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I was there yesterday when you checked in and I didn't notice that your audio sounded tiny.
I did the Heil element in a D104 carcass and had to add a matching transformer to get the impedance up. Probably what they were trying to do on that mic you have, but who knows for sure.? It works great.

73

Jim? ?WA8SDF

On Sun, Feb 2, 2025, 23:49 Richard Knoppow via <1oldlens1= [email protected]> wrote:

? ? FWIW, crystal and ceramic microphone elements look like capacitors.
The load impedance forms a high pass filter with the capacitance. The
higher the impedance the less the bass roll off. There is also an effect
due to the capacitance of the connecting cable, which is in parallel
with the element. If the cable capacitance is too high the level is
depressed since the two act as a capacitive voltage divider. In the bad
old days crystal mics and phonograph pickups were used to feed vacuum
tube grids more or less directly so the load was typically very high,
often several megohms. Crystal elements have the advantage of having
very high output level for a given amount of mechanical driving force
and, if carefully designed, good high frequency response. Because tube
amplifiers were expensive a crystal element could be economical for
cheap phonographs and PA mics. The disadvantages were sensitivity to
high temperatures (much about 90F), sensitivity to mechanical fracture
(scrape a pick up across a record or dropping a mic), high humidity.
There were several arrangements for sealing crystal elements to protect
them from humidity but they were often short lived. Eventually ceramic
elements began to replace crystals. They were much more rugged but had
significantly lower output. For the most part all of these have been
replaced with electret elements of some sort.
? ? ?Up until perhaps the 1970's there were perhaps a dozen makers of
crystal and ceramic phonograph pickups and every maker of microphones
made crystal or ceramic mics. All now completely supplanted by other
mechanisms.

On 2/2/2025 7:36 PM, Jim Shorney via wrote:
>
> Yes, I am quite aware of the D-104 head characteristics. I'm the guy who posts the attached graph whenever this comes up. For the TR7 470K x 2 is an ideal load for the cartridge with plenty of voltage left to drive the radio. I should think the same would have been true of your Kenwood as well unless it had a not very sensitive mic input. All three of my stands (including the Golden Eagle) are effectively UG stands now. No need to fool around with the active electronics in the T-UGxxx stands. That would be what a friend of mine calls enhanced uselessness. Maybe one of these days I will wire one of the neutered T* stands for my TS-570 and see how the D-104 head likes it. I actually have a D-104/UG around here somewhere that I used with my Tram D-201 back in the day. True high impedance, looking into the grid of a tube.
>
> On Sun, 02 Feb 2025 18:47:27 -0800
> "jerry-KF6VB via " <jerry= [email protected]> wrote:
>
>> On 2025-02-02 16:33, Jim Shorney via wrote:
>>> I have never run any electronics in a D-104/T-UGxx. Just a 470K or
>>> higher resistor in series with the audio line.
>>
>>? ? ?I probably wouldn't have bothered with my TR7 - I would have just
>> connected the D104 to that pin with the 470K resistor.? This was in
>> the mid-80's, and I wanted to hook it up to my TS-830S.? I don't
>> think that radio had a high impedance input.? I seem to remember
>> 50K or so.? But that was many years ago.
>>
>> The 20 megohms that the JFET presents to the Rochelle salts element
>> maximizes its bass response.
>>
>>? ? ? ? ? ? ? ? ? ? ? ? ? - Jerry, KF6VB
>

--
Richard Knoppow
Los Angeles
WB6KBL
SKCC 19998