Log in
Register
Home
Forums
New posts
Search forums
What's new
New posts
New profile posts
Latest activity
News
Members
Current visitors
New profile posts
Search profile posts
Features
Log in
Register
Search
Search titles only
By:
Search titles only
By:
New posts
Search forums
Menu
Install the app
Install
Reply to thread
Home
Forums
Pro Audio
Junior Varsity
QSC TouchMix 16 sound problem fixed (other touchmix versions may also get this)
JavaScript is disabled. For a better experience, please enable JavaScript in your browser before proceeding.
You are using an out of date browser. It may not display this or other websites correctly.
You should upgrade or use an
alternative browser
.
Message
<blockquote data-quote="Roy Andrews" data-source="post: 216334" data-attributes="member: 15263"><p>Please see posts #3 and #5 above by Brian Ingwell. I don't think any of us were aware of this issue until he mentioned it. I certainly wasn't. This is one of the problems with making schematics and service bulletins secret, as in the case of QSC and most other companies these days.</p><p></p><p>However, from an electronics perspective, the polarity situation makes complete sense... These are effectively blocking caps in the circuit design. If you are expecting to block a large positive DC voltage (eg phantom power) with a polarized capacitor of any type (in this case electrolytic), then the PLUS terminal of the capacitor MUST go to the point / connector / pin where you expect to receive this + voltage. Polarized capacitors are easily destroyed by applying reverse voltages. Under certain conditions, the explosion can be quite spectacular. In other cases, the top will bulge, and it merely stops acting like a capacitor.</p><p></p><p>If this doesn't make too much sense to you / you don't have an electronics background, then at least show this thread to your tech, I'm sure he will agree that this makes sense.</p><p></p><p>I reviewed the video, it is correct, other than the tech continued with the new caps installed backwards. At this point, I believe installing the caps backwards will only come back to bite you if the mixer gets connected to a FoH board with phantom power enabled. I do not imagine any other situation where a significant positive DC voltage would be applied to the AUX outputs... but there are others on this forum more versed in modern sound reinforcement practices, thus I could be wrong.</p><p></p><p>The Touchmix +48 only goes the the input jacks on a case by case basis if enabled in the software. It is never routed to the output jacks. Most likely just a coincidence that your auxes failed in a time period when you used +48v. My TM8 was stored (climate controlled office) for the entire pandemic, it went bad just sitting around doing nothing. Electronics can be funny that way.</p></blockquote><p></p>
[QUOTE="Roy Andrews, post: 216334, member: 15263"] Please see posts #3 and #5 above by Brian Ingwell. I don't think any of us were aware of this issue until he mentioned it. I certainly wasn't. This is one of the problems with making schematics and service bulletins secret, as in the case of QSC and most other companies these days. However, from an electronics perspective, the polarity situation makes complete sense... These are effectively blocking caps in the circuit design. If you are expecting to block a large positive DC voltage (eg phantom power) with a polarized capacitor of any type (in this case electrolytic), then the PLUS terminal of the capacitor MUST go to the point / connector / pin where you expect to receive this + voltage. Polarized capacitors are easily destroyed by applying reverse voltages. Under certain conditions, the explosion can be quite spectacular. In other cases, the top will bulge, and it merely stops acting like a capacitor. If this doesn't make too much sense to you / you don't have an electronics background, then at least show this thread to your tech, I'm sure he will agree that this makes sense. I reviewed the video, it is correct, other than the tech continued with the new caps installed backwards. At this point, I believe installing the caps backwards will only come back to bite you if the mixer gets connected to a FoH board with phantom power enabled. I do not imagine any other situation where a significant positive DC voltage would be applied to the AUX outputs... but there are others on this forum more versed in modern sound reinforcement practices, thus I could be wrong. The Touchmix +48 only goes the the input jacks on a case by case basis if enabled in the software. It is never routed to the output jacks. Most likely just a coincidence that your auxes failed in a time period when you used +48v. My TM8 was stored (climate controlled office) for the entire pandemic, it went bad just sitting around doing nothing. Electronics can be funny that way. [/QUOTE]
Insert quotes…
Verification
Post reply
Home
Forums
Pro Audio
Junior Varsity
QSC TouchMix 16 sound problem fixed (other touchmix versions may also get this)
Top
Bottom
Sign-up
or
log in
to join the discussion today!