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Author Topic: replacement crystal mic cartridge for D104  (Read 55666 times)
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w4bfs
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« on: July 27, 2010, 10:36:15 AM »

I think this may be a timely issue for D104 users ... replacement OEM elements are essentially unobtanium .... existing stock elements have a WIDELY varying sensitivity and frequency response ....

well anyway Kobitone makes several elements that Mouser stocks in a past (2006) catalog ....I could not find it in their most recent (2010) catalog .... low sales volume tends to make things dissapear !

go to Mouser.com and type in 25LM024 as a part number .... a 2 inch crystal cartridge with tech specs is available for a very reasonable price ....the Collins Collectors have reported good results from Kobitone products

I have just ordered 10 of them and will report results ... oh yes, I have NO connection with Mouser except as a satisfied customer
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« Reply #1 on: July 27, 2010, 02:45:51 PM »


dunno about them... last heard people were saying the kobitone was not quite up to the better Astatic cartridges... maybe the new model is better, we can hope.

But there were so many made that i'd just look for one at a hamfest or online I think...

             _-_-bear
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ka3zlr
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« Reply #2 on: July 27, 2010, 02:57:39 PM »

Or a Bob Heil Element and you'll have that Heil Sound...  Smiley

Look there's a HC104 Element it's on this web page:

http://www.heilsound.com/amateur/products/hc104/index.htm

Why yes the HC104 for the D104 and only $70 Dalla and be part of the Heil Zound Team. Cool
So Don't Delay Call Bob Today.. Cheesy

73

Jack.

Happy Campers here:

http://www.aralb.org/Heil/

Even Chipper was there
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ka3zlr
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« Reply #3 on: July 27, 2010, 03:22:45 PM »

Or a Bob Heil Element and you'll have that Heil Sound...  Smiley

Look there's a HC104 Element it's on this web page:

http://www.heilsound.com/amateur/products/hc104/index.htm

Why yes the HC104 for the D104 and only $70 Dalla and be part of the Heil Zound Team. Cool
So Don't Delay Call Bob Today.. Cheesy

73

Jack.

Many Happy Campers here:

http://www.aralb.org/Heil/

Even Chipper was there



For a few Dallas less you can Rob an HC5 element out of your "Heil Goldline" and get the job done qicker an cheaper.
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k4kyv
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Don
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« Reply #4 on: July 27, 2010, 03:56:31 PM »

You would think now that Astatic has discontinued the replacement D-104 xtal element, that someone would be producing an after-market replacement that would be close to identical, both electrically and physically, to the original.

I think the original crystal element has better low end response than the Heil replacement, based on the Heil spec sheet.  With a high enough load resistance, the original microphone element is nearly flat to below 100~, and I recall reading claims from Astatic that its undefined "response" went down below 50~.

I wonder if anyone has ever seen one of the original early 30s crystal elements.  It apparently used a mounting screw in the back instead of the foam pads and glue used in later models.  The very early D-104 heads have a big screw in the middle of the back plate, but inevitably when you open one up, there is just a nut inside to hold the screw head in place, its only function being to stop up the hole, and the mic has a standard replacement element with the foam pads.  The original D-104 was designed to mount in a ring, suspended by springs, just like the old double button carbon mics, so the crystal cartridge must have been hard-mounted to the case, and the acoustical isolation was provided by the springs.

The early 30s ads from Astatic mention an "improvement" in the original cartridge a year or two later after the mic went into production, that was supposed to have better frequency response and fidelity than the original.  That may be when they made the change in the mounting configuration, since later "vintage" heads that still have provisions for spring mounting do not have the big screw head in the back plate.  But I'd like to see an original just to learn how they did it when the mic first came out.

BTW, the one I picked up on ePay a couple of years ago has been refurbished and provided with a stock Astatic crystal element that I salvaged from a junk mic that still worked.  I wired it up for high-Z balanced output, and now use it with the push-pull preamp I built last winter.
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ka3zlr
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« Reply #5 on: July 27, 2010, 04:05:22 PM »

But I'd bet real money if you placed that HC5 element in there along with the rest of your collection of Mic's at the stand at your Station you'd get even betta response..an it'd B noticeable I betcha...These elements aren't brickwalled cuttoff for the headroom you enjoy Don you might B surprised.

You will notice a brightness  Smiley

Jack


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W2VW
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« Reply #6 on: July 27, 2010, 04:11:41 PM »

I've tested a number of Kobitones into a very high impedance load and can report they are not up to the task.
Several very vocal X-perts report they are. Too bad the big lie doesn't work for frequency response.
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nq5t
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« Reply #7 on: July 27, 2010, 11:14:58 PM »

But I'd bet real money if you placed that HC5 element in there along with the rest of your collection of Mic's at the stand at your Station you'd get even betta response


There's just something unhappy about turning a D-104 into just one more Heil mic.  Like taking a vintage Rolex shell and sticking a quartz movement in it -- even if it does tell time better than the original ..   Grin

Grant/NQ5T
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W2PFY
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« Reply #8 on: July 28, 2010, 10:13:21 AM »

I think if any of my three D-104 heads fail, I'll convert them to a condenser element.

One thing I have notice that all three of my mic's have a different sound into the same rig and all three have different level outputs as judged by the gain control. I think I'll look at them again for the most pos peaks of each for the same gain setting.
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w4bfs
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« Reply #9 on: July 28, 2010, 01:21:54 PM »

yup Terry .... the 3 wire head connector makes using electrets ok for both interface schemes .... hard to run an electret as balanced output and they are very breath pop sensitive (need lots of foam)...

I've experimented with using walkman earphone / ear buds elements as microphones .... put 3 or 4 identical ones in series, properly phased .... reports received are that they work quite well and sound good ...will generate breath pops too (more foam)...

can even place a series capacitor as a high pass with the corner freq at 500 Hz to 1 kHz and it gives the rising high end response but with phase shift .... still has less voltage output than the crystal element eebts (everything else being the same)
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Todd, KA1KAQ
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« Reply #10 on: July 28, 2010, 01:43:07 PM »

I think the Kobitones got a 'good rep' more as being an available substitute than actually sounding as good as a D-104. The old 'something is better than nothing'. They work, just not as well.

It's been a couple years, but at one point Astatic was still repairing mic heads if you sent them in, but had stopped selling the replacement cartridges in favor of keeping the remainder for their own service. No idea if they still do, IIRC they got sole 4-5 years ago. Might be worth looking into.
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ka3zlr
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« Reply #11 on: July 28, 2010, 02:16:11 PM »

Naaa the HC104 is a perfect fit he sends all the foam and components needed, and for those Ickems that just have to have eletrec condenser feed
he supplies the needed parts.

That man got it covered read the web site information is all there.

Bob is the man....

http://www.heilsound.com/amateur/products/hc104/index.htm

73

Jack.


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kt4ae
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« Reply #12 on: July 28, 2010, 03:33:55 PM »

I bought a handful of the various Kobitones from Mouser several years ago to try in an old Astatic 200 shell I have.   The results were pretty bad to my ear.  I tried the higher impedance 3/4" and the 2" and didn't like the sound of either as recorded without EQ on my son's Yamaha home 4-tracker.  I also put one of the small elements into a dead Peavey shell with the same unsatisfactory results.  It's been a while, but I think the sound was  very thin with almost no low end.

I bought these because at the time the buzz was that they sounded just as good as the real thing.   I can't see it but YMMV.

Harry, KT4AE
Maryville, Tennessee
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KX5JT
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« Reply #13 on: July 28, 2010, 09:15:49 PM »

I have had great success buying junky looking D-104's on ebay for like 10 to 20 bucks....

so far, out of the 3 or 4 I bought the original cartridges inside were fine!

Just a thought...

John KX5JT
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ka3zlr
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« Reply #14 on: July 28, 2010, 09:33:48 PM »

That's a cool way to do it, I couldn't believe what the guys were asking for 104's up at Butler Haa I just walked on.. Smiley

But ya know I'm just as Hooked on antiques as most of the group is I'm thinking, but sooner or later the 104 mystique is
a Fad man they bring in backround noise some of the more better condition ones your fighting with sibilance and ya know this
is 2010 audio has marked it's ground along the way, a guy offers a chance to upgrade the thing I have done this prior to
Bob's offer for myself and a few friends and I've really had no complaints, I mean ya have quite a choice of elements.

I know there not cheap..but hey weight the difference mystique or better performance an keeping the Desk Mic look. Smiley

Time changes try new things.

73

Jack.


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« Reply #15 on: July 29, 2010, 11:32:55 AM »

Sounds like you have not experienced a good working D-104 yet.

the 104 mystique is
a Fad man they bring in backround noise some of the more better condition ones your fighting with sibilance and ya know this
is 2010 audio has marked it's ground along the way, a guy offers a chance to upgrade the thing I have done this prior to
Bob's offer for myself and a few friends and I've really had no complaints, I mean ya have quite a choice of elements.

I know there not cheap..but hey weight the difference mystique or better performance an keeping the Desk Mic look. Smiley

Time changes try new things.

73

Jack.



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ka3zlr
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« Reply #16 on: July 29, 2010, 11:44:21 AM »

No I'm an Experimenter.. We Can dig it.

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W2VW
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« Reply #17 on: July 29, 2010, 11:50:42 AM »

Congratulations.

How much is a box of Wheaties these days anyway?

Nope I just make it up as I go along. I just became a hambone yesterday.


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ka3zlr
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« Reply #18 on: July 29, 2010, 12:04:22 PM »

Congratulations.

How much is a box of Wheaties these days anyway?

Nope I just make it up as I go along. I just became a hambone yesterday.




Gotta Snack some Wheaties the man says:



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ka3zlr
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« Reply #19 on: July 29, 2010, 12:31:51 PM »

Congratulations.

How much is a box of Wheaties these days anyway?

Nope I just make it up as I go along. I just became a hambone yesterday.




Are you concerned about my Fiber Intake I eat a balanced diet that the Doctors give me to follow.

Is there anything else ..??

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Steve - WB3HUZ
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« Reply #20 on: July 29, 2010, 12:40:48 PM »

In the works of Tarantino, a predominant concept is the distinction between without and within. It could be said that the premise of neodialectic deappropriation suggests that language serves to disempower the underprivileged. If semantic precapitalist theory holds, we have to choose between the neosemanticist paradigm of context and textual rationalism.

The primary theme of the works of Tarantino is the failure, and eventually the absurdity, of subdialectic truth. Thus, Foucault suggests the use of neodialectic deappropriation to deconstruct hierarchy. Reicher implies that we have to choose between Debordist situation and subdialectic materialist theory.
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W2VW
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« Reply #21 on: July 29, 2010, 12:54:09 PM »

Yes, I looked at several pages of google for a frequency response graph of a Heil HC-5 so I could post it next to that of a properly terminated D-104 and only found some specs which said 300-8K with a rise at 2K. Run-on sentences are my speciality.

Do you have access to such a graph?

Congratulations.

How much is a box of Wheaties these days anyway?

Nope I just make it up as I go along. I just became a hambone yesterday.




Are you concerned about my Fiber Intake I eat a balanced diet that the Doctors give me to follow.

Is there anything else ..??


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KB2WIG
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« Reply #22 on: July 29, 2010, 12:55:34 PM »

I use air for my diaelectric material.


klc
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ka3zlr
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« Reply #23 on: July 29, 2010, 01:14:03 PM »

Yessum. these catz got the answer for ayaething...if you can't build it or scared to it ain't my problem.
Dig that Quoting tarantino I feel important now Elated....



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k4kyv
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Don
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« Reply #24 on: July 29, 2010, 01:17:29 PM »

I refurbished the early model D-104 I got off the ePay auction that was posted on this site a  couple of years ago.  The element was bad, but I salvaged a good one from a junk D-104 I picked up from an antique shop.  I wired it for high-Z balanced output, using a 2-conductor shielded cord to feed the push-pull pre-amp I built last winter. Reports tell me that the balanced output D-104 standing alone sounds almost as good as the two mic combination I have used for decades.  The total resistive load on the mic is 20 megohms (10 megs of grid leak at each tube), but the plate current in each of the push-pull high mu triodes seems balanced and stable enough although this far exceeds the maximum recommended grid resistance per the RCA manual. The pre-amp unit has a built-in pre-emphasis curve in addition to the acoustical peak that comes with the D-104 crystal.

The early D-104 heads are 3/16" thicker than the ones made after 1937.  I have tried the same element in both heads, and the old thicker one seems to have slightly better low end, maybe due to the larger air cavity surrounding the element, or it may just be a placebo effect. But I would like to see one of the original first edition elements just to find out exactly how it was constructed and mounted. There may not be any still in existence (pre-1935) that actually works.

I use a slightly elastic fabric cord to suspend mine, instead of the springs.  I have a spring mounted desk mic (but I hate desk mics) and you can hear the springs vibrate whenever the mic is tapped.  It actually sounds kind of cool to pluck the springs while transmitting. The fabric cord (per PA0ASD) does a better job of acoustical isolation.

PA0ASD 1935 video at 2:15
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Don, K4KYV                                       AMI#5
Licensed since 1959 and not happy to be back on AM...    Never got off AM in the first place.

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