Mad Professor - Deep Blue Delay  [traced]

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Re: Mad Professor - Deep Blue Delay

Postby Seiche » 19 Dec 2011, 08:51

marshmellow wrote:Clean volume should be ever so slightly above unity gain. Input gain of 2 (360k/180k), output gain of 0,55 (12k/22k). If you want more you could reduce the 22k resistor. That would leave the effect volume unchanged and only boost the clean signal. If you want to boost both, increase the 12k resistor.

so using a 25k-50k pot in the feedback loop of the output buffer would give something like an overall volume control?
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Re: Mad Professor - Deep Blue Delay

Postby marshmellow » 19 Dec 2011, 15:02

Si señor!
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Re: Mad Professor - Deep Blue Delay

Postby mictester » 22 Dec 2011, 21:58

Seiche wrote:
mictester wrote:
DBD_Vero.gif

Hi mictester,

just a heads-up, the vero is missing a few part values, r7, c2, c5, c12, c13, c14, c15

cheers


Damn Windoze! Bits got chopped off the end of the list. However, I used the same component designations for both the Vero and the PCB versions, so the list is:

R7 = 33R R16 = 2k2 C5 = 1µ C12 = 10n C13 = 22n C14 = 1µ C15 = 47n

Hope this helps!
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Re: Mad Professor - Deep Blue Delay

Postby Seiche » 23 Dec 2011, 00:43

mictester wrote:Damn Windoze! Bits got chopped off the end of the list. However, I used the same component designations for both the Vero and the PCB versions, so the list is:

R7 = 33R R16 = 2k2 C5 = 1µ C12 = 10n C13 = 22n C14 = 1µ C15 = 47n

Hope this helps!

yes, i figured you did and cross-checked them before ordering. what i did notice is that unfortunately the vero layout doesn't seem to fit in a 1590B-sized enclosure with a battery, even after leaving out the extra rows and columns at the edges. Might fit in 125B though, plus that might give the possiblity of putting the jacks on top.
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Re: Mad Professor - Deep Blue Delay

Postby mictester » 23 Dec 2011, 02:04

Seiche wrote:
mictester wrote:Damn Windoze! Bits got chopped off the end of the list. However, I used the same component designations for both the Vero and the PCB versions, so the list is:

R7 = 33R R16 = 2k2 C5 = 1µ C12 = 10n C13 = 22n C14 = 1µ C15 = 47n

Hope this helps!

yes, i figured you did and cross-checked them before ordering. what i did notice is that unfortunately the vero layout doesn't seem to fit in a 1590B-sized enclosure with a battery, even after leaving out the extra rows and columns at the edges. Might fit in 125B though, plus that might give the possiblity of putting the jacks on top.


I always leave room at the edges because I usually drill holes for mounting - I use nylon spacers, screws and nuts.
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Re: Mad Professor - Deep Blue Delay

Postby HEAD » 23 Dec 2011, 14:51

... and furthermore: Operating this thing with a battery might not be the best idea. It simply draws too much current. I would never, ever use a battery for delays.

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Re: Mad Professor - Deep Blue Delay

Postby andregarcia57 » 31 Dec 2011, 20:40

oks!!!
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Re: Mad Professor - Deep Blue Delay

Postby Seiche » 04 Jan 2012, 09:58

mictester wrote:
Seiche wrote:
mictester wrote:
DBD_Vero.gif

Hi mictester,

just a heads-up, the vero is missing a few part values, r7, c2, c5, c12, c13, c14, c15

cheers


Damn Windoze! Bits got chopped off the end of the list. However, I used the same component designations for both the Vero and the PCB versions, so the list is:

R7 = 33R R16 = 2k2 C5 = 1µ C12 = 10n C13 = 22n C14 = 1µ C15 = 47n

Hope this helps!

I redid the component list for my build to have all the numbers and have them in order(makes it easier to populate and troubleshoot). I also noticed the pcb version leaves out C22 and continues with C23, whereas C23 corresponds to C22 on the vero. A bit confusing, but not really a problem. I'm planning to start populating today.

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Re: Mad Professor - Deep Blue Delay

Postby Seiche » 04 Jan 2012, 17:10

Almost done populating the vero board.
what if one would replace the 33R resistor with a jumper? Would that affect anything, like add noise or something?

what i can say is that the vero layout is a squeeze with green caps, everything barely fits. And I'm a little concerned about height when mouting this over the pots. Might have to use a 125B enclosure. I am gonna do the mod with the volume control. I was thinking about using a 10kB pot with a 2k in series.
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Re: Mad Professor - Deep Blue Delay

Postby culturejam » 04 Jan 2012, 17:22

Seiche wrote:what if one would replace the 33R resistor with a jumper? Would that affect anything, like add noise or something?

I doubt you'll hear much difference. That resistor will prevent "infinite" current draw (not likely an issue in this case), and it might help reduce noise if the pedal is on a daisy chain with 10 other effects.

For testing purposes, you're find with a jumper. Or with 47R or even 100R. At least in my own anecdotal experience, of course.
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Re: Mad Professor - Deep Blue Delay

Postby Seiche » 04 Jan 2012, 17:39

culturejam wrote:For testing purposes, you're find with a jumper. Or with 47R or even 100R. At least in my own anecdotal experience, of course.

"testing purposes"? what the hell are you talking about? this is going with me on the world tour! :blackeye

I'll leave the jumper for now and put everything together. If there is a problem, i might take it apart and replace the jumper with the proper resistor. I'm too lazy to wait for another order or to go outside and buy a single resistor (that might not even do anything). :slap:
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Re: Mad Professor - Deep Blue Delay

Postby Ghandi » 07 Jan 2012, 14:59

Hey guys,
I just had a peek inside a Deep Blue Delay,
the IC is a Analog Devices AD712, that's the chip that is also supposed to be in the Zendrive.

A very good, warm and at the same time hifi sounding op-amp that could add some of the warm sound to the dbd!

By the way I really like how that delay sounds!

Cheers
Ghandi

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Re: Mad Professor - Deep Blue Delay

Postby Seiche » 21 Jan 2012, 18:24

So I built this the other day.... it doesn't work.

Looking at the vero layout again comparing it to the schematic, i found that pin3 (as well as C19 and C22) of the pt2399 isn't grounded like it should be. I've added a connection in the vero I attached.

Also, after reading the datasheet of the voltage regulator, I think C23 and C24 (that aren't in the schematic, i guess mictester added them, but it seems like the original circuit worked without them) should be polarized and C24 should be 0.33uF. Not sure if that makes a difference though. (EDIT: just noticed, this has been discussed 1-2 pages back)

I will add the jumper and leave the caps for now and see if it works then.
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Re: Mad Professor - Deep Blue Delay

Postby Seiche » 21 Jan 2012, 20:03

added the jumper, still no signal going through (led lighting up).

i measured the voltages with a 9.05v battery:

IC1 (TL072)
4.3 8.56
4.3 1.38
4.3 3.2
0 1.11

IC2 (Pt2399)
5.05 2.5
2.5 2.5
0 2.5
0.09 2.5
2.27 2.5
2.5 2.5
0.65 2.5
0.65 2.5

Reg
8.56
0
5.05

Regulator is as expected, IC1 looks fine, I think. IC2 i have no idea if the voltages are normal, i have no experience with them.
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Re: Mad Professor - Deep Blue Delay

Postby marshmellow » 21 Jan 2012, 20:20

There is something wrong near the TL072. All pins but 4 and 8 should be somewhere around VB = 9V / 2.

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Re: Mad Professor - Deep Blue Delay

Postby Seiche » 21 Jan 2012, 21:53

marshmellow wrote:There is something wrong near the TL072. All pins but 4 and 8 should be somewhere around VB = 9V / 2.

thanks man! I looked at pin 5 and noticed i didn't put the jumper in that connects it to v_ref. :slap: :slap: :slap: voltages are good now.

anyway, off to round 2 of the debuggin. Now I get some signal through but only really really quiet. barely audible. And that's original signal and delays.
I figured there must be a wrong resistor somewhere, but they are all the right values (i checked the color code and measured them).
I changed the PT2399 (that i got from tayda) and same problem. When I hit the front end with a boost on full bore i can hear the delays better (still below unity) and they sound fine. I also changed the TL072 for another one. I checked the wiring, hidden trace cuts etc. (R18, C9 and C10).

what else could be wrong? should I shop for a couple of PT2399? Maybe I have to double check the wiring and vero traces once again. Sucks because i made it kind of neat, short wires and everything, and i have to disassemble the whole thing each time. :slap:
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Re: Mad Professor - Deep Blue Delay

Postby Seiche » 22 Jan 2012, 01:20

checked wiring, vero traces, cap values and checked the vero layout with the schematic, to avoid further mistakes.

i guess i will be buying some pt2399 on monday (i hate sundays). Hopefully I can source them locally. I have read bad things about the Tayda ones when i googled them earlier. Guess there is a reason why they are only $ 0.50 vs. $ 3-4 every else. Hopefully this'll cure it.
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Re: Mad Professor - Deep Blue Delay

Postby rocklander » 22 Jan 2012, 02:36

<US$1.50 at futurlec.. that's all I've ever used.. not had a problem yet.
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Re: Mad Professor - Deep Blue Delay

Postby Seiche » 22 Jan 2012, 02:40

rocklander wrote:<US$1.50 at futurlec.. that's all I've ever used.. not had a problem yet.

rockie, you have some experience with this circuit, no? the issues i described, could they originate from a bad chip or should I keep looking elsewhere in my build?
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Re: Mad Professor - Deep Blue Delay

Postby rocklander » 22 Jan 2012, 02:58

well I'm not sure just making a pedal from the cct equates to experience as such.. I am a solder by numbers kinda guy sorry bro, so can't really offer any actual technical advice.

if I was to hazard a guess (and it would be totally that) I'd be inclined to be looking round the opamp. reason being, I would expect (and this is purely speculation) that a delay passes the original signal through, and then adds the repeats to that signal.. I'd expect that if there was an issue with the PT chip (based on my pure speculation) the repeats only would be quiet/effected.. so if both the original signal and the repeats are low vol then I'd be thinking it's elsewhere.. didn't say anything previously cos I am completely stabbing in the dark, and was hoping that someone who actually understands this circuit (or for that matter ANY cct) might be able to offer better advice.

I've built one (based on my layout) and it worked first time... I suspect there was a certain amount of luck involved though. :blackeye
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