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The K3 has isolation transformers for the line input (mono),
and line output L and line output R (stereo). There are 3 sets of 2 transformers. In each set, the circuit diagrams shows the transformers in parallel with opposed phase. Please see the K3 Circuit diagram KIO3 Main Sheet 2, top left quadrant. one of each pair is labeled TTC-108 600 ohm line transformer 1.5 KV isolation, the other of each pair is labeled LM-NP-1001 600 ohm line transformer, 6.5 KV isolation. I'm going to take a stab at explaining this. I bet only one transformer of the pair is actually installed depending on availability or local laws or something like that. I would prefer the 6.5KV isolation ones. I mean bucking transformers would up be a way of measuring the leakage inductance from the primary to the secondary. That would just be plain weird. Larry |
Larry,
Note that there are only 3 transformers physically on the KIO3 board (not 6). So only one is used of each pair shown on the schematic. Note that one set is labeled as "ALT" meaning alternative. For that application, the phase is not critical, except that the stereo channels must match. Why it is represented that way on the schematic, only the designer can answer. I am certain it has something to do with the schematic to board layout program that was used. 73, Don W3FPR On 4/8/2014 8:51 AM, Larry Lopez wrote: > The K3 has isolation transformers for the line input (mono), > and line output L and line output R (stereo). > > There are 3 sets of 2 transformers. > > In each set, the circuit diagrams shows the transformers > in parallel with opposed phase. > > Please see the K3 Circuit diagram KIO3 Main Sheet 2, > top left quadrant. > > one of each pair is labeled TTC-108 600 ohm line transformer 1.5 KV > isolation, > the other of each pair is labeled LM-NP-1001 600 ohm line transformer, 6.5 > KV isolation. > > I'm going to take a stab at explaining this. > I bet only one transformer or the pair is actually used. > > > > > -- > View this message in context: http://elecraft.365791.n2.nabble.com/K3-line-in-line-out-transformers-tp7586831.html > Sent from the Elecraft mailing list archive at Nabble.com. > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to [hidden email] > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
These transformers don't have an industry standard form factor and
pinout. Therefore it is standard practice to place pads on the PCB which mate parts from multiple suppliers. It's smart engineering to avoid being locked into sole sourced components. Those transformers called out are made by Tamura and Shinholm (marketed by Bourns). Both make high quality transformers. 73, Josh W6XU > > On 4/8/2014 8:51 AM, Larry Lopez wrote: >> The K3 has isolation transformers for the line input (mono), >> and line output L and line output R (stereo). >> >> There are 3 sets of 2 transformers. >> >> In each set, the circuit diagrams shows the transformers >> in parallel with opposed phase. >> >> Please see the K3 Circuit diagram KIO3 Main Sheet 2, >> top left quadrant. >> >> one of each pair is labeled TTC-108 600 ohm line transformer 1.5 KV >> isolation, >> the other of each pair is labeled LM-NP-1001 600 ohm line >> transformer, 6.5 >> KV isolation. >> >> I'm going to take a stab at explaining this. >> I bet only one transformer or the pair is actually used. ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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