Using a D-104 with the 6300

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  • Updated 4 years ago

I wired up a D-104 to my Flex 6300.

The PTT keys up right away but audio is not accepted for 1.5 seconds both on AM and SSB

On SSB you don't even got ANY RF for 1.5 seconds. ON AM when I key PTT the carrier is immediate. but audio is delayed 1.5 seconds. The FHM-1 mike works normally.

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Burt Fisher

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Posted 4 years ago

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Ken - NM9P, Elmer

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Check whether your D104 is getting is power for the internal preamp from batteries or from the rig, and which line it it trying to get voltage. It may not be getting its power. You may have a weak battery, or have BIAS in the improper position and it may be causing basing problems.
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Burt Fisher

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I unkeyed the 20DB icon in the setup and the delay stopped, why? ( I did have to max out the gain).
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Ken - NM9P, Elmer

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Perhaps the +20 dB preamp over dives the compressor, resulting in overshoot until the compressor catches up? In any case, I'd you can get adequate drive without it, leave it off.
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np2g

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WOW!!! I buried my D-104 20 years ago .
(Edited)
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Burt Fisher

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Dig it up, it is much better than the stock mic
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Jim Bryce W5HFS

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Original D-104 had no amplifier and is what I use with my Collins equipment. Has anyone tried an original D-104 without an amplifier?
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James Kirk

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The original D-104 is designed to be used with a very high impedance as was the norm for vacuum tube inputs in the order of megohms. It will of course work with modern radios usually on the order of 600 ohms however it will not have the low end response normaly present when working into a high impedance. It will still have the characteristic peak at 2000 Hz which adds to clarity.
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Ken - NM9P, Elmer

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Original D104 is a VERY high impedance Mike designed for older tube type rigs. A modern rig will load it down and drastically alter the audio response curve. This is why they added a "preamp" which is more for impedance matching than for amplification.
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Burt Fisher

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I get much better reports with the D-104 than the stock mike
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Steve W6SDM

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One way to avoid the impedance issue with the D104 is to use the Heil conversion kit.  The new element fits in to replace the old one - a little bit of construction is required.  My D-104 restoration was mostly about nostalgia, although I do use the mic from time to time.  I have always got excellent reports with my restored D-104.  Mine does not have a pre-amp, it's one of the 1960s models.

Here's one source for the Heil HC-104 restoration kit at DX engineering.  http://www.dxengineering.com/parts/hls-hc51retrokit


This is my D-104 after I refurbished it and put it into use when I still had my 5000. 

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np2g

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If you must use the d-104. Then this is your best bet. Re element the puppy.
Otherwise you sound like your shorts are too tight.
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Burt Fisher

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I had a Heil PR-781 and the unmodified D-104 got better reports
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Jay -- N0FB, Elmer

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Possibly better reports because the impedance of the D104 was a closer match with the rig you were using at the time than the 781.  If you have a large impedance mismatch, your audio is going to be awful.  This is not a statement about the Heil element, it is about using the appropriate mic for the job.

I know you can can wire the D104 to the Flex, the question is why would you want to?  That you can do a thing, does not mean that you must or should do a thing.
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Steve W6SDM

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In my case, going to the trouble of restoring a D-104 was just for the nostalgia of having a mic that's been around since the 1930s hooked up to a modern radio and working.  I also did a lot of cosmetic work, buffing out the chrome to a gleaming shine.  I replaced the cord with shielded audio cable and an 8-pin connector for to fit my Flex.  I don't use this daily because I don't like using the grip-style PTT switch, but it's more of a novelty in the shack - much like my restored, vintage Vibroplex bug.
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Burt Fisher

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Because I got reports that the FMH stock mike sounded like I was talking on a telephone.
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Ken - NM9P, Elmer

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The FHM-1 will never sound as good as a quality studio Mike, but compared to many hand mikes it is pretty good. Here are a few hints to improving the sound quality...

1) make sure the slide switch is in the "wide" response position.

2) use the TX EQ to balance the audio response , cutting bass and boosting treble as necessary. Use the zoomed pan adapter to visualize the pattern as you make adjustments. Listen in a second receiver, preferably recorded and played back, and eliminate peaks and holes in your audio until it sounds good.

3) use appropriate amounts of compression (NOR, DX, DX+) to keep levels steady and Increase average talk power.

4) talk across the face of the Mike at a distance of about 2 inches.

Ken - NM9P
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Burt Fisher

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You know your stuff. My mike is not marked wide, just #1 #2.
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James Kirk

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 Tone setting 1, which is the default setting has a flat frequency response of 60Hz -16kHz and Tone setting 2, which rolls off some of the low-end frequencies (-6 dB @ 300 Hz) along with a +3 dB increase at 2 kHz for optimum articulation needed for DX/Communication quality audio.
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Burt Fisher

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It was set at #2, so for best quality, #1 would be better?
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Ken - NM9P, Elmer

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I would suggest setting up a "rag chew" profile using setting #1 and saving it. Then modify it to a DX profile by boosting the treble a LITTLE at 1 & 2K and perhaps raising the low TX cut odd to 200 Hz, depending on your voice and increasing the Compression to DX or DX+. Let the TX EQ do the work and leave the Mike switch in full range #1 setting.

Be sure to save it as a separate TX profile.
(Edited)
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Tim - W4TME, Customer Experience Manager

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The FHM-1 microphone has a tone control switch on the back of the microphone that is used for adjustment of the microphone's frequency response. 

Setting the Tone switch to the "1" (left) position will enable a wider frequency response, resulting in higher fidelity audio.  It is recommended that the Tone switch be set in the 1 position and use the software EQ to tailor the tonal qualities of the microphone with your voice. 

Setting the Tone switch to the "2" (right) position will roll off the bass frequency response resulting in more audio energy in your transmitted signal.  However the same effect can be achieved by setting the Tone switch to the 1 position and using the software EQ to reduce frequencies in the 50-400 Hz range.
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Ken - NM9P, Elmer

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Just noticed that "cut odd" in my previous post should read "cut off" frequency..... I hate auto correct!
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np2g

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D104
It has an impedance issue.Keep it attached to legacy gear . Rumors have it that Ten Tec Radios sound good with the D104  The hand held mike  . Mine sounds terrible.  Also there are better mikes out there than the 781 . (And it is not the price) 

You cannot make any mike sound great if it does not reproduce the correct information. 
No amount of EQ will do this .No tone switch 1  2 . NADA 

And throughout this discussion nary a mention of where the transmit hi / low cut  is set. Testing the "Quality" .

I guess the first thing we loose as we get older is our hearing.. 
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Steve W6SDM

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"
I guess the first thing we loose as we get older is our hearing.. "

Nope.  It's not.  My hearing is fine.  I wish i could say the same for everything else though.  :)
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geep

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I just rebuilt my D 104 Silver Eagle with a W2ENY kit, and had the same delay issues.  After reading the posts here, I began experimenting with various levels and found that when I adjusted the mike preamp gain to about mid point, turned off the 20 dB boost on my 6700 and set the mike gain with a default profile at about 30, the delay went away.  Seems odd that the input circuitry is responding like this, but the adjustments fixed the problem and the mike sounds reasonable ( in the monitor circuit, haven't put it on air yet.)  I do find it is now very sensitive to breath noises, so I am going to open the head back up and add a layer of thin foam rubber ahead of the element, like a pop filter on a handheld mike in hopes to get rid of that problem.
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Tim - W4TME, Customer Experience Manager

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To address the delay, make sure that the mic cable shield is connected to the Foster connector shell and that it is asl connected to mic-; the input is unbalanced and if the cable shield is not grounded, it makes a good antenna.