[Elecraft] K3 line in, line out transformers.

[Josh Fiden]

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.