Phase Evolution!

frequencycentral · Post by **frequencycentral** » 23 May 2009, 13:29

This build was a bit of an accident. I recently built a Phase 45 with JC Malliet's mods. The original concept was to fit the entire circuit including the pots on a piece of 9x37 hole perf. After buiding and testing the main board I wasn't really happy with the quite subtle phasing. All that hard work wasted? No way was that going to happen - so I cludged in a further two phase stages on a daughter board for a deeper phase effect. I never would have been able to squeeze a Phase 90 onto a board that small, so adding the 6x14 hole daughter board was a bit of a win really, getting the flexibility of the Maillet mods with a four stage phaser in the size of enclosure I chose, and with the pots mounted on the board which is my preferred building method.

As it evolved from one thing into another, there are two boards. If I was doing this again as an intentional build, I'd do a different layout with everything on one board. The possibility is also there to add as many daughter boards as you wish.......

Here is my original Phase 45 with JC Maillet's mods layout. R23 is mounted on the copper side of the board:

Here's the layout above but with the daughter board hookup points indicated:

Here's the daughter board layout. C4 is mounted on the copper side of the board between pins 1 and 5 of the 4558. R4 and R5 (both 10K) are mounted under the 4558's socket:

Here's JC Maillet's original schematic, the red letters, A,B, C and D correspond to where I hacked in the two extra stages:

Here's the daughter board schematic:

Finally, here's a link to JC's project on his site: http://www.lynx.bc.ca/~jc/pedalsPhase45.html

madmac · Post by **madmac** » 23 May 2009, 20:04

That is an impressive build!

You definitely have more patience than I do to do such a tight build on perf. I guess the original intent was not to have the daughter card but certainly a nice addition!

Does it sound more like a P90 now?

rocklander · Post by **rocklander** » 23 May 2009, 22:36

thank you very much!
I see the diode and transistors are listed in the schematic, but can you add their values to the layout too please?

frequencycentral · Post by **frequencycentral** » 23 May 2009, 23:02

rocklander wrote:
thank you very much!
I see the diode and transistors are listed in the schematic, but can you add their values to the layout too please?

I'll update and reload the layouts tomorrow with that information. I used 2n5487's as I wasn't able to find four matched 2n5458's in my stock. Definately worth the trouble of FET matching in this circuit. I used 4558's for all the opamps. The diode I used is not the part listed in the schematic, it's an equivalent 5.1 volt zener, works fine.

madmac wrote:That is an impressive build!

You definitely have more patience than I do to do such a tight build on perf. I guess the original intent was not to have the daughter card but certainly a nice addition!

Does it sound more like a P90 now?

Thanks! I don't have a P90 to compare it with. I assume it's close, though the circuits are not identical. Mine has a few different flavours too, due to the switchable ratio caps on stages 1 and 2, the ability to mix continuously between vibrato and phase, and the ability to change the bias - which I really under estimated at first but is very flexible.

rocklander · Post by **rocklander** » 23 May 2009, 23:54

frequencycentral wrote: The diode I used is not the part listed in the schematic, it's an equivalent 5.1 volt zener, works fine.

being a bear of little brain, I don't really understand this stuff very well, but is the zener affecting the sound, or is it just a protection diode?

frequencycentral · Post by **frequencycentral** » 24 May 2009, 00:04

rocklander wrote:
frequencycentral wrote: The diode I used is not the part listed in the schematic, it's an equivalent 5.1 volt zener, works fine.
being a bear of little brain, I don't really understand this stuff very well, but is the zener affecting the sound, or is it just a protection diode?

It just forms a part of the voltage divider for the vref, so no it does not affect the sound at all. Out of interest, the original P45 used a 1n5230 which is a 4.7v zener. JC's schematic states a 5.1v zener.

salocin · Post by **salocin** » 24 May 2009, 00:07

rocklander · Post by **rocklander** » 24 May 2009, 00:10

frequencycentral wrote:
rocklander wrote:
frequencycentral wrote: The diode I used is not the part listed in the schematic, it's an equivalent 5.1 volt zener, works fine.
being a bear of little brain, I don't really understand this stuff very well, but is the zener affecting the sound, or is it just a protection diode?
It just forms a part of the voltage divider for the vref, so no it does not affect the sound at all. Out of interest, the original P45 used a 1n5230 which is a 4.7v zener. JC's schematic states a 5.1v zener.

ah, cool. thanks for that

reveriesof · Post by **reveriesof** » 27 May 2009, 21:03

very nice build, i love it.

i've been wanting to do a phase45 type thing since i started building pedals. the daughterboard design adds a lot of flexibility. i'm thinking: 1 4pdt footswitch to connect A-D to the circuit, to allow mode switching between the subtle vibe and more phasey sound. and then possibly another switch (in a BB enclosure!) to move between a second set of controls for speed and blend. spaced like an analogman mini-bicomp so you can switch between or both at once, without stepping on the on/off switch.

i was planning on building it in a larger enclosure anyways since i lack your skills/patience to fit that so elegantly into something like a 1590. so might as well go crazy and use all the space available! switches! knobs! woooo

now a simple question that will make or break my hopes of adding switchable controls and different leds for each channel... can i leave 1 wire from each pot and from the daughterboard permanently connected to the circuit? so 1 switch would connect B,C,D to the circuit and change the LED color, with A always connected. likewise the other switch would connect 2 lugs from Blend and 1 lug from Speed, and change the LED. far as i can tell this shouldnt affect the circuit, having the components partially connected (as dead ends). someone wanna learn me some 'lectronics? before i order these freaking 12$ switches from smallbear?!

frequencycentral · Post by **frequencycentral** » 27 May 2009, 23:43

While I was matching FETs (using the GEOFEX FET matching fixture ) I noticed that by just pulling a couple of FETs out of my build would lessen the phasing effect, ie with two FETs pulled from the circuit signal still passed through those stages but was not phased. So it may be possible to just break the circuit at the A/D point in the schematic to prevent those two stages from contributing to the phasing effect. It this is the case, which I think it is, that would mean very simple switching between 2 and 4 stages of phase shift. Hope this helps!

rocklander · Post by **rocklander** » 27 May 2009, 23:53

I've been working on a PCB layout for this.. about 2/3 done, but (as usual) tying up the loose ends toward the end of the schematic is getting tougher.. will hopefully have a V1 layout by the start of next week.. be good to get some feedback as to viability.
will make it as a daughter board situation for now, then introduce an all in one board with switching later on I think.

frequencycentral · Post by **frequencycentral** » 28 May 2009, 00:25

rocklander wrote:I've been working on a PCB layout for this.. about 2/3 done, but (as usual) tying up the loose ends toward the end of the schematic is getting tougher...

I feel your pain! That perf layout I posted took three failed attempt to get right. I was determined to get it to fit. The tough bit for me was getting the arrangement of components around the FETs to fit. I just ended up with R23 being on the copper side, which was serendipitous when it came to retro-fitting the daughter board.

I'm just doing a layout for an 8 stage version of the Phase 90, I'm using LM324 quad opamps to save some space, but it's still going to be 39 x 14 holes. Incidentally, the FETs used in the Phase 90 are listed as 2n5952 which seem to be as rare as bull's milk. I've read that 2n5485 are a suitable sub. Anyone used any other FETs in the Phase 90 with good result? I'm going to have to match 8 for my build, so I guess that means buying 100!

salocin · Post by **salocin** » 28 May 2009, 10:23

frequencycentral wrote:Incidentally, the FETs used in the Phase 90 are listed as 2n5952 which seem to be as rare as bull's milk.

Tell me about it! I've been trying to source some here in New Zealand. Only place I've found has a minimum handling and shipping charge of $40 (on top of the component price)

frequencycentral wrote:I've read that 2n5485 are a suitable sub. Anyone used any other FETs in the Phase 90 with good result? I'm going to have to match 8 for my build, so I guess that means buying 100!

I think I might give the 2n5485s a go. I have a faulty Phase 90 ('proper' MXR one, not DIY) which I was hoping to try some new FETs in. Unfortunately the 2n5485s are $1.90NZ ($1.20US) at the local shop so could be an expensive exercise to buy enough to find 4 that match!

rocklander · Post by **rocklander** » 28 May 2009, 10:47

salocin wrote: Unfortunately the 2n5485s are $1.90NZ ($1.20US) at the local shop so could be an expensive exercise to buy enough to find 4 that match!

$0.94AU if you buy 'em from futurlec.com.au, and have cheaper sipping than jaycar, dse, radiospares or farnell.

rocklander · Post by **rocklander** » 28 May 2009, 12:37

okay.. here's my first attempt at a layout on this.. looking forward to being told where I"ve screwed up heh.
I followed the vero layout rather than the schematic so am pretty confident I'll have buggered something up.
{}{not even close to verified}{}

reveriesof · Post by **reveriesof** » 28 May 2009, 21:36

frequencycentral wrote:While I was matching FETs (using the GEOFEX FET matching fixture ) I noticed that by just pulling a couple of FETs out of my build would lessen the phasing effect, ie with two FETs pulled from the circuit signal still passed through those stages but was not phased. So it may be possible to just break the circuit at the A/D point in the schematic to prevent those two stages from contributing to the phasing effect. It this is the case, which I think it is, that would mean very simple switching between 2 and 4 stages of phase shift. Hope this helps!

Nice, helps a lot! Was the difference quite large between 2 and 4 stages? I think I'll actually set it up to switch between 2 and 6 stages. Since I'm taking the effort to make it switchable, might as well go HUGE.

salocin · Post by **salocin** » 28 May 2009, 21:58

rocklander wrote:$0.94AU if you buy 'em from futurlec.com.au, and have cheaper sipping than jaycar, dse, radiospares or farnell.

wow. Thanks rocklander. Had not checked futurlec before. The only place that stocks more of the items on my current shopping list is small bear! Still no reverse log pots though (bloody hot cake....

)
How long does it usually take to ship stuff over here?

Was about to go buy $30 of pots from Jaycar, but futurelec have them for less than half the price! (I'm assuming theirs are 16mm?)

rocklander · Post by **rocklander** » 28 May 2009, 22:32

salocin wrote:
rocklander wrote:$0.94AU if you buy 'em from futurlec.com.au, and have cheaper sipping than jaycar, dse, radiospares or farnell.
wow. Thanks rocklander. Had not checked futurlec before. The only place that stocks more of the items on my current shopping list is small bear! Still no reverse log pots though (bloody hot cake.... )
How long does it usually take to ship stuff over here?

Was about to go buy $30 of pots from Jaycar, but futurelec have them for less than half the price! (I'm assuming theirs are 16mm?)

yep, 16mm and all nicely sealed, by all accounts thus far nice pots

delivery is not great... the actual goods come from hong kong IIRC..
I tend to place my order, then leave it about 3 days and log onto their site (gotta log in to view order info).
if the order hasn't moved from 'entered' state to 'shipped' state I flick them an email asking if there's any reason, are they waiting on parts or something, and invariably they process the order heh. from there up to 5 days to get to godzone

.

this compared with effectsconnection.com which invariably gets stuff to me from stateside in less than 5 days

salocin · Post by **salocin** » 29 May 2009, 06:13

Have ordered some PT2399 and LM13700 as a trial run to see how it goes. Had forgotten about effectsconnection.com as well. They have some good prices. Small Bear has the p90 fets for cheaper than anyone I've seen, but still (from memory) 75c each so buying bulk adds up quickly, especially considering I've seen people say 80 fets reaped 2 matching sets!

Sorry to hijack the thread!

rocklander · Post by **rocklander** » 29 May 2009, 09:32

salocin wrote:Have ordered some PT2399 and LM13700 as a trial run to see how it goes. Had forgotten about effectsconnection.com as well. They have some good prices. Small Bear has the p90 fets for cheaper than anyone I've seen, but still (from memory) 75c each so buying bulk adds up quickly, especially considering I've seen people say 80 fets reaped 2 matching sets!

Sorry to hijack the thread!

I know people have great things to say about smallbear, but I found their service very poor on the one experience I had with them. significant delays and pretty terse emails from them when I asked about the order. ymmv