Modifying DBX 163X

beefy · Post by **beefy** » Sun Dec 13, 2009 1:04 pm

I didn't want to start a new post but I have a couple of questions about mods for the dbx163x. I'm trying to order the 1000 uf 35v caps from and that op amps from mouser those are the two mods I'm going to start off with. I'm having trouble figuring out which 1000 uf 35v caps to get. I know your using electrolytic aluminum caps but there is about a million of them on there? As far as the that 2180A thats easy enough to find on there so thats not a problem.(pun intended)

Also I'm a newb at this but I would like to try one other simple mod to this thing and was wondering which you one ou guys would think would be the most affective?

Thanks

Sean Sullivan · Post by **Sean Sullivan** » Sun Dec 13, 2009 2:23 pm

From Mouser I would get Nichicon HE series capacitors. The THAT 2180A is from Mouser. The op amps you'll have to get from Digikey most likely. You can also order 1000uF Pansaonic FM from digikey.

Brian · Post by **Brian** » Sun Dec 13, 2009 6:52 pm

You'd be looking for the lowest impedance caps you can get, put that in the search function and it will return Nichicon HE series. If it signal path stuff, go low ESR, if it's power supply or filtering, go with Low impedance, and you can get some with both characteristics.

beefy · Post by **beefy** » Sun Dec 13, 2009 7:11 pm

Thanks with both your replies I ordered the 1000 uf 35 caps the that 2180a and both nationals I figure I will start with that. thanks for the tip with ordering the caps. It helps a lot to know little things like that and I'd like to learn as much of it as I can.

One other question is how would I know what Voltage rating to order for other caps. It doesn't say on the schematics is there a way to tell or is that something someone more experienced with electronics would be better of figuring out?

Thanks for both your help.

Sean Sullivan · Post by **Sean Sullivan** » Sun Dec 13, 2009 7:24 pm

Just look at the caps themselves. It's ok to go for a high voltage if they will fit, but don't go lower. I used Nichicon HE 1000uF/50 V for C28 and C29 and Nichicon HE 470uF/25V for C32 and C33.

beefy · Post by **beefy** » Sun Dec 13, 2009 7:34 pm

Thanks I have two coming in the mail so when the get here I will crack them open thanks.

Brian · Post by **Brian** » Mon Dec 14, 2009 6:30 am

beefy wrote:Thanks with both your replies I ordered the 1000 uf 35 caps the that 2180a and both nationals I figure I will start with that. thanks for the tip with ordering the caps. It helps a lot to know little things like that and I'd like to learn as much of it as I can.

One other question is how would I know what Voltage rating to order for other caps. It doesn't say on the schematics is there a way to tell or is that something someone more experienced with electronics would be better of figuring out?

Thanks for both your help.

You need to know what the total voltage swing for the device will be and exceed that for most caps in the signal path,
and for the Power supply, you should cut the ac voltage in half for each side of a bipolar supply, after the transformer since it will be ahead of the caps, and exceed that, if you don't want to watch them blow up.

On a side note, it's also OK to put bypasses on the power supply caps.
I really didn't think it would do any good till I tried it and it has straightened out a bunch of gear I've done that with.

beefy · Post by **beefy** » Fri Dec 18, 2009 3:32 pm

Got my two in the mail yesterday plugged one in to hear it and it sounded pretty good stock. So I took the other one apart and put int the 1000 uf 35v caps and tried it out and it sounded like it cleared the signal up but wasn't compressing it was just adding gain I was hearing breathing from the vocal track I put it on. So I figured what the heck I'll put in the 2180s op amp in there and see what that does.

It was my first time soldering an op amp. I finally got it in there but I thought I fried the board with the heat gun but I figured live and learn I have another good sounding one anyway and decided to plug it in and try it out anyway. Man did it sound good I couldn't believe it.

I'll put the other two Ics in tomorrow and hopefully the soldering process will go a little better. Thanks for your help.

Brian · Post by **Brian** » Fri Dec 18, 2009 3:35 pm

Rock on!

sethl · Post by **sethl** » Mon Jan 11, 2010 8:01 pm

By scanning through all the posts here, I have a fairly good idea of what mods will benefit the 163x. One question that didn't seem to get resolved was the ferrite bead (replacing C2 I believe). Is there a recommended value?

Thanks!

germaniac · Post by **germaniac** » Tue Jan 12, 2010 2:52 pm

Hey Friends,

I'd like to know some more specifics about which ferrites beads too.

FWIW, if anyone doesn't feel like making a whole career out of modding the 163X, I've found just replacing the VCA with a 2180, the signal-path caps with films, and the signal-path opamps with a 2134 and an OP176 made a night/day difference. Mine have been slamming good for years that way. OTOH, maybe now I'll have to look into the PS and the rest of Jim's mods too. . . .

Joe

Sean Sullivan · Post by **Sean Sullivan** » Wed Jan 13, 2010 6:42 pm

The correct ferrite beads are out of stock, and I can't find a suitable replacement. They are Panasonic EXC-ELSA39. I think they'll be back in the stock early February.

I need some for 3 Aphex 651 I'm working on as well, so I have a bunch of projects that are 95% finished.

Sean Sullivan · Post by **Sean Sullivan** » Wed Jan 13, 2010 8:18 pm

Here are a couple pictures of mine. I'm going to change the bypass capacitors, I used the "wrong" size and it barely fits in the case. I have some left over from a console recap. And I still need the ferrite beads a 1 uF capacitor that will fit! I don't think you can buy mylar capacitors anymore, and all the polypropylene capacitors Wima makes are too large. But, this is a general idea, I think Brian wanted to seem some pictures.

Brian · Post by **Brian** » Thu Jan 14, 2010 7:56 am

Nice work! Thanks for the pics, and yeah, when putting in bypass caps I used polyester, they're smaller and very precice , so they can sound a tiny bit more harsh on he top end in the audio path but better mids, in bypass, they fit better to remove noise from the line.
Polypropylene is great for the audio path. If you take them out of the bypasses, save them.

germaniac · Post by **germaniac** » Thu Jan 14, 2010 8:58 am

Yeah, nice work ML! Thanks for the pix and for the ferrite bead part number. BTW, those ceramic caps on the trace side of your board look like they have about a half-inch of lead on them. As a rule of thumb, with local bypass caps right on the chip, you want that cap AS CLOSE AS POSSIBLE to the PS pins. In cases where you need a long lead to reach a ground trace, I'll usually attach the shorter lead of the cap to the pin and make the lead going to ground the longer one. FWIW.

Regards,
Joe

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