Deric wrote:I've wondered about static with the Max1044. I use a 1 Spot to power around 10 pedals including a PT-80 with a charge pump. I've measure the output of the 1 Spot with a supply voltage of 115VAC - 120VAC and between zero and 10 pedals and always get 9.4VDC. I have also measured the output while connecting and disconnecting other pedals from the chain to see if the voltage spiked. It never does.
That's been my experience. I've tried to set up circumstances for spikes, with sudden on/off cycles, under load, under no load, light load, full load, etc. I've cycled loading on and off instantly with a pulse generator driving a power MOSFET to switch the load on and off; got that to switch in under 100nS which should have driven any inductive or pseudo-inductive dumps crazy, and I've frequency-swept pulse loads on it from DC to well over 250kHz, and nothing shows up acting odd. There's no oveshoot, undershoot, oscillatory behaviour, or - worst! - "turn and run" inductive behaviour that I can find.
This was an outgrowth of the few boutiquers who thought the 1Spot was their frying problem; I characterized as well as I could. There are many high-dollar audio amplifiers that will go south on you with the frequency-swept switched loading. I got that from some stuff I read by Martin Collums; it seems to pretty ruthlessly expose oddities in amplifiers, which is what all power supplies are - just very dull ones.

Deric wrote:I have somehow fried 3 Max1044 chips in my PT-80. The last one popped when I added another pedal to the chain with everything powered up. I've since changed to a 7660S and so far, so good. I haven't noticed any difference in tone but since I have a few 1044's left I'll swap it out and listen when I get a chance.
I'd appreciate hearing about anything you find. I do know that the normal inverting configuration for the 1044 leaves pin 6 and 7 open, and possibly prone to static problems.
Deric wrote:Does the VV 10th Anniversary pedal have any other "protection" for the Max1044?
It has some careful considerations of the incoming RC time constants on the +9V line, and one subtle layout trick that I came up with that I think protects it in some very esoteric cases. No magic circuits, no.
Deric wrote:FWIW, I have sold the 1 Sopt at retail for several years and have never heard of one frying a pedal. We did see a very high failure rate with the 1 Spot itself when we first started selling them but they have been extremely reliable for the last few years.
That corresponds to the first vendor who supplied us 1Spots, I think. It was before my time, but I do know that there was one early manufacturer who had poor consistency. VS changed to a much more capable manufacturer a bit before I started.
WormBoy wrote:But if its static that's killing the chip, than the 15V or so that the 7660 can stand is still not very much.
No, it's not. However, it may be related to the open pin 6 and 7 I mentioned. The app note says to leave them open, even, and that makes me crazy from long experience with CMOS.
WormBoy wrote:I would suspect that the 1Spot is sometimes producing a little over 9.5V temporarily, and since that voltage is already close to the max of the MAX ... Has anyone fried a MAX with another power supply than the 1Spot?
I suspected that to - and that's part of why I did the elaborate testing. It may be there, given that there are many thousands of them in the field, but I can't find it by beating on a number of 1Spots trying to make it happen.
To answer your question, yes; I've fried a MAX1044 with a power supply other than a 1Spot. You see, the 1Spot is not the only switching power adapter I subjected to the tender mercies of my test bed. There is another widely advertised switching 9V power supply for effects, and two other 9V supplies that have been suggested at places I found on line for powering effects. So I ordered "victims" and beat on them all separately but equally. I can't say much about the others except that from what I saw, I would not run my pedals on them.
WormBoy wrote:So far, my Boss PSA has not given me problems, but I have only played my MAX-pedals at home, and not under more "extreme" conditions.
The Boss PSA is a standard low frequency transformer->rectifier->filter->linear regulator. It's almost impossible for it to give you problems **unless** the linear regulator shorts. When that happens, the output voltage will go to the internal voltage of about 12.5V, and your MAX will die, unless the short is to ground, in which case the internal fuse will (probably) open. Not the same animal.