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[miics]

Klaus Heyne wrote on Thu, 12 February 2009 10:01

...Is there a technical reason for this or is this marketing?

T-USA was fast to announce the purchase of the (original Telefunken) filament material, etc.  They charge USD8500.00 for a mic with what seems like a 2 dollar tube!!  

To me that is just unacceptable.  I know if I owned one and this happened I would take it as far as necessary to get my money back.

cheers,

[seedyunderbelly.com]

"""Currently, the VF14K tubes are hand-built in our laboratory""""

If that photo is correct  the metal chasis would be built by them  -but the tube?  

[Giles Jeremy]

Anybody know what the resistor is and what is it's function?

[rodabod]

I'd guess it's a series resistor to drop some volts before the (possibly) 20V heater.

[miics]

I concur.

[kats]

Well here's the rub:

A lot of rumor regarding exactly what the Vf14k is had been floating about. In reality what T-USA said originally was that this tube is "sonically and electronically" identical to a VF14.

Now "sonically" leaves some wiggle room, but "electronically" - not so much. What we need to know is exactly what tube they are actually using and whether or not it is electronically the same.

[rodabod]

From what I understand, only a VF14 is electronically the same as a VF14 (as I'm sure you well know).

[J.J. Blair]

I can't find anything online that says they reproduced the thing.  I have an e-mail from Toni, talking about it, and he only says that they hope people find it to be a suitable replacement, and he didn't want to just sell them to somebody who might put it in a bad mic, and blame the tube for the sound, thus giving it a bad rap, so until they get a solid rep, they are only going in the U47AEs.

I don't understand why he mentioned to me that he found 50 lbs. of the original filament material, which he very well may have.  I guess they just aren't using it.  

Like I said, I'd like to hear it.  If it's not quite as good as a real VF14, it would be nice to know if it's still the best option available, aside from getting the real thing.  I mean, I hear the difference between different brands of 6072s when I put them in a 251, so it's hard to imagine that this is going to sound identical to a VF14.  But I know that at Capitol, they have 5 U47s that are not being used at all, because of dead VF14s.  Maybe these could at least get those things up and running.  I'd rather have a 80% U47 sound than none at all.  

[Oliver Archut]

Hello guys,

Saturn sound used both tubes the 407a and 408a, the 407a would have been labeled as UCC88 in the European tube code.
The 407a is 2x 20V/50mA version of the 2C51, what is in essence nothing else than a commercial grade ECC88 with a different footprint.

Running both triode haves in parallel and the filament in series gives you a replacement tube for a VF14 that will work close to the specs of an VF14.
But of all the 407a tubes I found, none of them was mic grade material, even the so called 'super-tube' Western Electric ones did not meet the simple VF14 noise specs.

The 408a is na EF95 with 20V/50mA filament, so with a dropping resistor, a direct replacement could be archived.

But here again, not the WE/Northern Electric, nor the Ericson, that were supposed to be high grade tubes, are good enough to be used in a U47.

However, the 408a/VF95s specs are pretty close in impedance as well as technical data, the head room is about 5dB less.
The tube in the pic is not Ericson, WE or RCAs because it is missing the black nickel plates.

Putting a glass tube in an metal container might be marketing, but it is still a drop-in replacement.

If someone wants a U47, buy a Neumann U47 with a VF14. If you do not have the cash nor the cash to keep the great sounding museum piece running, get a new mic.

Best regards,



For a fair and honest discussion of the subject, it should be disclosed that my friend Oliver is a supplier to Telefunken-USA. K.H.

[kats]

Quote:

However, the 408a/VF95s specs are pretty close in impedance as well as technical data, the head room is about 5dB less. The tube in the pic is not Ericson, WE or RCAs because it is missing the black nickel plates.

Just to clarify: you reference a 408a/EF95 (not good enough) and a 408a/VF95s (better) as two different tubes, correct?

You also say the headroom on the 408a/vf95s is about 5dB lower than a VF14. That sounds pretty significant to me.

Is it, or is there something else in the signal path of a u47 that would make this moot?

And lastly, is the 408a/V95s the tube referred to that were used for transatlantic telecommunications, or was there another variant?

Thank you for your input Oliver.

[Oliver Archut]

Hello Guys,

I think 90% of all people that are involved in the discussion know that my company supplies microphone parts, like x-former, PSUs as well as other smaller parts like resistors, etc. etc.  

To clarify, the tube in the pic is, as it looks, no Western Electric, nor a tube from their sub devisions, nor RCA, etc.

The 408a would have been labeled VF95 (the 20V/50mA version of the EF95) and just from technical specs, those ones are very close from an electrical point of view (closer than the Nu-Vistor or EF86 and AC701 mod). The head room of this tube is 5dB lower, compared to an average VF14.

Do they use an 408a? The pic does not show the characteristic black Nickel plate that WE and RCA used.

Best regards,

[kats]

To clarify, T-USA told me specifically that the tube in the picture is NOT the tube they are using in the VF14k.  That pic is from one of their earlier attempts, but not the final incarnation.

[miics]

(...) If you want more info, call some of the T-USA distributors about what's in their current U47ae's.  There have been more than 1 of these tubes opened and more pictures other than that one are in circulation.

Cheers

[George_]

here we go..  

[kats]

This looks like a picture of the exact same tube that (has already been posted above).