Rehouse Holy Grail Reverb

[rodgaines]

Have have the older big metal silver box holy grail. I'm wanting to rehouse, make it smaller. I've never built a pedal, I've fixed a few that were messed up. I figure I could do this for starting out. What size box,knob,led,switch,toggle do I need. Keep in mind I'm ignorant to this and all suggestions will be greatly appreciated. Thanks Rod

[poppyman]

I'm a noob too but here's what I can suggest.

First check the guts of the pedal, I never owned a Holy Grail in a steel box but there's a good chance that the PCB will be as large as the box itself, which would make the rehousing a bit meaningless if you end up putting it in a box as big as the original.

Then I would take notes of "what goes where" especially if you are replacing parts.

I'd try to keep as many parts you can if they look in good working order. You could change the foot switch with a 3dpt switch.
A standard 5mm LED will do the job.

For the box I'd suggest the BB size (EHX xo large boxes), I don't think a big box holy grail PCB will fit in a smaller box, but then again you'll have to check with your pedal's guts first.
The knob can take any form and size.You can probably keep the old one. If you want to change the pot make sure you take the same value and type (usually it's printed on the pot.)
Then pick a good pedal parts/electronic retailer (mouser, smallbear, banzaimusic etc..) and get to work.

There are tones of tutorial about rehousing on the internet and old EHX pedals are good candidates, usually.

Good luck.

[jubal81]

Enclosure: 1590BB
Switch: DP3T - On-On-On toggle switch
Foot switch: 3PDT
Knob: 10K Linear potentiometer (16mm Alpha) and either a smooth shaft for press fit knob, depending on the shaft of the potentiometer you get
Two 1/4" phono jacks
DC jack: 2.1mm barrel.

Critical!!!!!
When you hook up the power, make sure polarity is correct before you power it up. I fried a Holy Grail that way.

You can get everything you need at Smallbear or Mammoth Electronics. I love Smallbear, but Mammoth has a more noob-friendly interface.

[MarcoMike]

you could even unlock the "room reverb" setting and "long/short" delay as in the Holier Grail... with some additional switches.

[disabled_shredder]

Macromike I have to ask pls go into detail about the unlocking the room reverb and long short delay I have a holy grail and would love to tinker with it! Sorry for thread jacking but in a sense you opened the can o worms!

[MarcoMike]

OK Shredder, but I am not able to reach my holy grail schematic, so I will just improvise:
if you are able to get the schematic files for holy grail and holier grail and compare them, you will easily see how you can uprgrade one into the other.
the reverb chip has four wires for mode selection, for a total of 8 combinations. 4 of which are: spring, hall, room and flerb. plus 4 more which are the "long/slow" counterpart.

let's call the 4 standard modes: 0-0-0, 0-0-1, 0-1-0, 0-1-1
the switch in the holy grail allows only 3 positions, so here you have standard spring hall and flerb. if you look at the schematic you see what to connect where for having e.g. room instead of flerb. otherwise you can use a different switch and allow all 4 modes.

and the further 4 slow modes, let's indicate them with 1-0-0, 1-0-1, 1-1-0, 1-1-1 are accessible if you add a switch, even just a spst which connects the two proper wire. connected is 1, disconnected is 0.

all informations provided rely only on my renowned bad memory.

[rodgaines]

Ok guys I rehoused the HG. I plug it up, everything is cool except the on/on/on toggle switch. I get hall in the up position and flerb in the middle and bottom?? Not really a biggie, I used hall mostly. Another thing.. The alpha pot, barely turn and big change. Have to be gentle and move it by barley touching. What used to be the whole turn is now from 0-1/2 way. I just you a little to wet it up a bit. Wonder why the 3 way switch is different. I but the wires all three on one side like the older "slider" switch. Any way thanks for all of your help. Any advise on the toggle would be great.

[MarcoMike]

I had the chance to take a look at the schematic.
in holy grail only Pio1 and Pio2 are used and mode correspond to:

             Pio1             Pio2
spring:  high              low
hall:      high             high
flerb:     low             high

room would be low-low.
the chip is CS4811, you can find the schematic online for pin identification.

if you get messed up effect, you probably have something wrong in the switch wiring. did you change it to a different toggle switch?
if one of the external wires was missing, or switch not working properly on that side, you coul end up with room-flerb-flerb. could this be the thing you're experiencing?

regarding effect's volume, did you change the pot to a different taper?

[rodgaines]

Yes I changed the switch. It had the old back switch 6 pin and I replaced with toggle on/on/on switch. I'm sure the pot is a different value also. I'm getting reverb in up position and flerb in middle and down position