The 251 Upgrade
Now available in four versions
The Original ELA M251 made by AKG for Telefunken Germany.
Yours for ONLY
We stand corrected on this price! AlanVeniscofsky at TeleFunken told us the correct price is $8 995. That sounds like a deal compared to some of the vintage units we see on E-Bay.
The FAR 251 is based on the famous ELA m251 Microphone, sold by the original Telefunken company in Germany.
The m251 was built by AKG for Telefunken as a replacement for the u47 after Neumann stopped selling the u47 to Telefunken.
The original 251 was the epitemy of Austrian vacuum tubemicrophone engineering and was very expensive due to the internal mechanical design. The AKG signature sound still had that mid-range dip in response around two kiloherz and a gradual 5dB response lift in the high end. But to make it sound a little more like the u47, that it was to replace, the AKG engineers needed to remove some of that top end... so they added a special little part to the circuit. We do too and it is part of the secret to making it sound right.There are not enough "O"s in the word smooooth to describe this mic.
This is a VERY smooth sounding microphone with a wide range of applications. It is exceptional for live string instruments or orchestras, acoustic guitars, vocalists, choral groups and choirs.
The secret is to start with a correctly built edge terminated capsule.
AKG original CK12 capsule
The original CK12 capsule was a work of wonder and had over fifty individual parts. It was very complicated to make, which is probably the reason why it was discontinued.
The great news is the RK12 and CEK12 are excellent alternatives and with a little electronic help from us they sound amazing. Especially when compared to the centre terminated stock capsules used in most of today's low end microphones.
We don't just say it's better...
...we measure it and send you the results!
With every upgrade we measure the electronics and acoustics of your microphone and print a book with the results, before and after our work, so you can see how the changes improved things.
And your ears will tell you the real difference the moment you lay down your first track.
A Choice for Every Budget
We have been working for a while now with a number of options for this style of mic. We know everyone has a budget to work with so we have four different ways for you to go. They all sound good. Each one just adds a little extra quality to the mic. The fourth level gets as close as we can to the original.
Option 1: The 251 BASIC
We take an APEX 460 or equivalent microphone and upgrade the stock preamp circuit to remove all the warts, using quality components, adjust the bias point and add a 6072 tube. This gives the preamp low distortion and wide response.
Then we replace the poor quality 32mm style stock capsule with an RK12 capsule and a new lower profile pedestal which puts the capsule at the right height, in the centre of the cage.
RK12 edge terminated capsule and low profile pedestal creates the m251 sound
New Capacitors create Transparency
We replace the critical capacitors in the audio path with a polystyrene input cap and a polypropylene output cap. These materials are recognized as the superior dielectrics to use in audio amplfiers. This gives you a transparent, low distortion sound path.
We also replace the electrolytic power de-coupling caps with larger value Nichicon caps which improves the low end clarity.
We put in a selected EH6072 vacuum tube to replace the noisy 12AX7 that came with your microphone when you bought it. Changing to a 6072 tube means the we need to adjust the bias voltage on the tube. This optimizes the circuit, allows more current to flow and lets the 6072 create the best sound with maximum headroom.
Or Old tube...
We usually have a small supply of Old Stock 6072 tubes which we can sell for a competitive price if you prefer.
To save you money we keep the stock transformer which works just fine. Actually it's very good if the truth be told.
We mod the power supply to get the voltage down to the original 251 voltage. This gets the capsule properly polarized.
And we add that one special capacitor that gives the 251 that really smooooooth high end; just like the AKG design engineers did many years ago. And Voila!
You have a low cost professional quality microphone.
How much better?
Just to show you the difference. Here is the distortion measurements of the internal electronics of a very typical APEX 460 before and after we upgrade it.
The difference is stunning to the clarity of the sound!
We add 2 dB more signal into the upgraded version above to make the actual output level be the same. The 6072 gives 2 dB less gain but the circuits are both making the same level out output in the graph so it is a fair comparison!
Option 2: The 251 Standard
Upgrade to the Peluso CEK12
The Peluso CEK12, Gold sputtered 34x14 mm, 6 micron, dual diaphragm capsule is shown below. It is a little brighter than the RK12 and we custom EQ each mic to create the response we want for our 251.
Peluso CEK12 capsule
And a New Transformer for this one
We replace the output transformer with Peluso BV11P which gives you 6dB more output, flatter frequency response and less high frequency distortion.
Below is the CARDIOD response of the FAR 251 Standard from 70 Hz to 20,000 Hz. You can see that it is very smooth and compares very well to the response of the original ELA m251. With the 251 "Standard" we used a tiny EQ cap like the original m251 to shape the top end response. This gives us the flexibility to adjust each capsule individually.
FAR 251"Standard" frequency response measured at 0.5 M from source
ELA m251 response graph from original manual
(0 dB line hi-lighted in red)
FAR 251 "Standard" Sound Samples
These examples were recorded simultaneously using four microphones. You can hear all the files on one page here.
The tracks below were recorded direct into our Presonus Firestudio project. The DAW was Logic Pro 8 and the sample rate was 44.1Khz. No compression or EQ was used.
Guitars were recorded about 20 inches in front of the guitar with the mic slightly above the top of the guitar body.
And one more thing for the techies ...
In our BASIC and Standard versions of the 251 we use a two stage preamplifier circuit. For those who don't know, this is a direct coupled two triode amplifier that has some real advantages as a microphone preamp. The technical name of the circuit used is "constant current draw amplifier". (CCDA)
The first stage tube is the normal "plate follower" circuit like the one used in the m251 microphone. The second stage is a direct coupled "Cathode Follower" stage. There is no capacitor between the stages so the signal transfer is virtually perfect.
The low output impedance of the cathode follower second stage drives the low primary impedance of the Peluso transformer MUCH better than a single stage 6072 circuit. This allows your mic. circuit to preserve the sound quality of the first stage amplifier and lets the 2nd stage do the dirty work of the driving the transformer. We get improved high frequency and low frequency response,lower distortion and more headroom.
Option 3: 251 Special Edition I or II
Now for those discerning ears that want to get closer to history we have the Special Edition. The internal preamp on this one is about as close as we can get to the original.
We re-wire things to use the original single triode design and keep all the quality capacitors as in the other models. This alone reduces the noise floor by 4 dB compared to the Standard and Basic models.
We also have wired this mic so it can use either the 6072 tube or the ultra-low noise, wide bandwidth 6922 tube. You can get one of each.
And for the single triode circuit we have to use the Tab Funkenwerk T14 replica transformer. Its virtually identical to the ones used in the late model ELA m251 microphones. It is designed to match the output characteristics of the single triode 6072 circuit.
It can be sold with either capsule:
Special Edition I with RK12 or
Special Edition II, with CEK12, it's your choice
What's the Difference in the Capsules?
The RK12 capsules are excellent value for the money. less than half the price of the Peluso capsule, they give you the classic response of the c12 capsules with the AKG "edge terminated" design. (the connection wire is on the edge of the capsule, not in the centre like a Neumann design)
The RK12 has a beautiful high response that is bright not sharp and they have a signature low end proximity effect that interestingly is very much like our best quality capsule from Tim Campbell. (see bottom of page)
The Peluso Capsules are quite a bit more expensive that the RK12. The difference in sound is that they are slightly brighter and they have an almost perfectly flat reponse below 1,000 Hz. This gives a very nice clean low end with little colouration.
We keep the 9- polar pattern circuit in our 251, which is actually the circuit used in the AKG c12 microphone. This is different than that 3 patterns (Cardiod, Omni and Figure 8) used in the original m251. Not a huge difference, but we thought you should know.
Audio Samples (Using 6922 Tube)
These audio samples were simu-recorded with the FAR 251 "Special Edition I" microphone found on this page using an RK12 capsule.
You can also here the machine cleaning the furnace duct-work in my neighbors home!
Option 4: The 251 "Custom Edition"
And for those who just want the best, we present the FAR 251 Custom edition. All the plusses of the Special Edition's 251 replica preamp circuit and a Tim Campbell CT12 capsule!
The CT12 capsule is handmade by Tim and is as close a copy of the original capsules as he can build. There are over 50 individual parts in this design. Tim has even sourced a roll of the original mylar film that was used by AKG for the diaphragms.
These capsules have to be experienced to be really appreciated but if you look up the word "mojo" in a music dictionary, it should have a picture like this:
Here is a voice recording done at Four Legs Records, proud owners of a FAR 251 Custom Edition and a FAR 47 Custom Edition
Big thanks for Steven Goldman for making and publishing this demo
FAR 251 Custom Edition, male voice at 6" from microphone
FAR 251 Custom Edition, L'Arrivee Guitar 18" from microphone
To get a quote for The FAR 251 Upgrade;
Basic, Standard, Premium or Custom edtions
just send a request to: