Boss DD-7 relay bypass?

[headcrash]

Hi all, first post here, although I have found lots of useful info and answers here since many years. So: big thanks to everyone contributing here!

I really like my Boss DD-7, but when used in front of a high(er) gain amp, the buffering and other stuff in the signal path is amplified to a decent hiss/noise. Which I don't like And I don't want to use a true bypass looper, because...well, I don't want to
So, since this is a rather modern pedal, there is no typical flip-flop based switching circuit (where I could attach a FET with relay), but a processor.
Using my oscilloscope and the schematic, I traced the respective outputs of the processor, where I was hoping to get some logic high for a FET+relay (bypassing of signals still is done the typical way, using JFETs, so I thought...).
But none of the five or so switching outputs of the processor does actually any switching.
I traced the signal output of the wet audio leg of the circuit, and it seems muting of the wet signal is done in digital domain (I think this is also why more active components than necessary contribute to the hiss ...).

I had some tiny uC-controlled bypass module lying around, but connecting its switching input to the momentary switch of the DD-7 does not work reliably or properly.

Does anyone have any idea what else I could do to get some switching signal?
I was wondering if there is a DPST version of the Boss momentary switch, so I could use the second contact to switch the aforementioned bypass module. But so for I've had no luck finding the manufacturer of those switches.
Schematic can be found here: http://www.synfo.nl/servicemanuals/B...VICE_NOTES.pdf, schem starts on page 18.

Would really appreciate any hint or idea !

[x-pro]

Am I correct that there are no control signals at the processor output on the buses? :
BYPASS_A_MUTE
DA_A_MUTE
BYPS_A_TO_B_MUTE
BYPASS_B_MUTE
DA_B_MUTE

[headcrash]

Thanks for the reply, x-pro!
Yes you are right, I cannot measure any change of level at these outputs. I think one of them was on a permanent high level (+5V-ish), can't remember which one. The others are on 0V. None of them changes its status, when pressing the footswitch.

[x-pro]

Basically, from the control of these output field-effect transistors you need to take a signal to control a relay. The latter will switch the bypass you need.
You can put a standard trigger on the native button and also control it via a relay. The relay needs a small size and gold-plated contacts. Just organize the input to the device in a standard way.

[headcrash]

Thanks x-pro. I know all that. Problem is: there is no switching signal happening, when I press the footswitch. It looks like Boss decided to omit the switching in analog domain, and rather let the signal-switching FETs be on permanently. Muting of wet signal is done inside the DSP.
Also putting an electronic switch parallel to the native switch resulted in an unreliable switching behavior. Sometimes it would switch on, sometimes not, sometimes it switched on for a fraction of a second.

[x-pro]

It looks like Boss decided to omit the switching in analog domain, and rather let the signal-switching FETs be on permanently. Muting of wet signal is done inside the DSP.
.

If they are all on all the time, then how is the bypass not summed with the processed signal?

[headcrash]

If they are all on all the time, then how is the bypass not summed with the processed signal?

Thank you x-pro!
Bypassing of processed signal is done in digital domain. This is what I wrote above in my first post: when I trace the effected signal, for example for output jack A, coming from the _DA_A leg, it is muted before that. I use TP32 for tracing the signal there (see page 19). I would have assumed, Q9 would mute the effected signal, but it's always on.

[g1]

BYPASS_A_MUTE line should toggle Q6. Check at TP40. From there the gate of Q12 is turned on or off to mute the dry signal.
(edit: TP40, not TP4. TP40 and TP41 should be both toggling when switch pressed)

[headcrash]

BYPASS_A_MUTE line should toggle Q6. Check at TP40. From there the gate of Q12 is turned on or off to mute the dry signal.
(edit: TP40, not TP4. TP40 and TP41 should be both toggling when switch pressed)

Thanks g1 for chiming in!
I did also check all the TP's on the collector legs or "outputs" of the switching transistors (Q4 - Q8). There is absolutely no "analog" switching going on in that pedal.

[g1]

My post #8 above got a bit mixed up with the edit, due to the schematic being broken up right at the area of discussion. So TP4 and TP41 should be the ones to check.
I don't want to argue about what is happening, but the schematic definitely shows some analog switching going on.
That leaves 2 possibilities: either the schematic does not match your version of pedal, or something is wrong with the pedal.