Need help on my first DIY ! (Phaser Kit)

[buisson]

Hello guys !
Electronic Beginer from France here.
I choose "The Phaser" Kit V2 from musikding (https://www.musikding.de/The-Phaser-Phaser-kit) for my first built.
I should have begun with a simplier "montage"... but I love that sound, so...

I've done everything by the books (I think so), but, when I plugged in for the first time :

Without 9V plugged :
- Bypass : Clear sound from my strat.
- Switch on : Noises....

With 9v plugged :
- Big Buzz
- Biggest Buzz

Maybe I missed something big during the built ?

Here are some pics of my Kit :






I've made some test. You can compare with the "Setup and Values" on the link above (for the Phaser kit)
I hope it will some of you a hint to help me !

My adapter : 9.4V

(mesured / should be)

IC1 :
1- 5v
2- 5v
3- 3.38v / 4.9
4- 0v / 0
5- 4.4v
6- 5v
7- 5v
8- 9.4v

IC2 :
1- 5.7v / 4.9
2- 5.35v / 4.9
3- 5.35v / 4.9
4- 0v
5- 5.55v / 4.9
6- 5.6v / 4.9
7- 5.9v / 4.9
8- 9.4v

IC3 :
1- 6.25v / 4.9
2- 5.8v / 5.2
3- 6.05v / 4.9
4- 0v
5- 5.4v / 4.9
6- 5.32v
7- 5.58v / 4.9
8- 9.4v

Q1-4 :
G : 5.4v / 2.2<>2.7
S : 5.4v / 4.9
D : 5v / 4.9

Q5 :
E : 5v
B : 4.4v
C : 3.5v / 3


I know it's not normal, but I don't know what to look for now....
Did someone have any idea ?


Thx !

[DIY Bass]

A quick look, but it looks to me as if you have the signal and ground connections on your jacks reversed.  Certainly on the output jack which is in better view and better focus, you have the blue wire soldered to the ground lug and the black wire soldered to the signal lug, but those wires are reversed on the board connections.

[buisson]

Thank you DIY Bass !
It was a noob mistake... I made it.... done !

In a sense, it's much better now : No noise when the 9V is plugged. So, again, thank you !

BUT, when I put the Effect ON, I have a very high Pitch noise over the guitar sound. The noise seems to be controled (in a kind of tempo way) by the Potentiometer.
No "Phaser" effect here. Just a high pitch noisy sound. I hope I haven't screw any parts !!!!

BTW, I haded in my first post, what the Values I've mesured sould be (when they are off mesure)

Any idea of what to test now ?

[duck_arse]

hello france, welcome to the forum.

please tell what part number your Q1 - 4 fets are marked. have you tried adjusting the bias pot? can you read the voltage at the gate of Q1, let's say, as you turn the bias pot from one end to the other, the voltage should change from about 0V to about 5V1 [or 5V6].

[buisson]

Hello Duck_arse,
the Q1 to 4, are marked "CEN 2N5457" (It doesnt correspond to their document, is it a problem ?)


I mesured the Values of the 3 lugs for each as I moved the bias from 0 to full :
No movement. The values are staying the same.
(I have one off value on the Q3 S : 6 instead of 5)


thank you !

[duck_arse]

bad news, I'm afraid - your T1 - 4 are in backwards. see the note on the schematic that shows the pinouts for 2N5457 and 2N5952 - the board silkscreen suits the 2N5952 .......

so you need to remove and refit anti-silkscreen facing. carefully, don't overheat the devices. it might be better if you cut the T1....4 legs as close to the circuit board as possible, then heat and remove each of the dead legs from the board, then reverse and resolder the fets.

[Mark Hammer]

This is an easy mistake to make.  I have made it more times than I like to think about.

[buisson]

duck_arse you're the man ! Wow !

I runed at the store, buyed 4 brand new 2n5457, unsoldered the old ones, soldered the sockets (I should have put those in the first place...grrr...) and the new Fets and....booommmm what a sound !!!
It Works ! Clear sound, no noise, Good Fx (by adjusting the bias) ! I'm so glad ! My first DIY pedal....  Thanks to you guys.

Thanks all of you for the support !!! I can't wait to choose my next kit ! (I will read & learn a lot here I think !)

I will take a pic as soon as have finished the enclosure (easy work tho !)

Thans again !!! 

[thermionix]

Wow, did you buy a matched set of four JFETs?

[Mark Hammer]

Looking at the schematic, the circuit is a clone of the MXR Phase 90.  That is not a criticism.  Au contraire, it suggests ways to make the circuit more interesting.

The "Depth" control is really an offset control.  That is, it sets the part of the spectrum where the sweep occurs.  I usually include this on any phasers I make for myself, because it is very useful.

Just like the classic Phase 90, however, this circuit uses a fixed amount of feedback/resonance, and a fixed width of sweep, that MXR felt was suitable for all speeds.  Ainsi, quelques changements a suggerer.

R15 (22k) sets the "intensity" of the feedback.  Make it lower and the peaks and notches are exaggerated.  Make it higher/larger, and the sound is more relaxed.  Do not go below 15k, or much above 39k.  But variations in that range will be interesting.

R27 (3m9) sets how wide the sweep is.  Some issues of the Phase 90 used 3m3 and those will sweep wider, by going even higher.  Usually, modulation effects, like phaser, chorus, tremolo, and flanger will include a sweep width control (usually called "Depth") that sets how wide the sweep is.  The way that human hearing works, we prefer shallow/narrow sweep when the speed is fast, and wide sweep when the speed is slow.  As with feedback, MXR picked a compromise value for R27, that would work acceptably for all speeds.  But it can be changed to produce better effects.  3m0 or 2m7 is probably as low a value as you want to make it, and values above 4m7 will not produce much that is useful.  So, if you can find a 2meg potentiometer, putting it in series with a 2m7 resistor, and using that in place of R27 will provide nice variation in sweep width.

Finally, all phasers are capable of producing vibrato if one cancels the clean signal.  When clean and phase shift are combined, tat produces the phasing effect, but when clean is omitted, you will hear a pleasing pitch change.  To produce this, simply desolder one end of R18, and install a toggle to reconnect it.

Et voila, on aura un phaseur capable a faire plusieurs truques!  Joyeux noel du Canada!

[buisson]

Wow, did you buy a matched set of four JFETs?

Yes, they have bags of  matched JFETs at the local electronic shop (my luck !)
BTW, what happen if they are not ?


Thank you for those tips Mark !
I will definitly have a look at it !
Merry Chrismas de France ! 

[buisson]

to delete...

[Mark Hammer]

Yes, they have bags of  matched JFETs ate the local electronic shop (my luck !)
BTW, what happen if they are not ?

The "turnaround" at the low and high end of the sweep is not quite as smooth and musical.  The FETs have a limited range of sweep.  If they are not matched, there is a risk that one or more of them might reach that limit before the others.  So, there could be 4 of them changing nicely for part of the sweep, but then near the top or bottom of the sweep only 2 or 3 are changing, and the other/s are standing still. 

That becomes even more important if one adjusts R27 for a wider sweep, or uses the "Depth" control in the kit to move the range higher up.

[thermionix]

Yes, they have bags of  matched JFETs ate the local electronic shop (my luck !)

Yes very lucky!  I can buy batteries locally, not much more.

Merry Christmas to you too!

[duck_arse]

.... don't forget DIY Bass ......

good work, buisson, your first build and your first fix. now you need to help out the next guy that comes along - send musicding an email, tell them what build and what happened, link them to this thread, and ask if they would consider removing the transistor half-moons from the silkscreen for T1....4, leaving just the "g" marked. this will force the builder to question his parts orientation a little more before soldering. hopefully.

what is your next build to be?

[buisson]

.... don't forget DIY Bass ......

Of course ! And again, to all of you : Thank you !

what is your next build to be?

I'would like to find the simpliest delay Circuit and the Simpliest Reverb Circuit and put them together. Any Idea ?

I will put a link in my thread on the Musikding forum (they are not very 'english' friendly there) !

[thermionix]

the simpliest delay Circuit and the Simpliest Reverb Circuit and put them together. Any Idea ?

A long steel pipe.

[Mark Hammer]

The Cavedweller delay project at the Madbean site is about as simply as it is possible to be.

[Govmnt_Lacky]

Does the stomp switch PCB need that jumper wire? I would think the 9V would be conveyed via a trace somewhere in the layers.

[PRR]

A long steel pipe.

Cooper Time Cube got away with plastic pipe. Steel would reduce losses but apparently not enough to matter. Before telephone speaking-tubes were WIDELY used. I'm still looking for an authoritative study.