"The Electron" a Cathode Follower Headamp Microphone Project

[rock soderstrom]

I know what you mean, these screwed holder have certain advantages.

M-Audio Nova would be a good candidate, but unfortunately I only have one of them left.

 

[KrIVIUM2323]

Everything could possibly fit in there, but if not, I'll put the OPT and C3 into the power supply unit. I think that would definitely be necessary if you want to use a 414 or TL103 style body, they really offer very little space, so a subminiature tube and external components are mandatory. The Apex460 is different story, lots of room.

Yes OPT and large coupling capacitors can be located within supply, it's one of the advantage of using a buffer as headamp: low out z can drive longuer cable without issue ( slew rate isn't compromised by cable capacitance). It open field to play with different transformers type, can be line or other not nescessarely mic optimized. I had interesting results with Carnhill line out transformers (9600/2400), i found bigger core offered more headroom in experiments and a slightly different sound than a mic level dedicated trans with same ratio ( ll1670xl).

The body ( and so headbasket style) is important soundwise as there will be little coloration from electronic ( theorically but with a ccs loaded cf i don't doubt it will be transparent... even transformers should bring low coloration as they'll probably be low ratio too).

From the circuits i've done with cf, it's mainly capsule/headbasket environnement you hear. From circuit: psu ( with 'regular' cf there is low psrr), out transfo in order of importance ime.

About ecc88: at which bias do you plan to use them ( how much current at quiescent point)?

 

[pasarski]

I thought that my next tube mic will be live in this body. Switches and all, and not a Neumann trademark infringement I think

 

[rock soderstrom]

After some theoretical considerations, I decided to simply try out the project in practice.

I opted for an SC440 body as a testbed which, as you know, has an USB port, which is no real disadvantage here as the mic needs a very specific "PSU" because half of the circuitry doesn't fit into the mic body anyway. Therefore the 7pol. Sommer cable will be hardwired too.

Moving on...

 

[rock soderstrom]

The actual power supply unit will be based on my tried and tested TPSU_2XFIL design. Two separate PCBs connected to a common mains transformer for two mics. This keeps the PSU very flexible to be able to supply different operating points and tube types. In addition, a second board is piggybacked on top with the needed required components of the impedance converter, so that the required housing is not getting too big.



If I am very happy with a specific setup, the PSU could also be made a little simpler and I can possibly use more components for both mics, such as the adjustable regulated heater. There is still potential for optimization. The question is how far you can go here without compromising the channel separation?

 

[rock soderstrom]

That is the current status. The layout is a bit spaghetti like , but I think it shows what I'm doing, if anyone wants to understand it. I have made small changes to the schematic.

 

[kingkorg]

That is the current status. The layout is a bit spaghetti like , but I think it shows what I'm doing, if anyone wants to understand it. I have made small changes to the schematic.

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Can't wait to try this one out!