9V Electric Mistress project file done (Bernardduur??)

[markusw]

Since I wanted to give Flangers a try and there isn't yet a layout for the 9V Mistress I decided to do one.
Basically, I just traced the original layout from Berdarddur's pics as I wanted to be as sure as possible to get it working  (I read a lot about problems with clock noise...etc).



Although I believe that everything is fine I still have to check it.



Some Qs and comments:

* Is it a good idea to have the gnd connections as a "ground plane" ??

* from Bernard's pics it seems that the two 130k resistors at the input were replaced with a 5.6k and a 1M (maybe 2M) to vref. Actually there was another 5.6k added from the input jack to the input cap. I suppose this is the mod performed by EH on Bernard's unit to avoid (reduce) the volume drop of the unit.
Bernard: it would be great if you could check if the input cap is still 39n as in the schem.

* From the pics it also seems as if the 200 ohm resistor between gnd and ps gnd is not used. Instead ps gnd is connected directly gnd.

* Also it seems that there is an additional electrolytic added directly to the ps jack. The two other ps electrolytics seem to be quite large (and of the same size). Maybe they were changed to larger values. At least the 100µ seems to have the same value as the 220µ (Bernard?)


* The funny thing is that I can't find the output wire although I really studied the pics very carefully. The pad that is connected to the 510R, the 8k2 and the 13k  is not connected to any wire. Any ideas??

* Do you think it's OK to replace the 82n near the output with a 100n???

* In the schem by Francisco a 1M-C (this is reverse log??) is indicated for Rate, In the deluxe version at ggg a 1M log. Considering that the LFO section is more or less the same: which one gives the better response?? OK, I think I solved this one

* Edit: one more: Would it make sense to add two resistors for gain control to the input buffer stage (to compensate for the volume drop when in true bypass??)

Thanks to Francisco, Stephen and Bernard for posting the schems and pics, btw!!

Comments on how to improve the layout are highly appreciated!

Once I've checked everything I'll post the complete stuff.

Thanks for your help in advance!

Markus

[BDuguay]

Cool!
Thanks for putting that together. I hopes everything checks out okay.
B.

[psst]

Nice!
I'll keep an eye on this post...

[markusw]

Nice!
I'll keep an eye on this post...

Your comments on this unit were a reason too to give it a try

Berdardduur: could you do me a big favour and check on your unit were the output wire is connected to. I suppose this should be possible without removing the PCB.
Thanks a lot in advance!!!

Markus

[Bernardduur]

I'll check in a while!

[markusw]

I'll check in a while!

Cool! Thanks a lot!

[markusw]

Would it make sense to add two resistors for gain control to the input buffer stage (to compensate for the volume drop when in true bypass??)

OK. I think I also solved this one. The headroom of BBDs is rather limited compared to e.g. opamps. Therefore, increasing the gain definitely doesn't make any sense. This limited headroom is also the reason for the 130k/130k voltage divider at the input. Isn't it??

 Maybe I can squeeze in a gain stage at the output...

Markus

[Bernardduur]

Let me see.

- input cap = .039 µf
- the PS filtering cap = 220 µf; without it you hear a lot of clock noise
- the output is the glob of goo next to the middle trimpot (on the backside). I guess I desoldered it when I took the pic

[markusw]

Let me see.

- input cap = .039 µf
- the PS filtering cap = 220 µf; without it you hear a lot of clock noise
- the output is the glob of goo next to the middle trimpot (on the backside). I guess I desoldered it when I took the pic

Thanks

Now everything is more or less clear!

BTW, how does it sound with bass??  Are there any issues with distortion (e.g. when used with an active bass)??

Markus

[Bernardduur]

Hmmmm, good question; never used it with bass.

Give me 5 minutes

OK, it sounds GREAT with bass. The unit sounds, to my ears, even better on bass then on guitar...... wow, this is a great discovery for me. No issues whatsoever with distortion or anything, altough I must say that I kinda lose distortion when the unit is on. I tried with both my P as J bass and with my Flipster preamp before it.

Nice! Now it is a shame I have it on my guitar board, have no place on my bass board and pretty much got used to my Small Clone (heavily modded) that I don't need it on bass.

[darryl]

Is this the same 9v Mistress as the one at Tonepad, I just finished building that one per the schematic and it is ticking like crazy. I have added some more filtering does'nt seem to do anything. It is Flanging just with a horrible tick, I have done the search on this and found a little advice. The strange thing is it so loud its like a pop at slow speeds that is. I hope this is OK to post this to your topic, if not I start a new one.

Thanks
Darryl

[markusw]

Bernard, thanks for your review! Seems I'm gonna like it

darryl, since it might well be that I have to deal with the same issues as you it's very OK for me

How close is your layout to the original one??

Markus

[Bernardduur]

Is this the same 9v Mistress as the one at Tonepad, I just finished building that one per the schematic and it is ticking like crazy. I have added some more filtering does'nt seem to do anything. It is Flanging just with a horrible tick, I have done the search on this and found a little advice. The strange thing is it so loud its like a pop at slow speeds that is. I hope this is OK to post this to your topic, if not I start a new one.

Thanks
Darryl

Yes, it is..... mine is real (found it in a dumpster) I have no pop or any noise at all as long as you keep the color pot low

[darryl]

I just layed it out on my own, just follow the schematic, did use two boards though one for LFO, and one for audio. So no real layout just go for it sometimes, tried a number of fixes nothing yet. I will note that in the Filter matrix mode it seems to work alright, it shuts off at the end of the pot turn. Lfo seems to stop to at the slow end of the resistence. I will keep working let you know.

Darryl

[markusw]

Good news!

It works ... and it sounds wonderful Just connected it the first time to my power supply and it immediately worked. Clock noise is not present. However, I replaced the two ps caps with ridiculously large ones (1000µ and 470µ). I'm very exited Tomorrow, I will check clock speed and also whether there is a volume drop. Will be interesting to see because I included the mods from Bernardduur's pics.
Hopefully, I can complete the project file this weekend. Thanks to EH for a terrific pedal!

Regards,

Markus

[nelson]

Excellent!

 

Good going Markus!

[markusw]

Just checked the clock frequencies.

With the clock trim at 50% (lugs 1 and 3 are wired like in Stephen's schem), the rate pot at 0% and the range pot at 100% the clock frequ range is from ~29kHz to ~212kHz, with the trim at 0 or 100% the range is from ~172kHz to ~880kHz (measured after the flip flop).

If my calcs are correct this would give a flanging freq range (lowest notch) of 56-416 Hz (clock trim at 50%) and 335 Hz to 3437 Hz. Please correct me if I'm wrong.

Just out of curiosity:  Bernardduur could you do me another huge favour and measure the clock frequency range on your unit at pin 1 or 2 of the 4013 (with rate pot at 0% and range pot at 100%) ? Thanks a lot in advance.


I believe there is still some volume drop (although I added the mods like in Bernard's unit) compared to true bypass but I can't say for sure since I did not connect the circuit to a stompswitch.

Regards,

Markus

[markusw]

Here is the promised profect file

http://www.diystompboxes.com/DIYFiles/up/9V_Mistress_project_file_v1.pdf

and here's a pic of the guts



The pots will have to be replaced with others but I'm still waiting for the rev 1M pot.

Please report bugs.


Have fun,

Markus

[markm]

NICE.
Thank you very much

[redeffect]

A HUGE thanks for all the hard work, R&D, layout, debugging,(the list goes on...) you did on this effect! You have done a truly great thing sharing your efforts with all of us. Guess it's time to finally build one
Thanx again, and all the best,
red