Neumann M147 tube (NOT 6111)

[ghiatorino]

Hi guys,
I need to change the tubes in my 2 Neumann M147.
Apparently there is a newer version (Circuit Diagram 02, pictures attached) which is not equipped with the old 6111 tube.
I asked Neumann to clarify the tube model, but they refuse to tell me what tube is. Nice folks, no comments.
The vanishing print on it may say a 6S6B-V .
Could anybody confirm?
cheers
Rino

 

[pucho812]

Is there anyway to just order a tube from Neumann?
I have found that with tube mics you can spend a lot of money to buy a lot of tubes to sit and find the ones best suited for microphones, or you can just buy 1 or 2 from the manufacture who already went through the sorting process to find the best tubes to use in their products.

 

[emrr]

I’m gonna bet Neumann wants the mics back for service.

 

[mjrippe]

The side shown in the photo looks just like the 6S6B-V that I have. Post a pic of the other side and I'll confirm.

 

[RuudNL]

Yes, it is a 6S6B-V.
Replaced one before.

 

[ghiatorino]

Neumann tech service wants the mic back, with a huge waiting list also.
And, not only does not sell spares, but refuses to confirm a part value, actually denying the right to repair your own stuff. But that would be a long off-topic thread.
How precious is the community, thanks everybody.

 

[RuudNL]

The good thing is that the 6S6B-V tubes are very consistent.
I have tested hundreds of them, but only a few were too noisy for a microphone.

 

[ghiatorino]

An update on this thread,
the mic is not working with the new tube, and sadly neither soldering back the old one.
The new tube has been carefully installed, following the arrow mark on it.
Something happened...
The PSU puts out weird voltages.
Anybody has a clue on the "sensing" structure of the microphone? Schematic?
Thanks

 

[Coop]

Not sure if they did change anything else besides the tube, but this seems to be the schematic for the first version

 

[TLRT]

I selected for noise ec1000 tubes,it was used also in m147/149

 

[RuudNL]

As far as I know, the EC1000 was used in the very early versions of the M147/149.
It can easy be recognized by the presence of the top lead (=grid connection).

 

[rmburrow]

What is the predicted life of the EC1000? Supposedly this was a probe tube for VTVM's. Possible AC701 substitute (with mods)?

 

[Tubetec]

Its a lot like the Ac701k with the top cap grid , looks like good examples are still available for reasonable money , around 35 STG .

 

[Tubetec]

 

[beatsnblunts]

Did u use heat sinks while de soldering/ soldering? if not might have fried something on the board. i sent mine into David Brown for retube and cleaning cuz i didn’t want to risk it.

 

[Whoops]

Is there anyway to just order a tube from Neumann?
I have found that with tube mics you can spend a lot of money to buy a lot of tubes to sit and find the ones best suited for microphones, or you can just buy 1 or 2 from the manufacture who already went through the sorting process to find the best tubes to use in their products.

Unfortunately I don't think this is the case, as far as I know Neumann charges 400€ to replace that tube.
Actually I think they replace the full pcb assembly with the tube already soldered.

It's the same with the M149 microphone.
So I would definitely send the F word to Neumann and replace the tube myself.

But most important is, are you sure the tubes are bad on both microphones?
Is that those tubes last forever...

 

[Hibiscus]

I'm in the same boat. I own an M147 which I bought used and which is still in good shape. For now, at least. The question is, as a home recordist, should I worry about it's life expectancy or does it last a lifetime? Im asking because to the microphone "purists" the m147 and m149 are not considered a proper Tube mic but a FET/Tube Hybrid. Does this imply that the tubes in a hybrid mic last any longer than they would in a non-hybrid mic? And if and when the tube does fizzle out, Neumann Incorporated replaces the whole PCB board and not just the tube for not 400€ but 600€! Who in their right mind would want to pay that?! Of course when I bought the M147 I naively thought the tube was easily replaceable like in a lot of other tube mics. Sadly, I was mistaken. The m147 and 149 seem to be a cash cow for Neumann and their tech team. I also read that the reason they replace not just the tube but the whole PCB is because you cannot solder out the tube and replace it without causing damage to the rest of the circuit board. I now hate Neumann. May Mikrotek Geffell rise all the more and bury their memory forever. If I could do it all over I would have bought a Gefell UM92.1s or a Telefunken ak47. I'm never buying Neumann again.

 

[beatsnblunts]

I'm in the same boat. I own an M147 which I bought used and which is still in good shape. For now, at least. The question is, as a home recordist, should I worry about it's life expectancy or does it last a lifetime? Im asking because to the microphone "purists" the m147 and m149 are not considered a proper Tube mic but a FET/Tube Hybrid. Does this imply that the tubes in a hybrid mic last any longer than they would in a non-hybrid mic? And if and when the tube does fizzle out, Neumann Incorporated replaces the whole PCB board and not just the tube for not 400€ but 600€! Who in their right mind would want to pay that?! Of course when I bought the M147 I naively thought the tube was easily replaceable like in a lot of other tube mics. Sadly, I was mistaken. The m147 and 149 seem to be a cash cow for Neumann and their tech team. I also read that the reason they replace not just the tube but the whole PCB is because you cannot solder out the tube and replace it without causing damage to the rest of the circuit board. I now hate Neumann. May Mikrotek Geffell rise all the more and bury their memory forever. If I could do it all over I would have bought a Gefell UM92.1s or a Telefunken ak47. I'm never buying Neumann again.

send it to David Brown (or your Tube mic repair tech of choice). but if it aint broke…. if its making noise then u either have a dirty diaphragm or a tube going bad.

 

[Whoops]

The question is, as a home recordist, should I worry about it's life expectancy or does it last a lifetime?

I would only worry if the tube was not good.
If you are an home recordist the tube will last for sure, there's a big probability that you or me fail much before the tube

Im asking because to the microphone "purists" the m147 and m149 are not considered a proper Tube mic but a FET/Tube Hybrid.

Nothing to do with any microphone "purist", I actually don't even know what or who microphone purists are.
But people say it's FET/Tube Hybrid and not a complete tube mic because that's a Fact.

I also read that the reason they replace not just the tube but the whole PCB is because you cannot solder out the tube and replace it without causing damage to the rest of the circuit board. I now hate Neumann.

If you think you hate them now then yo should open, and look at the insights of the M147 PSU

 

[Hibiscus]

I would only worry if the tube was not good.
If you are an home recordist he tube will last for sure, there's a big probability that you or me fail much before the tube




Nothing to do with any microphone "purist", I actually don't even know what ot who microphone purists are.
But people say it's FET/Tube Hybrid and not a complete tube mic because that's a Fact.




If you think you hate them now then yo should open, and look at the insights of the M147 PSU

If you think you hate them now then yo should open, and look at the insights of the M147 PSU

Lol. That bad, huh?