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Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems. |
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#1
Posted to rec.audio.tech,sci.electronics.repair
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Is this really what you'd expect from an audio balun
The schematic here seems completely wrong to me.
http://www.mcmelectronics.com/conten...ts/50-7725.pdf http://canada.newark.com/mcm-custom-...eld/dp/96K0889 |
#2
Posted to rec.audio.tech,sci.electronics.repair
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Is this really what you'd expect from an audio balun
On Sun, 5 May 2013 09:44:40 -0700, "Bob F"
wrote: The schematic here seems completely wrong to me. http://www.mcmelectronics.com/conten...ts/50-7725.pdf http://canada.newark.com/mcm-custom-...eld/dp/96K0889 Looks OK to me. It's configured as a series common mode stopper. What's the problem? d |
#3
Posted to rec.audio.tech,sci.electronics.repair
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Is this really what you'd expect from an audio balun
Don Pearce wrote:
On Sun, 5 May 2013 09:44:40 -0700, "Bob F" wrote: The schematic here seems completely wrong to me. http://www.mcmelectronics.com/conten...ts/50-7725.pdf http://canada.newark.com/mcm-custom-...eld/dp/96K0889 Looks OK to me. It's configured as a series common mode stopper. What's the problem? Will this design eliminate ground loop problems? My concept of baluns was that they isolated the two ends by placing them on opposite windings of a transformer. I am no expert, which is why I asked. |
#4
Posted to rec.audio.tech,sci.electronics.repair
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Is this really what you'd expect from an audio balun
On Sun, 5 May 2013 10:26:13 -0700, "Bob F"
wrote: Don Pearce wrote: On Sun, 5 May 2013 09:44:40 -0700, "Bob F" wrote: The schematic here seems completely wrong to me. http://www.mcmelectronics.com/conten...ts/50-7725.pdf http://canada.newark.com/mcm-custom-...eld/dp/96K0889 Looks OK to me. It's configured as a series common mode stopper. What's the problem? Will this design eliminate ground loop problems? My concept of baluns was that they isolated the two ends by placing them on opposite windings of a transformer. I am no expert, which is why I asked. That is a different thing. You need a transformer to kill a ground loop entirely, but yes, provided there is enough inductance in the coils this will still make a good job of getting rid of hum from a ground loop. The downside of the transformer method is that lower bass response is usually somewhat compromised. d |
#6
Posted to rec.audio.tech,sci.electronics.repair
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Is this really what you'd expect from an audio balun
On Sun, 05 May 2013 23:04:35 -0700, isw wrote:
In article , (Don Pearce) wrote: On Sun, 5 May 2013 10:26:13 -0700, "Bob F" wrote: Don Pearce wrote: On Sun, 5 May 2013 09:44:40 -0700, "Bob F" wrote: The schematic here seems completely wrong to me. http://www.mcmelectronics.com/conten...ets/50-7725.pd f http://canada.newark.com/mcm-custom-...n-rca-plug-rj4 5-shield/dp/96K0889 Looks OK to me. It's configured as a series common mode stopper. What's the problem? Will this design eliminate ground loop problems? My concept of baluns was that they isolated the two ends by placing them on opposite windings of a transformer. I am no expert, which is why I asked. That is a different thing. You need a transformer to kill a ground loop entirely, but yes, provided there is enough inductance in the coils this will still make a good job of getting rid of hum from a ground loop. If there's enough inductance to attenuate 60 (or 50) Hz from the power line, why won't it do the same for similar frequencies in the desired signal? No, because of the way the windings are arranged their inductances cancel each other out for the audio signal, but not for the induced hum. The downside of the transformer method is that lower bass response is usually somewhat compromised. For any sort of well-designed and properly terminated transformer, the lower 3dB point will be well below the frequency of any "musical note" you'll ever want to pass through it. So, no, bass response won't be compromised at all. Effects strat becoming apparent well before you hit the 3dB point. d |
#7
Posted to rec.audio.tech,sci.electronics.repair
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Is this really what you'd expect from an audio balun
In article , "Bob F"
wrote: Don Pearce wrote: On Sun, 5 May 2013 09:44:40 -0700, "Bob F" wrote: The schematic here seems completely wrong to me. http://www.mcmelectronics.com/conten...ts/50-7725.pdf http://canada.newark.com/mcm-custom-...-rca-plug-rj45 -shield/dp/96K0889 Looks OK to me. It's configured as a series common mode stopper. What's the problem? Will this design eliminate ground loop problems? My concept of baluns was that they isolated the two ends by placing them on opposite windings of a transformer. I am no expert, which is why I asked. It will stop ground loop problems for the range of frequencies where the transformers work. It's not clear what that is. Transformers have a limited working range of frequencies. The ones you posted have DC to MHz passthrough but limited common mode blocking. The other wiring of isolators blocks DC to MHz common mode but only passes through maybe 50Hz to 15 Khz; more or less depending on the quality. Isolators can do weird things to the impedance too. If this is pro-audio, the absolutely best fix is using balanced cables with balanced connectors. The audio quality will be superior to any other hack. -- I will not see posts from Google because I must filter them as spam |
#8
Posted to rec.audio.tech,sci.electronics.repair
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Is this really what you'd expect from an audio balun
Bob F wrote:
The schematic here seems completely wrong to me. http://www.mcmelectronics.com/conten...ts/50-7725.pdf This datasheet shows it is a VIDEO balun. Jon |
#9
Posted to rec.audio.tech,sci.electronics.repair
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Is this really what you'd expect from an audio balun
Bob F wrote: The schematic here seems completely wrong to me. http://www.mcmelectronics.com/conten...ts/50-7725.pdf That is a VIDEO Balun for 75 ohm unbalanced to 100 ohm balanced. It is not intended for audio. It is to use Cat5 wire for 75 Ohm video from security cameras. http://canada.newark.com/mcm-custom-...eld/dp/96K0889 Another link to the same part. |
#10
Posted to rec.audio.tech,sci.electronics.repair
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Is this really what you'd expect from an audio balun
If these small transformers won't provide the characteristics you want/need,
you could look for an opto-isolation solution. -- Cheers, WB .............. "Bob F" wrote in message ... The schematic here seems completely wrong to me. http://www.mcmelectronics.com/conten...ts/50-7725.pdf http://canada.newark.com/mcm-custom-...eld/dp/96K0889 |
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