oscarhuang
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I should say that is not a vacuum tube. Better answer?
U47 with Phaedrus VF14 M tube
- Thread starter oscarhuang
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Help Support GroupDIY Audio Forum:
Ok mate, I get it. So basically when that module is fitted in a U47 the microphone is not a Tube mic any-longer and it is a solid state mic, that's it?
Doesn't that defeat the purpose?
There's so many good Solid State circuits around why waste an U47 in a solid state conversion instead of buying a solid state mic?
tubes are getting harder to find, and stock is constantly decreasing. it's a good idea to have a reasonable backup to fix mics like these in the event that tubes are phased out of everything.
oscarhuang
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That isn’t a vacuum tube. My first diy mic was a U47. And I used EF800 then I fell that sounds great. Then somebody said one of the Secret for U47 is the tube. Check online the VF14 cost $3000-$5000 and some fake tubes appear as well. I never had a real VF14 so I don’t know how is real U47 sounds like. Then I found Phaedrus tube and I wanna try it. I had build some FET mics as well U47 fet, u87 and so on but U47 still the best for my test. So in your opinion,what is the best tube for replace VF14? Thanks.
I understand what you say, but it will take a long time until "tubes are phased out of everything", it will not be in our lifetime that's for sure
let me put it another way: this product is not meant for DIY microphones or conversions. it was developed as a last resort to repair real u47s with damaged tubes that cannot be replaced. There are a few advantages to using a not-tube-tube like this over finding a replacement tube. Namely, that you can make sure that it affects the gain and FR in the exact same way, so as to not change the overall sound of the mic on paper. This comes at the expense of losing harmonic distortion and (debatably) tube microphonics. The other (and potentially more valuable) advantage is that it doesn't require modification of the broken u47's circuit, which may allow it to be repaired later with better technology and keep its value.
I really don't know mate, but I would prefer to have a tube in an U47 (than any solid state circuit) even if it behaved a little different than the VF14M.
To be honest I really don't care about the VF14M, that tube is long gone, the best tube for an U47 mic is one that still exists in the present whatever that is.
People need to forget and bury the VF14 for good, it doesn't exist and will not exist again, don't make it ghost, we should move on an accept the U47 with different tubes.
oscarhuang
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Of course. We must tried some different tubes and find the best one. That’s why I bought Phaedrus VF14M. Otherwise I never known this sound.
Yes, but Phaedrus VF14M is not a tube...
oscarhuang
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Sometimes just curious. I bought “Telefunken” VF14K tube and now I fell that is a really stupid decision!
Why do you say that?
I never tried that one, but it doesn't sound good?
I never tried that one, but it doesn't sound good?
Ricardus
WILL SOLDER FOR FOOD
Its solid state.
oscarhuang
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Doesn’t sounds good to me. IMO EF800 better than VF14K.
Now i'm starting to feel you are trolling us. Have you red the moamps 3 page article i posted on VF14 including comparing it to other tubes, as scientifically as possible. What more would you like? There is a tube that can replace vf14 for cheap, to the point any difference you hear might be in your head. It's in the article! VF14 is not expensive because it's special, but because it's rare.
My understanding is it's a solid-state circuit in vaccum tube guise.
It's not the first time it's done. Out of my head I think of the Fetrons that were used in the Mesa Boogie amps. Also the extinct Retrotube line.
Fetrons were basically one or two JFET's and one ot two passives.
Of course Peavey had their own Transtube technology, but it was a circuit, not a component for direct replacement.
The main advantages claimed by Teledyne for the Fetron were the reliability (nothing wears out) and lesser power draw (no heaters; smaller xfmr and less heat).
Along the years there have been a number of attempts at producing swap-in replacement, mainly for the family of dual-triodes 12A_7, particularly the 12AX7 in an attempt to avoid microphonics, for use in high-gain guitar amps. Most failed because they didn't "sound" like the vacuum tubes they were meant to replace. It does not mean they aren't good enough, it just shows the dominance of acquired taste and confirmation bias. Most guitarists would not be seen with a solid-state input circuit in their amp, but they rely on a $0.50 circuit for their overdriven sound.
AFAIK Phaedrus is the only company dealing with VF14 substitutes. Rightly so; I'd better spend time on replacing $1000 tubes than $10.
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oscarhuang
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I don’t understand what you means I’m trolling you. So you are reading my full post and pick one sentence then said I’m trolling you. That’s so funny. I never read any moamps. So as a Diyer to post a diy gear should they need to buy all the equipments to test ? Sorry I don’t have any equipments to do the test. Just for fun.
The VF14M is particularly rare (and thus expensive) because it was factory selected for low-noise. I believe only 20-25% of the tubes that were delivered to Neumann were actually considered good enough to receive the "M" stamp. The rest was returned to the TFK factory.
The tests conducted by moamps are pertinent to the transfer curves, so would be a good indicator of their sonic imprint.
However, one very important test that was conducted by Neumann was the ability to operate with a very high grid-leak resistor. It's a direct result of purity of the vacuum. Impurities result in grid current, which generates noise and shifts the operating point.
That's the main reason why the grid-leak resistor in tube condenser mics rarely exceed 500 Meg. There was a notable exception using 7Gig resistors though. I don't remember what model it was...
An important issue there is the number of samples is too small. They are 70 years old, so they may have drift significantly.
I don't see it in the article, but I think only one VF14 has been tested, out of two. Did Milan (moamps) select one or did he consider they were similar enough?
It is quite possible that, with the legendary Teutonic quality control, all VF14's were within strict tolerance...
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Ok, i guess it might be a language barrier. Here's the link again, you'll find most answers there, make sure you read all three pages. For what i suggested you dont need special gear, just a pc and a sound card, but forget that.
http://www.moxtone.com/mU47_U47_part3.html
oscarhuang
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Sorry. That’s language problem. I read this few years ago and it’s help a lot. I bought a used EF13 but didn’t last too long then it dead. The reasons I didn’t wanna buy those Telefunken EF vacuum tubes are
1st very expensive
2nd never known if that is low noise for microphones
3rd never known how how time leftover
4th hard to find it
Sorry again for misunderstanding
moamps
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May I quote myself?
"Since I happened to come by two VF14's and a dozen of EF14's, EF13's and EF12 's (pictured above; click to enlarge), I thought it would be a real shame if I missed this unique opportunity to do a comparative testing of the lot and hopefully fill in some blanks for myself, as well as others.
The measurements presented in this article have been averaged to obtain 'typical' values for each tube type tested. Of course, the small size of the test sample (only four tubes per type) increases the chance of error, but the results will still be useful for identifying trends, obtaining basic data and providing a ballpark idea of what to expect from these tubes. After all, some data is better than none."
And what I can say is that the two VF14s I analyzed were almost identical in terms of parameters.
Thanks to everyone who visited my site. In any case, this will encourage me to continue publishing articles that may be interesting and useful to someone.
