As  my Sowter Choke Input was acquisitioned by my friend. Then I have to consider some replacement. Actually my friend was interested with Hashimoto or similar, but as most of the Choke Input was designed for power amp, instead of preamp, so the specification and requirement (especially for minimum current demand) were different.

Luckily, as my preamp uses quite big current, then I can consider some Choke Input for power amp usage. One of them is the Hashimoto C-25-150CH. This choke is designed for Input application, rated at 25 H and 200 mA maximum current. DCR is claimed around 205 Ohm. Spec wise, it’s all very good to best. As material, Hashimoto is quite confident with its Orient High B core (forget Permalloy or Amorphous). Internally, this choke should be a C-Core type, with extra electrostatic shield. Oh, Hashimoto also put extra work to make this choke as a magnetic shield type. I think they do understand that Choke Input could radiate enough flux and/or electromagnetic things. Definitely, a magnetic shield design will be a nice addition. Build quality of this choke is also quite superb. With around 2.4 Kg weight, this is a heavy weight championship (remember, this is only a choke!)

The second one is a Tamura A-4004. Although it’s rated only 10 H and 200 mA maximum (or 2.5 H at 400 mA), this choke only around 10% lighter than Hashimoto Choke Input above. Physically size, this Tamura also a little bit smaller than the Hashimoto. Before, I was considering A-4006 (Amorphous) also. But due to some other consideration (as my Aikido Preamp already has Duelund CAST Ag Silver Capacitor inside), then I think non-Amorphous core will give a nice combination with it. Right or wrong? We shall prove it later…