alidav Posted April 12, 2018 Report Share Posted April 12, 2018 I want to build a TRS TRS cable to wire a Tascam dr100 line out to a canon 5d MK III mic in. can anyone suggest me a detailed scheme that helps? Quote Link to comment Share on other sites More sharing options...
Derek H Posted April 12, 2018 Report Share Posted April 12, 2018 I know you’re looking to DIY but Sescom makes exactly what you’re looking for a good price. http://www.sescom.com/product.asp?item=LN2MIC-TASDR100&LN2MIC-TASDR100 Quote Link to comment Share on other sites More sharing options...
alidav Posted April 12, 2018 Author Report Share Posted April 12, 2018 yes but seems to be quite easy to make it with few cents. Quote Link to comment Share on other sites More sharing options...
Allen Rowand Posted April 12, 2018 Report Share Posted April 12, 2018 1 hour ago, alidav said: I want to build a TRS TRS cable to wire a Tascam dr100 line out to a canon 5d MK III mic in. can anyone suggest me a detailed scheme that helps? Once you know the input and output impedances of your devices, use a calculator like http://www.nu9n.com/tpad-calculator.html to determine your resistor values. You'll need to build two T pads, one for each unbalanced channel. You might be able to build the pads inside a 1/4" TRS connector, but it'd be a lot easier to use a small project box. Quote Link to comment Share on other sites More sharing options...
Derek H Posted April 12, 2018 Report Share Posted April 12, 2018 Your call. For the hours it would take me to figure it out, build it, screw up, re-build it I’d rather just buy it and move on in life. I make most of my own cables but this kind of thing I usually buy off the shelf. But go for it if you have the time. Quote Link to comment Share on other sites More sharing options...
alidav Posted April 12, 2018 Author Report Share Posted April 12, 2018 1 hour ago, Allen Rowand said: Once you know the input and output impedances of your devices, use a calculator like http://www.nu9n.com/tpad-calculator.html to determine your resistor values. You'll need to build two T pads, one for each unbalanced channel. You might be able to build the pads inside a 1/4" TRS connector, but it'd be a lot easier to use a small project box. assuming that Tascam dr 100 line out is 200 ohm and the mic input on any reflex is 10 Kohm the result give resistors of 21 ohms 4952 ohm, quite hard to find. do I make something wrong? I have to wire a Tascam stereo line out into the canon 5d stereo mic input. on the specs of tascam line out is 200 ohm, but cannot find any info about mic in Quote Link to comment Share on other sites More sharing options...
Allen Rowand Posted April 12, 2018 Report Share Posted April 12, 2018 1 hour ago, alidav said: assuming that Tascam dr 100 line out is 200 ohm and the mic input on any reflex is 10 Kohm the result give resistors of 21 ohms 4952 ohm, quite hard to find. do I make something wrong? I have to wire a Tascam stereo line out into the canon 5d stereo mic input. on the specs of tascam line out is 200 ohm, but cannot find any info about mic in You're looking at the H pad values, you need a T pad. If your impedances are correct, the resistor values are: (R1) 9904 Ohms (R3) 42 Ohms (R2) 160 Ohms If I had to build this pad out of what I have in the garage, I'd use: (R1) 10k ohms (R3) 47 ohms (R2) 100 ohms + 47 ohms. If the pad wasn't enough I'd add another 20 ohms to R2. But yeah, I'd probably just buy the Sescom cable. Even if I had all the parts on-hand to build the pad, the value of my time is more than the cost of that cable. Quote Link to comment Share on other sites More sharing options...
alidav Posted April 13, 2018 Author Report Share Posted April 13, 2018 I found this https://www.ebay.it/itm/Attenuatore-AUDIO-STEREO-SAA25-linea-25dB-per-mic-film-DJ-periscopio-Facebook-/183130225339 Quote Link to comment Share on other sites More sharing options...
stacysound Posted April 13, 2018 Report Share Posted April 13, 2018 15 hours ago, Allen Rowand said: You're looking at the H pad values, you need a T pad. If your impedances are correct, the resistor values are: (R1) 9904 Ohms (R3) 42 Ohms (R2) 160 Ohms If I had to build this pad out of what I have in the garage, I'd use: (R1) 10k ohms (R3) 47 ohms (R2) 100 ohms + 47 ohms. If the pad wasn't enough I'd add another 20 ohms to R2. But yeah, I'd probably just buy the Sescom cable. Even if I had all the parts on-hand to build the pad, the value of my time is more than the cost of that cable. Ditto to what Allen said. You can be fairly loose with the component values. Even if it changes the impedance slightly, you’ll still be fine. You can build these in TA3 connectors with 1/8 W resistors. They’re quite small. But you need to have good eyes, and a steady hand. Quote Link to comment Share on other sites More sharing options...
John Blankenship Posted April 13, 2018 Report Share Posted April 13, 2018 Based on the specs, this is likely how the Sescom pad is wired (or very close to it): 5 K. ohms IN >——-\/\/\/\/\/\/\——|—————> OUT | | | / \ / 100 ohms \ / | | __|__ Quote Link to comment Share on other sites More sharing options...
LarryF Posted April 13, 2018 Report Share Posted April 13, 2018 This L pad as recommended by John, has about 34 dB of attenuation. The previously recommended H pads and T pads require an additional resistor and are only necessary if you are trying to match input AND output impedances. Generally this is not necessary when going from a lower impedance output (most audio outs) to a high impedance input (most inputs). The L pad is easier to build as it only requires two resistors and is just as effective and much easier to build in a connector. Best Regards, Larry Fisher Quote Link to comment Share on other sites More sharing options...
alidav Posted April 13, 2018 Author Report Share Posted April 13, 2018 21 minutes ago, LarryF said: This L pad as recommended by John, has about 34 dB of attenuation. The previously recommended H pads and T pads require an additional resistor and are only necessary if you are trying to match input AND output impedances. Generally this is not necessary when going from a lower impedance output (most audio outs) to a high impedance input (most inputs). The L pad is easier to build as it only requires two resistors and is just as effective and much easier to build in a connector. Best Regards, Larry Fisher being an unbalanced stereo cable, line to the mic input, I have to build 2 of them obviously Quote Link to comment Share on other sites More sharing options...
alenK Posted April 13, 2018 Report Share Posted April 13, 2018 FWIW, When I recommended the H-pad in another thread on this subject, I assumed the context was a balanced line out to a balanced mic in. I did not recognize that the use of the term "reflex" as referring to a digital single lens reflex camera and I hadn't guessed that the recorder had unbalanced outputs. A pair of L-pads does seem like the better choice in the intended scenario. Quote Link to comment Share on other sites More sharing options...
Derek H Posted April 14, 2018 Report Share Posted April 14, 2018 He also said TRS TRS. I got that he meant a cable with a 3.5mm on both ends. Quote Link to comment Share on other sites More sharing options...
alidav Posted April 14, 2018 Author Report Share Posted April 14, 2018 I need a solution to attenuate the signal from a recorder to feed a DSLR, no matter if a box with 2 trs females or a cable, a box maybe is more easy to build for me. anyway this UK guy makes this nice tool very convenient. https://www.ebay.it/itm/ATT40-STEREO-AUDIO-ATTENUATOR-40dB-REDUCE-LINE-LEVEL-TO-MICROPHONE-LEVEL/112899580191?hash=item1a4956e11f:g:THUAAOSwE0JY-nza Quote Link to comment Share on other sites More sharing options...
Wandering Ear Posted April 14, 2018 Report Share Posted April 14, 2018 I built an xlr cable with a pad in the xlr to take line level feeds from a console into a trx742 (mic level only). Probably took me half an hour total. It's a handy tool to have in the kit, especially since I personally dislike barrel adapters. If this is something you will use a lot, building it into a cable is an elegant and very doable solution. Quote Link to comment Share on other sites More sharing options...
beatsbooster Posted May 11, 2018 Report Share Posted May 11, 2018 For this particular case i think i would buy the cable, it seems more handy that handling all the extra boxes and stuff, but if you enjoy doing this projects go for it is very simple to build and it would cost you a third of the price. Have you decided yet? Quote Link to comment Share on other sites More sharing options...
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