Need some D-104 input

[AF9J]

Hi Everybody,

You guys are a great group, and your input, and assistance has been beyond  appreciated.  As some of you may remember, I've briefly mentioned in the past, that I was on AM for a very short time back in 1995 (before TVI issues drove me off).  The setup was a Ranger 1, an HQ-110, and an Astatic D-104 mic (I bought it brand new from AES in Milwaukee).  I've always loved the look of the D-104 (very cool).  Unfortunately, I sold my old D-104 off at least 10 years ago (oh well, it was one of the amplified ones [I didn't realize it at the time I bought it], which are a mixed bag for decent audio).  Well, I want to get another D-104.  Unfortunatley, Heathkit, didn't list in the manual I have (thanks for the copy Bob!) the mic impedance requirements for the Cheyenne. Since it's hollowstate, I'll assume that like most hollowstate designs, it requires a high impedance mic.  Since the D-104 was discontinued 3 or 4 years ago, I'm going to have to look online for a used one

Would you guys have any info, on what models of the D-104 I should look for, that are high impedance?  I naturally want to avoid the low impedance versions, and the junky, Roger Beep models that were made for CB.  I also prefer the the ones that have the PTT lever on the neck, and NOT the base.  Well, I'd better get going. Time for my 27 mile commute to work.

73 & have a good day,
Ellen - AF9J

[K3ZS]

Ellen-
You want the plain old D-104 with the UG8 stand.   This is marked on the base of the mike stand.   The one with the preamplifier is marked T-UG8.   For older transmitters you don't want the one with the preamplifier.   They are still commonly found at pawn shops, flea markets and on ebay at reasonable prices at around $25.

[K3ZS]

I just checked epay, most of the D-104's available have the preamplified base.    I believe the head is the same on all models.   I suppose that if you remove or rewire the base to bypass the preamp, it would function the same as the one without the preamp.   My estimate of $25 may be too low if you use on-line sources.   I found mine for $10 a few years ago at a hamfest.

[K3ZS]

Sorry for the repeated postings.   I checked on completed auctions on ebay, the ones without the preamps generally sell for less.   The older ones without the preamp also are identified by the "G Stand" on the base.

[AF9J]

That's OK Bob. Thanks for the info!

73,
Ellen - AF9J

[WBear2GCR]

The usual plan if you use the D-104 direct into a tube front end is to remove the input resistor (the one to ground) and dump in a 10 to 20 Megohm resistor in its place.

Otoh, a D-104 WITH an amplified base can be a bonus, since it contains a battery clip for a 9v battery. That is good if you put a single JFET "impedance converter" circuit into the base. That is merely a follower circuit using a JFET - no gain. Since the JFET has a scary high input impedance the mic element "sees" the JFET as a nearly optimal high-Z, but the follow configuration of the JFET makes that output fairly low-Z, for driving the mic input of the rig.

There are a number of good schematics for the circuit floating about, including some in past threads here on amfone.net.

What you should know is that all of the crystal mic elements in D-104s are NOT equal in quality, frequency response or overall sound. AND, some are simple weak or dead. Also there were some mic elements that were ceramic elements, not crystal - different beast entirely. Most were the crystal type.

Also, one that was used extensively by a smoker will be tough to get the smell out of... you can take the thing apart, and remove the fiberglass or felt that sits in front of the element (probably not a bad idea anyway) and clean the metal parts, but the elementi itself can not be cleaned, so that may be a consideration for you.

The other option is to replace the Astatic element with another type of mic element entirely, assuming you like the 'look and feel' of the "chrome lollypop" that is...

                    _-_-WBear2GCR

[AF9J]

Putting in a 10 or 20 Meg resistor.  Hmmmm, that's a thought Bear.  Although, I always assumed that if you ran too high of an impedance the mic output would get too low (in spite of the audio benefits very high impedance can give you).  Also, you brought up a very good point about used mics.  They can be very yecchy when you get them.  I'm not a smoker (never was, and frankly, my asthma would freak out if I smoked), so if I wind up with a smoker's mic, I'd have to do some serious cleaning (besides, I can't stand the semll of cigarettes).   

BTW, I dig your avatar, a polar bear singing into a mic that kind of looks like an SM-58 (my fave mic for singing [I had a personal one I took to every gig I played]), with a guitar strapped across his back (yes, I'm a chick lead guitarist [it was fun giving some of the so-called hotshot guy axesligers the fits, who thought the first few rehearsals, that I couldn't keep up with their playing, LOL!!]).

73,
Ellen - AF9J

[Todd, KA1KAQ]

5 meg input resistor should be sufficient. I used a 4.7 meg in my transmitter (12AX7 amp), sounds just fine. You might want to experiment with your particular transmitter to see what best suits your voice.

The crystal head is the one you want, it sports a black tag on top. Astatic also made a ceramic version, with a green tag. The best thing to do is try out the mic before buying, seldom an option. Crystals that have been banged around, sat in damp, hot, or otherwise-compromising environments should be avoided if possible. Not sure why an older crystal head would sound better than a newer (70s/80s-on) head - perhaps the quality of materials used. My baseline D-104 came with the transmitter and pile of stuff I got back in '88, and it was old then. It's always worked great, even though I dropped it twice in the last few months. *THUD*!Talk about a noise that will make you cringe! 

Go with a 'straight', or unamplified stand. Or you can rip the crappy little amp out of it and wire it straight through, if desired. Address any need for amplification or equalization elsewhere.

Although not a perfect filter, I've found that the Astatic stands you see at hamfests/fleamarkets with the straight, black cords are usually the older style without the amp. Sometime in the 70s (maybe earlier) the coiled cord was added, or straight gray cord. You can also check the type of tag, method of attachment, and so on. Older tags are metal, held on with rivets, newer are metallic with adhesive holding them on. Even the font used on the tags is a clue to age.

Get a good mic head, get the set dialed in where it sounds decent, then you can experiment with other mics, equalization, and so on. The D-104 isn't the best mic for every application or situation, but most agree that it is the overall best with respect to minimum modifications/maximum results. There's a reason they are so prevalent. 

[WBear2GCR]

Putting in a 10 or 20 Meg resistor.  Hmmmm, that's a thought Bear.  Although, I always assumed that if you ran too high of an impedance the mic output would get too low (in spite of the audio benefits very high impedance can give you).  <snip>

No, the opposite happens...  the mic is unloaded so the output rises to nearly maximum... In the case of crystal mic carts, the unloading also effects the shape of the frequency response curve, the least loaded being the flattest and and having the least LF rolloff.

BTW, I dig your avatar, a polar bear singing into a mic that kind of looks like an SM-58 (my fave mic for singing [I had a personal one I took to every gig I played]), with a guitar strapped across his back (yes, I'm a chick lead guitarist [it was fun giving some of the so-called hotshot guy axesligers the fits, who thought the first few rehearsals, that I couldn't keep up with their playing, LOL!!]).  73,
Ellen - AF9J

Thanks!  That's what I really look like... 
And I do play a little guitar, but I can't sing worth a damn... no voice 
Not so sure about my so-called guitar playing either...


           _-_-WBear2GCR

[N3DRB The Derb]

I'm wondering if the presence rise in the D-104 would not sound so good on the typical female voice.  I think it would be very peaky sounding on a womans voice. I think flatter with a bump in the mid bass area from 300 to around 1K would be better but of course I dont know how "female" Ellens voice is. 99%+ of amers are dudes, and what works for us may not be good. I would think you'd want to bump the mid lows, slightly scoop the 1k to 3K range, and then rise again above 3k so your s's and f's stand out.

anybody else got an opinion?

[AF9J]

Gee Derb,

You had to go and complicate things didn't you!  Now I have to worry about sounding too upper midrangey with the typical mic mods!  I don't sound like Goldie Hawn, but by the same token, I certainly don't sound like Suzanne Pleshette from the Bob Newhart Show. I'm in-between pitchwise, and tonewise.  Hmmm how do I put it.  Have you ever heard of a group called "The Donnas?"  Listen to the singing on the song "Don't Break Me Down", off of their album "Gold Medal" (which was released in 2004), and you'll get a pretty good idea of my voice.   Waaaaaa!!!! Why must everything be shades of gray!!!!!!    LOL!!   OH well, I guess I could just run an outboard EQ (so much for a compact station).

73,
Ellen - AF9J

[W1GFH]

You might check out some old crystal mics which don't have the D-104's artificial rise at 2500 Hz, like the Astatic JT-30, Turner 22X, etc. Don't know what Miss Cheyenne has in her speech amp, some rigs have frequency shaping LC networks designed to give that 2500Hz bump or limit everything below 500 Hz and above 3K. I would suspect that the Cheyenne has some frequency shaping before and after the speech amp so that the supplied ceramic mic would sound punchy. Stock 1960s rigs were all about "punch", not hi-fi.

EDIT - Yup. http://www.vintage-radio.info/heathkit/diagrams/mt-1.gif

[k4kyv]

I'm wondering if the presence rise in the D-104 would not sound so good on the typical female voice.  I think it would be very peaky sounding on a womans voice. I think flatter with a bump in the mid bass area from 300 to around 1K would be better but of course I dont know how "female" Ellens voice is. 99%+ of amers are dudes, and what works for us may not be good. I would think you'd want to bump the mid lows, slightly scoop the 1k to 3K range, and then rise again above 3k so your s's and f's stand out.

anybody else got an opinion?

I'm aware of how hyellowey a woman's voice sounds on slopbucket.

[WBear2GCR]

Fwiw, Mah-cee sounds "ok, fine!" on Tim's rig...

            _-_-WBear2GCR

[Steve - WB3HUZ]

Eh, get the D-104 and try it. If it doesn't sound good, sell it and try another. I see tons of them for sale at fests, so getting one should be easy.

[W2VW]

Things are easier with an MPF102 fitted into the mic stand. The transmitter might have a layout that can be problematic with a simple grid resistor swap. Hum can be a problem where it once was not. Easy to convert the impedance inside the mic and then it can also be used on other rigs. Also makes for easy experimentation when someone wants to re-invent the wheel. A 9 volt battery and switch will have to be used though. The on/off PTT isn't fast enough for the circuits commonly seen.

[AF9J]

Hi Joe,

Hmmmm.  Now I'm worried.  A lot of you think I may end up dealing with a midrage boost in my audio, if I use a D-104.  That would make me sound honky.  I hate midrange honk.  The only audio experience I have (with the exception of fooling with practice PAs to set up vocal mics), is with guitar amps.  Most guitar amps that are based upon 50s & 60s designs (such as Fender, Vox, and Marshall amps), are quite midrangey.  Since even these type of amps (which are not even ment for vocal applications [although Marshall did market PA versions of their amps that only had minor differences from the guitar amps]), are this way, I have to assume that the speech amp in the Cheyenne is too. For some reason, the whole idea of a V-shaped (as seen on a graqphic EQ) audio profile didn't seem to start occurring until at least the 70s. Just listen to the rock & roll records from the 50s & 60s - they all sound midrangey (and using a standard graphic EQ profile to listen to them, makes them sound pretty bad). Some of this is probably due to technological limitations, some of it (I think) is just due to listener preferences at the time.

BTW - I would use the stock mic for the Cheyenne, but it didn't come with it. It came with an EV (I think) bannana style (like Ten Tec would sell you for their rigs in the 70s) mic.  There was no PTT switch on it, or not even a base for it.  I can't find it, so I think I might have tossed it.  So, I'm at Square 1 for a mic.  I took a look at the JT-30.  It's basically considered a classic mic for Blues Harmonica.  I've seen blues harp players use them.  That must have one heck of a frequency profile, to deal with the screech of a Harmonica.

73,
Ellen - AF9J

You might check out some old crystal mics which don't have the D-104's artificial rise at 2500 Hz, like the Astatic JT-30, Turner 22X, etc. Don't know what Miss Cheyenne has in her speech amp, some rigs have frequency shaping LC networks designed to give that 2500Hz bump or limit everything below 500 Hz and above 3K. I would suspect that the Cheyenne has some frequency shaping before and after the speech amp so that the supplied ceramic mic would sound punchy. Stock 1960s rigs were all about "punch", not hi-fi.

EDIT - Yup. http://www.vintage-radio.info/heathkit/diagrams/mt-1.gif

[Steve - WB3HUZ]

Things are easier with an MPF102 fitted into the mic stand. The transmitter might have a layout that can be problematic with a simple grid resistor swap. Hum can be a problem where it once was not. Easy to convert the impedance inside the mic and then it can also be used on other rigs. Also makes for easy experimentation when someone wants to re-invent the wheel. A 9 volt battery and switch will have to be used though. The on/off PTT isn't fast enough for the circuits commonly seen.

Like this. TNX to Dave.

[W2VW]

Yeah only THAT one was not designed in SP land.

[WBear2GCR]

Hi Joe,

Hmmmm.  Now I'm worried.  A lot of you think I may end up dealing with a midrage boost in my audio, if I use a D-104.  That would make me sound honky.  I hate midrange honk.

The D-104 will not sound "honky" if you use a FET in the base as a follower, AND the mic element isn't shot.

It is simple enough to throw ur rig into a dummy load, and monitor on ur receiver, even record it.

>  The only audio experience I have (with the exception of fooling with practice PAs to set up vocal mics), is with guitar amps.  Most guitar amps that are based upon 50s & 60s designs (such as Fender, Vox, and Marshall amps), are quite midrangey.  Since even these type of amps (which are not even ment for vocal applications [although Marshall did market PA versions of their amps that only had minor differences from the guitar amps]), are this way, I have to assume that the speech amp in the Cheyenne is too.

Don't assume anything. Test.

> For some reason, the whole idea of a V-shaped (as seen on a graqphic EQ) audio profile didn't seem to start occurring until at least the 70s. Just listen to the rock & roll records from the 50s & 60s - they all sound midrangey (and using a standard graphic EQ profile to listen to them, makes them sound pretty bad). Some of this is probably due to technological limitations, some of it (I think) is just due to listener preferences at the time.

Ellen, I have no idea what ur talking about here!??
Many recordings from the 50s and 60s are just fine.
A whole lot of them did lack LF response, but that is because the equipment in the recording/pressing chain did not support LF extension. Try listening to some of the re-issued pressings of vintage rock from companies that care - Sundazed it one (local too). The sound is just fine.

Listening back to old pressings on a good system can be surprisingly good.

BTW - I would use the stock mic for the Cheyenne, but it didn't come with it. It came with an EV (I think) bannana style (like Ten Tec would sell you for their rigs in the 70s) mic.  There was no PTT switch on it, or not even a base for it.  I can't find it, so I think I might have tossed it.  So, I'm at Square 1 for a mic.  I took a look at the JT-30.  It's basically considered a classic mic for Blues Harmonica.  I've seen blues harp players use them.  That must have one heck of a frequency profile, to deal with the screech of a Harmonica.

73,
Ellen - AF9J

Try ur SM-58. It will work fine. Use an external switch or footswitch for PTT.
Done.

The old JT-30 is selected for harmonica playing because it breaks up nicely when it is pushed by the closely coupled harmonica...

Ellen, u've got an Extra class licence? AF9J sounds like an Extra...
If so, you've gotta jump in a get ur feet wet.
Just go and try stuff.

As I said, a regular dynamic mic will work fine.
Test ur rig's freq response, and get that flat or curved internally as you like.
That's where the fun is... go for it!

          _-_-WBear2GCR

[W1GFH]

As I said, a regular dynamic mic will work fine.
Test ur rig's freq response, and get that flat or curved internally as you like.
That's where the fun is... go for it!

          _-_-WBear2GCR

I gotta agree with Bear. Why speculate when you can get the facts? Do a frequency sweep test on the Cheyenne (K1JJ has posted methods in the board's tutorial section).  This'll give you baseline regarding what any mic is seeing at the input.

[AF9J]

Yeah, I know Bear.  I just can't afford to cough up a lot of money expirimenting.  So I'm trying to save myself (as much as possible) from expensive failures.  And yes I'm an Extra ( been one since 1994), and I've built QRP rigs, and restored my Kenwood TS-820.  I'm probably going to go with a D-104, and expiriment with it.  It sounds like the best way to go..

73,
Ellen - AF9J

[W1GFH]

Anyhow, I think all this fretting is premature. You are going to have a PW signal with the Cheyenne and will need some audio punch. Additionally, study the skizmatic of Cheyenna's speech amp, a buncha L-C at the input, probably intended to shape input for optimum performance in a mobile environment.

[WBear2GCR]

Yeah, I know Bear.  I just can't afford to cough up a lot of money expirimenting.  So I'm trying to save myself (as much as possible) from expensive failures.  And yes I'm an Extra ( been one since 1994), and I've built QRP rigs, and restored my Kenwood TS-820.  I'm probably going to go with a D-104, and expiriment with it.  It sounds like the best way to go..

73,
Ellen - AF9J

Zero dollars, unless you count some patch cables.

Computer + freeware = FFT tester of significant capabilities
Computer + freeware = audio signal generator of significant capabilities

All you need to check the audio on ur transmitter is right there.

Got a 'scope? even easier...
No scope?
Time to get one!
They're pretty darn cheap these days for any post 1975 Tektronix... you want a 100Mhz scope or better, then ur ok.
Can't be a ham on AM without a scope... 

Ellen, you said you sounded best on an SM-58, right?
So, why not use an SM-58? Or at least a mic that uses the same element... you can buy elements, and retrofit them as you wish - of course you may not get the identical polar pattern in a different package, but in this case it's no big deal.

Build one of the FET followers for the D104 and you'll have less to think about.

                _-_-WBear2GCR

[AF9J]

A very good point Joe.  OK, a D-104 it is for now. It'll give me a baseline to start with, and I can take it from there.  Thanks for the suggestions from you, Todd, and Bear.  You guys are great.  It looks like I'm putting the cart before the horse.  I think I need to look into a baseline first, before I start going crazy (hmmmm, maybe I should bring home that audio generator from work, that's in my office, that nobody uses, and sweep the freqs).  Also, as has been said, since I can't strap powerwise since I live in an apartment building (without risking the same disastrous RFI results I had back in 1995, when I was last on AM), I may want to have a little less fidelity, and a little more punch to get through.  Bear, I wish I had the SM-58, it's gone.  I gave it to my best friend to use for her home recording studio setup a couple of years ago.  I think I'll wait on that.  Right now, I need to concentrate more upon getting the rigs going.  It looks like i'm getting way ahead of myself.  As for an O-scope:  Yeah, that might end up being in my future.

73 to a great group
Ellen - AF9J