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I have a TC Electronics Hall of Fame 2 pedal. When I use it with my One Spot power supply, there is a pronounced 120 Hz hum through the pedal, which is present whether or not anything is plugged into the input. When I use a 9V battery in the same pedal, there is no extra noise added. Has anybody else had this experience? I'm trying to decide if my One Spot is defective in some way, whether a different power supply would avoid this problem or if that's just what happens with small AC transformers to 9V DC. Given that DC shouldn't carry frequency information, I'm a little puzzled.
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11-08-2024 11:43 PM
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Contact TrueTone
1 Spot should be high quality, 1 year warranty
"Triple filtered output for clean, quiet power"
If it's a 1 SPOT Pro it has a 5 year warranty
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I have experienced that too with some pedals, especially digital ones.Try switching some pedals around or make sure no digital pedals are in the same DC-loop/ daisy chain.
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Thanks for the responses! The One Spot is at least 10 years old, maybe 12, so out of warranty.
I have had the HOF2 for three or four years (maybe?). It's the only pedal in the signal chain.
Pedals are too often too much of a headache as far as I am concerned. All those damn knobs, so all of my pedals spend years at a time in a box, unused. My amp has no reverb built in, so I use this sometimes.
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Could it be the result of a ground loops? Do the amp and pedal have a common earth? If not that can be a source of noise. I also have a hof and a flashback mini. Digital pedals are prickly, demanding good power headroom and well isolated supplies. I run my pedals on 2 different boards from Trutone smps bricks. One is a cs6, the other a larger capacity cs7. Have not had an issue with either supply.
Last edited by EastwoodMike; 11-09-2024 at 04:39 AM.
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I use this Diago. Had it over 7 years with no problems. DIAGO POWERSTATION Guitar Pedal or FX 9 Volt Power Supply
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Switching power supplies can be noisy. I've about given up on using them. I've found two methods of keeping pedals quiet. One is batteries, and I tend to use 9V rechargeable lithium batteries in a battery box, for easy removal/switching and recharging. The other is a cable that connects to a standard USB port and raises the voltage to 9VDC. It requires a polarity reverser to get the center terminal negative, but I have a couple of those that I've made. Both these methods can be less than perfect if one is using a complicated pedalboard with many pedals, but I don't do that. I confess to having rarely connected as many as 3 pedals at a time, but never had them all active at the same time.
I suspect that at least part of the noise problem is having the polarity switched, with the pedal case being the positive side of the circuit, not the ground. I haven't really done any investigation of this, though, so I could be wrong. Seems logical to me, but I have no proof.
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Thanks! The amp and One Spot are plugged into the same power strip.
Since I don't get the hum using a battery, it seems likely that the power source is the culprit. I hadn't thought about the pedal being digital, but I suppose it is since it's got a USB port and one can download things into it. [edit: this thing eats batteries like crazy. I put in a brand new Energizer 9V and in four hours of playing time it was drained to 7.5V! A power supply is necessary]
So if switching power supplies, which it sounds like this one is, can be problematic, what are the alternative types of powers supplies? I had assumed they were all straightforward transformers which (I think) should isolate the DC output side from the AC input side. The Diago is also a switching design, it seems.
I am suddenly reminded that I took my reverb pedal over to a friend's to try there because of hum; he has multiple digital pedals powered from a supply, which I play through every week and don't get any hum; I don't remember that I got any hum when I took the HOF2 over there and tried it; I'll ask him what power supply he's using. It's a much larger brick than mine, I remember that much. Looking around at online pictures, it might be an MXR Iso Brick.Last edited by Cunamara; 11-09-2024 at 05:55 PM.
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If you have two things plugged in with three prong plugs, you might try a ground lift adaptor on one or both to see if that makes any difference. If it does, you had a ground loop.
It's the three prong to two prong adaptor. Cheap and useful to have around if you ever play somewhere that doesn't have three prong outlets.
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I don't know about the HOF, but I believe that power supplies have improved greatly in the last 10 years.
I have two Cioks supplies and have never had any noise problems. One of their important features is that every power outlet is isolated by itself, which probably helps a lot. I have one digital pedal, a Keeley Halo, on it and never a problem.
Might be time for an upgrade! Especially if it is fine on your friend's supply.
Luckily it's always fun to buy more gear!
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Looking around online, the Ciok SOL had caught my eye. It looks like it does not use a wall wart, although the photos were a bit unclear on that point.
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I use 115vAC to 9vDC transformers regularly in several different devices. None of them hum.
When I get hum, it's usually a ground loop caused by something like two amps, each of which has a three prong power cable. Say, I run them from the L and R outputs of my ME80 pedalboard. I can expect hum. If I then use a ground lift adapter, the hum disappears.
I have been told that this is not the safe way to handle the problem and that I should, instead, use an "isolation transformer". I mention it because I don't insist that everyone else make the same mistakes I make.
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Might be a simple ground loop but hasn't been my experience when I've had noise with pedals. Had problems when I used a Voodoo power supply. Mount it underside your board and listen to the pedal above it hum.
So one solution is a well shielded and isolated power supply. I think Strymon Zuma is the best but they are expensive and not small. I've had good luck with Dunlop MXR power bricks and they are a good space saver solution with lots of high power outputs. Wall wart supply but seems well constructed and it helps with the small form factor which works well on small boards. I find a 4 or 5 space board as easy to deal with as a single pedal but that's a discussion for another day. Never had a noise problem with the MXR,
I don't own a 1Spot but I question the isolation and shielding of what looks to be an inexpensive wall wart. Try keeping it farther away from you pedals.
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Stupid question but can you reproduce the noise in multiple locations?
I have 2 Cioks DC5s. One for my acoustic board one for my electric. They fit underneath a PedalTrain Nano. Have swaped many pedals on these boards over the years and all have been quiet. Even with tube amps and single coils.
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alltunes, not at all a stupid question. I live in an old house with wiring that I suspect was personally done by a previous owner; I have had to fix the grounding on multiple outlets to get rid of open grounds, reversed wires, etc. I have those all straightened out according to my outlet tester, but it's still an old house with fairly crappy wiring. as noted, I did not have this problem when I took the pedal over to a friends house and used his power supply. I did have some hum problems when taking my amp, pedal, 1Spot, etc., to another location to play. in fact, I gave up on using it after that, so it's probably been a year or so since I plugged the pedal in.
Just fiddling around this afternoon, I noted that the 1 foot long patch cable I was using to plug the pedal into the amp was at least contributing to the problem, as the noise would get worse or better as I wiggled the plug around in the jack. It seems like there's a soldering problem or maybe a broken wire strand at one of the plugs; I replaced that with another patch cable and the hum is still present, but reduced; wiggling the plug around in the jack doesn't make any difference.
As far as ground loops go, the 1Spot is not grounded and has two prongs only, so I doubt a ground loop is the issue.
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Why don’t you just buy or borrow another 9v power supply and try that? They do go bad sometimes, and you really should have spares of everything.
Is your power supply really close to the amp? That can sometimes induce hum.
Please, never, NEVER use a ground lift adapter on any musical equipment! Sure, it can work but can also be potentially fatal.
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I use Cioks power suppies only (DC10 and Baby2). No wall wart. And all my noise issues solved once and for all.
Originally Posted by Cunamara
Before that, my Keeley Compressor 4Knobs captured the radio signal from Vatican City (no joke!
).
Sergio
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This is the advice I got and I think it's exactly right. Originally Posted by Gilpy
Here's a question. I connect two amps to the L and R outputs of my pedalboard. Both amps have three prong plugs. I put a ground lift adapter on one of the amps.
At that point, aren't both amps still connected to ground, one directly and one through the ground wire of the patch cord? In that configuration are you still protected against being electrocuted if one of the chassis gets 115v AC in it? Or will the ground wire (the outside shield) in the patch cord melt away while the chassis remains hot?
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Yes, it can work. But do you want the path from the 120v hot conductor to ground to go through your guitar strings in case of a malfunction? Originally Posted by rpjazzguitar
You always want the shortest, best connection to ground for both your amps. That’s not through your patch cord. Never use a ground lift on your amp.
In addition to being a musician, I worked as a live sound engineer for many years and have encountered a lot of hum, buzz and ground loops. I have never found a problem that was worth the potentially lethal risk of using a ground lift adapter.
If everything is plugged into the same (hopefully correctly wired) outlet, then the problem is with your equipment and that’s the place to correct it.Last edited by Gilpy; 11-09-2024 at 09:13 PM.
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I just ordered the Cioks SOL. Who knows, maybe I'll end up adding a *second* pedal to my signal chain. I don't think I can legally play straight ahead jazz then, though. The jazz police may hunt me down. I'd be a back alley jazz fugitive. Originally Posted by Gilpy
I may have just found the name for my next band... The Jazz Fugitives.
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That's probably the action of the hasher you're hearing, giving you an output "signal" that isn't a nicely continuous 9V but something between that and a kind of block wave that has very short dips to 0V 120x per second. Originally Posted by Cunamara
I've had a comparable situation with the stock PSU of an ART preamp that caused a very annoying artifact in the output. Spent a lot of time hunting down the problem, creating a filter to use on the AC input, shielding all the wires and connectors that weren't already and even making certain the low and high voltage cables were properly separated (learned that from an electronics ace colleague while working with moving-base driving simulators, where you really don't want any unexpected signals in the loop).
In the end I got a 2nd, used ART preamp that came with a much bigger aftermarket PSU. That preamp had its own internal noise problem (got my money back for that
) but it turns out the PSU solved my hum issue.
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I have found that some power supplies just don't get along with some pedals, e.g., I had a Boss reverb pedal that was noisy with anything other than the original supply or a specific brand (Mutec, IIRC) that Boss said was an authorized replacement. You could try swapping in different power supplies to see if that makes a difference. FWIW, I recently started using a lithium iron battery pack instead of 9V power supples for the pedals I have that need external power. This is mainly to reduce the tangle of wires in my stage set-up, but it does also remove a potential noise source. Originally Posted by Cunamara
Last edited by John A.; 11-12-2024 at 05:49 PM.
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Well, if You get a Nano board with a reverb and a tuner the Jazz Police can’t catch You.
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Plus a looper and maybe a delay and, of course, proper EQ. And yea.. you can fit all that on a small board. Originally Posted by Herbie
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The Cioks SOL arrive today. Interestingly, the power outputs (of which there are five) are RCA jacks which are switchable for a different voltage and amperage configurations. It came with about 10 different cables to plug into pedals with different requirements, everything from 9V to 18V, and more specialty cables are available. It's quite compact, not as tall as most of my pedals and with a footprint barely larger.
Plugged it in, connected my HOF2 and… nary a hum to be heard. Problem solved. Thank you to everyone who pointed me in the right direction! And, if I ever decide to get any of my other pedals out of the storage box that they're in, I'll have juice for them. Except for the Yamaha Magicstomp, since that takes AC which this power supply does not do.
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