D-104 Microphone Preamp

Fully built board: www.ebay.com/i...
New eBay account. Use link below. Keeping old link above as it is shared in many places.
www.ebay.com/i...
Here is a demonstration of a D104 preamp with adjustable Bass and Treble controls. The preamp allows this microphone to be used with modern radios while maintaining excellent sound quality.

[@richardmcsween9096]

That’s the best sounding board,,,I installed mine today and my audio checks came back with great results,,,my setting are both treble and bass up all the way,,,it cranks,,,Buy one. You’ll be happy👍👍👍

[@ab9te534]

Awesome! Thank you for the feedback Richard. Glad you are happy with it!

[@fyzooman]

@@ab9te534 hey brother,good day,where can I buy this board? Pls send me the info,thanks.

[@heffptbo]

Where from

[@Hobo-Henry]

I just did the mod on a Uniden pc66xl (inside the radio of course) using a Ranger SRA-198 mic. it works great it don't pick up outside noise and adds more bass and punch/more treble without having to use a power mic. it took only a little time at the radio shot to get it dialed in. great product.

[@jeetea7577]

Just bought the board, cant wait to try it out.

[@UDX-21]

Nice unit, 13th like here. I will purchase one next week. I also pushed all the buttons on your channel, 15th new member of the family. Stop in for a coffee sometime, 21 in S.C.

[@ab9te534]

Thanks for subscribing Dirty Diaper 21! I will watch for your order and get it shipped out right away!

[@UDX-21]

@@ab9te534 I will order on Thursday .Thanks. LOL

[@UDX-21]

Ok, I just ordered one. Thanks, JT

[@canalrodrigobetim]

Hi, I have a D104 and it's here, but unused, I have it as a "trophy" I love it, I've always wanted to hear the sound it offers and today you took my curiosity away. Very nice video, congratulations and thanks. pu2rwo

[@danw1955]

I need to invest in one of these, as I would like to use it on my Galaxy TX95-D. I have an old gray base D104 from 1975 that still has the crystal element, and I used to use it with an external preamp for impedance matching. Unfortunately the preamp disappeared into a black hole somewhere, so rather than try to build another one, I think I'll take the easy route.😄 This particular D104 came with no pre-amp installed, so it's kind of limited to the radios I can use it with, since the crystal element has a very high impedance. I'll probably need to hot glue a 9v. bracket inside for power.😉 Thanks for the E-bay link AB9TE!

[@arconeagain]

There is plenty of bass in a D104, try running one on a valve radio. The problem is not with the element itself, it is to do with impedance. That includes ones with preamps as well.

[@Aleziss]

sounds really nice ! there is no gain adjustment by what I can see, will you some day have a version with a third pot and add a gain level ? what I would REALLY like to see in microphones or radios is a NOISE GATE, compressors pull all the low sounds, bring room echo but as soon you add a touch of noise gate, it becomes clear, no background echo or noises, just pure voice... if you ever do a newer version, that would be a first I think ! (besides getting external processing units like the W2IHY). Nice job !

[@ab9te534]

A noise gate would be great! Something I will take into consideration for a future version of this. As for the gain control I might consider adding one. So far I have found that the output level it is at works well with the radios I have tried it on. On my IC-7100 I run the MIC GAIN at 50% and it works really well. I have gotten a few requests to add a volume control though.

[@Aleziss]

@@ab9te534 Thanks for the reply ! By the way, you do not ship to Canada ?

[@Ferret488]

I bought one to use with a D-104 and Electret cartridge upgrade. The output of the Electrets is 9 vdc from the battery. Straight into my Yaesu FT-301D I can peg the meter and adjust back, but it is very tinny. With this amplifier board I only get 203 mV out and no modulation. Very disappointing. I recently bought the new board on ETSY that supposedly will work with Electrets and has gain boost. We'll see how well it does.

[@Tinman386wisconsin]

That's really cool! I have always liked the Turner mics better because the d104 always sounded so tinny. I'm curious about the original board that has the voltage pot, is the new board set to max voltage with a 9 bolt battery and mic gain controlled at the radio instead? I'm looking at it like the stock electret mic is that correct?

[@edgarleonayala]

I put the board and it has a hummm. please suggest so that i can fix the problem. if I have a battery, i dont have to connect the cable to the input from the radio with power?

[@johnkaveski7953]

how do i get one of your boards.would love to try it in one of my many d 104 microphones.

[@ab9te534]

Hi John. If you click the arrow to expand the video description I have a link in there for the listing on eBay.

[@travisg6672]

Will these work with a 4 pin galaxy dx959 or cobra radio?

[@ab9te534]

It will work with them. You will need to supply power to the board though since the radio doesn't put out voltage from the MIC connector. It can be powered with 5 to 15 volts DC.

[@rongann1955]

I am curious how the pre-amp would sound on an Yaesu Ft 101ee. Any reports?

[@rongann1955]

Has anyone tried this modification on a Yaesu FT 101? Thanks

[@RobertTKlaus]

Very cool, but will it work with the electret condenser upgrades that many of us have, and others will have to get at some point? Also, no gain control?

[@justinf6951]

I tried it with the electret and it did not seem to work so well ! It worked fine with the stock one

[@radiocanaltv4872]

Greetings, I have one of those microphones, but it is platinum or rilay, could you post a video or at least explain the combination of the 5 colors to combine them? Thanks for your videos. Tampa, FL.

[@grafton261]

would enjoy buying one of these but maker doesn't ship to Australia , shame on that as there are a few that would love to have things like this

[@ab9te534]

Hi Allan. Thank you for your interest in the kit! I have edited the eBay listing now so that it allows shipping to Australia :)

[@edgarleonayala]

We cant't see very well the microphone cable conections to the board. It is too dark. Please put more light on another video so we can see clearly where it goes.

[@alanpenfold3688]

Hi where can you buy the but the board from

[@paolomichielin4849]

Bella modifica! E' possibile avere il numero della scheda amplificata? Grazie.

[@ab9te534]

The link is in the video details. Thanks!

[@j.kevinhunt147]

Will this preamp work with an electret condenser mic? Some of the older Icoms (730, 735) require higher mic output so it's hard to use a computer headset as there just isn't enough output to drive the transmitter audio stage to an output that will produce more than a couple watts of RF. It seems that connecting this board in the same manner as on the D-104, by connecting the + 8VDC bias supplied by pin 8 of the radio, the electret condenser would have the amplification needed for these radios. The original D-104 preamp works well with an electret condenser element upgrade. Seems worth a try at this price to see if it would permit use of a gaming type headset with an IC-730 or IC-735. Any thoughts?

[@ab9te534]

I have not tried it yet with a electret condensor microphone. It very well might work although the DC bias would still need to be applied to the electret mic element. There are two isolation capacitors on the input of the preamp so in theory you could still apply the bias to the electret mic element and it shouldn't affect the amp.

[@stevewaechter7759]

Are these avaiable now? I need one.

[@BADBONES1959]

I BOUGHT 2, I TRIED TO INSTALL ONE TO NO AVAIL, I'M SURE IT WAS MY FAULT. I PLAN ON TAKING MY OTHER ONE TO MY GURU WHO IS EXTREMELY MORE QUALIFIED THAN I

[@hilldwler420]

On an am carrier it’s not gonna get much better. Such a natrow bandwidth on am less tHan 5khz on either side of the frequency.

[@jackfiamingo9180]

Is this for use with the original crystal cartridge or will I need to update the head with a electret condenser (or some other type of) pick up?

[@ab9te534]

Hi Jack. This is for use with the original element.

[@mikebolton5577]

How do you adjust the preamp gain for louder modulations?

[@Machria23]

Did you have the "electret condensor" element (upgrade) installed or is that with the orig. salt crystal?

[@ab9te534]

That is with the original element.

[@andrevoz9819]

Would this board work with D-104 and FT-1000D? My D-104 has a 9v battery in the base. I would like to see how that extra bass would sound with a D-104 and FT-1000D.

[@ab9te534]

Hi Andre. It should work just fine with your FT-1000D. Thanks for looking!

[@Aleziss]

oh I forgot to ask, what was your bandwidth setting on AM ? on my 7300, when you change the bandwidth setting on receive, it also affect the transmitted audio...

[@ab9te534]

On the 7100 the TBW cannot be changed on AM. When I switch to AM the menu option is not there.

[@Aleziss]

@@ab9te534 You don'T have a FIL1-2-3 on AM receive ? I also lose the TBW but the FIL1-2-3 does impact the transmitted audio on the 7300 even though it is for receive filters.

[@ab9te534]

@@Aleziss I do have the different receive filters but I don't think they affect the transmit audio. I will have to try it out.

[@Aleziss]

@@ab9te534 great, with your sdr receiver it is the right tool for sure to test this. On my part, I can assure you that it has least has an effect on TX when on FM, changing receive filter makes a change in the transmitted bandwith... I have a doubt with AM though, I cannot test my own transmition with another station to try it out... I am thinking about getting a SDR receiver now because of you !!

[@ricksmith7987]

will this board work on a d104 silver eagle and a kenwood ts 440 s which requires a low impeadence microphone ??

[@ab9te534]

Yes it will!

[@ricksmith7987]

do i need to change the mic element

[@ab9te534]

@@ricksmith7987 if it is the factory element you are good to go. If it has been modified with an electret element then the preamp would need some minor changes to the input to prevent from being overdriven.

[@Fireguy-]

Will the board work with the old crystal element or should a newer element be used? If yes, what element do you recommend?

[@ab9te534]

It will work with the Crystal element.

[@jeetea7577]

@@ab9te534 I bought one of your boards (it came today to SJ, California) do you have a source for new elements in case mine is kaput? I have a mic tester and with a fresh battery in the mic seems to make some output and my switch operates correctly. Thanks in advance, cant wait to try it.

[@ab9te534]

@@jeetea7577 I don't have a source of replacement crystal or ceramic elements but I may offer an electret replacement for it in the future. There are some I have been looking at and am going to evaluate.

[@jeetea7577]

@@ab9te534 cool, standing by....

[@SKYHAWK0115]

Doesn't seem to operate with enough base. Too tinny !

[@ab9te534]

Did you listen with headphones on? If you are just watching on a laptop or phone you won't hear the lows.