Author Topic: Holy (or Holier) Grail Reverb Schem  (Read 26236 times)

GreenEye

Holy (or Holier) Grail Reverb Schem
« on: March 30, 2005, 08:27:15 AM »
Anyone got the Holy Grail or Holier Grail reverb schems?  I think someone said this before: why aren't there more reverb DIY projects?

nelson

Holy (or Holier) Grail Reverb Schem
« Reply #1 on: March 30, 2005, 08:32:06 AM »
I thought the holy grail was a digital FX pedal same with most reverbs, hence the reason there aint many DIY jobs.
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R.G.

Holy (or Holier) Grail Reverb Schem
« Reply #2 on: March 30, 2005, 08:35:04 AM »
Quote
I think someone said this before: why aren't there more reverb DIY projects?

The simple answer is that the chips to do that amount of delay are quite hard to get. Even the SAD1024 is marginal for a reverb, requiring a severe band limiting of the input signal to avoid aliasing.

The Princeton Technologies PT239x chips are intended for an almost-reverb suitable for karaoke stuff, and may be acceptable.

The Alesis reverb chips are what is in the Holxxx Grail I believe. They suffer from being highly unavailable too, although they do exist.
R.G.

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sonicparke

Holy (or Holier) Grail Reverb Schem
« Reply #3 on: March 30, 2005, 09:42:34 AM »
This may be a rediculous question, but would it work to open up a lexicon or TC reverb and use whatever chip is in there for a stompbox reverb?  Could you basically just drop one in the Holy Grail or would you have to design an entirely new circuit from scratch?

puretube


inverseroom

Holy (or Holier) Grail Reverb Schem
« Reply #5 on: March 30, 2005, 10:11:42 AM »
I read somewhere--I think it was the Analog Man book--that the Holy Grail reverb chip has already been discontinued.  Matthews apparently bought enough to last several lifetimes, though.

ninoman123

Holy (or Holier) Grail Reverb Schem
« Reply #6 on: March 30, 2005, 12:11:59 PM »
Righto its digital, would be crazy hard. Do the reverb project on GGG. You can buy a reverb tank for cheap from www.tubesandmore.com.

SeanCostello

Holy (or Holier) Grail Reverb Schem
« Reply #7 on: March 30, 2005, 12:29:03 PM »
Quote from: sonicparke
This may be a rediculous question, but would it work to open up a lexicon or TC reverb and use whatever chip is in there for a stompbox reverb?  Could you basically just drop one in the Holy Grail or would you have to design an entirely new circuit from scratch?


TC Electronic reverbs, and all Lexicon reverbs since the late 1970's, use DSP chips. These are not performing a single function, but are running code contained on a ROM in the unit.  I believe that TC Electronic uses Motorola 563xx parts + a FPGA for memory access, and that the high end Lexicons use TigerSHARC DSPs.

Putting one of these DSPs into a box would do nothing. Even putting the entire A/D, D/A, RAM, etc. circuit would do nothing without the code that is on the ROM. The key to high end reverbs is the algorithms they use, and these are HIGHLY protected trade secrets. If you copied the code on the ROM, that would be copyright infringement. If you reverse engineered the units and implemented the algorithms yourself in different code, that is protected by law, but it is pretty difficult to do.

Plus, the Motorola and TigerSHARC DSPs would probably not work well with batteries. You would want to use a DSP that has lower power consumption, yet high enough speed to compute several hundred delay taps, if you wanted to get the quality of the Lexicon or TC Electronic reverbs.

Sean Costello

DaveTV

Holy (or Holier) Grail Reverb Schem
« Reply #8 on: March 30, 2005, 01:03:52 PM »
Here's a digital reverb circuit I've been working on for some time now. I need to upload the lastest version of it, which has the input opamp changed to a non-inverting opamp buffer with unity gain (I was experimenting with boosting the signal a little at the input). The circuit is based around the reverb chip used in the Alesis Picoverb (now made by Wavefront Semiconductor). In fact, it's taken almost directly from a circuit in the spec sheets for this chip, which I assume is probably VERY similar to the circuit used in the Picoverb.

I was able to get these chips by contacting Wavefront directly. DIY digital pedals aren't impossible!

DiyFreaque

Holy (or Holier) Grail Reverb Schem
« Reply #9 on: March 30, 2005, 01:05:31 PM »
OK, don't know how off the wall this would be, but I've idly wondered about it.

How about those kits that do the echo, reverb, etc. for the CB radios?  They're obviously digital and might make a good guitar mangler.

Case in point, the TRB-1 Turbo Echo Board, which has alien voice, reverb, repeater & endless echo functions with on-board modulation and echo volume range.  Probably powers off of +12V(?).  Maybe with some clever modification it might make a fairly unique stompbox.

http://bobscb.com/kits/tr_kits.htm

$39.95.

Cheers,
Scott
(putting the Freaque in DIY with this idea, I'm sure)

Mark Hammer

Holy (or Holier) Grail Reverb Schem
« Reply #10 on: March 30, 2005, 01:25:41 PM »
Quote from: inverseroom
I read somewhere--I think it was the Analog Man book--that the Holy Grail reverb chip has already been discontinued.  Matthews apparently bought enough to last several lifetimes, though.


Yes.  Apparently, Crystal Semiconductors has discontinued the CS4311 (I think that's the part number).  I managed to download the datasheet before that happened a few years ago, and it looks like an interesting chip.  It also seems like there are some simple toggle-switch mods that might be feasible to add sounds to the limited repertoire of the Holy Grail, since only a few of the available algorithms seem to be employed in either the Holy or Holier Grail.  

At the same time, this is not the sort of chip you monkey around with unless you know what you are doing.  Perhaps more importantly, it is a regular feature of many DSP chips that they are SMT/SOIC, requiring teeny soldering tips, close pin spacing, and very thin PCB traces.  Clearly off limits to 99.9% of DIY types.  If *making* the boards wasn't bad or hard enough, troubleshooting them would be next to impossible without the appropriate technology.  Just TRY to imagine finding a hairline crack in a trace on a board.

Nah, there are some things I leave to the pros.

E-money

Holy (or Holier) Grail Reverb Schem
« Reply #11 on: May 04, 2005, 12:37:08 PM »
Quote
Do the reverb project on GGG. You can buy a reverb tank for cheap from www.tubesandmore.com


Please elaborate, what is GGG?

The Tone God

Holy (or Holier) Grail Reverb Schem
« Reply #12 on: May 04, 2005, 12:41:35 PM »
Quote from: E-money
Please elaborate, what is GGG?


General Guitar Gadgets.

http://www.generalguitargadgets.com/

Andrew

nelson

Holy (or Holier) Grail Reverb Schem
« Reply #13 on: May 04, 2005, 12:48:24 PM »
Quote from: E-money
Quote
Do the reverb project on GGG. You can buy a reverb tank for cheap from www.tubesandmore.com


Please elaborate, what is GGG?



http://www.generalguitargadgets.com
My project site
Winner of Mar 2009 FX-X