tone control on your d104-m

[bob85]

this simple kind of mod will only work on mics that use very high impedance cartridges, it works by changing the cartridge load impedance which has a dramatic effect on crystal and ceramic cartridges.

 

[2RT307]

Thanks for bumping this thread, Robb. I will likely be doing it to mine.

Let us know how you make out, Homer. I have a brand new one that I'm temted to try it on.

73,
RT307

 

[curlyjo]

Thanks Bob. Just wondering. I bought an Allen Bradley pot from eBay to go with my D104 . It is to large to fit inside. Would like to find one that can fit inside of my Mic. 73's

 

[Robb]

this simple kind of mod will only work on mics that use very high impedance cartridges, it works by changing the cartridge load impedance which has a dramatic effect on crystal and ceramic cartridges.

So what you are saying is that by adding the right resistance in parallel with the element, you find the element's best impedance match point so its best audio character/'range' can be found?

If so; think I understand this mod now . . .
Think my mic just has a cartridge that is out of spec; otherwise this mod would have worked. Unless, this element I have may need more resistance because it is out of spec. Is that possible?

 

[bob85]

yes thats how the tone works rob, the lower the terminating impedance the less bass it can produce,

those old ceramic cartridges hardly ever sound exactly the same as each other even when they are in good working order, the older black faced ones tend to sound a bit sweeter to my ears,
some go low in output and sound thin, i have loosened a few up by playing music through them as you would headphones or a loudspeaker.

 

[The Mad Scientist]

Has anyone tried this mod with the old minuiteman II d104's? If so which resistor was replaced with the trim pot?

What were the results?

 

[Ez2cDave]

wire weasel, here is a link to the PDF i got the cap mods for the D104 desk mics from:
http://www.google.com/url?sa=t&source=web&cd=1&ved=0CBYQFjAA&url=http://www.mods-ham.com/02_Mods/Other-Mods/Astatic%20D-104/DG2IAQ%20Modification%20Sheet%20ASTATIC%20D-104%20Silver%20Eagle.pdf&rct=j&q=d104 mods&ei=H0A7TuWSJsffiAK2vdiODA&usg=AFQjCNH3_MBpEhGtmUuz3I5P_Xb_shSUJQ&sig2=mrls6gy7dPxBILyYVy11ag&cad=rja

This LINK is FUBAR . . .

However, in the interest of my fellow radio enthusiasts, you will find the PDF attached below for EASY DOWNLOAD . . . NEVER let Data DIE !

 

[Shadetree Mechanic]

Just found this again. I originally found this as a link on the Deep South Radio Foroum. Then I signed up here and the rest is history. Anyway I just picked up a D104M6B and I plan on playing around with it some. This is some good info just giving it a bump.
Chris

 

[GrandNational]

I just swapped the guts out of a cr-577 mic into an old d104. Sounds great.

 

[Shadetree Mechanic]

I just happened to download this picture before photo bucket blurred it.