Sub 37 Filter Cutoff: First Batch vs. Revised Batch

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Blackout
Posts: 238
Joined: Mon Aug 26, 2013 9:19 am

Re: Sub 37 Filter Cutoff: First Batch vs. Revised Batch

Post by Blackout » Sun Jul 26, 2015 6:45 pm

hi all , i have a reply from Markus....

"Hi.... My Sub37 serial number is 0581X ( "X" being my last omitted number) the manufacture date was 06/15. I did not know about this problem with the earlier Sub37s. I thought it was a bit strange having that great big Pot there but now I can see why they have revised it as it is the pot that would get most abuse over time. I hope you guys can get yours sorted out. Best wishes from Markus."

so we have narrowed it down now. the change happened somewhere between 5400 and 5810 in only the last month or so. And we can confirm that Markus did not make the change himself, it was done in the factory.

GregVDS
Posts: 157
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Re: Sub 37 Filter Cutoff: First Batch vs. Revised Batch

Post by GregVDS » Mon Jul 27, 2015 8:46 am

That's a valuable info we have here.

What Moog should offer is an unlimited warranty time for that particular problem.

To change all the earlier pcbs by the new one with the heavy duty pot is a bit hard on them surely (to track down every machine, and offer change for everyone). But maybe to offer free of charge pcb exchange when the problem arises in the future, even if out of 1 year in the States/3 years in Europe would be great, as expected from the already great client support Moog offers. Now that's their decision to offer this or not. I hope it will be the case, so, the day my filter knob begin to fail, I know I can ask for the new pcb to my shop, and replace it myself (it should be quite simple to pull off all the knobs, open the box, unwire the several ribbons, unscrew the pots shafts, replace pcb and rebuild. Maybe after that a recalibration procedure is needed, but shouldn't be too difficult to run it ourselves.

Now, a public acknowledgement from Moog of the filter knob problem would be great.

All the best,

Greg

Mickleman
Posts: 9
Joined: Fri Jan 10, 2014 6:27 am

Re: Sub 37 Filter Cutoff: First Batch vs. Revised Batch

Post by Mickleman » Mon Jul 27, 2015 10:24 am

Hi All,

I have sent the following email to Moog:

"I own a Moog Sub37 serial number SBT01203 and my warranty is due to expire in September 2015, so far the synth is working brilliantly and nothing has gone wrong to date. However, I am concerned about the discussion on the Moog Phatty forum re the Sub 37's Filter Pot failing and we have noticed that Sub 37's built from either May or June 2015 now have a larger pot fitted. My concern is that once out of warranty if the pot on our Sub 37's fails we will be liable to pay for a replacement even though it is a known fault. Can you please confirm if there is a plan in place to offer free of charge a PCB exchange when the problem arises in the future? I think most users will be happy to install themselves. As it stands this is a major issue waiting to happen." I have know idea what if any the response will be but will inform this forum as and when one arrives.
Sub 37 Tribute, Slim Phatty, MF104M, MF108M, MF103, Moog EP3 Pedal, Doepfer A-100 System 2, Doepfer Dark Time, Korg R3, Korg SQ-1, Roland Gaia SH01, Roland Juno Di, Roland SE-02, Roland Sonar V Studio 100, MFB Tanzbar, Alesis Nanoverb 2, Strymon Big Sky.

XAXAU
Posts: 92
Joined: Sat Oct 12, 2013 4:33 pm
Location: Sweden

Re: Sub 37 Filter Cutoff: First Batch vs. Revised Batch

Post by XAXAU » Mon Jul 27, 2015 7:49 pm

Scary! Mine´s in the 9XX! Thinking of dumping it while the dollar is strong.

Sardino
Posts: 5
Joined: Thu Jul 23, 2015 9:23 am

Re: Sub 37 Filter Cutoff: First Batch vs. Revised Batch

Post by Sardino » Mon Jul 27, 2015 7:59 pm

Sorry for my ignorance but... How can I find out which pot I have?
My sub's serial is x751x,date of manufacture 06/15

Blackout
Posts: 238
Joined: Mon Aug 26, 2013 9:19 am

Re: Sub 37 Filter Cutoff: First Batch vs. Revised Batch

Post by Blackout » Tue Jul 28, 2015 6:54 am

hi Sardino, this is a good question.

here is a pic of my Sub37 (SN...low 400)...filter knob, with the knob removed:

Moog Knob pic.JPG


as you can see, the shaft is black plastic. all the shafts are black plastic.

i have a sneaking suspicion that the new "fixed" pot will have a metal shaft, as most traditional chassis-mounted pots have this. It makes them stronger.

if i am right, then it will be as simple as a user just having to pull of their filter knob to see if they have a plastic shaft underneath (faulty Sub37) or metal shaft (revised/fixed Sub37).

i will ask Markus to check on this. lets see what he says. if anyone else can shed a light on this also it would be appreciated, it may save a lot of people voiding their warranty by opening up their Sub37's just to check!

Cheers,
Blackout

Sardino
Posts: 5
Joined: Thu Jul 23, 2015 9:23 am

Re: Sub 37 Filter Cutoff: First Batch vs. Revised Batch

Post by Sardino » Tue Jul 28, 2015 8:41 am

Thanks, I would have a look into this when I get home

Dapifer
Posts: 117
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Location: Northern Ireland/Leeds, U.K

Re: Sub 37 Filter Cutoff: First Batch vs. Revised Batch

Post by Dapifer » Tue Jul 28, 2015 10:43 am

I had the filter issue repaired and then failed again. It was in April there that I emailed Amos or Andy with the problem again and they told me that they had found a permanent solution which was to replace that entire circuit panel. I have received it back now and it is much more sturdy feeling. They were great with their customer support so I'd suggest if you feel this problem is starting to happen again then contact them and they will get the problem sorted. I had mine sent off and returned within a week with the new panel replaced so most distributers probably have the new panels waiting as spare parts for replacements.

MooMoo
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Joined: Fri Jul 24, 2015 5:13 pm

Re: Sub 37 Filter Cutoff: First Batch vs. Revised Batch

Post by MooMoo » Tue Jul 28, 2015 2:55 pm

Blackout wrote:here is a pic of my Sub37 (SN...low 400)...filter knob, with the knob removed:

That's useful, and something I hadn't thought of. D'oh.
Your filter pot looks (to me at least) identical to the attack pot. Hopefully someone with a very recent sub37 can post a similar photo showing how theirs looks.

It also shows that the mounting of the filter pot isn't "unusual" in any way which could contribute to the problem. I'm guessing, without any evidence to the contrary (my earlier post was ignored, it seems), that the old filter pot is the same as the rest of the pots on the board. This, I think, only really leaves two possibilities.
So, either the larger filter knob is the cause of the problem (causing stresses on the pot which the smaller knobs don't), or it's because the filter knob is adjusted more than the others. This seems to suggest the latter. That some people have had problems after only very little use suggests it's not just the amount of use that knob gets that makes it fail, so perhaps it's a combination of both factors. If it really is just down to that knob getting used more, then it means the other knobs/pots presumably would suffer the same problems sooner or later, and I don't think I've seen anyone report problems with other knobs (pot-related ones anyway). With the amount of use some units must have had by now, I guess the other pots are fine, and it really is down to the large knob.

Blackout
Posts: 238
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Re: Sub 37 Filter Cutoff: First Batch vs. Revised Batch

Post by Blackout » Tue Jul 28, 2015 6:47 pm

hi all, Markus has confirmed that his pot has a METAL shaft.

sub37metalpot.jpg


so the result of this is ...it will be easy to tell if you have a "faulty" Sub37 or a "revised/fixed" version. You simply lift the filter knob up and off. and look to see if the shaft below is a black plastic one or a metal shaft.

if it is a metal shaft, you have one of the "revised/fixed" Sub 37s.
Last edited by Blackout on Wed Jul 29, 2015 6:02 am, edited 1 time in total.

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MRNUTTY
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Re: Sub 37 Filter Cutoff: First Batch vs. Revised Batch

Post by MRNUTTY » Tue Jul 28, 2015 10:34 pm

The SMT pot itself really isn't faulty - any of those front panel pots are more prone to failure than a full metal, panel mounted pot. It's merely the large knob (that blackout I believe pointed out), and the propensity for heightened frenzied twisty attention the filter cutoff control itself attracts. Just be careful with your knob's they're all prone to failure with too much unrestrained twisting. The large knob merely accelerated the failure there before any other knob.

Would be intersting to see what the Sub Phatty filter pot implementation was. I didn't look into it before I sold mine. If it was a similar SMT type as well, then I would concede existance of a new fault mode. Although much may depend on PBC mounting pads, and solder composition and deposition.
VoyagerEB, Minitaur, LittlePhattyII, 4xSlimPhatty, Sub37, MF[2x101,2x102,103,104M,105,105B,105M,2x107,108M], 3xCP251, XV351, MP201;
Virus C; SuperNova; Micro-Q, MicrowaveXT; Kronos; Eventide H3000, GTR4000, H8000FW, 5xH9; 2xLexicon300L; 2xKSP8, K2500; EX5

Blackout
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Re: Sub 37 Filter Cutoff: First Batch vs. Revised Batch

Post by Blackout » Wed Jul 29, 2015 6:14 am

MRNUTTY you may be right, but the bottom line is that the filter pots are failing. and in the future the Sub37's that have low serial numbers with the "faulty" pot will be worth less on resale. Thats the reality and bottom line. They will be the serial numbers to "avoid" and this is a real disappointment and shame. Aside from the fact that the filter pot is destined to fail , its not a matter of "if but "when". And depending on how much treatment you give the filter knob will depend on whether this problem falls before the warranty expires and its Moogs problem, or if it ends up being OUR problem. And that date for many is already closing in.

I personally dont want to be stuck with a lemon. The time to take action is now...

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MRNUTTY
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Re: Sub 37 Filter Cutoff: First Batch vs. Revised Batch

Post by MRNUTTY » Wed Jul 29, 2015 7:44 am

@blackout, yeah I agree. But this is the public record, and we need to keep our analysis straight for the next guy/gal that tries to figure out what he/she bought, or might buy. Until Moog tells us what the problem is, or an especially authoritative root cause is done, we shouldn't be calling the device itself faulty. My experience says it's just the wrong part for the job. It should have been a panel mount pot when a large knob is combined with an especially enthusiastic control like Filter CF - but that's just the kind of rhetoric we need to avoid for now :-)
VoyagerEB, Minitaur, LittlePhattyII, 4xSlimPhatty, Sub37, MF[2x101,2x102,103,104M,105,105B,105M,2x107,108M], 3xCP251, XV351, MP201;
Virus C; SuperNova; Micro-Q, MicrowaveXT; Kronos; Eventide H3000, GTR4000, H8000FW, 5xH9; 2xLexicon300L; 2xKSP8, K2500; EX5

Blackout
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Re: Sub 37 Filter Cutoff: First Batch vs. Revised Batch

Post by Blackout » Wed Jul 29, 2015 8:49 am

MRNUTTY wrote:It should have been a panel mount pot when a large knob is combined with an especially enthusiastic control like Filter CF -


hi MRNUTTY...i agree 100%. this is the design/maunfacture problem. its the combination of both the most used knob on the panel, and the extra large knob that puts sideways pressure on the pot, plus i believe sub-standard pots. the other pots (that are used less and have a small knob) will fail earlier than normal, but probably in 10 years, not 10 months.

a good question that someone has already asked is why this problem has not happened to the Sub Phattys. i have a Sub Phatty myself and it has the same big knob for the filter. Maybe they changed pot suppliers and the Sub Phatty pots just had more resilience? or maybe they were metal shaft pots from the start.i should pull mine apart and take a look now that the warranty is expired on it. might give some answers.

Toom
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Re: Sub 37 Filter Cutoff: First Batch vs. Revised Batch

Post by Toom » Wed Jul 29, 2015 9:26 pm

The pot that was used to replace the old faulty pot is now starting to exhibit the same issue as the original, cutting out at different frequency intervals. I've contacted Moog for help. I really hope to be able to resolve this problem once and for all.

I'd be interested to find out if the Sub Phatty has a heavy duty pot or similar to the Sub 37.

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