I bought a LP from ebay just before xmas and there’s a bit of an issue with it. Since owning it I’ve updated the OS to the latest version but a problem has occurred that the LP controls itself. For example I can leave the LP with the preset button emitting yellow (meaning preset hasn’t been altered) and not touch it, but after a while it will go red and a values of one of the knobs will change on its own accord. For example say if a preset has the pitch of osc2 set to 0, it will change itself in accordance to the knobs’ position, resulting that the pitch could suddenly change a couple of semi-tones. This happens to all the knobs and I’ve re-installed the OS. This problem happened once before but then sorted itself out, however its gone back to acting randomly.
I’ve read that it could be a grounding issue, however I live in the UK where the plug sockets are earthed and I’ve changed the power lead but still no luck. For some reason the LP doesn’t do this strange behaviour if the knobs are all set to 0? Has anyone else had this issue and managed to fix it?
I have had this issue. Seems to only happen to me while the LP is warming up. After being on for a half an hour, I don’t recall it happening. I also purchased a used LP stage 1, 2 weeks ago. The 1st time I was like what the hell is going on. I’m not sure what the issue is.
I also had an issue not being able to change what variable any of the 4 knobs is changing. Ex. In the Osc section, osc 2 freq is selected, I want to alter osc 2 waveform press the button and nothing. This only happened with the ARP latched. I cancelled out the arp and all returned to normal. I’m not at a performace level yet, but it would have caused major issues had I been playing live.
strange. this problem happened before and I overcame it by leaving the LP on for a few hours with all the knobs set to zero (fully to the left/ 7 o’clock). For some reason the problem doesn’t happen if all the knobs are set to zero, however as soon as I positioned the knobs the problem will reoccur again???
Is this part of the beauty of analogue or just a fault with the synths’ power unit?
Sounds like a power issue to me. When I switched out the LED’s in the LHC, a couple of the leads were touching, and it threw the whole thing for a loop. Maybe Amos could help you figure out what’s going on? I got hollered at the last time I told someone to open their synth…and rightfully so.
my LP is a stage edition (first edition with silver back). This might sounds a little dumb but who is Amos? as i’ll be needing help to resolve this issue. I have seen that you can buy a replacement power unit for LP, and have been told that you can mod the first stage edition of the LP with the power unit of the stage II edition resulting in having USB support!
i got a reply from moog support via email and i was told to open up the front panel and ensure that the cables are in place. Sadly that hasn’t appeared to help as the problem still persists!
Amos Gaynes is the man at Moog who usually posts on these forums, but has been rather busy lately working on the various projects that keep Moog Music profitable. As far as I can tell, he’s the number one LP resource at Moog Music. He’s responsible for doing the custom light job on my Stage I.
I hope you figure out the problem. I’ve never encountered such an issue myself, but my instinct tells me it could be a bad power cord. Simple, I know, but try that. Then e-mail Amos at moogmusic.com.
cheers voltor07, one of the firsts things i tried was change the power cable and the plug socket the LP was connected to. I’ve even plugged it into another room to see whether the it could be faulty power plug sockets, but no luck.
I’ll ask this Amos guy has he did help build the machine!
Have you had a response regarding the problem yet?
my Little Phatty just started to have the same problem that people have been complaining about here - and it’s incredibly irritating!
no matter what I attempt to do, the Oscillator section’s knob setting changes itself for each parameter accordingly
so as you said, if I was to alter the Oscillator level to 12 o’clock and then press the waveform button it will move itself to that respective position too, regardless of the preset
I don’t think it is a problem with the OS as some people have suggested because I have had OS 2 installed on my LP since last summer and this problem has never occurred
Hi; Amos here… I’m back from NAMM, mostly, although I still have dozens of emails to catch up with. I’m sorry to hear about these problems and I’ll certainly do my best to help. In general, it seems safe to say that a Little Phatty with no earth connection problems will not have wandering parameter values, and a phatty with some sort of earth connection problems can indeed have wandering parameter values. The origin of the problem could be the mains power, could be the mains power lead to the synth, or it could be a problematic connection within the synth itself. I will discuss this with the rest of our engineering team and come up with some suggestions. Anyone who is having this sort of trouble is welcome to email me at (my name) at moogmusic dot com for more direct assistance.
any more news on the subject.
i’m in the UK too, had this exact problem a few years ago. i love the sound but couldn’t deal with it and Turnkey at the time just exchanged it instead of finding a solution. so i exchanged 3 different MLP before giving up.
i then wrote to Amon who wrote a lenghly email of things that could have been the cause, earthed power issues, cables etc etc… i bought another MLP, moved to a different studio, and still the problem persists.
any ideas?
Ddr
i own a LP se I (silver back) updated to OSII
i have the same issue using some of audio cables (dunno exactly which type). When i plug it (for example) into an audio interface the issue appear. if i replace the jack with another cable, it disappear.
kabubi, it sounds like a case of bad cable. If there’s a short in one of the cables, you’ll have a grounding issue. I’d throw away the offending cable or label it “not for use with LP”.
just an update to say, still working on this… I’ve been talking this week with head engineer Cyril Lance. We have a few speculations but no solid theory yet.
Is anyone in the USA having this problem? Or only outside the US?
Anyone with this LP problem, please let me know the Volts/Hz of your country’s power grid. Let’s see if there are any common factors there.
It’s definitely the case that poor/no ground on the power cable can cause this.
It’s definitely the case that stray voltage on the audio cable can cause this - “stray voltage” can be due to a short/bad ground on the audio cable, OR due to a power problem with your mixer or powered speaker that puts AC or floating ground on the audio cable.
however, in a case where you know beyond a shadow of doubt that the connection to ground is perfect on the AC power side, and you have no other cables plugged into the Phatty, and you still get this same problem… then there may be an unknown factor at work. That is what we are trying to determine now.
please read this message carefully and try to rule out all of the above, and then report back and let me know. Thanks!
Maybe Amos could help you figure out what’s going on? I got hollered at the last time I told someone to open their synth…and rightfully so. 
I forgot. 