1 Spot Problems???

[mrscientificterms]

Has anybody ever known pedals to have problems with 1  Spot power supplies?  I have an MXR Smart Gate that took a dump on me when running on a one spot.  Passes signal in bypass mode, led lites up when on, but no gate.  I'm not worried about the gate, really.  Just curious about your thoughts as there definitely seems to be some folks who think these things kill pedals.  cheers and thanks!

[R.G.]

Has anybody ever known pedals to have problems with 1  Spot power supplies?

Yes, I have known pedals to have problems with a 1Spot. Not many, but some. There is actually a list of incompatible pedals on the web site at visualsound.net. By and large, they are pedals with large DC current drains, big digital processing sections, and their own internal switching power supplies that put pulse loading on the 1Spot at almost but not quite the switching frequency of the 1Spot itself.

But we have yet to find analog pedal that did not have some other problem that would not work well with a 1Spot. Could happen, but I chase these down and try to find them.

I have an MXR Smart Gate that took a dump on me when running on a one spot.  Passes signal in bypass mode, led lites up when on, but no gate.

I'd be interested in trying that combination out, to see if both the 1Spot and the Smart Gate were in good repair. Either could be faulty, or it could be that it's a real incompatibility. In either case, I'd like to find out.

The first question I ask in situations like this is "What brand of 1Spot is that you have?" Very often the answer is "... a G****ke 1Spot" or "one I ordered from this company on the net" or some other brand. The term "1Spot" is the trade name for the 9V power supply sold by Visual Sound. However, they are so popular that people like to refer to any small plug in switching power supply that makes 9Vdc as a "1Spot". We sometimes have to have discussions with ebay sellers who like to say they're selling "1Spots" but aren't. I don't know that the others are not fine, reliable products. But I do know that the 1Spot (tm) that we sell has been extensively and exhaustively tested specifically for use with pedals and that it's the only one I know of where every single unit is tested at the end of the assembly line by plugging it into a whine-prone distortion pedal and listened to for signs of hum, noise and whine. Someone else may do this now, but that's how we've always done it.

So - what brand of "1Spot" is that?

... there definitely seems to be some folks who think these things kill pedals. 

Yes, there definitely are some folks who think these things kill pedals. I've investigated several of these, including some pedal makers who thought 1Spots were killing their pedals. As yet, we have not found any instance where a (1) properly designed pedal (2) that was not otherwise defective would die with (3) a properly operating 1Spot.

We *have* found issues where either 1 or 2 was a problem. We haven't found any instances of a faulty 1Spot killing a pedal; usually they simply quit working, rarely they will make a whine in the sound.

As a bit of history, the "1Spot killed my pedal" issue first arose when some pedal makers got back pedals that were dead. They did the right thing and asked how the pedals were being powered, having found burn marks on the PCBs, shorted parts inside, obvious evidence of too much power being liberated. When the user replied "I use a 1Spot" (of whatever brand...  ) the pedal makers jumped to "hmm... that thing is killing my pedals; I won't warranty any pedal using it", and the "1Spots kill pedals" legend was written into the internet.

When I looked into this, I first tried to make a known-good 1Spot kill a pedal. I couldn't. No amount of reverse connection, shorting, intermittent shorts, whatever, would kill the pedal. I tried putting a reverse protection diode directly across the output, both ways. The diode never even got hot because the 1Spot self limited its current, turning off and trying to restart after a bit. I looked with some very fancy scopes for overshoots and spikes under harsh, intermittent loading conditions. No dangerous ones found.

Finally I got in touch with a person who thought a 1Spot killed his pedal. It turns out that he also had one of the pedals that are powered from 9Vac wall warts on his board. Moreover, the 9Vac wart used exactly the same size and color plug as all Boss PSA compatible power supplies. Plugging 9Vac into any pedal we tried burned out the pedal. Any pedal designed for 9Vdc. We now believe that this was the origin of the "1Spot" kills my pedal legend. Because in spite of searching (like I'm doing now!) for a pedal killing, we haven't found it.

We have also provided 1Spots to the pedal makers who had questions for testing, as well as quietly testing their pedals that we bought, so they could try out the 1Spots. So far, everyone we have worked with has found that the 1Spot does not kill their pedals. I welcome any interaction with someone who has evidence to the contrary. If it is failing, I want to be all over it.

I can't say with any certainty that a 1Spot has never killed a pedal, not least because it's logically impossible to prove a negative. But I can say that I can't think of any way it can, and I'm in a position for that to mean something. And I can't find any case where a pedal was thought to have been killed by a 1Spot where it can be recreated. What I can tell you with certainty that there are literally tens of thousands of pedals being powered by 1Spots as their only power source every day, and getting just fine results. We have a lot of positive evidence.

I'd like to chase this down further with you. We can do this in the forum, or by PM, but please send me the exact make/model of the MXR gate you're having problems with, and I'll try to replicate the issue. It is always possible that as newer pedals start incorporating switching power supplies inside that there will be more incompatibility problems. But it's also possible that there's a simple fix.

Let's talk.

[svstee]

They kill pedals if said pedal has the wrong polarity. 
I doubt it is the 1spot that made your MXR die.

[mrscientificterms]

Great bit of info, RG.  Thanks.  The 1 Spot is, in fact a Visual Sound product.  The pedal is an MXR Smart Gate 135, the  version in the black box.  Actually not a bad unit, not my fav., but quite competent.  To be clear, I understand that pedals die.  I have played for thirty years and currently own about a hundred various pedals ,and enjoy tinkering around with them, so I am not totally new to all of this.  Just seemed odd that it worked fine and then wham-o!   These things happen.  The MXR is SMD, so into the boneyard it will go.  Nothing appears to be blown up, the footswitch tests fine, but I'll probe around on it a bit more and report what I see. 

[Paul Marossy]

Could just be a coincidence. It might have been fixing to die on you anyway, no matter what power supply you used...

[R.G.]

They kill pedals if said pedal has the wrong polarity. 

Well, if the pedal has no reverse polarity protection at all, yes. But the single reverse diode is a complete protection from the 1Spot itself. That was one of the things we tested in great detail. Yeah, a 1Spot can kill a pedal with no reverse polarity protection at all if hooked up backwards. I think a 9V battery would too, but ... hey! Another thing to try out! 

The 1 Spot is, in fact a Visual Sound product.  The pedal is an MXR Smart Gate 135, the  version in the black box.  Actually not a bad unit, not my fav., but quite competent.  To be clear, I understand that pedals die.  I have played for thirty years and currently own about a hundred various pedals ,and enjoy tinkering around with them, so I am not totally new to all of this.  Just seemed odd that it worked fine and then wham-o!   These things happen.  The MXR is SMD, so into the boneyard it will go.  Nothing appears to be blown up, the footswitch tests fine, but I'll probe around on it a bit more and report what I see. 

Let me know what you find. If, in fact, you decide to pitch it, I'd be very interested in obtaining the corpse so I can try to figure out what happened, too.

[Processaurus]

With the 1700mA the 1 spot can provide, it's probably possible it could finish off a pedal with a failing part/partial short faster than a regular 200mA power supply, if the defective pedal was drawing under the 1700mA that would trip the short circuit protection in the power supply.

[liquids]

They kill pedals if said pedal has the wrong polarity.

Well, if the pedal has no reverse polarity protection at all, yes. But the single reverse diode is a complete protection from the 1Spot itself. That was one of the things we tested in great detail. Yeah, a 1Spot can kill a pedal with no reverse polarity protection at all if hooked up backwards. I think a 9V battery would too, but ... hey! Another thing to try out!

I've got 2 VS 1 Spots.  I've had them a few years now, and I got the 2nd one as a backup, though I doubt I need it!   Now I test my pedals and my breadboard rig with one of them rather than 9v.  I use the other one that has seen little to no use for the rest of my pedals / live pedalboard.

As for the dedicated 'breadboard rig' 1 Spot,  I've done quite a few 'bad' things with it, and it keeps on working just fine.  I do wear my goggles whenever there is a threat, keep in in mind.  

But I've fried too many caps (pop!) ICs (backwards, explode, or just plain dead) and pots (spark!) with it to count...not that I'm proud, but it happens, unfortunately, since I'm rather mistake prone.  I also regularly cross ground and 9v rails as I'm tinkering when everything is 'live,' sometimes for quite a while until I can figure out where it's happening....Usually it reaches a point where it 'ticks' on and off as indicated by LEDs until the crossed connections are, well, uncrossed.  And it keeps going like nothing ever happened...I'm beyond impressed.  At this point, if I ever 'kill' it, I will probably bury it like an old friend.        

Just to say, it's a great product not just for users, but 'abusers' like me.  

[R.G.]

With the 1700mA the 1 spot can provide, it's probably possible it could finish off a pedal with a failing part/partial short faster than a regular 200mA power supply, if the defective pedal was drawing under the 1700mA that would trip the short circuit protection in the power supply.

That is true. There is a class of pedal failures where a 1Spot can be detrimental to the pedal faster than a smaller power supply. It happens for exactly the reason you note. However, the same can be said for a battery, as I'll get to below.

If a pedal has an internal failure such that it pulls more than its normal current, but less than the available current in (for example) the 1Spot, and if it would be more profoundly damaged by the difference between a smaller current limit, such as the 100ma of a 78L09 regulator or some other low limit power supply, then the pedal could be finished off by the bigger power supply but not the smaller-limit one. This is much like falling off a cliff. If you start by assuming that you're absolutely going to fall off a cliff, how much you get hurt depends on how tall the cliff is. Cliffs of only a few feet have different consequences than 100 foot cliffs. To extend the analogy, you might, however, want the 100 foot cliff to hang glide from sometimes.

Exactly what happens is heavily dependent on the exact part that's failing, how it's failing, how fast it fails, and how much current is available to do that. If it's a matter of, say, burning out bonding wires on an IC, then you can get pretty low "permanent damage" thresholds for reversing the power supply. Some of the bonding wires, especially in older ICs, are -very- thin gold wire that may melt at 20-100ma depending on how it was bent and bonded into place. Many ICs specify maximum currents per pin at low-ish values. I do know a couple of those by heart and they vary from 20ma per pin up to 200ma/pin for the power pins. If there's not an IC, but a bipolar transistor, the pins are bonded with sterner stuff. Damage is by internal heating. But as I nattered on about in my articles on component aging at GEO, reverse-breaking the base-emitter diode even once permanently damages the noise operation of a bipolar. This kind of consideration goes on for days, and both can and has been the subject of scholarly conventions of us geeky-types, with lovingly taken electron-microscope pictures of cratered junctions, fried silicon, and shattered bonding wires.

One interesting tidbit I came up with is that the internal resistance of a 9V NiMh battery, when new and freshly charged, can be as low as one ohm. That means that the short circuit current is as much as 9A (N.B. for a while, declining over perhaps a minute as it discharges rapidly). Most reversed semiconductors look like a diode junction to the substrate material, so the peak current is lower, perhaps (9-0.7)/1 = 8.3A roughly. But still enough to melt some things inside ICs and small signal transistors. No, not all 9V batteries put out that much, and not all devices are permanently damaged by one reversal - but that's how myths get started.

This kind of analysis is what brought polarity protection to be a permanent part of the effects wrapper (*http://geofex.com/Article_Folders/wrapper/wrapper.htm*), since momentarily connecting a fresh 9V the wrong way can damage things in an unprotected pedal if the planets are aligned (in)correctly.

What we found in the history of the "1Spot kills pedals" legend is that sometimes people saying this were comparing a failing pedal powered by a 1Spot and by a current-limited power supply of some much lower current. In the limited condition where the right situation happened, the smaller power supply would limit before the 1Spot. It's worth noting that a ... battery... could in some situations have had much the same issues as the 1Spot, possibly worse, based on the available current. As always, in forensics (anybody watch "Bones" or "CSI" out there? We're looking at dead electronic bodies...) the exact conditions matter a lot. Invisible grit or fiber on the body, how it fell, whether its power was reverse biased, how big its bonding wires were, these all matter a lot. There's no substitute for actually knowing, in detail, what happened.

[Ben N]

Not to hijack the thread, or anything, but: what kills a 1-Spot?
I've been happily running my PB off mine for a couple of years (including a couple of testimonials around here) with no problems (well, ok, a Line6 Chorus didn't like it, but that box was noisy with any power supply). A month or so ago I had to pack up my pedalboard for a while. When I plugged it back in, no power from the 1-Spot, nada. No external sign of damage, and no intermittence when I wiggle the cord (not that I'd expect that with the nice, heavy lamp cord it comes with). I'm sure it's not under warranty anymore, but I'm reluctant to pry it apart, and even if I did, I don't know that I'd have enough information to troubleshoot it.

[R.G.]

Not to hijack the thread, or anything, but:

Then don't. Please don't multitopic the thread. I'll start this as a new one.

[mrscientificterms]

OK, so I have been super busy of late, but I took a minute and poked around in the dead gate to no avail.  I agree with the mention above that this was likely a tired pedal, I bought it used, it had velcro on the back, etc ....  I use the VS one spots all over the place.  RG-- I can't find the section in your website where you list the pedals that aren't happy with the spot, can you post a link?  thanks.

[R.G.]

RG-- I can't find the section in your website where you list the pedals that aren't happy with the spot, can you post a link?  thanks.

It's not on my personal web page, geofex.com. That's purely personal, predating my working for Visual Sound. I make a real effort to keep what I do personally separated from what I do professionally for work.

The 1Spot compatibility chart is here: http://www.visualsound.net/PDF/1SPOTCompatibilityChart.pdf

I'm told there is an update in the works. We (here I'm speaking as R.G. who works for Visual Sound  ) do update this as we get new info on pedals that come out.

[tysonlt]

Just looking at this out of interest. I had a boss psu that I used with a tc nova repeater and nova dynamics (my beloved compressor). Just plugging those bad boys in would trip the psu over and it would turn off.

I got a 1spot and never looked back, however I notice that TC Electronic is not listed in the compatibility sheet above. Is there any reason for this? I can testify that it works

[DavenPaget]

Just looking at this out of interest. I had a boss psu that I used with a tc nova repeater and nova dynamics (my beloved compressor). Just plugging those bad boys in would trip the psu over and it would turn off.

I got a 1spot and never looked back, however I notice that TC Electronic is not listed in the compatibility sheet above. Is there any reason for this? I can testify that it works

Maybe VS wrote the list before TC E got popular ?

[tysonlt]

Could be. I am a bit of a TC fan I must admit. The move repeater is just perfect for me. (Or would be if it had midi... Hmm....)

[R.G.]

I'm told that the VS web page is due for some sincere maintenance.

[Earthscum]

I had a Zendrive type pedal I made for a friend fail on me with a 1-Spot. From the circumstances he described, it sounded like a combination of unplugging and killing power at the same time. I put a reverse protection diode across the DC jack (don't know why I didn't in the first place), and it's been fine since. It seems like the 1-Spot maybe doesn't absorb a spike like a battery does? I've never used one myself, but from the small glitches my friends have reported (much less than other supplies they used to use), this points towards it being the case. I was considering, at one point, making a power conditioner of some sort (AMZ Filter looks great, but RS doesn't sell that choke anymore... Steve have anything that subs well?) just to put in-line and see if they get any quirkiness afterwards. What do you think? Probably wouldn't know for some time, because they are such, seemingly, random instances.Whenever they have issues, it's almost always on power-up. I believe one of my buddies has to power up everything first, then plug in his last pedal, or it glitches one of his other pedals. He may have just got another 1S for that pedal, though, now that I think about it.

From my friends' reports, though, Praise to the 1-Spot! lol... most of the people I know that use power supplies have swapped over to the 1S, and a couple have gone through several supplies before settling on the 1S. Even the glitchy setups are most stable with the 1S, once they figured out a couple work-arounds (above).

[R.G.]

I had a Zendrive type pedal I made for a friend fail on me with a 1-Spot. From the circumstances he described, it sounded like a combination of unplugging and killing power at the same time. I put a reverse protection diode across the DC jack (don't know why I didn't in the first place), and it's been fine since. It seems like the 1-Spot maybe doesn't absorb a spike like a battery does?

Good insight. The output of a DC power supply - any of them - is a filter cap fed by a diode. The diode won't let any current go back into the power section, so whatever transient absorption happens is entirely the result of the filter caps. I suspect that a power transient was induced by the unplug/kill actions you mention. Later vintage 1Spots have some transient suppression on the output, but a reverse biased zener of about 12-15V outside the 1Spot (or any other power supply, including linear ones  ) is not a bad idea.

I was considering, at one point, making a power conditioner of some sort (AMZ Filter looks great, but RS doesn't sell that choke anymore... Steve have anything that subs well?) just to put in-line and see if they get any quirkiness afterwards. What do you think?

It's hard to tell. Filters are very application-specific. A big inductor/cap filter seems nice to anyone who hasn't messed with power filtering before, but can cause problems. Series inductor/shunt cap is a great lowpass filter, right? Um, what happens if it has too little damping and rings at the frequency where L and C are resonant? The voltage at the junction of the L and C at resonance depends on damping more than anything else, and can be in the hundreds (or in unusual cases, thousands!) of volts. Critical damping makes all this go away and it reacts like you'd think a second-order lowpass should. This high voltage at resonance is one of the bases of the Tesla coil's operation, BTW.

This is one reason I don't put random filter circuits out on geofex. LC filters can get you into trouble as well as out. And if they don't happen to have good attenuation at the frequencies you're trying to filter, they can serve the same purpose as a new coat of paint. That is, they look pretty and make you feel good, but don't really change the functioning much. I had a lesson in this myself, with the 1Spot. One of the manufacturers whose pedals have an internal stepdown switching regulator that did not work and play well with the 1Spot asked us to come up with a plug-on filter to make it all nice and simple. I spent nearly a week with simulation, tinkering, measurement of RF, and just tinkering as well as rising frustration. The result is that I could make a filter that would do it - but it would cost more than dedicating another $20 1Spot to just that pedal.

We sometimes get people thinking that a 1Spot has killed their pedal. I investigate these personally. I have found only one instance where a failure in a 1Spot killed a pedal. That was when one of the two output caps in there shorted. The 1Spot shut down, the short cooled and the 1Spot came back up and ran normally on the one remaining filter cap. However, the shorting had shorted the 9V to 0V, and the internal series regulator in the pedal was not designed to take an input short during operation. A $0.03 diode inside the pedal from regulator output to input like all the regulator app notes show would have made this a non-issue, and there would have been only a momentary glitch. Instead, the output caps on the regulator inside the pedal back-conducted through the pedal's internal regulator and killed the regulator.

I've warned several forums about this issue. Another way this can happen is if you have a daisy chain with unused positions and let the outside barrel of a connector touch a grounded pedal housing or pedalboard metal. This instantly shorts the 9V supply and can kill any regulators with similar design flaws in any connected pedals. This can happen with *any* power supply.

Probably wouldn't know for some time, because they are such, seemingly, random instances.Whenever they have issues, it's almost always on power-up. I believe one of my buddies has to power up everything first, then plug in his last pedal, or it glitches one of his other pedals. He may have just got another 1S for that pedal, though, now that I think about it.

Sounds reasonable. If a pedal has some kind of funny internal power setup, including possibly a *big* internal filter cap, it could cause big current draw during power up and set off the very fast current limit in the 1Spot.

From my friends' reports, though, Praise to the 1-Spot! lol... most of the people I know that use power supplies have swapped over to the 1S, and a couple have gone through several supplies before settling on the 1S. Even the glitchy setups are most stable with the 1S, once they figured out a couple work-arounds (above).

I appreciate the feedback. I do investigate 1Spot issues personally, so I do appreciate hearing any odd situations that come up. If you capture one in the wild, let me know.