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Author Topic: Holy Grail, Holy Hum!  (Read 526 times)
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Dynaflow
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« on: December 09, 2006, 11:10:11 pm »

 
 Ok, I've had this Holy Grail reverb from Electro-Harmonix for like a year (got it last Xmas) used it once or twice. It has the adapter that came with it. Reading its reviews on Harmony-Central (or Harmony Dewd Central as it were) and it appears its common there is a hum (sounds like power supply filtering issue) that gets so bad it almost makes it unusable. I hav'nt taken it apart yet, futzing with the P/S jack seems to make it quiet down (its still far from silent). Since this appears to be a common problem on these units, has anyway ran across it and found a good fix?
 On a positive note, when its not humming and you can get it to quiet down, it sounds extremely fine. I was playing 'Lenny' through it into the Superlead 100 at a apt. volume (WAY CLEAN) and it sounded so mighty fine. The flerb setting is a little weird, I guess useful in the right song. Anyway, any idea's?

Regards,

Dyna

Ps: It uses a 1/8 phone jack for the p/s adapter, a bit different than usual barrel type plug. It uses no battery at all.
« Last Edit: December 09, 2006, 11:19:34 pm by Dynaflow » Logged

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EKDENTON
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« Reply #1 on: December 12, 2006, 05:53:26 pm »

i have one of those barrell type plugs that I soldered to a battery strap so I can run an external 9v battery on all my boxes. If you think it is the power supply maybe you could rig up a battery to the 1/8" phone jack just to see if running on a battey is quieter. It may suck alot of juice, maybe that is why they don't have it on a battery, but if you tried that at least you would know if it is the power supply.
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Dynaflow
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« Reply #2 on: December 12, 2006, 07:12:22 pm »

 Yeah Ed, its my understanding it draws so much juice a 9v batter won't last very long at all.

Regards,

Dyna
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rockgardenlove
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« Reply #3 on: December 29, 2006, 04:36:57 am »

I'd say open it up and up the value on the PS filtering.  
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tubenit
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« Reply #4 on: December 29, 2006, 06:19:08 am »

Dynaflow,

I had a Holy Grail that I used with a VibroChamp I used to own. It had NO hum to it at all and was very quiet. Had a great reverb tone, IMO.  I compared the reverb to my Princeton Reverb and view them just different without one being signficantly better than the other. I do think the Holy Grail sucked some of the tone of the amp away.

Have you tried it on different 117vac outlets to see if it still does it?

With respect, Tubenit
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Dynaflow
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« Reply #5 on: December 30, 2006, 02:15:08 pm »

 Yeah, does it at gigs (multiple) and at home. Its something that was mentioned in Harmony Central (I know not the resource for unbiased info) as a problem, many units sent back. I'll open it up and check out the filtering, it seems that diddling with the jack sometimes causes it to work ok. Its probably a easy filtering fix. I like the sound of the unit, its a awesome sounding reverb. It may suck tone, have'nt been able to use it long enough to tell, but then again I was using my 100 watt Marshall and its got so much punch its hard to tell sometimes... :D

Regards,

Dyna
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jjasilli
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Took the power supply test. . . got a B+


« Reply #6 on: January 06, 2007, 09:53:35 pm »

Quote
Dynaflow,

I had a Holy Grail that I used with a VibroChamp I used to own. It had NO hum to it at all and was very quiet. Had a great reverb tone, IMO.  I compared the reverb to my Princeton Reverb and view them just different without one being signficantly better than the other. I do think the Holy Grail sucked some of the tone of the amp away.

Have you tried it on different 117vac outlets to see if it still does it?

With respect, Tubenit

Same here, still have the pedal.  So does a friend of mine.  But I do hear the hum complaint from others now & then.
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jzad
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« Reply #7 on: February 25, 2007, 03:57:26 pm »

 I have a holy grail that does the same thing did you change the filtering at all? Did you find a way to solve the problem?
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Dynaflow
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« Reply #8 on: February 26, 2007, 02:57:02 pm »

 Haven't looked at it yet, probably should now I'm between projects... Heck even if I had to put together another power supply instead of the wall wart I'd consider it, its truly is a great sounding pedal IMHO.

Regards,

Dyna
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« Reply #9 on: February 26, 2007, 03:33:36 pm »

i just popped open the wall wart for the holy grail and it has a 2200uf 6v capacitor. I'm assuming this is a filter capacitor. Does anyone know if changing this value may make a difference in our hum problem?
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Dynaflow
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« Reply #10 on: August 31, 2007, 11:53:48 pm »

 Sorry this solution took so long to look into, those that have the pedal, or want to file it away for future reference. Its totally the power supply. Wife went back home to Texas so I had a bit of undisturbed free time, was jonesin' for some reverb and loved this one before it started giving me problems (almost immediately after purchase two xmas's ago). Was playing the 100 watt marshall cleanly and low (of course, hey I'm in a apartment, my neighbors love my playing, but not with that monster turned up) and decided I'd try it again. Hum started immediately. I jiggle the jack, had the thing open before, does'nt appear to be a problem. I figure what the heck, I have wall warts around, so I find a old Danelectro 200 ma 9.6 volter graft on the mini 1/8" plug onto it. Fire it up. Silence, perfect lovely reverb, no hum at all. So simple fix, should have gotten to it long ago, it truly is one of the better pedal reverbs I've heard. Does spring and plate and flerb (flanged reverb). The extreme in spring or plate gives that Led Zepelin almost reverse sounding reverb with a delayed attack thats really a trip. Soooo, looks like my amps will have reverb again and for that I'm REAL happy. And yeah, I feel like a horses ass for waiting so long to fix something so simple. :D

Regards,

Dyna
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« Reply #11 on: September 01, 2007, 06:16:26 am »

Just like building amps... The power supply needs to be quiet!

My favorite reverb pedal is the Boss RV-2. It came out around 1983. I still got it and still use it.
It looks like all the modern Boss pedals... You know I can't believe it's that old!
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Dynaflow
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« Reply #12 on: September 01, 2007, 01:49:49 pm »

 I hear ya' boss, seems like the majority of amp building related problems is hunting down electrical noise from power supplies. I figured it was probably power supply related due to it being a 60 cycle hum, but figured I'd have to get creative with some filtering inside. Oh well, I guess wall warts do have some pluses (I'd almost like to mail this one to EH after running it over with my forklift at work). :D

Regards,

Dyna
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duke of earl
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« Reply #13 on: January 01, 2008, 08:53:42 pm »

I hate every EH pedal I've ever played. They all suck tone bigtime and yes they are all noisy. sorry to be so negative but the truth is the truth. I've got an old Clone Theory (70's) for sale if anyone is interested.
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