New Phaser Design - “Causality 4” – Built with you in mind!

[frequencycentral]

I'm mystified as to why your perfboard is a mirror image of mine. I thought you lived on the other side of the planet, not on the other side of the Sun!

[doc_drop]

I'm actually from a mirrored galaxy only accessible through the worm hole of a Microsoft Operating System. That and you'll notice from the mirrored text that I did in fact mirror this image just to throw Star Fleet off my trail!

Phazerz on KILL!

Oh, and I remember vivedly seeing that movie when it first came to US TV. It made a big impression on me.

[sundgist]

I have modified the vero layout to the MkII version. It's getting a bit tight down in LFO corner. I havn't replaced the MkI layout, that's still here.

A few moved components and extra trace cuts, if your upgrading from MkI. Most notably the jumper at x16/y16 needs removing. This means having to desolder the opamp, no way around that I'm afraid. The trace cut at z10 will need jumpering (z9/z11), this has not been shown here so bear that in mind. Watch for the trace cuts at v6 and z17.
I've taken the Vref to the inverting input from the divider at the LFO by means of a wire across the board.
Unverified as yet but will update once I've completed it.

In the pipeline is an extra stages board, the connections to which i've included on this and the original Mk1 layout. Hopefully to appear sometime over the coming week.

[sundgist]

I'm nearing the end of modding up to MKII.
Do any particular diodes work better than others? From what I can make out on the pictures they look like 1n914/1n4148. Is there any advantage using something with a higher/lower voltage drop?

Funny how writing down things sets off different trains of thought.
I'm wondering how using leds would affect things? I now like the idea of having an indicator showing the rising or falling sawtooth. Might need to jump this bit out onto a breadboard.

[frequencycentral]

I'm nearing the end of modding up to MKII.
Do any particular diodes work better than others? From what I can make out on the pictures they look like 1n914/1n4148. Is there any advantage using something with a higher/lower voltage drop?

Funny how writing down things sets off different trains of thought.
I'm wondering how using leds would affect things? I now like the idea of having an indicator showing the rising or falling sawtooth. Might need to jump this bit out onto a breadboard.

I'm curious about that too. In my imagination using LEDs would give a visual indication of the waveshape. I hope it works out like that.    Please do break it out onto breadboard and report back. I'm just guessing, but maybe as LEDs have a higher forward voltage the shape pot could be a lower value.

[sundgist]

I'm nearing the end of modding up to MKII.
Do any particular diodes work better than others? From what I can make out on the pictures they look like 1n914/1n4148. Is there any advantage using something with a higher/lower voltage drop?

Funny how writing down things sets off different trains of thought.
I'm wondering how using leds would affect things? I now like the idea of having an indicator showing the rising or falling sawtooth. Might need to jump this bit out onto a breadboard.

I'm curious about that too. In my imagination using LEDs would give a visual indication of the waveshape. I hope it works out like that.    Please do break it out onto breadboard and report back. I'm just guessing, but maybe as LEDs have a higher forward voltage the shape pot could be a lower value.

I'll give it a go.

[doc_drop]

I actually tried with LED's. It didn't change the wave shape response very much. And the LED's barely lit up at all. I was looking for a place to add a rate LED. I tried in a few locations, but either the signal wasn't strong enough to light them, or it sucked tone in a massive way. I gave up after not too much trying...

If anyone can figure out a rate LED technique, please share!

[sundgist]

   MkII vero layout is verified working. 

and I'm liking this a lot. Thanks to the both of you for working this out.

I've been having a play with the LFO shape diodes, swapping between diodes and various LEDs. A pot whose taper spreads out both extents of a pots travel and bunching up in the middle would be ideal for the shape pot as it does little for most of the central part of it's travel. Using LEDs instead of diodes you can get visualisation of the LFO waveform, in the centre of the pot they flash with equal duration, at either extent one will stay on longer than the other, fading nicely. There are some compromises.
Firstly with the stock 1M pot you only get the lowest forward voltage leds (1.6 in my case) flashing at each extent of the pots rotation. Not really visible unless the lights are out. In the centre of the pot both flicker dimly. Possibly low current hi-brite types may be better but I only used what I had.
Lowering the pot to 500k, 100k, 50k, 10k gives more and more light from the leds and the waveshape is quite clear. Unfortunately the lower the pot, the faster the slowest speed. So much so that even at 500k a lot of the slow range I like is lost, and the led show is a bit feeble.

I still like the idea of having the LFO represented visually. Unless I pick up some low current LEDs to try, I will be looking at keeping the diodes and pot as stock (with an ideal taper if possible) and just buffering some leds. I've already got one led running off the opamp output, but preferred seeing the rising and falling sides of the waveform working together.

I actually tried with LED's. It didn't change the wave shape response very much. And the LED's barely lit up at all. I was looking for a place to add a rate LED. I tried in a few locations, but either the signal wasn't strong enough to light them, or it sucked tone in a massive way. I gave up after not too much trying...

If anyone can figure out a rate LED technique, please share!

I've got an extra bright LED running from the output of the opamp (output to the range pot) via a 3.9k resistor to gnd using a millenium 2 bypass. I'm using it as a bypass led. This fades in and out nicely, there are no pops and doesn't affect the sound in any way. Can't see why it should it's not in the audio path here. I don't know what it might be doing to the LFO waveform, haven't hooked a scope up to it, but if anything it's certainly not audible. I tried with a few different types of led, some worked better than others and with different value series resistors.

[doc_drop]

Glad to hear it sundgist. I think it is a pretty cool circuit myself.

I'll have to give your rate LED solution a shot. I am getting ready to put this in a box, so now would be a great time to get the rate LED working.

Now, set that phaser on stun and enjoy playing! (That's what my morning entertainment is going to be...)

[doc_drop]

I've got an extra bright LED running from the output of the opamp (output to the range pot) via a 3.9k resistor to gnd

That works perfectly sundgist. Thanks.

I think I tried that while breadboarding, but I probably didn't pay good enough attention since I was really concentrating on other things.

I used a 2k2 resistor and an extra bright green LED, FYI. Call me cheezy, but I love a nice blinking LED that reflects the changes to the LFO. It is nice to see sawtooth up/dn versus triangle as you make changes to the settings...

[frequencycentral]

If you use another LED the opposite polarity (with it's own resistor) and hook it up to +ve instead of ground, it will be the mirror image of the first LED. As one fades out the other will fade in.  

[sundgist]

If you use another LED the opposite polarity (with it's own resistor) and hook it up to +ve instead of ground, it will be the mirror image of the first LED. As one fades out the other will fade in.  

Works for me.
Thanks, hadn't even crossed my mind.

[doc_drop]

O.K. I now have extra bright blue and green LEDs flashing alternately. It is one of the sexiest things I ever saw!

This is definitely going to be a part of my final build. My inner child is smiling a huge smile right now. And somehow this level of fancy lights seems right for such a cool circuit.

Thanks for the tips guys!

[frequencycentral]

Here's the artwork for the 5 knob MkII PCB, it includes pads for the addition of an extra stages daughter board - more on this some other time! The 3 knob MkI version can also be built using this layout.

[frequencycentral]

[sundgist]

O.K. I now have extra bright blue and green LEDs flashing alternately. It is one of the sexiest things I ever saw!

This is definitely going to be a part of my final build. My inner child is smiling a huge smile right now. And somehow this level of fancy lights seems right for such a cool circuit.

Thanks for the tips guys!

I'm sat in a darkened room at 1 o' clock in the morning, have been noodling away on my guitar for the past hour, watching the lightshow. Been messing about with some rhythmic plonking by setting the regen near max, range at min, falling sawtooth and letting the bass strings ring while playing up on the higher strings.
I'm finding it a lot easier and quicker dialing in the right speed and shape with a visual cue. The LEDs are a lot more interactive than I expected, reacting to the width control as well.
Gave the resistors a bit of fine tuning to balance the brightness between them and get the right amount of fade.

I find it funny that we have people here painstakingly biasing their fuzzes just right, finding new ways to get 'that' sound, filling boxes with rare mojo components, and I'm over the moon with a pair of flashing lights
...............time for bed I think, I need to get my baggy eyes to work in a few hours.

[doc_drop]

and I'm over the moon with a pair of flashing lights

Well, at least I'm not entirely alone in the world. It is completely cool and actually useful to see the LEDs do their work.

In hindsight, it would have been useful to have this set up while breadboarding...

[sundgist]

2 and 4 extra stages vero layouts. Will be verified when built, but should be OK.
Can anyone answer a thought I had while drawing these out. What effect would wiring a different LFO to some stages have? Wierd multi modulated phasing

[doc_drop]

Nothing new to add. Just some pics of my finished product. Unfortunately the lettering got dark during finishing. But I like the Star Ship Enterprise caught up in a "Causality" in the middle...

[frequencycentral]

All good phasers deserve a Star Trek themed graphic, I've got a nice one done for my MkII. Though it seems that I'll be modding and rehousing my MkI rather than building a fresh one,  as no one wants to buy my MkI prototype. 

.....and it seems I should put together a perf tutorial!