Telefunken ELA M 251 Clone Tube Microphone Build Thread (D-Ela M 251E)

[micaddict]

Dany, did you send the updated version to Ben and Veronica, too?
Outside measurements are likely the same, but perhaps it helps if they have the definitive version?



Henk

 

[poctop]

Dany, did you send the updated version to Ben and Veronica, too?
Outside measurements are likely the same, but perhaps it helps if they have the definitive version?



Henk

The Outside Footprints is the exact same mouting hole ....etc.. as this was intented at first for the Ht-11A ,
the minor modification should not affect the adaptation outcome 
Thanks for checking Henk, 
Best,
DAN,

 

[dmnieto]

The Outside Footprints is the exact same mouting hole ....etc.. as this was intented at first for the Ht-11A ,
the minor modification should not affect the adaptation outcome 
Thanks for checking Henk, 
Best,
DAN,

The new PCBs won't fit the HT-11A?

 

[poctop]

The Outside Footprints is the exact same mouting hole ....etc.. as this was intented at first for the Ht-11A ,
the minor modification should not affect the adaptation outcome 
Thanks for checking Henk, 
Best,
DAN,

The new PCBs won't fit the HT-11A?

The PCB are made For the Ht-11A No Worries,
Best,
DAN,

 

[Woot]

Thanks DAn,

I think a couple of little square tabs sticking out from the rails so we can utilise the original mounting holes would work a treat... but Veronica and Ben are the experts, I'm sure they'll figure it out perfectly.

Matt

 

[poctop]

New Run is on the way ,
Best,
Dan,

 

[dmnieto]

New Run is on the way ,
Best,
Dan,

So how do we order the PCBs?

 

[poctop]

New Run is on the way ,
Best,
Dan,

So how do we order the PCBs?

Not Yet,
I will report back when they are in stock , that should be pretty soon,
Best,
DAN,

 

[JessJackson]

I'm loving mine cutting with it every day for an upcoming E.P.

Does anyone have an extra outer body or knows where to get some piping from the exact dimensions of the outer body. i'd like to extend it longer similar to c12 in size and i want to put a trouchel connector on the bottom.

 

[dmnieto]

I'm loving mine cutting with it every day for an upcoming E.P.

Does anyone have an extra outer body or knows where to get some piping from the exact dimensions of the outer body. i'd like to extend it longer similar to c12 in size and i want to put a trouchel connector on the bottom.

You mean like an extra sleeve from the APEX 460 for example?

 

[poctop]

I should have them as of tommorow ,
Best, 
Dan,

 

[JessJackson]

I'm loving mine cutting with it every day for an upcoming E.P.

Does anyone have an extra outer body or knows where to get some piping from the exact dimensions of the outer body. i'd like to extend it longer similar to c12 in size and i want to put a trouchel connector on the bottom.

You mean like an extra sleeve from the APEX 460 for example?

yeah exactly!

 

[dmnieto]

I have one extra, pm me

 

[poctop]

they Arrived,
Best,
DAN ,

 

[baadc0de]

they Arrived,
Best,
DAN ,

Where to order? Price?

 

[poctop]

they Arrived,
Best,
DAN ,

Where to order? Price?

I updated the website ,
should work fine now, had so Many issues with it Lately

http://www.vintagemicrophonepcbkit.com/order2.html

Best,
Dan,

 

[dmnieto]

Dany, I have a question... Have you experimented with trying to use double coil latching relays instead of single side stable? It may be possible by the use of a shorting switch and a 558 timer to generate the pulses for the correct latching.
For example in my current build, the XLR cable has approx 1.2Ohms resistance. In figure of 8 we are adding 66mA (for a drop of almost 100mV in the heater voltage) compared with cardioid mode. Also, holding an energized coil next to a Hi-Z section does look problematic... What are your thoughts on this?

 

[poctop]

Dany, I have a question... Have you experimented with trying to use double coil latching relays instead of single side stable? It may be possible by the use of a shorting switch and a 558 timer to generate the pulses for the correct latching.
For example in my current build, the XLR cable has approx 1.2Ohms resistance. In figure of 8 we are adding 66mA (for a drop of almost 100mV in the heater voltage) compared with cardioid mode. Also, holding an energized coil next to a Hi-Z section does look problematic... What are your thoughts on this?

the cable resistance you need to account by adjusting the heater voltage with the Voltmeter on the mic pcb itself there is a pad for such measurement on the mic pcb
the heater Voltage is regulated from the psu so this tiny pull of current for the pattern the regulator will take care of that, as per the voltage used in the relay this is DC voltage so same as polarisation or B+ so this is not a problem.  the H-Z section is most sensible to passage of current to an easier path then the one defined on the circuit such as grease and dirt from flux allowing then a path to ground or another part of the cicruit , Since implied parts of the relay are isolated from the pcb this is not an issue at all, no to be confused with high impedance corresponding issues versus nanoscopic stray field,  Once I received my upgraded tube i will post a simple clip of the noise figures wich are totally in range with the other design I have made so far or I would not have simply issued this one .  Mostly this design have been sucessfully implemented in the Blackspade Line of microphone so you dont have to worry at all,  I am not sure if you have completed your build yet but give it a try yourself you will be convinced then and keep me posted.

hope this helps,
Best,
DAN,

 

[dmnieto]

esistance you need to account by adjusting the heater voltage with the Voltmeter on the mic pcb itself there is a pad for such measurement on the mic pcb
[...]
the heater Voltage is regulated from the psu so this tiny pull of current for the pattern the regulator will take care of that
hope this helps,
Best,
DAN,

Yeah, I know I can adjust the heater voltage to account for losses in the cable... what I am saying is that there is going to be 100mV difference between the switch placed in cardiod mode vs figure of 8. (there will be a 350mA drain in cardioid and 416mA in figure of 8 because of the relays). I am not sure how much the tube will be affected by that though.

 

[poctop]

esistance you need to account by adjusting the heater voltage with the Voltmeter on the mic pcb itself there is a pad for such measurement on the mic pcb
[...]
the heater Voltage is regulated from the psu so this tiny pull of current for the pattern the regulator will take care of that
hope this helps,
Best,
DAN,

Yeah, I know I can adjust the heater voltage to account for losses in the cable... what I am saying is that there is going to be 100mV difference between the switch placed in cardiod mode vs figure of 8. (there will be a 350mA drain in cardioid and 416mA in figure of 8 because of the relays). I am not sure how much the tube will be affected by that though.

The Supply for the relay is taken from the regulated heater supply so it should remains constant despite the extra draw.
Best,
dAN,