How would you go about getting a Neumann U47 ?

[paulcheeba]

Off the shelf Heiserman makes the best all round clone these days. Stam makes the best budget version. As mentioned Dany’s “Poctop” makes the best DIY ,materials imo.

 

[mhelin]

Maybe Danny has used a DC-DC module in his new VF14 , I guess were going to find out soon .

How would you do that, I mean you are supposed to have the DC/DC converter to bring first the voltage down and current up for some 6.3V heater of an EF804 for an example, and then further the current down into the 29 ohms resistor to have it match a real VF14? Maybe using that VF14 screen pin which is connected to ground as reference so the DC/DC converter work with the 1780 ohms limited current for the heater supply and then just resistors are used to set up the current into the VF14 heater pin? So that's a EF8XX adapter really.

 

[Barry Hufker]

I have a Signal Art Electronics U48 that I like very much. I prefer the cardioid/figure 8 combination more than cardioid/omni. I think that's more versatile. It has a Heiserman M7 capsule and the tube complement is a matched pair of Western Electric 408a (6028) pentode valves. I don't know how close it is to an actual U48 (or 47), but It is really quite a nice sound.

 

[Tubetec]

Mhelin,
Ok yeah ,
what I suggested wouldnt be possible without some modifications to what already exists , so not truely a plug and play solution , youd need to get rid of the 1780 ohm resistor for a start , rearrange the heater,
but otherwise , in principle , why not ?


Theres what 10-12 thousand U47s out there ?
and many of them sound bad because theres to few viable alternatives to the VF14 and the owners are afraid to change them incase it harms the resale value. Some of the VF14 subs are obsessed trying to recreate the mechanical limitations and flaws of the original ,that strikes me as shady practice to be involved with .

I have used an EF86 in tube mic and have been very happy with the results ,
Mullard is my usual choice , with the mesh anode ,

Just thinking outside the U47 box for the moment ,
A tube mic that runs off a single rail low voltage DC supply makes your device a lot more inherently safe and simplifies cableing and connections ,an smps is all you have to worry about on the safety approval side and thats presumably handled by the reputable manufacturer .

 

[GeorgeToledo]

Off the shelf Heiserman makes the best all round clone these days. Stam makes the best budget version. As mentioned Dany’s “Poctop” makes the best DIY ,materials imo.

Heiserman has had two different parts vendors complain about non payment for body parts and capsule parts.

I don’t think not being satisfied with all of the parts you bought somehow (ethically or legally) allows you to use them on production mics and not pay who you bought them from.

I think just using the search engine here would turn up some gross behavior but maybe it got deleted.

The way a company treats vendors can reflect how they deal with customers and other issues.

https://groupdiy.com/threads/aputis-m49-u47-bodies.72996/page-6#post-1079398
The posts about non payment for capsule parts, from yet another vendor, were at GS and got deleted, though I think I have them on a HD.

And Heiserman v. STAM is yet another incident I’m just recalling.

And screwing people on an M49 body buy…

etc etc etc

 

[Tubetec]

Just looking over details of the K103 , seems to be single membrane loaded with a drilled plate at the back , maybe there other tweeks the DIYer could try with it ?
Appears to sell for 100-150 second hand ,

A TLM seems like a good transplant candidate in its own right for a cardioid only tube mic and you get the Neumann badge of honor thrown in ,


A single rail dc-dc tube mic of this sort could be put together very quickly and simply , multipin xlr to power input at the mic end on to standard 3 pin XLR at the output , no vintage PSU enclosure required , all the electrode voltages of the tube and capsule handled internally in the mic body
Maybe a few steps of HPF to cut proximity effect , depending on source and distance ,

 

[Mammals]

Not sure if this is posted upthread, but I've been seeing in my feed for the past three days or so that Thump Recording in Brooklyn is selling a U47 at what is apparently a nice price these days. You should be able to find the details via a little internetting. Apparently I'm post 47—maybe this news is good luck.

 

[Toobme]

Stay away from the 1G resistors.

I’m glad to hear this, as I’m finding these hard to source (at least with options).
Could you explain briefly why, and what to sub with instead of Gigs? Several Megs?
Thanks very much!

 

[GeorgeToledo]

Not sure if this is posted upthread, but I've been seeing in my feed for the past three days or so that Thump Recording in Brooklyn is selling a U47 at what is apparently a nice price these days. You should be able to find the details via a little internetting. Apparently I'm post 47—maybe this news is good luck.

I was just looking. It appears to have the fixed low output transformer BV8b, not a BV8. One of the less desirable configurations. A few years ago these or nuvistor U47 were selling for about 10 to 12k USD (someone I know even got one for 9k a few years back)…but I haven’t been keeping up on it.

 

[Tubetec]

The higher you go with the grid resistor value the more chance the tube starts to become noisy over time ,
I think something like 40meg is the max normally specified for the EF86 , you can go beyond that but theres no guarantee of satisfactory performance , some tubes will stand very much more than 40 meg and work for years others wont be suitable but might be fine in a preamp with <1Mohm .

 

[Khron]

I’m glad to hear this, as I’m finding these hard to source (at least with options).
Could you explain briefly why, and what to sub with instead of Gigs? Several Megs?
Thanks very much!

TE connectivity RGP0207 series @ Mouser or Digikey.

 

[tomas.borgstrom]

I’m glad to hear this, as I’m finding these hard to source (at least with options).
Could you explain briefly why, and what to sub with instead of Gigs? Several Megs?
Thanks very much!

100-200M is usually fine. If you go too low you lose low end. It varies a lot in the vintage microphones. 8M for AC701 in ELAM 250 (which is very low) to 400M for EF86 in U67. The recommended value in the tube data sheets are always a lot lower.

 

[paulcheeba]

Heiserman has had two different parts vendors complain about non payment for body parts and capsule parts.

I don’t think not being satisfied with all of the parts you bought somehow (ethically or legally) allows you to use them on production mics and not pay who you bought them from.

I think just using the search engine here would turn up some gross behavior but maybe it got deleted.

The way a company treats vendors can reflect how they deal with customers and other issues.

https://groupdiy.com/threads/aputis-m49-u47-bodies.72996/page-6#post-1079398
The posts about non payment for capsule parts, from yet another vendor, were at GS and got deleted, though I think I have them on a HD.

And Heiserman v. STAM is yet another incident I’m just recalling.

And screwing people on an M49 body buy…

etc etc etc

I was unaware of these (il)legal business practices. Datapanik sells great vintage mics.

 

[LuckyNat]

I'd say, the odd way the tube is under powered, and the exact nature of the transformer and the way it's loaded, account for much more than only 20% of the U47's sound.

That percentage figure people come up with is all to do what your brain is focusing on.

It's like if you decorate your house and make a small mistake .. no-one else will notice (it makes 0.1% difference) but it might be the first thing you see when you walk in the room and it will play on your mind (making 80% difference).

Same with audio - it's easy to change perspective by focusing on different aspects.

 

[MicMaven]

What would the best and "cheapest" way to get hands onto a Neumann U47 ?
-> Straight up getting one of the full kits that are available out there ? ... Would you go for a clone?
* * *
And well for a even bigger question would you even go the route to a U47 or would say another project makes more sense to tackle ?

Good Day Mr. @Shroomystic. Re-reading your original post after the several replies confirms you ask multiple questions, inviting multiple replies in various directions. Perhaps you could identify a particular objective to focus discussion in a singule direction. The last line quoted above essentially converts your inqiry into "What microphone or project should I get?" which is fairly wide open.

The cheapest way to acquire a Neumann U47 is to purchase a Neumann U47, either new or used, at a discount price. No other option will be a Neumann U47. Even so, you may not attain the precise sound you desire, as some experts suggest no two Neumann U47s sound exactly alike.

You also ask whether purchasing or building a clone or copycat product styled after the Neumann U47 will achieve the objective (whatever that is, although I presume you mean it will sound something like a real U47.) While that may be a lower cost option, it appears you will not likely attain the sound of an actual Neumann U47. Close, perhaps, but not really.

You ALSO ask whether you should consider other, yet unspecified projects, instead. This may get you even more varied and different suggestions, especially considering you have not announced a singular, unequivocal objective.

I am NOT being critical in any way. It is often it is difficult to identify a singlular, focused objective you wish to attain. Nevertheless, I suspect you may continue to receive varied suggestions without reaching a consensus until you clarify what you really want. Therefore, I respectfully suggest you rephrase your question with a more focused description of what you really want to accomplish. Otherwise, you have opened the door for all possible suggestions in all possible directions.

Just MY take. Good luck in any case. James

 

[mhelin]

Mhelin,
Ok yeah ,
what I suggested wouldnt be possible without some modifications to what already exists , so not truely a plug and play solution , youd need to get rid of the 1780 ohm resistor for a start , rearrange the heater,
but otherwise , in principle , why not ?

I don't think you have to remove the resistor limiting the current to about 50 mA, you will get enough power (over 5W) for the heaters anyway. For 6.3V @ 200 mA you need only 1.26W.

 

[Cqwet Dbdfte]

What would be reasonable source characteristics for SPICE modeling a capsule in a tube circuit?
What is the largest signal magnitude into the grid?
A brief look at VF14 and a 10:1 transformer looks like a net voltage loss. Would not a higher gain/lower noise tube be better?

 

[Mr. Moscode]

The original U47 and all the other classic condensor microphones we are cloning is built with parts of the highest quality. . . .

Available at the time! Every modern part you get will have some variation from the audible OE performance, depending where it is in the circuit.

There is something to be said about a mic that looks like the OE and sounds pretty close or exceeds OE performance.

 

[Toobme]

Thanks @Khron and @tomas.borgstrom - very interesting. I’m glad that is the case as these are easier to get.
This makes room for some experiments to hear any differences among the values one could try out.
Cheers

 

[tomas.borgstrom]

Available at the time! Every modern part you get will have some variation from the audible OE performance, depending where it is in the circuit.

There is something to be said about a mic that looks like the OE and sounds pretty close or exceeds OE performance.

If you have the knowledge high quality raw material you will be able to do it just as good or better. The microphone bodies etc at the cheap end of DIY are often very resonant. The cheap capsules I've tried sound way off.