Just Friends: 1 - Metropolis: 0, a word of WARNING

Cwejman, Livewire, TipTop Audio, Doepfer etc... Get your euro on!

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autopoiesis
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Post by autopoiesis » Sat Oct 29, 2016 7:20 pm

wsy wrote:
yghartsyrt wrote:
Leverkusen wrote:
Isn't Maths doing it too? being reminded at this frightens me a bit...
Maths also puts out a pulse wave on the trigger input. Has never been a problem for me though.

If I remember correctly a lot of function generators do this.
Not quite the "trigger" input - it's on the "integrate in" input, and only when you have "CYCLE" turned on.
Hasn't caused a problem yet, but yeah, it kinda gives one pause and a bit of concern.

It's fairly potent- around 10 volts, and seems to have quite a bit of current sourcing (i.e. it's not just through a 100K resistor,
knocking down the current to a 0.01 mA or so. It's more than enough to override what a Rene can put out on it's clock outputs.

Good to know.... and good justification to design modules so that inputs AND OUTPUTS can sustain continuous
short to ground, V++, and V--. There were some unbelievers here, IIRC....

- Bill
Maths and Function both also send a 10V pulse out of the "signal in" or "integrate in" jack when you trigger a transient shape via their Trigger inputs. It's not just during Cycle mode.

I know because I like to mult gates to both inputs (one of which attenuated) in order to derive ARSR shapes, and I avoid doing this with Function out of concern for my gate source. I confirmed this behavior and it drove me to impulsively sell the Function out of indignance, only to buy one back because I missed its other capabilities.

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L.C.O.
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Post by L.C.O. » Sat Oct 29, 2016 7:59 pm

Moderately worried about my Just Friends after reading all this.
Will hold further concern until we hear from Gil et al.

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MATSmile
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Post by MATSmile » Sat Oct 29, 2016 10:19 pm

Ugh.... yeah. I'm glad I passed on this one :sadbanana: Sorry to hear about Metropolis man.

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onthelees
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Post by onthelees » Sat Oct 29, 2016 11:34 pm

aroom wrote:I'll just quote Pichenettes from this thread :

viewtopic.php?t=170592
pichenettes wrote:I think the designer(s) of the JF wanted to normalize the "Run" input to -12V so that it was set to a known, easily detectable voltage when nothing is patched in the jack (detecting unpatched jacks is tricky indeed).

The issue of doing it by connecting the "switch" of the jack straight to -12V is that there is a temporary short to -12V during the insertion of the jack, which can cause the module on the other end to send an excess of current, and exceed the current drive capability of an op-amp or GPIO. A more sensible choice would have been to insert a small resistor (2 or 3k is low enough) between the -12V rail and the "switch", so that, in the event of a short during insertion, only (12 - -12) / 2k = 10mV of current is at most sourced or sinked on either sides. In normal operation, this would cause only a small voltage drop (100/102 x -12 = -11.7V).

I made a similar mistake early in the genesis of Tides, though I found it before the module went in production.

Meanwhile, the problem can be avoided by first patching the jack on the JF side, and only then patching the other side.
OK, so I think this is how my QCD and Grids got fried, since they were both patched into the Run input of my Just Friends but I didn't make the connection until now. First, I am grateful that both Mutable and 4ms were willing to repair my modules at no cost. But, beyond that, I want to hear from Whimsical on this. Based on Oliver's note, a mod should possible to revent any large amount of current from flowing backwards at the cost of only a modest voltage drop. If Whimsical is calibrating or depending on the -12V, then a software change should be able to adjust for any new offset. I am hoping they will step up to the plate and do the right thing,and not pretend it's not an issue.

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Post by jimmie » Sun Oct 30, 2016 12:58 am

Is Maths at the same risk?

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yghartsyrt
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Post by yghartsyrt » Sun Oct 30, 2016 3:53 am

wsy wrote:
yghartsyrt wrote:
Leverkusen wrote:
Isn't Maths doing it too? being reminded at this frightens me a bit...
Maths also puts out a pulse wave on the trigger input. Has never been a problem for me though.

If I remember correctly a lot of function generators do this.
Not quite the "trigger" input - it's on the "integrate in" input, and only when you have "CYCLE" turned on.
Hasn't caused a problem yet, but yeah, it kinda gives one pause and a bit of concern.

It's fairly potent- around 10 volts, and seems to have quite a bit of current sourcing (i.e. it's not just through a 100K resistor,
knocking down the current to a 0.01 mA or so. It's more than enough to override what a Rene can put out on it's clock outputs.

Good to know.... and good justification to design modules so that inputs AND OUTPUTS can sustain continuous
short to ground, V++, and V--. There were some unbelievers here, IIRC....

- Bill
You are right. I assumed the just friends was set up like a lot of functions generators. But as folks pointed out, it seems that the Run In might be normalled to the -12v rail. THAT is something entirely different.

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Leverkusen
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Post by Leverkusen » Sun Oct 30, 2016 5:04 am

At least the upgrade instructions for the new firmware suggest that it's a known issue and whimsical cares about it:

http://www.whimsicalraps.com/pages/just-type

(...)
* FIRST: Insert a (long) mono patch cable into the RUN jack
* THEN: Connect this cable to your soundsource
* Turn on your synth case
(...)
IMPORTANT! TURN OFF YOUR SYNTH! REMOVE THE CABLE FROM YOUR SOUNDSOURCE, THEN FROM THE RUN JACK, AND RESTART. THIS IS TO MAKE SURE JF WON'T DAMAGE YOUR SOUNDSOURCE

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pitri
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Post by pitri » Sun Oct 30, 2016 5:21 am

Leverkusen wrote:At least the upgrade instructions for the new firmware suggest that it's a known issue and whimsical cares about it:

http://www.whimsicalraps.com/pages/just-type

(...)
* FIRST: Insert a (long) mono patch cable into the RUN jack
* THEN: Connect this cable to your soundsource
* Turn on your synth case
(...)
IMPORTANT! TURN OFF YOUR SYNTH! REMOVE THE CABLE FROM YOUR SOUNDSOURCE, THEN FROM THE RUN JACK, AND RESTART. THIS IS TO MAKE SURE JF WON'T DAMAGE YOUR SOUNDSOURCE
sorry but that sounds rather rediculous :despair: ... is that a design flaw or the only possible way?

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wsy
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Post by wsy » Sun Oct 30, 2016 7:04 am

More bad news: I pulled my Maths out of the rack to see if there was an easy "cut this trace and stick a
100K resistor in there" and there isn't. Either the board is multilayer (possible but unlikely) or the trace routes
under the jacks where I can't follow them.

The fix (if possible) will be much more complicated than I had hoped.

Boy, am I glad I design all my modules with a 100K input protection resistor ahead of the diodes and a 1K output
protection resistor between the jack and the output TL072 (and 100K protection on the feedback path).

How about it, MakeNoise? Got a fix? Blowing up other people's modules when they jack outputs to inputs is uncool.

- Bill
"Life is short. But we can always buy longer patch cords" - Savage

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lasesentaysiete
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Post by lasesentaysiete » Sun Oct 30, 2016 7:27 am

pardon my ignorance, especially since I don't own one (but am thinking about it), but could this be a problem with a buchla 281 clone as well? Specifically, the toppobrillo?

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Post by jimmie » Sun Oct 30, 2016 7:37 am

Maths is such a famous module and a looot of people have one and it's been quite a while. We should have heard the "problem" by now or what?

(Sorry I'm talking about Maths but Just Friends but looks like we're talking the same "issue" so...)

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Krater
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Post by Krater » Sun Oct 30, 2016 8:00 am

seriously, I´ve never heard of Maths frying another module with its inputs, whereas the JF obviously did. There must be a difference.

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Nofrenchtests
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Post by Nofrenchtests » Sun Oct 30, 2016 8:02 am

There are plenty of other threads about the Maths problem.

As far as 'dangerous' vs 'unprotected' modules, I'm inclined to side with the creators of the dangerous modules, because people will always do stupid things, if not intentionally. All modules should have proper protection against stupid. That said, I don't know which modules by which brands are protected, so I have to assume that none are. I'm all for certification, even if its only for whether the inputs and outputs are safe to +/-12v, and that the red stripe for negative is clearly marked on the pcb. Shit, I'll even start it. How do you Patreon?

'This Product is Bare Minimum Certified.'

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Post by adam » Sun Oct 30, 2016 8:05 am

pitri wrote:
Leverkusen wrote:At least the upgrade instructions for the new firmware suggest that it's a known issue and whimsical cares about it:

http://www.whimsicalraps.com/pages/just-type

(...)
* FIRST: Insert a (long) mono patch cable into the RUN jack
* THEN: Connect this cable to your soundsource
* Turn on your synth case
(...)
IMPORTANT! TURN OFF YOUR SYNTH! REMOVE THE CABLE FROM YOUR SOUNDSOURCE, THEN FROM THE RUN JACK, AND RESTART. THIS IS TO MAKE SURE JF WON'T DAMAGE YOUR SOUNDSOURCE
sorry but that sounds rather rediculous :despair: ... is that a design flaw or the only possible way?
it's a design flaw but give him a break - this kind of thing sinks companies, he may be facing a large bill to fix this

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Krater
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Post by Krater » Sun Oct 30, 2016 8:08 am

I´m aware of this Maths-"issue" and the threads about it, but as far as I know, no module XY was damaged in this context.

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Leverkusen
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Post by Leverkusen » Sun Oct 30, 2016 8:35 am

Krater wrote:I´m aware of this Maths-"issue" and the threads about it, but as far as I know, no module XY was damaged in this context.
Yes, that was my thought too - everyone has a Maths and I've never heard of something gone wrong besides function oddities. Anyway I am still a little concerned so...
yghartsyrt wrote:
You are right. I assumed the just friends was set up like a lot of functions generators. But as folks pointed out, it seems that the Run In might be normalled to the -12v rail. THAT is something entirely different.
...can someone enlighten us dummies and drain the source of uncertainty? WHAT is something entirely different?

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ghrobbing_tristle
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Post by ghrobbing_tristle » Sun Oct 30, 2016 8:43 am

I was also sadly affected by this, but it hasn't diminished my enjoyment of Just Friends. I totally get the frustration, though, coming from both users and fellow designers; it was definitely a shitty night when my brand new Random Sampling got fried after connecting one of the gate outs to the RUN jack.

I spoke to Trent about this at Machines in Music a few weeks back, and he was deeply concerned about it; I certainly got the sense that he wanted to be proactive in figuring out a fix, and I wouldn't take his extended (perhaps permanent) leave from the forum as an indication that he's ignoring the issue at all.

One thing that bums me out, especially coming from other designers, is the need to bad-mouth the guy; there's a design flaw, it's affecting other modules in limited circumstances and that sucks, no doubt, but there's no need to go on a crusade tarnishing someone's reputation. At least some, like Pinchettes and Dr. Etch-&-Sketch, are trying to think through why the design decision was made in the first place, however faulty, and willing to make recommendations.

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thisisprisma
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Post by thisisprisma » Sun Oct 30, 2016 8:46 am

so best to not plug anything at all in RUN... at least for the time being...

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atrostor
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Post by atrostor » Sun Oct 30, 2016 8:53 am

thisisprisma wrote:so best to not plug anything at all in RUN... at least for the time being...
More like, plug it into RUN first and plug it out of it last.

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akrylik
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Post by akrylik » Sun Oct 30, 2016 9:03 am

ghrobbing_tristle wrote:(snip)
At least some, like Pinchettes and Dr. Etch-&-Sketch, are trying to think through why the design decision was made in the first place, however faulty, and willing to make recommendations.
I would love to read this discussion and learn. Do you have a link?

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Nofrenchtests
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Post by Nofrenchtests » Sun Oct 30, 2016 9:04 am

ghrobbing_tristle wrote:I was also sadly affected by this, but it hasn't diminished my enjoyment of Just Friends. I totally get the frustration, though, coming from both users and fellow designers; it was definitely a shitty night when my brand new Random Sampling got fried after connecting one of the gate outs to the RUN jack.

I spoke to Trent about this at Machines in Music a few weeks back, and he was deeply concerned about it; I certainly got the sense that he wanted to be proactive in figuring out a fix, and I wouldn't take his extended (perhaps permanent) leave from the forum as an indication that he's ignoring the issue at all.

One thing that bums me out, especially coming from other designers, is the need to bad-mouth the guy; there's a design flaw, it's affecting other modules in limited circumstances and that sucks, no doubt, but there's no need to go on a crusade tarnishing someone's reputation. At least some, like Pinchettes and Dr. Etch-&-Sketch, are trying to think through why the design decision was made in the first place, however faulty, and willing to make recommendations.
A number of us are awaiting email replies, it has also been brought up on the Lines forum, where he is more active. It would seem that they have been aware of it before the last couple of days, and has now mentioned it obliquely in the Just Type documentation.

No one has gone on a crusade, and if anything the badmouthing has been against modules without protection.

That all said there are a few ways this could go:

WR doesn't respond at all.
WR says that this isn't all on them, and does nothing.
WR comes to the table and discusses how to solve this problem with the customers it seriously affects.

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ghrobbing_tristle
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Post by ghrobbing_tristle » Sun Oct 30, 2016 9:08 am

No one has gone on a crusade, and if anything the badmouthing has been against modules without protection.
You're right - I should have clarified. This was mainly stuff I heard in person at MiM, not anything I explicitly read here on the forum.

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lasesentaysiete
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Post by lasesentaysiete » Sun Oct 30, 2016 9:13 am

akrylik wrote:
ghrobbing_tristle wrote:(snip)
At least some, like Pinchettes and Dr. Etch-&-Sketch, are trying to think through why the design decision was made in the first place, however faulty, and willing to make recommendations.
I would love to read this discussion and learn. Do you have a link?

this thread.


I'd think the safest thing to do would be to leave a patch cord plugged in at all times, no? Long enough to be used anywhere in your case. Maybe not so practical in certain situations, but this is more or less what the designer outlned, isn't it?

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Post by mdoudoroff » Sun Oct 30, 2016 9:25 am

lasesentaysiete wrote:I'd think the safest thing to do would be to leave a patch cord plugged in at all times, no? Long enough to be used anywhere in your case. Maybe not so practical in certain situations, but this is more or less what the designer outlned, isn't it?
If you have anything plugged into RUN, then you’re in RUN mode, whether a signal is present or not. That’s probably not what you want. I’d suggest maybe taping a little flap of fabric above (and laying over the jack) as a reminder to handle it with caution.

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lasesentaysiete
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Post by lasesentaysiete » Sun Oct 30, 2016 9:27 am

mdoudoroff wrote: If you have anything plugged into RUN, then you’re in RUN mode, whether a signal is present or not. That’s probably not what you want. .
ahh, yeah, no good. Obvious I've never used one! :doh:

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