DBX 120

[CJ]

I do not know if you read the last pdf in the list, but it was compression artifacts in the digital realm, seems that when they try and compress in digi land, they get a whole new set of problems and wouldn't you just know that was going to happen.

Some of the new testing methods can be tried out on the old stuff, if you have the bench for it.

 

[wiz1der]

[quote author="mediatechnology"]

Personally, I'd LOVE and ADORE a stripped-down, "use-it-on-an-aux-send" version, with one input, one output, NO EQ, no summing; just the pre-filters, the fancy clipper and the post-filters.

OK then. That would easily fit on a 900 series form-factor. Hasn't Rob (handcrafted tone) done some 900-series stuff? I seem to recall a gate he did that looked 900-ish.[/quote]

YES!! I dont recall seeing anything 900 here ever.
This would be so nice as a aux send to fatten things up, for that reggaetastic dub super thick bass vibe...

I dont know if it's too early but..... Count me in for 4 9120's!

 

[clintrubber]

[quote author="wiz1der"]YES!! I dont recall seeing anything 900 here ever.
This would be so nice as a aux send to fatten things up, for that reggaetastic dub super thick bass vibe...[/quote]
I'm not familiar with the 900-PCB-size, (if that would start rolling) I'm just curious to how universal or usable in other systems that would be. I guess a 900-intended PCB can always be used in a normal not too deep 1RU box, right ?


Apart from this, I've been searching for how the Ashdown bass-amps do the sub harmonic. I found a schematic, but it lacked the 'sub gen PCB' section :evil:
But I stopped my search when I read a user-comment about 'two basses at once'; then I knew enough... sounds like the 'OC-2-way'.
In case anyone has more specifics w.r.t. Ashdown please tell.

Bye,

Peter

 

[clintrubber]

[quote author="mediatechnology"]Peter: IIRC it's a 44 pin (22 dual row) edge card format. I read that the rackframes are dirt cheap on eBay but I'm not sure I believe that.[/quote]
Thanks for the info Wayne.

I think I've seen frames pop up here in NL as well, but I won't be starting yet another kind of format. Am using a few 3RU for Eurocards already and am working on a 6RU for another format, so adding a third taste would let me end up with a stack of stuff that's only containing a few modules on the left, a power supply on the right and an empty hole in the middle

BTW, 900-racks are 3RU as well, right ? It'll all be fine.

 

[Sleeper]

Here's the outline as measured off my 900 series comp.
there is a tiny bit of wiggle room with the length, it depends on how you were to bracket the front panel. the dbx has a cast aluminium jobby with mounting bracket built in. a simple right angle bracket would do the trick.
The 15 pins are on both sides.
the ones marked detector in and cv in go to the auxiliary connectors on the back of the 900 rack, so these could be used for anything you wanted.
power is supplied by the 900rack psu.
(I was thinking of etching up a blank card and just attaching some existing projects to it, thus the long edge card pins)
Kelly

 

[Gus]

Keith I would change the LM339s on page 3 meter section and see if that fixes it. Also check resistance between the inputs of the comparators on good and ones that are failing

FWIW a board I fixed in the past had 319s on it they seemed to fail more than other parts on the board(but the 319s would last on other PCBs? so most likely some circuit design problem not the chip) never did figure out what was the problem the circuit looked like the inputs should be protected on power up and operation and the shop used static protection when working on the boards.

Other things to test might be whammys, the boss pitch shifter, danelectro chili dog.

 

[Sleeper]

Yeah, it's a drag because I haven't been able to find any 30 pin cards...
The size factor format is available in perfboard, but with 44 and more pins, but not 30... this was just from looking at the usual sources, mouser digikey alied etc.
I have a mess of double sided copper boards from a surplus pile, so for me, a home etch makes sense.

I certainly wouldn't mind if someone picked up the ball here and ran with it.
I'm sure there are quite a number of projects that could be easily pasted into this format...
Kelly

 

[clintrubber]

[quote author="mediatechnology"]15/30 pin connectors.[/quote]
15-pins, hmm, sounds like there could be floating something suited around here.
Pic shows 2.375" width for 15 traces, but could anyone add what's the exact pitch of them ? (centre-to-centre) ?

Thanks,

Peter

 

[SSLtech]

0.156"

Keith

 

[clintrubber]

[quote author="mediatechnology"]For quick shots I still can't beat my floppy-based Sony Mavica. It's just rip-n-go with that camera.[/quote]
Apart from newer stuff, we still have one of those at work and it's still going strong. I like it a lot, have in fact been using it last week with a HP-box that doesn't do fancy datadumps.
What you said, rip-n-go. A camera with a 3.5" floppy drive, so cool.

 

[clintrubber]

[quote author="SSLtech"]0.156"[/quote]
Thanks all for the info. Looks like 'normal' spacing over here as well then, nice.
Number of contacts is still something else though, dbx does 15, BA283-cards 18 pins and the spares I have are 22. FWIW...

 

[Gus]

looking at some of the pictures reminded me of the older STD bus.

 

[Sleeper]

I'm not at the computer with the illustrator file to check the exact spacing and width of the pins, but the drawing is correct.
I suppose a much smaller interface board could be made, perhaps with the card edge , a header section for molex connectors and short length of blank board for attaching your pcb...
I suppose the length of blank should be adequate to hold some of the more standard board sizes... eurocard, ssl pcb, whatever.

Kelly

 

[wiz1der]

yes!

 

[Sleeper]

Hi EZ.
Like this. etch this one up at home and your in business.
I've got .100 headers already as well as .100 ribbon cable here so I went that route.
I don't really see any need to go double sided on this, but maybe a 1/16th thickness board would be a better fit than a 1/32nd.
If somone wants to make these at a pcb house feel free.
trick or treat.
Kelly

 

[wiz1der]

NICE!

This will allow us to put almost a lot of different projects into a tidy 900 rack space!

Now all we need is the 120 circuit put onto a smaller card?

 

[SSLtech]

Heh...
I just remembered a classic example of a song with a low-octave synthesizer example...

http://youtube.com/watch?v=FfLY0Yh0Hp0

-Check out the mistracking when he goes up the octave later on in the song...

Keith

 

[clintrubber]

[quote author="SSLtech"]Heh...
I just remembered a classic example of a song with a low-octave synthesizer example...

http://youtube.com/watch?v=FfLY0Yh0Hp0

-Check out the mistracking when he goes up the octave later on in the song...

Keith[/quote]
I know that song quite well - always have been fond of the 'weird' sound - just never realized it was done by means of a sub !

Weird BTW, with some Dutch treat-talk in another thread here's a HC-clip... showing the Netherlands :roll:

 

[Consul]

I have the crazy idea in my head of trying my hand at a software version of the 120 (well, I have to do something to apply this new calc knowledge I've been gaining). Not having a unit, though, will be depending on other people telling me what its attributes are. After all, the idea is to code in the flaws, too, I think.

So, question number one: Can anyone tell me the slopes and corner frequencies of the filters?

Anyway, that's about that. Thanks!

 

[leigh]

Just found this thread... man, I wish this discussion had happened a couple years ago, when I was figuring out these boxes on my lonesome.

I recently discovered that dbx publishes the 120xp schematic themselves, a modern colorized version of the original schems I'd seen before:
http://www.dbxpro.com/Download/discontinued.htm

Also, after getting way deep into my hardware investigations, I did make a software plug-in version of a dual-band subharmonic synth. Called the Lowender, it's commercially available here: http://www.refusesoftware.com/ (Mac only for now; Windows coming soon!)

The big difference in method between a dbx 120 and an octave pedal (as clintrubber points out) is the dual band action of a 120. The biggest advantage to a dual band approach, in my opinion, is that by having each frequency-divider see only half an octave of bandwidth, you avoid the annoying octave hopping glitches of a wideband pedal. By only looking at half an octave, the divider doesn't get confused whether the fundamental is, say, 110 or 220 Hz.

When I was playing around with modding a 120XP, I tried widening the bands, to have it cover more ground. It started octave-hopping, and it was then I realized the wisdom of dumbing things down for those poor, easily-confused flip-flop dividers.

cheers,
Leigh