DBA Echo Dream 2

[SonusFluxa]

I don't have the pedal in front of me, but looking at the layout, I believe the DPDT is sine/square.

[reggy1]

Thanks for the clarification, mate. Thanks also for your helpful input here and elsewhere.
Not looking forward to pot/switch wiring on this one, but am looking forward to the final product.

[hobbyseason]

Could anyone with a working build of this possible (please) take the time to measure some voltages of the ics?

Has anyone tried running at 12v?

Thanks :):)

[mug]

I'm won't be able to measure mine until next week since I gave it to a friend, but then I can do.
IMHO a charge pump to 18V is essential for this baby, otherwise there is no modulation. Like this one.
Do you have specific problems with your build? When mine did not kick in it helped to swap some PT2399 until I found a good one!

[hobbyseason]

Thanks mug. Ill hold tight until then.

Seems to be the pt2399. I tried a bunch of different chips with no luck.

I was going to eventually build an 18v charge pump but surely the delay should be working at 9 or 12v.

Ive fucked something up surely

[Sergio]

When i built the pareidolia i remember having serious problems, but i tried it at 15 and 18 volt and worked right , it seems these two share the same ic.

[mug]

hey there, finally I opened mine and got the following:

all pots at noon, shape swith at sine
supply (wall wart) 9.28 V  -  charge pump delivers 15.13 V

PT2399
1  3.26   16  0.68
2  3.28   15  0.66
3  3.29   14  3.29
4  3.29   13  3.72
5  3.25   12  0
6  3.26   11  0
7  3.29   10  3.27
8  3.27   9   6.53

2206CP
1  0       16  0.97
2  4.91   15  0.97
3  5.10   14  1.8 - 2.3 (oscillating)
4  7.71   13  1.7 - 2.2 (oscillating)
5  4.06   12  0
6  4.12   11  0
7  2.56   10  2.58
8  3.42   9   4.01

NE5532 (substitute for the MC33172p - just found out I did this )
1  3.26   8  7.71
2  3.70   7  3.73
3  3.54   6  3.36
4  0       5  3.54

78L05
I  7.66   G  0    O  6.59

Although I'm surprised the charge pump does only deliver 15 V instead of 18 V it works nicely.
Hope this will help to get your's running!

[reggy1]

G'day Mug, just stumbled across this. I built this quite some time ago and got it working without too much trouble. It certainly has a wide range of sounds available! I have lent mine out as well, so I can't comment too specifically, but I also remember that I could only measure a little over 15v from my 7660s-based charge pump, even though it gave me 17.35v when not connected to the circuit. I put it down to current draw and was going to substitute a 1054-based pump with a higher current capacity, but never got around to it.
Just a couple of general observations regarding voltages. The output of 78l05 should read 5.00v and that voltage should appear on pin 1 of the PT2399.
The output of the charge pump, or very close to it, should appear at pin 4 of the 2206cp. The data sheet says min 12v.    7.71v would probably be too low to operate the chip reliably. Likewise, I would expect the charge pump output to appear at the input of the 78l05.
If all IC voltages are still wanted, I will certainly post them when I get the pedal back. The borrower loves it, so I might have to bribe him with the loan of something else out of the ordinary.

Reg

[reggy1]

Hey Mug, just realised that perhaps you had forgotten that the PT2399 is upside down on the layout. That would make the measured voltages more logical, although I would still expect the Vin of the chip, Pin1, (or pin9 if you have forgotten the upside down bit, to be 5v which should be the output of the 78l05.

Cheers

[reggy1]

Just had another thought.
Will try to get them all into the one post next time.
Are you using a 78l62 regulator? That would explain the higher voltage at pin1 (or 9) of the PT2399.
Not sure how voltages higher than 5v affect the longevity of the already flakey PT2399 chip.

Cheers (Finally)

[mug]

Hey reggy,
thanks for your comments - it's a really cool pedal, I wouldn't give it away again since it takes a lot to get it back...
Indeed I missed the upside down PT2399 when measuring, so here's the readings in the correct order:

1  6.53   16  3.27
2  3.27   15  3.29
3  0        14  3.26
4  0        13  3.25
5  3.72   12  3.29
6  3.29   11  3.29
7  0.66   10  3.28
8  0.68   9    3.26

I never checked the voltages in this circuit before, but you're right both the IC supplies look strange... however it sounds good

I'll check the 78l05 (could be I picked a cheap one that might be off) and try a different charge pump as well some day  - I've been working on a chasm reverb for ages that gave me massive headache so I'm fed up with debugging at the moment

[hobbyseason]

thanks again mug!

I kinda gave up on this one but i decided to pull it out for one last go today.

after comparing my voltage with yours (they were very close) i noticed one of the pins of the pt2399 was way off.

on closer inspection i had one of the cuts on the wrong row ffs! i quickly fixed it and still no luck, then i tried a different pt2399 and booom psycho fuzz/modulation/oscillations. this thing is amazing. i little bit of ticking but not tooo bad.

:D:D

[BetterOffShred]

Ok so I was the one who requested this a long time ago, and I finally just got around to building it! Man I feel guilty, but that's how it goes.   So I built it as per the layout, I used the specified values on everything, and I used a 7660 charge pump putting out 16.9V at the board IN.  It just wouldn't go.  No matter what, I tried everything, 15 different 2399's.. and then finally I realized I had Blend 1 and 2 swapped.  Now it runs and sounds pretty good.  A few observations.. Maybe someone can confirm for me.. Modulation is always on, and has two wave shapes.  You turn it "off" by turning the depth all the way down (least depth).  The SPST switch just turns off your dry signal so you get 100% wet signal for the modulation settings if you turn the delay off?   That's what this all sounds like to me after playing with it a bit.  
Anyway:
7805:   I 12.1  O 4.96 G 0
PT2399:
1  4.9   16  2.4
2  2.4   15  2.4
3   0     14  2.4
4   0     13  2.4
5  2.9   12  2.4
6  2.5   11  2.4
7  0.6   10  2.4

2206:
1  0                    16  2.4
2  1.6-9 (mod)     15  4.7
3  1.6-9 (mod)     14  4.5
4   12.1               13  4.5
5  6.6                  12  0
6  6.7                  11  0
7  3.5                  10  3.6
8  4.6                  9    1.6

5532:
1  5.9    8   12.1
2  6.0    7    6.0
3  5.7    6    6.0
4  0       5    6.0

I'm really happy I built this.  I've built about 9000 fuzzes lately and It felt really good to throw down on a Profundis with mod board and then this.. Now I can stack 4 delays.  Next Delay.. The Sagan!  Why not.
-Brett

[iamregistered]

Hey all, posted this questinon on the main site but figured I'd ask here. Switch 2 is listed as 'SPST' on the layout, with connections to lugs 2 and 3. SPST switches only have 2 lugs. Is Switch 2 meant to be a SPDT on-on switch instead? Thanks in advance.

[squirrels]

BetterOffShred: That’s how mine works as well regarding the modulation and dry signal. I wound up hardwiring the wet/dry switch on since I didn’t really care for the wet only signal. How does it sound at higher voltage compared to standard 9 volts, or did you not even bother with lower voltage?

[Marbles]

Hi there!

It doesn't really matter if I'm correct. Most of us don't really have SPST switches I think (and DBA maybe neither if this is copied from the original). If you use a SPDT switch, and you only use lugs 1 and 2 (or only 2 and 3) you have the same effect as using a SPST switch.

So if you have an SPST lying around, use that. If you have an SPDT, use that and only use 2 lugs, and leave 1 outer lug unsoldered.

[iamregistered]

Thanks for the reply, Marbles. Makes complete sense.

I looked up some info on switches which confirms what you've said. This site helped out: SPST, SPDT, DPST, and DPDT Explained