Phase Evolution!

[Pakaloabob]

TBH I can't remember back to exactly what it sounded like...

... that's exactly why I decided to add a switch for 2/4 stages. I definitely enjoy the deeper four-stage version, but it is nice to still have the option to hear the original circuit.

I was slightly concerned about the D-S orientation because I used the FC layout for my daughter board, but the Tonepad PCB for the main board which has the D-S junction reversed. I guess they must be interchangeable since it seems to work fine.

And just when I thought I had the circuit tweaked to my liking you suggest the regen. path! 
Maybe I'll try out a pot for even more tweakablility, but I have read that there still needs to be some sort of fixed resistance in place to prevent self oscillation IIRC. The phase 90 regen. resistor is 22k. Maybe 10k pot with a 10k resistor as in Causality 4?

[frequencycentral]

With FET phasers I find that 12K is really the minimum value you'd want for a regen resistor to avoid self-oscillation. So try a 12K with a 10K pot, bearing in mind that 22K of total resistance will still give you some regen, so if you want to be able to return to your pre-regen sound you'd want a higher value pot. 22K, or 47K even, whatever value you find gives the most pleasing range.

[MrStab]

hi guys,

sorry to necro, but i've come across this and am curious to try the additional 2 phase stages because it doesn't seem to involve much mutilation of the original board.

have i got this right, and would it work for a switched version (see super-pro diagram)?


(original here: http://4.bp.blogspot.com/-L2bL1ktlylg/UBaHQm0J0JI/AAAAAAAACDQ/22foalfFnOA/s1600/MXR+Phase+45.png)


the letters correspond to Rick's markings on the JC Maillet schematic earlier in the thread. if it helps, blue wires represent "inputs" to the switch, yellow is "bypassed" back to the board (ie. 2 stages), red is to daughterboard, grey is from daughterboard back to main board.

both "bypass" and daughter board output would converge at the same spots on the board (D and C) - could that be a problem? all i have are DPDT switches. i guess i'd need a 4PDT to rectify any issues?

my FETs aren't socketed, as i didn't really plan to build my Phase 45 but i've come to love it and it's part of my live rig. so i'm paranoid about replacing the original FETs (i don't wanna go without when i have shows coming up), and i can't remember the matched values i put in there lol (but it's one of a handful of possibilities), so it'll involve much testing. not to mention wasting cash on 10x 2n5952s that might not match.

cheers!

[duck_arse]

the daughter should wire in just like if you were doing a true bypass. which of course, you are. draw your circuit with 4 opamps instead of 2, draw the fets on the first and last stages, add the double pole switch after 1st/before 4th stage, link the 2 million 10k resistors, and that's it.

I refuse to read vero. and you made me follow a link to another vero.

[MrStab]

noted, and my apologies! i somehow thought "oh, i'm only asking em to look at one part of vero" lol. i'll save you a 3rd episode with the daughterboard layout i did last night. if i just do a regular TB (the bypass, not tuberculosis) setup then i could maybe get a status LED in there too for ease of use.

thanks! will probably be a while before i try this, but i'm waiting on a new soldering iron & glue gun in the post so i'm over-compensating with the theoretical side of things.

[duck_arse]

you wanna join us overthinking the noise gate?

[MrStab]

the "...Tonepad Revisited" thread? i built/regularly use one that's based on an amalgation of that and all the suggested fixes around the web, minus the momentary switch, not sure i'll have much to offer and i can't remember the circuit all that well but i'll have a read

[Boba7]

Just wanted to thank you for the daughterboard layout. I just added it to my phase 45, and love it like that! I find that it doesn't quite sound like a phase 90, but more like a cross between 45 and 90, which I like. The ratio switch is subtle but worth it in my opinion. I already had installed a mix pot and a volume pot (full vibrato tends to be louder, that way I can still get unity gain).
Now thinking of a regen path, but in a 1590b enclosure it's gonna be tricky...

Thanks a lot for all the useful information!

[zobi]

Hi !
I m looking for cool mods & upgrades for a mxr phase 45 like.
I saw you made a 4 stage version  , it does interest me so so much but, if I understand how it should be done with a daughter board, I don't think I ll be able to do it all by mysaelf: to follow your exemple, I may need , your exemple !
...links of pictures and schematics don't work...
Could someone publish them or send it to me ? ? ?

[zobi]

  https://www.youtube.com/watch?v=aHN6AViJAvI