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Hi you all folks...my bass player friend has Behringer BDI2 and asking me he needed more on the presence knob and more lower end on over all tone...please advice which resistors/capacitors should be replaced...i know Behringer BDI21 is a copy of the SANSAMP Bass Driver..so here is the schematic of the latter...thank upu guys in advance...

http://guitar-gear.ru/wp-content/uploads/2016/06/Sans_amp_scheme.jpg


Maybe it can help. I did it to 2 units of my own and they sound much better now:

https://www.youtube.com/watch?v=l8MbcoSsc14

You have audio when the effect is on or off because it's likely something happened in the delay line. The "dry" signal is split and sent through the delay line through C8, but also passes through the R8. The delayed signal gets mixed in through R29. If you're gettinf clean signal, that suggest something happened after C8 and before R29. Is your clock still setup right? If you turn the mix all the way up, so you get anything? Can you post voltages? Also, do an audio probe all the way through the delay line, starting with C8 and see where you're losing it.

Well, I measured voltages from five minutes ago. My values have NOTHING in common with the values in the PDF document (Is that due to the 3PRR extra voltage?). And in the IC2 (NE750) I became voltage fluctuations almost in every pin. Or are they caused by the extra Modulation PCB? Here they are:

IC1(4558)                             IC2(NE570)                               IC3(MN3005)                                 IC5(MN3101)

1.  7.43                                 1.  0.01                                     1.  14.79                                        1.  14.16
2.  7.43                                 2.  1.75                                     2.  7.09                                          2.  7.09
3.  7.39                                 3.  1.75                                     3.  Varies 4 - 9                                3.  0
4.  0                                      4.  0                                         4.  Varies 4.41 - 9.20                       4.  7.09
5.  7.39                                 5.  Varies 1.79 - 1.81                 5.  0                                               5.  6.68
6.  7.42                                 6.  1.76                                     6.  7.09                                          6. 7.34
7.  Varies 7.40 - 7.47             7.  Varies 2.91 - 3.04                  7.  4.01                                         7.  7.04
8.  14.85                               8.  1.76                                     8.  0.93                                          8.  0.93
                                            9.  1.76
                                            10.  Varies 3.48 - 4.24
                                            11.  Varies 3.30 - 4.21
                                            12.  Varies 1.82 - 2.04
                                            13.  14.86
                                            14.  Varies 1.63 - 1.75
                                            15.  1.72 - 1.83
                                            16.  0

Audio probe did not made yet. But I insist. Strangest of them all is, the thing WORKED before I boxed it. Anyway I will make the promised and recommended audio probe and will write the results.

Bye,
Ariosto

Don't worry that you do not yet have a working project.  You picked a very difficult build even for an experienced builder, and it would not be unusual for that person to have to find and fix problems to get it working. 

Your board is (probably) not bewitched, but it is a complex build that might have more than one issue in it that you will need patience to find and fix.  You already have corrected the big problem of trying to build the board with two different sets of memory chips where only one of the two sets is supposed to be used.   Any time you find and fix a problem you can see if the board works, and if it does not start over looking for the next problem.

Go back and measure all or your voltages again and see what you get because removing the extra set of memory chips may have changed some of those voltages.  Then check to make sure you have good ground connects on the board for the different parts of the circuit diagram that shows a connection to ground.    It may take a while to work through these issues, so don't worry if you set it down for a while and go build another project where you might learn a bit more that will help you get this one working.  It helps to realize that you probably have 99% of the board put together correctly and you just need to find a fix a few things to get it working.

Thanks a lot for the advice! I must take a deep breath, make a pause and come back to the "operation table". Well, step 1 should be measuring the voltages again. What I don´t know is how to detect if an IC is dead or not. Another way to find the problem could be using an audio probe from the output back to the input, but as already said, I become audio signal when the effect is engaged, the "Level" and "Blend" potentiometers are working correctly obviously without delay signal......

Throbbing pulse sounds like the modulation is on.

So on pin 7 of IC6 you get cleanish audio signal, yes? Have you adjusted the bias trimmer while audio probing its output?

Yes, it means clean audio signal WITHOUT delay. It sounds a bit distorted but I guess that it is normal... I tried adjusting both BIAS trimmers in search of audio signal in the following ICs but nothing happened.

[15v operation]

Sounds like something it shorting some where. When you audio probed, did you check the output of the delay chip? I believe you should only be getting delayed signal out of that, no 'clean'. And also, when you take the circuit out of the box, does it work again?

I took the circuit out of the box, hoping that everything would come back to normality again, but no way. I used a bit audio probe, but I began from the input, when in fact is the opposite, must go back from the output. It is very frustrating and time demanding, but there is no other way to find the problem. I´ve got a theory: As I am using the 3PRR, could be any chance that some component died due to the new voltage? How could I know it?

Ariosto

So it worked on 9V and then you increased the voltage?

You can't do that, the 571 will need its biasing resistor values changing for the new voltage.

Mmmm, no. I´ve build it with the 3PRR from scratch.

As in the official Aquaboy PDF says:

"15v operation
Higher supply voltage means more headroom in the signal path which many guitar players like and the Aquaboy sounds
very good at 15v. You will need to change R13 and R14 to 36k to increase the bias output from the compressor. The
biasing procedure will be the same, although the clock frequency range will change a bit. The FDBK control may go into
self-oscillation at an earlier point at 15v operation, so you should socket R30 and increase its value to get the response
you want.
Important: if you run the Aquaboy at 15v it needs to be regulated! Use a Road Rage, 3PRR, or similar charge pump
with a regulator. Feeding more than 15v to the MN3005 could result in damage. One important consideration here is using
a charge pump introduces a second clock into the circuit and this can result in heterodyne (clock noise). If using a charge
pump I suggest you test your build carefully beforehand to ensure you get a good result."

Must I re-check the values of R13 and R14 again? Is there a way to know if I damaged an IC then? Why did it worked out of the box and then died? Why do I have audio signal in both positions?

Thans a lot for your help.

Sounds like something it shorting some where. When you audio probed, did you check the output of the delay chip? I believe you should only be getting delayed signal out of that, no 'clean'. And also, when you take the circuit out of the box, does it work again?

I took the circuit out of the box, hoping that everything would come back to normality again, but no way. I used a bit audio probe, but I began from the input, when in fact is the opposite, must go back from the output. It is very frustrating and time demanding, but there is no other way to find the problem. I´ve got a theory: As I am using the 3PRR, could be any chance that some component died due to the new voltage? How could I know it?

Ariosto

Bias 2 affects the biasing of IC4, does adjusting it change the distorted signal you get at pin 7?

Scruffle! H  E  L  P   !!!!!! With the audio probe I get audio signal (distorted and with a throbbing pulse included) only in IC6. No signal in IC4, neither in IC7. I think the pedal is bewitched. Must I desolder the whole components and begin everything from the beginning again?

Bias 2 affects the biasing of IC4, does adjusting it change the distorted signal you get at pin 7?

I can say you next Monday, because I forgot the power supply in the Music School where I work. By the way, do you have experience with the Aquaboy Delay? I experienced a very strange issue with mine.

Ariosto

I must sadly revive this post. I succeed 100% with the build, calibration, and the modulation worked fine!........... Out of the box. As soon as I boxed everything -which was a hell of a creative job- I did haven´t no delay signal anymore. But surprisingly, the signal pass thru when the pedal is engaged. Checked the signal with the audio probe (not completely yet) and it is apparently everything alright. Later I decided to play a bit with the trimpots and all I´ve got now is a distorted delay signal at low volume. I checked the voltages but as I have a 3PRR the values are not equal as in the PDF. Some advice out there?

Ariosto

I have the same problem with mine, only that still stranger. I could calibrate the whole thing, worked OK out the box, and as soon as I boxed everything (PRR and modulation PCB included) BUMP! no delay at all. I tried to reclibrate the trimpots and all I´ve got now is a distorted and low delay signal. The Universe is a very strange place.

Ariosto

BIASING REPORT AFTER TRXPN-OUT:

..... Disconnected the TRXPN (as the user Scruffle recommended), I began with the biasing procedure again. The bad new is, that the Total Recall refuses to work. Although the "Level" and "Blend" controls are working normally, but not the Delay and consequently the Feedback knobs. Anyway I proceed according to the instructions in the PDF document:

IC7 removed
DELAY - full up
FDBK - a little less than halfway up
MOD - all the way down
LEVEL - about 1/3rd up
BLEND - doesn't matter (you should leave the circuit output disconnected since we will be audio probing)
CH/VB switch - doesn't matter
All the trimmers in their halfway position to start

Well, I become audio signal WITHOUT DELAY through the audio probe in IC6 (pin3 sounds louder as pin4). Adjust the trim until becoming undistorted signal.
In IC4 pin7 I became distorted audio signal, and GAIN 1 makes no variation as I rotated the trimpot.
Reinstalled IC7 and still no delay signal........

Is maybe the 4558 in IC4 dead? As curiosity, I checked the other ICs with the audio probe and I become signal in everyone of them. I could check the wiring again, but it worked more or less good before. Very strange.

Hope that someone could give a tip, thanks in advance!
Ariosto

The document is saying you can use either 2 x MN3005 OR 4 x MN3008.

So the short answer is settle for the 2 x 3005 and use the TRXPN board elsewhere.

I have no idea where else could I use the TRXPN. I thought it was designed only to use with the Total Recall. Yet another stupid question: What if I change to the 4 x MN3008 configuration?

From the Madbean´s TRXPN PDF Document:

"The TRXPN is an expansion board for the Total Recall project. It allows one to use four MN3008 BBDs in place of two
MN3005 (both totaling about 550ms of delay). The TRXPN has its own bias trimmers for the two added BBD stages and
when wired to the TR main board, they are inserted as stages 2 and 3 of the delay."

Does it mean that if I installed two MN3005 in the Total Recall and two MN3008 in my TRXPN could I have incompatibility issues?

Get rid of the TRPXN board and re-bias your two MN3005.

OK, I´ll do it. The question is, can I after the re-biasing connect again the TRPXN, or is it completely useless?

I didn't see in your pictures that you're trying to use 2 x 3005 and 2 x 3008, the 4047 clock is only good for driving 2 x 3005 unaided, that will probably cause issues.

The voltages on this look mainly fine apart from your BBD bias voltage on IC6 is definitely too low and IC7 is probably a little high, plus pin 6 & 7 measure the same but I'm thinking that's probably a typo but worth checking again in case there's a short there.

Thank you very much for the reply!
Als I already said, I am a noob who is slowly learning yet. You mean, I must replace the two MN3008 in the TRPXN, or the CD4047 instead?