开云体育

Yes. The path through the 470K is a high level input intended for ceramic, crystal, and other high output mics. That is where the UG stand variants with a D-104 head should be connected regardless of whether the preamp is used or not. It also has the benefit of bumping up the load resistance that the "naked" D-104 cartridge sees.

You can always add it to the TR5. It was also not present in very early production TR7s unless added by Drake service.

73

-Jim
NU0C

On Fri, 23 Feb 2024 17:00:30 -0800
"Paul Christensen" <w9ac@...> wrote:

Looking at the Drake Service Manual, the TR7 engineering gang included a 470K mic input resistor between pins 1 and 4 on the mic connector.? That gives the TR7 owner the option of using it on pin 1, or excluding it on pin 4.? That's in addition to a ~150K resistor at the base of the mic preamp transistor. Interesting, it's not like that on the economically downsized TR5.

Paul, W9AC

Ah.
I didn’t look at that page I guess.
Thanks a bunch for the info.
Ed

Naw, just look at the structure of the URL and see if it contains extra junk beyond the base address. It's like shortening a eBay link. It doesn't always work out but it seems to more often than not.

Note: I am not a html programmer or internet guru. I just pick up tricks like this as I go through life. :)

73

-Jim
NU0C

On Fri, 23 Feb 2024 16:33:59 -0800
"Paul Christensen" <w9ac@...> wrote:

Yup, I shoulda' used TinyURL.

On page 17 in the replacement cartridges. If you have a MC-563 then your head model is probably a 10DA.

73

-Jim
NU0C

On Fri, 23 Feb 2024 18:28:48 -0600
"Ed KG5UN" <maikranze@...> wrote:

Nope.
I saw nothing there that will help me identify exactly what mic I have.
Ed


On Fri, Feb 23, 2024 at 6:26?PM Jim Shorney <jimNU0C@...> wrote:

The link to the Astatic catalog that I posted should help you. Note that
the nomenclature for the head and the stand are different.

73

-Jim
NU0C

On Fri, 23 Feb 2024 18:01:50 -0600
"Ed KG5UN" <maikranze@...> wrote:

Sorry if I am hijacking the thread, but I wanted to ask a question.

I have a model 10 Astatic mic with no data plate on it.
It has the MC-563 element in it.
Would that make it a 10C or a 10D?
I really dont care for the way it sounds, would the 470K ohm resistor

help?

Thanks,
Ed
KG5UN

On Fri, Feb 23, 2024 at 5:52?PM Jim Shorney <jimNU0C@...> wrote:

I suppose you mean the D-104-C? In catalog 197 it is listed only 3 dB
lower than the crystal version. Interestingly they don't specifically

say

which is in the T-UP9-D104 "Silver Eagle". That suggests to me that at

some

point they did begin to quietly phase out the crystal and replace them

with

ceramic. Who's going to know? You would have to open one up and few

would

want to do that. I have a garage sale find Golden Eagle and two T-UG8
models all gelded with the 470K resistor mod. I used the Golden Eagle

on my

TR7 for a while. I still plug it in now and then for fun. It looks like
hell, the lacquer coating on the stand neck is trashed. I also have a

NOS

cartridge tucked away in a drawer but I'm not going to cut it open.

Maybe I'll replace those 470K resistors with low noise film

resistors... :D

Admittedly it may be urban legend that the crystal cartridge was phased
out in later years but I have heard and read about it being so since
sometime in the late 70s. Another bit of lore is that you can "make it
sound better" by poking a pin hole in the diaphragm but I think all of

us

here are smarter than that. Take it all for what it's worth.

Here's a reference that appears to be wrong based on catalog info:



Some nice pics on this page:



Does anyone remember seeing the D-104 on a short non-G stand (probably

an

E-1 stand) used as a broadcast mic in the SciFi channel Battlestar
Galactica reboot?


73

-Jim
NU0C

On Fri, 23 Feb 2024 12:48:05 -0800
"Richard Knoppow" <1oldlens1@...> wrote:

Astatic made another model the C-104 with a ceramic element. Very
similar except the output is about 10db lower. This is for the

element

alone. If there is an amplifier the output levels are probably the

same.

I have not searched for a data sheet on the C-104.
Astatic made ceramic versions of many of their crystal mics and
crystal phono pickups. The ceramic has the advantage of not being
vulnerable to heat or moisture.

On 2/23/2024 8:51 AM, Jim Shorney wrote:

My "secret" is to do away with the amplifier and replace it with

a

series 470K resistor. This is actually an old-timer's trick to mellow

out

the frequency response of the D-104 head. The amplifier is enhanced
uselessness for our radios. It will happily drive just about any radio

this

way and you get rid of a failure point (actually two if you consider
potential battery leakage). This works with any T-UGxx stand.

My understanding is that later D-104 heads used a ceramic

cartridge.

The same fix applies. The D-104 head likes to see a high impedance

load,

the higher the better.

I have three T-UGxx variants that I have done this to and tested

on

the air with good reports. And they can be used with VOX.

73

-Jim
NU0C

--

73

-Jim
NU0C

--

73

-Jim
NU0C

--

73

-Jim
NU0C

>"That gives the TR7 owner the option of using it on pin 1, or excluding it on pin 4."

Sorry, a moment of dyslexia.? It should read the other way... including it on pin 4, excluding?it on pin 1.?

Paul, W9AC

Looking at the Drake Service Manual, the TR7 engineering gang included a 470K mic input resistor between pins 1 and 4 on the mic connector.? That gives the TR7 owner the option of using it on pin 1, or excluding it on pin 4.? That's in addition to a ~150K resistor?at the base of the mic preamp transistor.??Interesting, it's not like that on the economically downsized TR5.

?

Paul, W9AC

>"Word wrap broke your link. This should fix things."

Yup, I shoulda' used TinyURL.? Clean PDFs of the same articles from Jim, K9YC are attached.

Paul, W9AC

?

Even shorter.



On Fri, 23 Feb 2024 18:20:11 -0600
"Jim Shorney via groups.io" <jimNU0C@...> wrote:

Word wrap broke your link. This should fix things

--

73

-Jim
NU0C

The link to the Astatic catalog that I posted should help you. Note that the nomenclature for the head and the stand are different.

73

-Jim
NU0C

On Fri, 23 Feb 2024 18:01:50 -0600
"Ed KG5UN" <maikranze@...> wrote:

Sorry if I am hijacking the thread, but I wanted to ask a question.

I have a model 10 Astatic mic with no data plate on it.
It has the MC-563 element in it.
Would that make it a 10C or a 10D?
I really dont care for the way it sounds, would the 470K ohm resistor help?

Thanks,
Ed
KG5UN

On Fri, Feb 23, 2024 at 5:52?PM Jim Shorney <jimNU0C@...> wrote:

I suppose you mean the D-104-C? In catalog 197 it is listed only 3 dB
lower than the crystal version. Interestingly they don't specifically say
which is in the T-UP9-D104 "Silver Eagle". That suggests to me that at some
point they did begin to quietly phase out the crystal and replace them with
ceramic. Who's going to know? You would have to open one up and few would
want to do that. I have a garage sale find Golden Eagle and two T-UG8
models all gelded with the 470K resistor mod. I used the Golden Eagle on my
TR7 for a while. I still plug it in now and then for fun. It looks like
hell, the lacquer coating on the stand neck is trashed. I also have a NOS
cartridge tucked away in a drawer but I'm not going to cut it open.

Maybe I'll replace those 470K resistors with low noise film resistors... :D

Admittedly it may be urban legend that the crystal cartridge was phased
out in later years but I have heard and read about it being so since
sometime in the late 70s. Another bit of lore is that you can "make it
sound better" by poking a pin hole in the diaphragm but I think all of us
here are smarter than that. Take it all for what it's worth.




Here's a reference that appears to be wrong based on catalog info:



Some nice pics on this page:



Does anyone remember seeing the D-104 on a short non-G stand (probably an
E-1 stand) used as a broadcast mic in the SciFi channel Battlestar
Galactica reboot?


73

-Jim
NU0C

On Fri, 23 Feb 2024 12:48:05 -0800
"Richard Knoppow" <1oldlens1@...> wrote:

Astatic made another model the C-104 with a ceramic element. Very
similar except the output is about 10db lower. This is for the element
alone. If there is an amplifier the output levels are probably the same.
I have not searched for a data sheet on the C-104.
Astatic made ceramic versions of many of their crystal mics and
crystal phono pickups. The ceramic has the advantage of not being
vulnerable to heat or moisture.

On 2/23/2024 8:51 AM, Jim Shorney wrote:

My "secret" is to do away with the amplifier and replace it with a

series 470K resistor. This is actually an old-timer's trick to mellow out
the frequency response of the D-104 head. The amplifier is enhanced
uselessness for our radios. It will happily drive just about any radio this
way and you get rid of a failure point (actually two if you consider
potential battery leakage). This works with any T-UGxx stand.

My understanding is that later D-104 heads used a ceramic cartridge.

The same fix applies. The D-104 head likes to see a high impedance load,
the higher the better.

I have three T-UGxx variants that I have done this to and tested on

the air with good reports. And they can be used with VOX.

73

-Jim
NU0C

--

73

-Jim
NU0C

--

73

-Jim
NU0C

With a TR7 I use the high level input which puts the total load on the cartridge to a around 1 Meg. What the higher load does is bring up the low end response (see attached graph). There's not much more you could get with a JFET. You could go even higher with the resistor value until you get into the low pass filter effect of the cable capacitance or the point of not enough drive to the radio. Just my personal opinion but I don't see the need to complicate things with a JFET. The resistor is simpler and easier for non-techy hams to implement.

The solution to the chassis ground issue of the Foster connector used in the 5/7-line is nicely described by Bob Heil.



See the section on RFI Removal.

Word wrap broke your link. This should fix things.

,-Cable%20shields%20are&text=The%20problem%20is%20that%20any,injected%20into%20the%20audio%20circuitry

73

-Jim
NU0C

On Fri, 23 Feb 2024 16:05:28 -0500
"Paul Christensen" <w9ac@...> wrote:

Jim's 470K resistor solution is a good one where the transceiver limits
audio response to what we're normally accustomed to for SSB. I use a 470K
resistor in the base of a D104 when using my Drake TR5 and Kenwood TS-830S
transceivers. For AM and ESSB modes, the JFET source follow helps to extend
the low-end range by completely unloading the crystal mic element.

Another reason to use a JFET as a source follower isn't always apparent: by
keeping the source Z low, the attenuation effect from mic cable capacitance
is minimized. True, it's really only needed on longer than normal mic cable
runs but it does help with physical microphonics on a cable with a high
source Z. For example, kick a mic cable with a high source and termination
Z and you'll hear it. But sure, we don't kick our mic cables. With a
capacitive source, which the crystal element is, cable capacitance creates a
voltage divider. The level at the mic jack is reduced but the frequency
response is unaffected with a capacitive voltage divider.

The worst case occurs when a mic with a highly resistive source Z feeds a
long cable. In that case, the parallel capacitance of the cable in series
with the high source resistance creates a low-pass filter. The JFET as a
source follower *placed at the source end* solves either problem.

Unrelated but I recently rewired the 4-pin mic jacks on my TR5 and TS-830S
transceivers. In both instances, the mic ground pin isn't bonded to the
chassis at the mic connector. Instead, and despite what the TR5 schematic
shows, the ground pin is attached to the audio shield and the shield is
connected to a 0.1" header on a PC board some considerable distance away
from the mic jack. That's a classic example of the so-called "Pin 1
problem."


roblem,-Cable%20shields%20are&text=The%20problem%20is%20that%20any,injected%
20into%20the%20audio%20circuitry.

Paul, W9AC




Paul, W9AC


-----Original Message-----
From: [email protected] <[email protected]> On Behalf Of Jim Shorney
Sent: Friday, February 23, 2024 3:18 PM
To: [email protected]
Subject: Re: [DRAKE-RADIO] Drake T4XC and D-104 wiring


That does not change what I wrote.

73

-Jim
NU0C

On Fri, 23 Feb 2024 09:48:33 -0800
"jerry-KF6VB" <jerry@...> wrote:

On 2024-02-23 08:51, Jim Shorney wrote:

My "secret" is to do away with the amplifier and replace it with a
series 470K resistor. This is actually an old-timer's trick to
mellow out the frequency response of the D-104 head. The amplifier
is enhanced uselessness for our radios.

*** My homebrew amp is just a source follower. It has no voltage gain.
Its only purpose is to present a high impedance to the element.
I see that the "silver eagle" had a 26dB amp in the base. I scratch
my head as to why that might ever be needed. Crystal elements put out
plenty of volts as is.

- Jerry, KF6VB

--

73

-Jim
NU0C

On 2/23/24 17:52, Jim Shorney wrote:

Some nice pics on this page:

Yep.? A pic of one my favorite mics. An Electro-Voice? 638 that I use
with my TR7 and I'll use another 638 I have with the new to me T-4X.


73

Stan
KM4HQE

I suppose you mean the D-104-C? In catalog 197 it is listed only 3 dB lower than the crystal version. Interestingly they don't specifically say which is in the T-UP9-D104 "Silver Eagle". That suggests to me that at some point they did begin to quietly phase out the crystal and replace them with ceramic. Who's going to know? You would have to open one up and few would want to do that. I have a garage sale find Golden Eagle and two T-UG8 models all gelded with the 470K resistor mod. I used the Golden Eagle on my TR7 for a while. I still plug it in now and then for fun. It looks like hell, the lacquer coating on the stand neck is trashed. I also have a NOS cartridge tucked away in a drawer but I'm not going to cut it open.

Maybe I'll replace those 470K resistors with low noise film resistors... :D

Admittedly it may be urban legend that the crystal cartridge was phased out in later years but I have heard and read about it being so since sometime in the late 70s. Another bit of lore is that you can "make it sound better" by poking a pin hole in the diaphragm but I think all of us here are smarter than that. Take it all for what it's worth.



Here's a reference that appears to be wrong based on catalog info:



Some nice pics on this page:



Does anyone remember seeing the D-104 on a short non-G stand (probably an E-1 stand) used as a broadcast mic in the SciFi channel Battlestar Galactica reboot?


73

-Jim
NU0C

On Fri, 23 Feb 2024 12:48:05 -0800
"Richard Knoppow" <1oldlens1@...> wrote:

Astatic made another model the C-104 with a ceramic element. Very
similar except the output is about 10db lower. This is for the element
alone. If there is an amplifier the output levels are probably the same.
I have not searched for a data sheet on the C-104.
Astatic made ceramic versions of many of their crystal mics and
crystal phono pickups. The ceramic has the advantage of not being
vulnerable to heat or moisture.

On 2/23/2024 8:51 AM, Jim Shorney wrote:

My "secret" is to do away with the amplifier and replace it with a series 470K resistor. This is actually an old-timer's trick to mellow out the frequency response of the D-104 head. The amplifier is enhanced uselessness for our radios. It will happily drive just about any radio this way and you get rid of a failure point (actually two if you consider potential battery leakage). This works with any T-UGxx stand.

My understanding is that later D-104 heads used a ceramic cartridge. The same fix applies. The D-104 head likes to see a high impedance load, the higher the better.

I have three T-UGxx variants that I have done this to and tested on the air with good reports. And they can be used with VOX.

73

-Jim
NU0C

--

73

-Jim
NU0C

Jim's 470K resistor solution is a good one where the transceiver limits
audio response to what we're normally accustomed to for SSB. I use a 470K
resistor in the base of a D104 when using my Drake TR5 and Kenwood TS-830S
transceivers. For AM and ESSB modes, the JFET source follow helps to extend
the low-end range by completely unloading the crystal mic element.

Another reason to use a JFET as a source follower isn't always apparent: by
keeping the source Z low, the attenuation effect from mic cable capacitance
is minimized. True, it's really only needed on longer than normal mic cable
runs but it does help with physical microphonics on a cable with a high
source Z. For example, kick a mic cable with a high source and termination
Z and you'll hear it. But sure, we don't kick our mic cables. With a
capacitive source, which the crystal element is, cable capacitance creates a
voltage divider. The level at the mic jack is reduced but the frequency
response is unaffected with a capacitive voltage divider.

The worst case occurs when a mic with a highly resistive source Z feeds a
long cable. In that case, the parallel capacitance of the cable in series
with the high source resistance creates a low-pass filter. The JFET as a
source follower *placed at the source end* solves either problem.

Unrelated but I recently rewired the 4-pin mic jacks on my TR5 and TS-830S
transceivers. In both instances, the mic ground pin isn't bonded to the
chassis at the mic connector. Instead, and despite what the TR5 schematic
shows, the ground pin is attached to the audio shield and the shield is
connected to a 0.1" header on a PC board some considerable distance away
from the mic jack. That's a classic example of the so-called "Pin 1
problem."


roblem,-Cable%20shields%20are&text=The%20problem%20is%20that%20any,injected%
20into%20the%20audio%20circuitry.

Paul, W9AC




Paul, W9AC

Astatic made another model the C-104 with a ceramic element. Very similar except the output is about 10db lower. This is for the element alone. If there is an amplifier the output levels are probably the same. I have not searched for a data sheet on the C-104.
Astatic made ceramic versions of many of their crystal mics and crystal phono pickups. The ceramic has the advantage of not being vulnerable to heat or moisture.

--
Richard Knoppow
Los Angeles
WB6KBL
SKCC 19998

On 2024-02-23 12:17, Jim Shorney wrote:

That does not change what I wrote.

Didn't say it did.

- Jerry, KF6VB

73
-Jim
NU0C
On Fri, 23 Feb 2024 09:48:33 -0800
"jerry-KF6VB" <jerry@...> wrote:

On 2024-02-23 08:51, Jim Shorney wrote:

My "secret" is to do away with the amplifier and replace it with a
series 470K resistor. This is actually an old-timer's trick to mellow
out the frequency response of the D-104 head. The amplifier is
enhanced uselessness for our radios.

*** My homebrew amp is just a source follower. It has no voltage gain.
Its only purpose is to present a high impedance to the element.
I see that the "silver eagle" had a 26dB amp in the base. I scratch
my head as to why that might ever be needed. Crystal elements put out
plenty of volts as is.
- Jerry, KF6VB

--
73
-Jim
NU0C

I don't know of anyone who has needed to replace them but it should be possible to find or build a suitable substitute. You should be able to test them by watching the voltage swings at pins 1 and 8 of P102, as well as pins 2 and 6 of U101, while you VERY slowly rotate the knob. TP108 should toggle high or low depending on which direction you are turning the knob.

73

-Jim
NU0C

On Fri, 23 Feb 2024 11:04:26 -0800
"K6OXN Bob" <bobk6oxn@...> wrote:

Does anyone have a source for these optical sensors?

Already covered. Twice. Thank you for your comments.

73

-Jim
NU0C


On Fri, 23 Feb 2024 12:06:41 -0500
"Omni" <selcor@...> wrote:

That is not a problem. J-104 controls which way the frequency goes with relation to knob rotation. When all else fails read the manual. The setting of J-104 is detailed in Section 2-3 on page 2-2 of the RV75 Operator’s Manual

That does not change what I wrote.

73

-Jim
NU0C

On Fri, 23 Feb 2024 09:48:33 -0800
"jerry-KF6VB" <jerry@...> wrote:

On 2024-02-23 08:51, Jim Shorney wrote:

My "secret" is to do away with the amplifier and replace it with a
series 470K resistor. This is actually an old-timer's trick to mellow
out the frequency response of the D-104 head. The amplifier is
enhanced uselessness for our radios.

*** My homebrew amp is just a source follower. It has no voltage gain.
Its only purpose is to present a high impedance to the element.
I see that the "silver eagle" had a 26dB amp in the base. I scratch
my head as to why that might ever be needed. Crystal elements put out
plenty of volts as is.

- Jerry, KF6VB

--

73

-Jim
NU0C