Moog Music Forum

Toom the "once and for all" fix for all the early faulty Sub37's with a manufacture date before 06/15 is to demand that Moog install the same metal shaft pot as the "revised/fixed" Sub37's they are now making in the factory as per Markus' video.

Sorry I didn't reply earlier...So I just had a look at the shaft and mine is metal too like markus's.Serial 0751x date of manufacture 06/15

thanks Sardino. That is consistent. you are one lucky guy! congratulations.

I think most people could get over the 'wobbliness' of the original pot, but to have a faulty pot that doesn't work as it should is definitely an issue. I'm not sure what will come of this, but at the moment I'm more than willing to work with Moog to find a fair solution. They're not Apple, they can't just recall all these synths to replace the board. But at the same, they can't just not comment on this issue. The cutoff filter pot is the most iconic parameter on an analog synth, surely this can be resolved.

@toom, I agree. However, this report is relatively new. Got to give them time to figure out a proper response. That takes time to 'crunch the numbers' so to speak.

@MRNUTTY, Definitely.

just to update everyone, Markus has told me that he is going to explore the metal pot further and make a new video. he is going to show how it is attached, and how it is wired up, whether it is a hole that can be drilled or a new PCB, etc. should be very interesting to see the results of his investigation.

Looking forward to seeing his findings.

I've attached a photo of the top of my board (sorry, didn't take a photo of the back at the time, I will try to get one of those this weekend). I'm willing to bet that the old boards can be retrofit with a heavy duty pot, and that there shouldn't be any problem drilling them. Mind you, I don't think many people will be comfortable doing this (myself, included).

As you can see from the top view, all the circuitry avoids the pot. My guess is the same is happening in the back (similar to Markus' board).

WRT to drilling: as mentioned before, if the PCB is an multilayer board, and it's virutally guaranteed to have at least a ground layer. Moreover, multilayered cards are always built with an even number of layers, and a ground layer with a power plane (same as a layer) is the most likely setup, with 2 or 4 layers for signals. All that being given, it IS possible to drill a multilayer card successfully. Assuming you aren't drilling through a signal, you can sand down, and remove any spurs in the ground and power planes to remove shorts. Unfortunately, you can't really 'test' for residual shorts since the impedance between power and ground is often too low to discriminate 'normal' from a short without a 'smoke test'. So, while I've actually done stuff like this before*; I DON'T recommend it. The resulting clearances violate all sorts of design rules in PCB design, testing is iffy, skill needed is very high, and needless to say you'll violate your warrantee, and probably ruin it. With enough public outcry Moog will respond responsibly, we just need to have some patience - it'll work itself out.

*- in one instance I used a bandsaw to cut off a section of a memory array from a Prime computer memory board to use in a Radio Shack Color Computer III memory expansion.

I've contacted Moog Tech support and have asked them to reply to this forum topic. Hopefully someone will respond.

Hello Everyone. I took the Sub 37 apart and made another 5 minute video showing a little more detail on the metal Pot in the revised edition. I have seen the image from TOOM and can say that there has been a revision on the circuit board to accomodate the newer metal pots. the Holes for the metal pot contact pitch are spaced further apart than that of TOOMs surface mount Pot. It also looks as though 6 tracks on the rear of the board may have been moved around to make space for the pot though I cannot confirm this without seeing the reverse side of TOOMs board. It may be possible to drill the board to replace the Pot but there is the possibility that it is a multi-layered board and without knowing for sure I would not recommend it unless we gain this knowledge first. I have done this type of surgery in the past but there was a ground and power plane running through the middle of the board, I had to countersink the hole and paint it so it did not make contact with the metal thread of the pot. If Moog could let us know what was in this area of the board or let us know if it could be done without breaking tracks within the board then at least we could be more comfortable in the knowledge that older Sub 37s can be repaired in the distant future after warranties have run out.

We would like to address the concerns regarding the Sub 37 filter cutoff control:

All Moog instruments are rigorously tested and designed to last a lifetime. Less than 0.9% of all Sub 37s have experienced a problem with the filter cutoff control. Although rare, when the the failure does occur it happens almost immediately due to a faulty wiper in the filter cutoff pot. These few occurrences are not an indicator of an impending issue. If the filter cutoff on your Sub 37 works properly, it will serve you well for years to come. The original Sub 37 filter cutoff control has been used on multiple Moog instruments over the course of the last decade, and it has proven to be extremely reliable in all applications.

It is our objective to continuously improve the designs of our instruments and our goal is always a 0% failure rate. Therefore, we have taken the extended measure of implementing a design change to further reduce the likelihood of failures in the future.

We have repaired all effected units that have been brought to our attention. Should you experience an issue with the cutoff knob on your Sub 37, please contact our support department and we will handle it immediately.

Please only contact our support department if you are experiencing an issue.

Markus Fuller just posted a video showing and explaining the new metal pot being used: https://www.youtube.com/watch?v=RwNVLUN92_E

Thank you Moog for responding.

Moog Music wrote:Less than 0.9% of all Sub 37s have experienced a problem with the filter cutoff control.

i dispute this figure, but regardless this is "so far".. have been returned with this problem...in less than 12 months of the synth being on the market. How many more have the problem but are just "living with it" for the time being. It is certainly the canary in the coal mine however, as you have correctly forseen...

Moog Music wrote: It is our objective to continuously improve the designs of our instruments and our goal is always a 0% failure rate. Therefore, we have taken the extended measure of implementing a design change to further reduce the likelihood of failures in the future.

you have seen this is a potential disaster in the future and to avoid it you have (rightly) changed the design to fix this issue, so there are no more faulty units being made in the future. Which is a good thing. You have to admit your mistakes at some stage along the line. But what we want is our original / potentially faulty units brought up to spec please...

Moog Music wrote: We have repaired all effected units that have been brought to our attention.

how have you repaired them exactly? by kicking the can along the road (hopefully past the end of the warranty?) and putting in another SMD pot (as many on this forum have reported?) or using the new revised PCB board and metal pot?

Moog Music wrote: Please only contact our support department if you are experiencing an issue.

We will ALL be experiencing an "issue" with our resale Moog if we dont contact you now. because now our faulty batch units are already serial number "blacklisted" until this issue is fixed....and we can contact you for how long....only until our warranty expires? for some this is only a few months. Can you promise Moog that this problem will be "fixed" with the metal pot for free regardless of the Sub37 age in the future? This i think is what we all want if you are not prepared to fix the faulty synths now...

Thanks
Blackout

Blackout wrote:Thank you Moog for responding.

Moog Music wrote:Less than 0.9% of all Sub 37s have experienced a problem with the filter cutoff control.

i dispute this figure, but regardless this is "so far"..over 600 synths!! have been returned with this problem...in less than 12 months of the synth being on the market. How many more have the problem but are just "living with it" for the time being. It is certainly the canary in the coal mine however, as you have correctly forseen...

Moog Music wrote:
Can you explain your math?
Even if we round up to 1%, and 6000 synths, that would be 60 synths, not 600. Is my math wrong?
I have a Sub37 in the 2000 range, so this involves me.