Mad Professor - Deep Blue Delay

john-houston · Post by **john-houston** » 30 Nov 2014, 18:02

jorgelopes wrote:make sure that the pin 4 of the pt2399 is connected to the ground

I just did a continuity test with my multimeter and I found that there's a link between pins 3, 4 and GND.

Nocentelli wrote:Then you need to think why opamp pin 8 is not 9v. Is the 33r resistor you have installed definitely 33 ohms, or could it be 3k3?

The resistor is the right value. I unsoldered the regulator and measured voltage again. Now the pin 8 of the opamp is 8,88 V (with an input voltage of 9,06 V).

john-houston · Post by **john-houston** » 01 Dec 2014, 09:23

Hello guys. I've changed the wrong regulator with the right one.
I still can't hear the wet signal. The readings are:

IC2
3.25---6.52
3.25---3.25
3.25---3.25
0.00---3.25

PT2399
4.67---2.32
2.32---2.32
0.00---2.32
2.06---2.32
4.65---2.32
2.32---2.32
0.00---0.69
4.26---4.30

Nocentelli · Post by **Nocentelli** » 01 Dec 2014, 18:12

john-houston wrote:
IC2
3.25---6.52
3.25---3.25
3.25---3.25
0.00---3.25

Pin 8 should be 9v, or very close since it is directly connected to the power rail. I don't think this is causing your lack of delay, but it hints at some other problem(s) with the build.

Also, pin 3 and 5 should be more like 4.5v since they are connected to the 10k/10k voltage divider.

Lastly, your PT chip pin 4 is clearly not grounded, since you have 2 volts on it. I didn't ground pin 4 on the layout (mine seems to work as it is) but you can probably kludge a link from pin 3 to pin 4 on the copper side to eliminate potential problems with this.

john-houston · Post by **john-houston** » 02 Dec 2014, 13:10

Ok... I found the problem.
A cut near the opamp was not done well and there was something like a short circuit.
I also grounded pin 4 of the PT chip. Now it works!!
Thank you!!

Nocentelli · Post by **Nocentelli** » 02 Dec 2014, 16:55

Excellent news!

seyda · Post by **seyda** » 13 Dec 2014, 21:24

Nick123 wrote:Changing level pot with the same one but with a log tapper instead of the linear one could help.

thanks, Nick ! Will try ...
sorry for the late response, notification didn't work.
seyda

LaloFP · Post by **LaloFP** » 11 Feb 2015, 02:35

Hi guys, im building this pedal on protoboard trying mods and works great!

my problem now is trying to add the tails mod

Im using this as reference:
http://pedalparts.co.uk/docs/Tails.pdf

I cant find the j112 or the 2n5457 where I am, so I used an mpf102 (i googled it like a replacement)

When the switch is ON it works but the repeats arent clean as without the mod. it get a little dirty if I play many strings.

When the switch is Off, I get new repeats too... but more dirtier and quiet!

Is the mpf102 a bad replacement? I see on the datasheet that the maximum values are lower, but I dont know how to calculate the values generated in the schematic

what do you think?

mpf102 datasheet: https://www.fairchildsemi.com/datasheets/MP/MPF102.pdf
2n5457 datasheet: http://www.onsemi.com/pub_link/Collateral/J111-D.PDF

LaloFP · Post by **LaloFP** » 12 Feb 2015, 01:26

today... double-checking everything, I realized that I puted the Source and Drain inverted!!! now it works fine

gambit07 · Post by **gambit07** » 24 Jun 2015, 14:44

Hi guys, I tried building this delay for the third time now. 1 only got clean sound while engaged, the other no sound at all, the third one had a very distorted/muddy/motorboat kind of delay sound and the effect will just go on and on until i turn down the feedback knob..

this isn't my first build, (i built the causality 4 mk2 phaser..on perfboard and lots more) i built the rebote 2.5 before.. but never a DBD. so, i wanted to try this one. I used mictester's layout for perf and also implemented the corrections noted by fretzburner. I've read this post (from the beginning) for about 3 times now.

Im not a voltage-checker type of guys, coz I'd rather check the traces first and all the components before I dive into voltages and all, and most of the time after verifying that every component and solder traces are spot on, the effects kick in. so, im wondering, am I missing something here, or should i just ditch this one and use a different layout (which would be a pain).

I would really like to know if there's something wrong with the layout i'm using, so that i could just fix my build and have all three boards fired up.

here's a couple of pics of my build. Please help me out. Thank you.

kaya112 · Post by **kaya112** » 11 Jul 2015, 17:44

My build :

Kinsky · Post by **Kinsky** » 04 Oct 2015, 22:05

My friend has built DBD for me on veroboard some time ago. It works good but I always wondered why it is so dark. I do not mean delay part - for "ambient delay" (as its designer has called it) it can be so heavy filtered - but dry path. This is horrible tone sucker (one can call it "tone warmer" also).
Please take a look RMAA plot i measured.

https://onedrive.live.com/redir?resid=4 ... hoto%2cpng
In case the picture doesn't appear - there is HF rolloff from 2kHz 1,5db per octave, also LF rolloff down from 200Hz
I have also mesured Memory Toy dry path and it is totally flat - IMO this is right approach, delay's dry path should be ...dry, not eq'ed, warmed or "analogized"

Can somebody confirm my measurement and check if that EQ curve was designed and maybe propose different values of components to straighten it up?

Nocentelli · Post by **Nocentelli** » 05 Oct 2015, 04:31

The input and mixer output stages have very small value caps in the feedback loops, presumably to roll off ultra high treble and reduce noise/hiss, but I didn't notice any significant darkening effect on the dry path in my build. It might be worth checking these values (47p and 100p) are correct in your build. It's possible higher values (e.g. 470p and 1n) were used in error, which would cause the effect you describe:

https://www.google.co.uk/search?q=deep+ ... UPt4pUM%3A

Whalestone · Post by **Whalestone** » 05 Oct 2015, 20:40

Nocentelli wrote:The input and mixer output stages have very small value caps in the feedback loops, presumably to roll off ultra high treble and reduce noise/hiss,

Note that the input stage according to the schematic should yield a -3dB @ 40Hz HPF and a -3dB @ 9kHz LPF, resulting in a frequency response not entirely unlike that which can be seen in Kinsky's plot.

Kinsky · Post by **Kinsky** » 06 Oct 2015, 00:02

Cap values on my DBD are correct. 47p and 100p.
I dared to desolder them! I even dared to switch my moded DBD on and play (but only at bedroom levels)!
Now I am home, I can easily recognize the timbre of my guitar. I feel like I have left long dark tunnel and saw the sunlight

I can't proceed Rightmark Audio Analyzer measurements right now, but i trust my ears - I like this delay so much better now.

I am newbee not aware of your forum tradition and rules, but if I have right to name my mod, I call it "The Supersonic Mod"

Try it on your own risk - I hope 40kHz oscilation will not kill you nor damage your boutique amps

Haradax · Post by **Haradax** » 27 Oct 2015, 18:58

Many times I have read that people have problem with PT2399 delay in such a way that they must disconnect the power jack and plug it back. Last week it happened with my DBD (sea urchin) which worked fine for almost two years. I replaced several different PT2399 chips with no result, so it's not a problem with the chip.
At first I did not notice that this began to happen since I started to use a new power supply for my pedals. I experimented a bit and noticed that there is no problem if only DBD is connected to PSU. By connecting more effects on the daisy chain, problem is becoming more frequent.
DBD draws about 30-40 mA, but while connecting to the PSU it takes a little more.
Ensure for DBD about 200mA and there will be no such a problem.

mictester · Post by **mictester** » 27 Oct 2015, 21:21

Haradax wrote:Many times I have read that people have problem with PT2399 delay in such a way that they must disconnect the power jack and plug it back. Last week it happened with my DBD (sea urchin) which worked fine for almost two years. I replaced several different PT2399 chips with no result, so it's not a problem with the chip.
At first I did not notice that this began to happen since I started to use a new power supply for my pedals. I experimented a bit and noticed that there is no problem if only DBD is connected to PSU. By connecting more effects on the daisy chain, problem is becoming more frequent.
DBD draws about 30-40 mA, but while connecting to the PSU it takes a little more.
Ensure for DBD about 200mA and there will be no such a problem.

There is a well-known problem with the 2399 IC. If the delay is set to a short value, the IC can "lock-up" at power-on. If it's left in this state, it can lead to the destruction of the IC. I came up with a simple power-on circuit for this IC:

: Anti-Lockup.png (4.93 KiB) Viewed 2867 times

This completely eliminates the problem.

Haradax · Post by **Haradax** » 28 Oct 2015, 13:40

mictester wrote: There is a well-known problem with the 2399 IC. If the delay is set to a short value, the IC can "lock-up" at power-on. If it's left in this state, it can lead to the destruction of the IC. I came up with a simple power-on circuit for this IC ...

I know about that, at first I was sure that's the problem, and planed to make similar circuit as daughterboard. But problem is definitely somewhere else, had nothing with the "delay time", because also blocking at the maximum. I've done many tests. Chip just don't want to work if not get enough power in the start.

I read that problem usually occurs when using the Boss 200mA adapter (or similar), especially if we connect few pedals more with daisy chain on it.
Before I got (made) a stronger adapter, I solving the problem in a way that first plug the power into DBD, then to the other pedals.

I measured that all 5 connected pedals (including DBD) draws about 110mA, a really not much for 200mA adapter. I have no instrument with which I could measure the peak value while connecting power to DBD. Only estimate it is around 150-200mA.

simaura · Post by **simaura** » 13 Jun 2017, 16:48

Hi guys!
I tried to build this delay, but I got some problem (and I didn't find anything with the search).
At the output, the delay level is too high compared to the dry signal, it seems the PT2399 is overdriving the signal.
I checked with a probe the output after the first opamp, and it has no distortion, or signal overload... I don't know how to fix it!
here you have the voltages:

OP275:
1 - 4,16
2 - 4,21
3 - 4,21
4 - 0
5 - 4,21
6 - 4,23
7 - 5,19
8 - 8,49

PT2399

1 - 5,01
2 - 2,34
3 - 0
4 - 0
5 - 3,47
6 - 2,24
7 - 0,76
8 - 0,80
9 - 2,14
10 - 2,14
11 - 2,14
12 - 2,14
13 - 2,11
14 - 2,09
15 - 2,09
16 - 2,09

I already double checked opamp resistors, and connections around the PT..

Funkomat · Post by **Funkomat** » 16 Jan 2018, 08:32

DimebuGG wrote:Happy New Year!..

Better late than never...

I based this layout according to measurements of a 1590B-type enclosure.

Hey guys,
has this layout ever been verified?
If not, would you please point me to the verified layout..?

rocklander · Post by **rocklander** » 16 Jan 2018, 19:43

Funkomat wrote:
DimebuGG wrote:Happy New Year!..

Better late than never...

I based this layout according to measurements of a 1590B-type enclosure.
Hey guys,
has this layout ever been verified?
If not, would you please point me to the verified layout..?

a read of the thread will reveal

Mad Professor - Deep Blue Delay [traced]