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janvanvolt
Joined: Nov 24, 2005 Posts: 285 Location: Mainz, Germany
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Posted: Mon May 05, 2008 8:50 am Post subject:
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Well. that was it. Tantalums... replaced with normal elco caps, no short anymore.
testing now.
Update: Filter now working over expectation. holy crap ! _________________ Homepage - http://www.czmok.de
My dIY - http://diy.czmok.de
Film/Music - http://gfm.me |
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frijitz
Joined: May 04, 2007 Posts: 1734 Location: NM USA
Audio files: 54
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Posted: Mon May 05, 2008 12:16 pm Post subject:
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unit-sound wrote: | Well. that was it. Tantalums... replaced with normal elco caps, no short anymore. |
Ah, very good. Thanks andrew!
Ian |
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andrewF
Joined: Dec 29, 2006 Posts: 1176 Location: australia
Audio files: 4
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Posted: Mon May 05, 2008 7:52 pm Post subject:
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What is it with Tant.caps?
they seem so sensitive, but to what? voltage spikes, reverse voltage?
I certainly won't bother using them in synth ccts anymore, I need components that can handle my luddite tendencies. |
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RF
Joined: Mar 23, 2007 Posts: 1502 Location: Northern Minnesota, USA
Audio files: 28
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Posted: Tue May 06, 2008 5:27 am Post subject:
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Tantalums are sensitive to reverse voltage...
I use tantalum caps in my modules quite often. (I scrounge them from scrapped equipment) I don't recall ever having a problem with them...
bruce |
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blue hell
Site Admin
Joined: Apr 03, 2004 Posts: 24079 Location: The Netherlands, Enschede
Audio files: 278
G2 patch files: 320
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Posted: Tue May 06, 2008 12:26 pm Post subject:
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One could consider ceramic caps now they are becoming available with larger capacitance values. _________________ Jan
also .. could someone please turn down the thermostat a bit.
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janvanvolt
Joined: Nov 24, 2005 Posts: 285 Location: Mainz, Germany
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Posted: Sun May 25, 2008 7:08 pm Post subject:
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Hi,
a finally got my panel from Schaeffer earlier last week so i finished all cabling today.
I just observed one strangeness (which somebody could help me out with):
- When switching modes with the rotary, i seem to have a short "short" in the whole power rail. not sure if it is +15 or -15V. besdies that the filter is working.
no other tantalums in the circuit, so i definitely can rule this one out.
ideas anyone ? _________________ Homepage - http://www.czmok.de
My dIY - http://diy.czmok.de
Film/Music - http://gfm.me |
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guitarfool
Joined: Feb 26, 2007 Posts: 160 Location: Maryland
Audio files: 8
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Posted: Sun May 25, 2008 7:35 pm Post subject:
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unit-sound wrote: | When switching modes with the rotary, i seem to have a short "short" in the whole power rail. not sure if it is +15 or -15V. besdies that the filter is working. |
You're probably using a "make before break" rotary switch. As it is rotated, it connects the wiper with the next contact before disconnecting with the previous one. Since the rotary switch in the Threeler selects alternately from V+ and ground, you're getting momentary shorts between V+ and ground.
Not all rotary switches are this type, but many are. Usually (like when switching between audio sources) it is a good thing. But not in this case
Anyone who hasn't built theirs yet (like me) should take this as a "heads up". |
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janvanvolt
Joined: Nov 24, 2005 Posts: 285 Location: Mainz, Germany
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Posted: Mon May 26, 2008 10:37 am Post subject:
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Any idea if i can put in CAPs to limit the short ? (e.g. ground connection?)
final solution might be another switch. _________________ Homepage - http://www.czmok.de
My dIY - http://diy.czmok.de
Film/Music - http://gfm.me |
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guitarfool
Joined: Feb 26, 2007 Posts: 160 Location: Maryland
Audio files: 8
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Posted: Mon May 26, 2008 11:31 am Post subject:
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unit-sound wrote: | Any idea if i can put in CAPs to limit the short ? (e.g. ground connection?)
final solution might be another switch. |
You might try a current limiting resistor between V+ and the switch. I would think something like at least 1k might work. 1k would give you a current of 0.015 amps at a power dissipation of 0.225 watts (although briefly). Too large a resistor might cause the voltage at A0 and A1 to be too low. I haven't looked at a spec sheet for the DG409. |
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frijitz
Joined: May 04, 2007 Posts: 1734 Location: NM USA
Audio files: 54
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Posted: Mon May 26, 2008 1:08 pm Post subject:
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unit-sound wrote: | - When switching modes with the rotary, i seem to have a short "short" in the whole power rail. not sure if it is +15 or -15V. | Unit --
Thanks for bringing that up. Yes, you need a break-before-make switch. Alternately, you can probably put a 10k resistor in series with either the V+ line or the ground line. I should have thought of that.
Ian |
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Funky40
Joined: Sep 24, 2005 Posts: 875 Location: Swiss
Audio files: 1
G2 patch files: 5
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Posted: Mon May 26, 2008 3:19 pm Post subject:
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and which ones are break bevore break switches ?
which would be the right ones from mouser ? ( locally i can get Lorlin, are those fine? ) |
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janvanvolt
Joined: Nov 24, 2005 Posts: 285 Location: Mainz, Germany
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Posted: Mon May 26, 2008 4:22 pm Post subject:
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Funky40 wrote: | and which ones are break bevore break switches ?
which would be the right ones from mouser ? ( locally i can get Lorlin, are those fine? ) |
never mind about the switch.
i now soldered a 10K in series to ground and the problem is no longer existant.
Thanks Ian for the Hell of a filter _________________ Homepage - http://www.czmok.de
My dIY - http://diy.czmok.de
Film/Music - http://gfm.me |
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guitarfool
Joined: Feb 26, 2007 Posts: 160 Location: Maryland
Audio files: 8
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Posted: Mon May 26, 2008 4:35 pm Post subject:
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Funky40 wrote: | and which ones are break bevore break switches ?
which would be the right ones from mouser ? |
the Alpha rotary 2P4T is Mouser part number 105-SR2511F-34NS
The "NS" stands for non-shorting, (break before make) as opposed to shorting, designated by a part number ending in just "S".
There's also the Alpha plastic enclosed type, Mouser part number 105-SR2611F-34-38RN. Both of these have round shafts and solder terminals (not PCB mount).
I prefer the 1st type myself. |
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frijitz
Joined: May 04, 2007 Posts: 1734 Location: NM USA
Audio files: 54
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Posted: Mon May 26, 2008 7:27 pm Post subject:
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unit-sound wrote: | never mind about the switch.
i now soldered a 10K in series to ground and the problem is no longer existant. |
Good, thanks! I thought that would work, but I haven't actually tried it.
Ian |
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Funky40
Joined: Sep 24, 2005 Posts: 875 Location: Swiss
Audio files: 1
G2 patch files: 5
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Posted: Tue May 27, 2008 3:13 pm Post subject:
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guitarfool wrote: | the Alpha rotary 2P4T is Mouser part number 105-SR2511F-34NS
The "NS" stands for non-shorting, (break before make) as opposed to shorting, designated by a part number ending in just "S".
. |
thanks, it came just in the right moment.
I also was not aware that there are shortening and non shortening types. |
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jnuaury
Joined: Feb 28, 2008 Posts: 161 Location: chicago
Audio files: 9
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Posted: Thu Jun 05, 2008 3:23 pm Post subject:
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does anybody want to show off their front panel for this?
ive been really interested in this bad boy but i think i need to see how much front panel real estate it takes up |
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etaoin
Joined: Jun 30, 2005 Posts: 761 Location: Utrecht, NL
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Posted: Tue Jun 10, 2008 1:07 pm Post subject:
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My Threeler appears go work great, although the (2)134's are running warm. Are they supposed to? _________________ http://www.casia.org/modular/ |
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frijitz
Joined: May 04, 2007 Posts: 1734 Location: NM USA
Audio files: 54
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Posted: Tue Jun 10, 2008 2:37 pm Post subject:
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Etaoin wrote: | My Threeler appears go work great, although the (2)134's are running warm. Are they supposed to? |
I don't remember them running warm, but I may not have checked carefully. Are they clipping against the rails when they get warm? Are they always warm, even with low feedback?
Unfortunately, I don't have one set up right now. I'll try to check this later in the week.
Ian |
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etaoin
Joined: Jun 30, 2005 Posts: 761 Location: Utrecht, NL
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Posted: Tue Jun 10, 2008 11:23 pm Post subject:
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Hehe, something is very wrong with mine. The res pot just went up in flames! I turned it slightly from zero on up and a big flame burst out of the side. Haven't seen that since I first began in electronics some 25 years ago Back to my workbench... _________________ http://www.casia.org/modular/ |
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etaoin
Joined: Jun 30, 2005 Posts: 761 Location: Utrecht, NL
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Posted: Tue Jun 10, 2008 11:40 pm Post subject:
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Okay, found it. I'm using pcb-mount Alphas. But if you mount those flush with the pcb, the pads on the pot are actually touching the extra two holes and causing shorts. A short from +15V to the wiper burned out the pot. So you need to mount Alphas slightly off the board (or isolate those extra holes). _________________ http://www.casia.org/modular/ |
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blue hell
Site Admin
Joined: Apr 03, 2004 Posts: 24079 Location: The Netherlands, Enschede
Audio files: 278
G2 patch files: 320
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Posted: Wed Jun 11, 2008 6:54 am Post subject:
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Etaoin wrote: | [...]a big flame burst out of the side. |
You seem to have a /power/ supply _________________ Jan
also .. could someone please turn down the thermostat a bit.
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frijitz
Joined: May 04, 2007 Posts: 1734 Location: NM USA
Audio files: 54
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Posted: Wed Jun 11, 2008 7:28 am Post subject:
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Etaoin wrote: | Okay, found it. I'm using pcb-mount Alphas. But if you mount those flush with the pcb, the pads on the pot are actually touching the extra two holes and causing shorts. A short from +15V to the wiper burned out the pot. So you need to mount Alphas slightly off the board (or isolate those extra holes). |
Ouch! You're saying the little legs on the slider terminal are hitting the pads for the smaller size pot? I'm not sure what I can do about that -- the board is layed out to accept two pot sizes.
Ian |
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bridechamber
Joined: Oct 06, 2007 Posts: 64 Location: Saint Paul, MN
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Posted: Wed Jun 11, 2008 8:01 am Post subject:
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I just tried trimming those little stops on the middle pin with a wire cutter, and that worked pretty well. Sorry it's necessary, though; that's one I never would have thought of. |
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RF
Joined: Mar 23, 2007 Posts: 1502 Location: Northern Minnesota, USA
Audio files: 28
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etaoin
Joined: Jun 30, 2005 Posts: 761 Location: Utrecht, NL
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