34.1V. 

Abe and I have been troubleshooting my -15V rail issue; we think we've isolated the issue to those NTE159s.  I'm awaiting to get some replacements in the mail.  I understand the Rev B boards won't be using this power supply *yeeeehaw!*

DY

 

[abechap024]

PS factory sent out the boards via fed ex! Scheduled to get here on the 3rd!!
;D

 

[chrispbass]

PS factory sent out the boards via fed ex! Scheduled to get here on the 3rd!!
;D

Hi Abe, will you do another run of these in the future?
Cheers
Chris

 

[abechap024]

I have some extra. Message me if interested.
Regards,
Abe

 

[abechap024]

Arrived today. Getting ready to ship them all out ASAP.

Thanks you all.

I still have some left for those who weren't able to get in on the pre-order. Its 35$ plus 5$ flat shipping around the world to payment AT acsoundstudio.com

Get your soldering guns ready!

Abe

 

[damnyankee]

YES!!!!

By the way, is there a new BOM for these???

DY

 

[abechap024]

Hi All,
Boards should be sent out to me on the 1st. I'm really excited. Here is a BOM for the CLX-VU  ;D build (CLX is 160 in roman numerals)
This is for the THAT chip build 2nd rev:

BOM for 2nd REV CLX-VU THAT chip based Build
PCB Board for REV2 CLX-VU Build
The Schematic for CLX-VU 2nd Rev




Also I'll upload the discrete vca build BOM in a bit. For those eager enough to try it . All in all the That chip is cheaper and sounds great. But the Discrete VCA seems like a fun challenge all in itself.

 

[dandeurloo]

sweet sweet sweet!

 

[grantlack]

awesome, even with dales and bourns trimmers it's only going to end up being $75-80.  quick lead spacing question- the poly cap spacings on the board go down to 5mm, correct?  it looks like it, but i figured i'd ask before i order.  i also see mixed lead spacings on the 10pF ceramics (.2" in the RMS section and .1" above the THAT section), are there any other .1" fellas that i'm not seeing?   way to go abe!

 

[abechap024]

Hi Grantlack,
Thanks for asking, I should update the BOM with pin spacings. The two .33uf cap spacing are 7.5mm to 22.5mm and the .47uf polyester goes down to 5mm - 15mm and the 4.7uf polypropylene goes 5mm - 22.5mm

 

[damnyankee]

Hmmm...this is how I have it wired.  But when I check the pads on the Alt PS to ground, I get:

Pad 1: -46.7
Pad 2: *ground*
Pad 3: +17
Pad 4: -48.2
Pad 5: +18.5

Everything is wired correctly.  All solder joints are good.  Maybe I'm missing something:
*snip*

Ok, I think I have a working power supply.  Replaced the NTE159s which were fried & re-oriented the NTE129's:

Pad 1: less than -18V (NTE159's were fried)
Pad 2: *ground*
Pad 3: ~ +16V
Pad 4: -34V (NTE129's not oriented correctly)
Pad 5: +34V (NTE129's not oriented correctly)

(This is with Antek 2x25V output trafo which x 1.414 = ~35V output which to me is too high, so I'll be replacing with a smaller output trafo)

I never knew electronics could be so much fun!  I replaced every major component in that power supply and wouldn't it figure it was the last two components I checked (the NTE159's). Cooked-o-rama! :-[

 

[abechap024]

So the BOM is updated:

www.acsoundstudio.com/DIY/160vu/BOM/2ndREV/Information/Circuit1.jpg
www.acsoundstudio.com/DIY/160vu/BOM/2ndREV/Information/CLX_VU%20bom%20THAT%20CHIP.pdf
www.acsoundstudio.com/DIY/160vu/BOM/2ndREV/Information/PCB_Board.jpg

found replacements for those rather expensive NTE128/NTE129 pairs

and they sell them at mouser!  2N3053/2n4037

Cheers,
Abe

 

[baadc0de]

These are also available with farnell for us european DIYers.

 

[Citrus Hill]

Hi Abe,
payment sent for two PCB's. Thanks for such a cool project!
Rob Mc.
Citrus Hill Studios

 

[abechap024]

Confirmed. PCBs will be sent out on Monday.
Thanks!