Hammond 193A, 200H @ 40mA choke

I hadn't seen this choke discussed at all for audio, but the specs on paper make it look like an interesting anode load.

Hammond's page here

Says 2k DCR.

Should be fine for that purpose.

They are an excellent company. If you have technical questions email them. I asked a technical question about a 278CX that was running at 90c under load and they looked into it, revised an engineering change, and sent me an updated version to test that runs 10c cooler free of charge.

EDIT: You haven't seen it discussed because it's just been released. It's a new model.
 

PRR

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What's the HF like?
A lump that size may have 300pFd self-capacitance. No less without much extra expense and increase of DCR.

Plot it on a reactance cart, if you can.

The 200H at 50Hz is 60Kohms. The 300pFd with 60K falls past 9kHz.

Yes, re-figuring with 20Hz makes 24k and 22.5kHz.

It is liable, even sure, to also have leakage inductance and a top resonance.
 
Here a (quick & dirty) test with a 2P29L which I did a year ago ... didn't note the output cap-size and load impendance - i was more focussed on mA vs. distortion when I run this test.
 

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  • 2P29L FR 18mA 5.5V Bias.png
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I can't say much about sound quality. First i didn't have another choke to compare. Second I didn't focus on pure choke loading cause the gain is too high for my system. It was more a proof of concept (with benchtop supplies) to see how microphonic the 2P29L are and to have a measurement reference vs. choke + parafeed (LL1930).

From a technical perspective I like these chokes. They are not expensive, have a good FR (despite they are marked as power supply chokes) and a resonable low DCR.

btw. the sticker on the chokes states 30mADC not 40mA.
 
It's not so easy to find plate chokes in Europe. Most people use active loads. Some guys are still winding chokes and transformers but not as many as before. Not even much from China. Looks like plate chokes are in decline. More in the USA probably but I'm in London so shipping and import charges make them expensive. There is always Lundahl LL1668 but they're not cheap. There are probably choke winders in some European countries - just a question of finding them.