Morley Crystal Chorus Box

[chance]

Hi guys,

I have 3 layouts for the Morley Crystal Chorus Box based of the factory schematic dated 08/05/1996. One layout is as per factory schematic, no true bypass, no mods. A second layout is a true bypass version and the third is with true bypass and 3 mods. One is the intensity mod which I have seen on Boss CE-2 clones, either change the value of the 5p cap or add another in parallel; not too large in value. Second mod removes  the dry signal 'vibe' mod. There is also a 1M pull-down resistor on the modded version, whether you need it or not on this build I don't know. If you don't need it then leave it out. The pull-down resistor is not on factory schematic or true bypass version but the space is there if you need to install it. Run this off regulated neg tip 9v dc. Also on layout is information regarding second output for stereo which can be utilised without a daughter board or left out providing you amend a certain jumper.  D1 1N4003 can be substituted with 1N4001. MC3403 can be replaced with another quad op-amp like LM324. As of 15/11/2017 this layout is now verified. If you downloaded the layouts I posted prior to this date please download these newer ones as there were 2 critical errors which I have corrected. The worst one was a missing cut beside pin 4 of the MN3207 which shorted the power. The other was the placement of the 1M8 resistor connected to IC3 which involved shifting a link and 2 resistors slightly. Use the newer layouts as reference in case you have already started on the boards. Mine is not boxed yet but sounds good, I have not found a single demo online for reference. I will post up a layout utilising MN3007 BBD instead of MN3207 soon. 17/11/2017 UPDATE: Please ditch layouts uploaded prior to this  date, when I made the corrections mentioned above 15/11/2017 I forgot to update the unpopulated boards also. They are all good now.

[chance]

Here is the schematic...

[chance]

LM324 works fine as a substitute for MC3403, lot of depth in this, intensity mod is not necessary really. Sounds really good, no noise. Trimmers are best about dead centre. Might look at a level control though.

[chance]

Actually there is a demo by gearmandude. I like this thing better than my Boss CE-2 clone.

[Mark SL]

What is up with the 1.8M resistor on the bottom right ad the double link jumper that are supposed to go into the same hole? The cut and jumper layout has a different setup than the one with the components.

[chance]

Aah, thanks for spotting this, I simply did not update the unpopulated boards after I cmade the corrections yesterday. Stand-by for a quick update...

[chance]

Layouts now updated, good spotting. I have got too many projects in my head at the moment, cheers!

[chance]

17/11/2017 UPDATE: Please ditch layouts uploaded prior to this  date, when I made the corrections mentioned above 15/11/2017 I forgot to update the unpopulated boards also. They are all good now.

[chance]

After testing this and the Morley Sapphire Flanger (similar circuit) I find that the quad op-amp specified in the schematic MC3403 doesn't perform well and distorts a lot, same with LM324. I replaced it with an MC34074PG and it sounds awesome now, problem solved. MC34074 series isn't all that common, I had to get these from the UK (I'm in OZ) but I have a bunch of more common quad op-amps on the way for testing.

[chance]

Tried some more quad op-amps and found that HA17324A and LM2092N are also perfect replacements for the MC3403, sounding I'm sure as originally designed, and they are common devices too!