| Author |
Topic: Electro-harmonics walwart 9v ac/dc adaptor |
Dave Zirbel
From:
Sebastopol, CA USA
|
Posted 25 Oct 2008 5:39 pm |
|
Would it be ok to use a generic 9v adaptor from Radio Shack for a Holy Grail reverb, rather than buy the Electro Harmonics one?
Thanks
Dave |
|
|
 |
Jon Light
From:
Saugerties, NY
|
Posted 25 Oct 2008 5:55 pm
|
|
It MUST be tip positive. The 'standard' Boss type adaptor is tip negative. As long as you make sure to get this right, there shouldn't be a problem. I do note that the EH power supply is rated at 500mA which is pretty robust. Because of that I'd steer away from a cheap 200mA adaptor.
I've run the Grail on daisy chains from generic sources with no problems.
Note, also that the power plug is a straight mini---not a barrel like the Boss type, consistent with the general standard of tip pos (straight plug) or tip neg (barrel plug).
There are probably exceptions to that last statement but my observations bear out this generalization. |
|
|
|
Dave Zirbel
From:
Sebastopol, CA USA
|
Posted 26 Oct 2008 7:39 am
|
|
Thank you Jon! 
Dave |
|
|
|
Ken Fox
From:
Nashville GA USA
|
Posted 26 Oct 2008 8:53 am
|
|
| A lot of the cheaper DC supplies do not have proper capacitor filtering, resulting in hum in the device. |
|
|
|
Jim Sliff
From:
Lawndale California, USA
|
Posted 26 Oct 2008 9:09 am
|
|
| Quote: |
| consistent with the general standard of tip pos (straight plug) or tip neg (barrel plug). |
Some thought on adapters - and some advice (stuff often discussed on guitar forums but something I have not seen much of here):
I probably have more tip-positive barrel jack effects than ones that require mini plugs. I've simply found that certain companies favored mini plugs at times; Ibanez used to use them along with several other companies (when Ibanez was making the 800 series), Klon uses it, but most, whether positive or negative tip, have changed to the Boss-size jack (and some are tip positive, so you have to check carefully before inserting anything! The ons that drive me nuts are odd-size Boss-style jacks - sometimes the outer diameter is fine but the inner post (positive) is larger. I found an electronics store near my office that carries every plug imaginable with a board of jacks and plugs so you can see what fits your unit - it's been really helpful when I've bought od, off-brand effects with no adapter.
Always make sure you have the polarity right - and ALWAYS make sure it's a (example) "9 VDC" effect and NOT "9VAC" - and there are plenty of gadgets that use AC-to-AC adapters. Them make sure (as previously mentioned) that the amperage of the adapter is sufficient (a 500ma will handle most normal effects; 200 will as well, but some things need a bit more so i I don't know I err on the high side). It's something you have to watch using a "One Spot" or other daisy-chain adapter (one wall wart with multiple plugs hooked to it) - make sure you have enough current.
Last note - I recommend (and most effects companies do the same) using a "regulated" adapter. The only way to know is labeling or packaging; they look the same. But the voltage will be more consistent and they cause less noise (unregulated cheapos are a crapshoot - if you find an eBay deal for $5 9V wall-wart it's a 99% chance it's unregulated). But unregulated ones work fine with SOME effects - I do a lot of mixing/matching as I have boxes full of the darned things!
Last note (I promise!) - Most off-brand and many name-brand adapters hit your effect with more voltage than the "9V" printed on them - the Boss ones put out about 9.7V, some import-name ones I have kick out 11-12V and two Sony 9V adapters I won actually put out 14V! Some effects work great with the extra voltage (some OD and distortion pedals you can actually fine-tune the sound of by power supply voltage!) - some become paperweights ("swirly" gadgets and delays are usually picky about correct voltage). So I check EVERY adapter - even new - with a multimeter for voltag before using it (that's why I have so many - I end up buying spares that are closer)
_________________
No chops, but great tone
1930's/40's Rickenbacher/Rickenbacker 6&8 string lap steels
1921 Weissenborn Style 2; Hilo&Schireson hollownecks
Appalachian, Regal & Dobro squarenecks
1959 Fender 400 9+2 B6;1960's Fender 800 3+3+2; 1948 Fender Dual-8 Professional |
|
|
|
Jon Light
From:
Saugerties, NY
|
Posted 26 Oct 2008 9:38 am
|
|
I totally welcome the correction about my straight plug/barrel plug +/- comment. My observation was based on a fair number of fx I have and have had but nothing like a comprehensive sampling. And even if I were confident in my statement I never---NEVER---take anything for granted. Especially re: AC to DC and AC to AC----came close to frying something dear to me and I know that many others have come closer than close---stir fried goodies---from not noticing or even realizing that some transformers step down voltage without converting the AC to DC. In a world smarter than this one somebody would have introduced a connector protocol that standardized these differences.
Yeah, right.
This is how the DC polarity thing will look on the adaptor:
TIP NEGATIVE:
TIP POSITIVE:
 |
|
|
|
Dave Zirbel
From:
Sebastopol, CA USA
|
Posted 26 Oct 2008 9:49 am
|
|
Thanks for all responses. I think I will play it safe and get the recommended part from Electro-Harmonics.
Dave |
|
|
|
Jerry Overstreet
From:
Louisville Ky
|
Posted 26 Oct 2008 4:31 pm
|
|
For those who know how to use a DVOM, you can check the polarity of a DC adaptor fairly easily. I also reverse said polarity to the device end of the connectors of suitable replacement adaptors if I need to.
AC to AC units with only 2 same size blades won't indicate polarity. |
|
|
|
ajm
From:
Los Angeles
|
Posted 27 Oct 2008 8:28 pm
|
|
To reply/add to Jim Sliff's post:
1) What is the name of the store that has examples of all of the plugs? The only ones I can think of in the South Bay are Signal Electronics and Torrance Electronics.
2)It has been my experience that a 200 ma DC adapter will often handle multiple floor boxes, often up to 8-10 (theoretically). There are exceptions, like many of the reverb and digital delay pedals. Some of those can draw a LOT of current and really eat batteries. I have seen a Boss tremolo pedal that ran off of a single battery and drew 20 ma, which is still relatively low. Most of the distortion / preamp / compressor / flanger / phaser pedals are good for around 10-20 ma.
3) I'm not sure what some companies consider "regulated". To me it would mean some kind of voltage regulator inside to give a constant voltage output regardless of current draw. I have seen some "regulated" types that are the same circuitry as the unregulated ones.
4) I know what you mean about a "9v" adapter putting out 12-14 volts. It has been my experience with the unregulated ones that anything less that the full rated current will result in a higher voltage. In other words, a 9v/200ma adapter will put out 9v when delivering 200ma, but if you're only using one pedal that is asking for 10 ma the voltage is going to be around 12-14v.
(Jim: I'm sure that you know all of this stuff, but I wanted to try and clarify/add a couple of things.)
Finally, for what it's worth, there are a few videos on youtube where some guy demonstrates how a certain pedal behaves with different adapters. The one that you might think would cause the least problems is usually the one that is the worst. There doesn't seem to be much rhyme or reason to matching pedals and adapters sometimes. As with many things, you just have to try and see what works. |
|
|
|
Bob Hoffnar
From:
Austin, Tx
|
Posted 27 Oct 2008 9:04 pm
|
|
I picked up a Radio Shack adapter while I was on the road that worked fine. Got it in some outlet mall in Oregon on the way to a gig. They had a selection of tips and transformers ready to go.
_________________
Bob |
|
|
|
Dave Mudgett
From:
Central Pennsylvania and Gallatin, Tennessee
|
Posted 27 Oct 2008 9:16 pm
|
|
FWIW - I was testing some recently built vintage-style no-reverb amps with a Holy Grail last week, and the blasted EH adapter caused the thing to hum like a beehive. This was straight into a low-gain tube amp, and the noise was horrible. I could understand this in a high-gain amp, but not in these. We tried several HG units and several of the same type of adapters, but every combination was buzz-city. At first I thought it was clock-noise from the HG itself, but we did find some generic adapter that worked OK. Unfortunately, we have no idea what brand adapter that was - it had the voltage DC and polarity diagram, but no other markings - it was just lying around the shop.
I don't know if we just got a bad batch of EH adapters, they moved to an unregulated design, or what. But we're looking for a substitute. For cheapies, we've found the Danelectro 9v supplies to work pretty well for any effects that use Boss-style supplies, but as Jon notes, they don't fit the HG - the jack and polarity are wrong. We may try soldering the correct jack to a Dano with the correct polarity arrangement and see what happens. Or Radio Shack sounds like a reasonable option - at least they have some options and you can take it back with no hassle if it doesn't work well. |
|
|
|
ajm
From:
Los Angeles
|
|
|
|
