The $5 DIY Tube Condenser Microphone!!!

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
Hi Guys....I have been fooling with some Sub Mini Tubes and decided I would try to make a Tube condenser Microphone....

This Mic took me about 3 hours to put together Includeing etching the PCB and it only costs about $5 in Parts.....

An externally hosted image should be here but it was not working when we last tested it.


It uses the 6418 Sub mini Power amp Pentode tube (the same Tubes as used in the AT3060 tube mic) and a generic Omni-directional Electret Condenser element and the PCB is only about 1.5in By 1.2in.....

I used the body of a Old mic that I killed by hitting to many times with a drum stick and it is a Fairly sold Mic even though it is Put together a Bit half assed.....

How does it sound?? Well it sounds very good actually...It has a very clear and clean Low end but is a Bit lacking in the High end but that is due to the shitty capsule, It also has very little noise and has a very nice Tubey sound, also the Output is EXTREMY Hot, It clip my Preamp if I have it above about 2 so i might add a 10db or 20db pad at a Later date, It might also be because I used a Very high gain NPN Transistor.....

I believe this design can also be easilly modified to work with a regular Condenser Capsule by omiting the Two 4.7k resistors comeing off the Capsule so the Capsule gets the full 48v polarizeing voltage......

I just thought that I would share this design with you and let you know that you can build a Good sounding Tube mic for very little money and without a Lot of Parts....


Cheers
 
This looks interesting. Could you post a schematic? Well done for having the drive to put effort into making something that most people would just go straight out and buy. I have always found you often get a much improved piece of kit for a ridiculously small outlay that way.

I do recall someone posting details of a ribbon mike they had made on their kitchen table from scratch recently. He reckoned that was pretty good too. It made me remember experiments I did in the 60s with Reslo mikes, making new ribbons from very thin aluminium foil which used to line the inside of cigarette packets in those days. Saved a few pounds, ( a lot then), at the cost of a throw away bit of foil and an hour of time!
 
hi, here is the schematic.....


An externally hosted image should be here but it was not working when we last tested it.



There is actually a Small error in the PCB design above but it instn"t enough of an error to render it non-working....If you look at the schematic you will probably find the error quickly enough and make the necessary changes......

Also depdending on the Transistor used you might try changeing the Value of the Biasing reisstors, also adjusting the resistors that come off of the Power pins of the tube could use adjusting to bias it correctly...I have noticed that from Tube to tube you might need to use different Values.....

This curcuit can also be modded for regular Condenser Capsules and Fetless electrets.....


Cheers
 
Minion said:


I believe this design can also be easilly modified to work with a regular Condenser Capsule by omiting the Two 4.7k resistors comeing off the Capsule so the Capsule gets the full 48v polarizeing voltage......

I just thought that I would share this design with you and let you know that you can build a Good sounding Tube mic for very little money and without a Lot of Parts....




Cool little circuit! You should be able to use a regular large diaphragm condenser if you replace the input circuit with the 'usual suspects' as in a 1G resistor between the capsule and the phantom supply polarizing voltage, then feed it through a <1000p capacitor, followed by a 1G resistor to ground... don't see why that wouldn't work. I have a 6088 here that i could triode strap and build up with a 797 capsule... maybe I'll give it a try when i have a minute.
 
It's been a while, but is there still a schematic and/or BOM?

Hi. I'm new to this forum and I really want to build a mic! Just finished 2 compressors and a sub-mini tube mic sounds fun. i got the tube, just need the schematic posted again (it was deleted) and the bill of materials. Can anyone help me out? It would be much appreciated,

dan.
 

Attachments

  • 0bf2_1.jpg
    0bf2_1.jpg
    8.2 KB · Views: 1,360
Hi Guys....I have been fooling with some Sub Mini Tubes and decided I would try to make a Tube condenser Microphone....

This Mic took me about 3 hours to put together Includeing etching the PCB and it only costs about $5 in Parts.....

TubeMicPics.jpg


It uses the 6418 Sub mini Power amp Pentode tube (the same Tubes as used in the AT3060 tube mic) and a generic Omni-directional Electret Condenser element and the PCB is only about 1.5in By 1.2in.....

I used the body of a Old mic that I killed by hitting to many times with a drum stick and it is a Fairly sold Mic even though it is Put together a Bit half assed.....

How does it sound?? Well it sounds very good actually...It has a very clear and clean Low end but is a Bit lacking in the High end but that is due to the shitty capsule, It also has very little noise and has a very nice Tubey sound, also the Output is EXTREMY Hot, It clip my Preamp if I have it above about 2 so i might add a 10db or 20db pad at a Later date, It might also be because I used a Very high gain NPN Transistor.....

I believe this design can also be easilly modified to work with a regular Condenser Capsule by omiting the Two 4.7k resistors comeing off the Capsule so the Capsule gets the full 48v polarizeing voltage......

I just thought that I would share this design with you and let you know that you can build a Good sounding Tube mic for very little money and without a Lot of Parts....


Cheers
Hi Minion, ...can you -pls!- post the schematic, again. thx, Wim
 
Minion's NPN MSH4 "ish" 6418 tube preamp circuit

set heater at 10mA via Ohm's law...measure V across the heater resistor or use a POT and a series resistor to be safe. I've wondered if a LM334Z and a 6.8R~7.5R resistor would work or add too much noise? Or a AA NiCAD on the heater and 2-3 9V batteries for B+?

http://www.sdiy.org/oid/zapnspark/FrankenTubeUpd.pdf

microporium

http://naiant.com/x-v-tube-kit-microphone/

http://s13.postimg.org/patw5krxj/k270.png

How do I calculate the input impedance on this preamp? JAN 6418 Tube based

http://diyaudioprojects.com/Tubes/6418-Tube-Preamp-Headphone-Kit/

http://www.naiant.com/images/MSH-4v2_Condenser_Mic.GIF

https://frank.pocnet.net/sheets/127/6/6418.pdf

http://el34world.com/Forum/index.php?topic=13702.0


I realize not all my thoughts are $5 thoughts. If you try the NPN circuit, maybe use a transistor with quite a bit of current-gain [if you have something to measure that, so much the better]. And to LinkWitz-MOD the cheap Electret if you use one??

http://www.linkwitzlab.com/images/graphics/microph2.gif

http://www.linkwitzlab.com/sys_test.htm

Courtesy of the Internet Wayback Machine:

3c033d273YBwEAOw==
 

Attachments

  • 6418_MODDED_MSH-4.gif
    6418_MODDED_MSH-4.gif
    16.5 KB · Views: 723
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.