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Post by drbill on Jan 15, 2021 16:27:19 GMT -6
I chatted a bit with Matt yesterday re: the 251. Very excited to hear this when it's finished. It is quite obvious that Heiserman has not only gone the extra distance that most clones have not reached, but has exceeded beyond that to the point of being a 1:1 clone. No doubt it will be a special mic.
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ericn
Temp
Balance Engineer
Posts: 14,921
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Post by ericn on Jan 15, 2021 16:37:05 GMT -6
New to this site. Got a link to this thread, and had to chime in because I am such a 251 nerd. I've spent a bunch of years rebuilding and tweaking vintage and repro versions, and testing an analyzing dozens of vintage 251's and C12's. This is great news. I've gotten the chance meet Eric and talk to him about mics, and his attention to the things that in my experience have turned out to be the important parts of a character of a mic have me excited to hear what he's come up with. I am also happy to see that he's recreated the internal perspex structure of these mics, because I believe that they are part of the sound of a 251. I have a 251 that I have considered to be the gold standard of where I like these things to sit, tonally. A number of people have agreed with me, and sent me various 251's they were considering buying to compare. As with most mics, 90% of the difference between one mic of the same variety and the next is the capsule. And in mics such as 251's, C12's and 47's, where a simple plate loaded circuit is used, with a minimum or no filtration employed, the capsule is generally the first thing you notice as why two may not sound alike. When I acquired a vintage 250, Tim worked with me on tuning that mic's CK12 so that I had a matched pair of ELAM's. His understanding of the CK12 is truly remarkable. It might be the most complicated capsule that is in common existence. So many variables that are required to be aligned properly in order to achieve proper tonal balance. Not to mention, AKG sputtered their mylar in a completely different manner than everybody else, and even that affects the movement of the mylar in a way that makes the sound of these capsules unique. Oliver had hipped me to this maybe years ago, by showing me microscopic images of the different gold layers and how the movement is affected. I differ from Tim's experience in one area: I have a large pile of NOS white paint, 5 star GE 6072's. I find their tone to be extremely uniform. It's been more about noise floor when I choose one over another. I have found other makes of 12AY7's to get outside the tonal ballpark, particularly new ones. They lack in either top end, low end or both. I'm doubtful that anybody can execute a 6072 that replicates the tone of the GE. Hearing that bottom octave missing on the new EF86's that Neumann is using, and I'm sure they tried their hardest to find the best tube available, makes me even more skeptical. Other tubes are available, and I know that Tele has used the 12AT7, but the bass response of those makes the mic no longer sound like a 251. But as Eric well knows, the relationship between the tube and transformer has everything to do with the frequency balance. If he finds as suitable tube, I suspect something other than a T14/1 will have to be employed, without modification. But for me, even with all the mics I have in my collection, I always consider my ELAM's to be the crown jewel. It's presence peak is problematic on some instruments and voices, but it gives a richness and intimacy that nothing else does, and makes my job as an engineer so much easier, when used on the correct sources. OH, piano, airy voices, acoustic guitar ... nothing beats it. I can't wait to hear these. Great to see you over here JJ , we all hope it becomes a habit.
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Post by Johnkenn on Jan 15, 2021 16:37:37 GMT -6
New to this site. Got a link to this thread, and had to chime in because I am such a 251 nerd. I've spent a bunch of years rebuilding and tweaking vintage and repro versions, and testing an analyzing dozens of vintage 251's and C12's. This is great news. I've gotten the chance meet Eric and talk to him about mics, and his attention to the things that in my experience have turned out to be the important parts of a character of a mic have me excited to hear what he's come up with. I am also happy to see that he's recreated the internal perspex structure of these mics, because I believe that they are part of the sound of a 251. I have a 251 that I have considered to be the gold standard of where I like these things to sit, tonally. A number of people have agreed with me, and sent me various 251's they were considering buying to compare. As with most mics, 90% of the difference between one mic of the same variety and the next is the capsule. And in mics such as 251's, C12's and 47's, where a simple plate loaded circuit is used, with a minimum or no filtration employed, the capsule is generally the first thing you notice as why two may not sound alike. When I acquired a vintage 250, Tim worked with me on tuning that mic's CK12 so that I had a matched pair of ELAM's. His understanding of the CK12 is truly remarkable. It might be the most complicated capsule that is in common existence. So many variables that are required to be aligned properly in order to achieve proper tonal balance. Not to mention, AKG sputtered their mylar in a completely different manner than everybody else, and even that affects the movement of the mylar in a way that makes the sound of these capsules unique. Oliver had hipped me to this maybe years ago, by showing me microscopic images of the different gold layers and how the movement is affected. I differ from Tim's experience in one area: I have a large pile of NOS white paint, 5 star GE 6072's. I find their tone to be extremely uniform. It's been more about noise floor when I choose one over another. I have found other makes of 12AY7's to get outside the tonal ballpark, particularly new ones. They lack in either top end, low end or both. I'm doubtful that anybody can execute a 6072 that replicates the tone of the GE. Hearing that bottom octave missing on the new EF86's that Neumann is using, and I'm sure they tried their hardest to find the best tube available, makes me even more skeptical. Other tubes are available, and I know that Tele has used the 12AT7, but the bass response of those makes the mic no longer sound like a 251. But as Eric well knows, the relationship between the tube and transformer has everything to do with the frequency balance. If he finds as suitable tube, I suspect something other than a T14/1 will have to be employed, without modification. But for me, even with all the mics I have in my collection, I always consider my ELAM's to be the crown jewel. It's presence peak is problematic on some instruments and voices, but it gives a richness and intimacy that nothing else does, and makes my job as an engineer so much easier, when used on the correct sources. OH, piano, airy voices, acoustic guitar ... nothing beats it. I can't wait to hear these. Great to have you here!
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Post by timcampbell on Jan 15, 2021 17:00:39 GMT -6
Hey JJ so good to see you here.
You are certainly right about the noise floor.
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Post by chessparov on Jan 15, 2021 17:03:24 GMT -6
JJ, where would you consider your 251 to be, along the brightness spectrum? (bright/neutral/dark) Thanks, Chris P.S. It's cool you're here!
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Post by timcampbell on Jan 15, 2021 17:42:26 GMT -6
He has a pair of them. They are certainly very open sounding. So is my own
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Post by Ward on Jan 15, 2021 17:47:10 GMT -6
New to this site. Got a link to this thread, and had to chime in because I am such a 251 nerd. I've spent a bunch of years rebuilding and tweaking vintage and repro versions, and testing an analyzing dozens of vintage 251's and C12's. This is great news. I've gotten the chance meet Eric and talk to him about mics, and his attention to the things that in my experience have turned out to be the important parts of a character of a mic have me excited to hear what he's come up with. I am also happy to see that he's recreated the internal perspex structure of these mics, because I believe that they are part of the sound of a 251. MASSIVE SNIP for reading ease. Welcome aboard! It's been great chatting recently on another site. Your wise words are very welcome here! tskguy Heiserman mdmitch2 and wave are doing amazing work.
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Post by jjblair on Jan 15, 2021 17:55:02 GMT -6
JJ, where would you consider your 251 to be, along the brightness spectrum? (bright/neutral/dark) Thanks, Chris P.S. It's cool you're here! Bright is misleading, because bright can be harsh. I like the term "open." I find a CK12 that is "neutral" is dark to my taste. I would call a K47 neutral, and that's not what I want in a 251 or C12. But any 251 or C12 that has been sent to me or passed through here always gets a comparison against this, and I don't know that I've heard any vintage capsules that sound more open than this one. That's where the magic is on a CK12. It achieves high end in a way that my buddy calls "classy." Nothing else can bring the high mids to the front like this in a rich, complex and smooth way. K67s do it in a harsh way, and even the Josephson version lacks the harmonic complexity and smoothness. What's funny though is, as open as the top end on my mic is, it sounds dark compared to a C800G. Now THAT is a bright mic.
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Post by chessparov on Jan 15, 2021 18:20:37 GMT -6
Thanks! Besides the manifold other reasons...
I'm bummed there's no Anaheim NAMM this year. It would have been cool, to directly sing/try all the 251 Styles, and hear any differences.
Hmmm... I have to pay more attention to "Open".
Been conditioned to being generally apprehensive, of brighter toned microphones.Albeit lower $$ range. Thanks, Chris P.S. Guys, do you consider the Bock 251 kinda "Dark"?
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Post by timcampbell on Jan 15, 2021 18:23:07 GMT -6
There is always Nashville.... maybe.
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Post by drbill on Jan 15, 2021 19:23:22 GMT -6
Most of the modern "brighter voiced" mics tend to sound bright - or if pushed - harsh to my ears. The vintage mics have that beautiful "open" sound - even when pushed that just sounds glorious. Very rare to find that in most modern mics that don't cost a fortune. I guess what I'm saying is - there's a fine line between "bright" and "open", but when standing on that proverbial line, it becomes quite obvious. Super excited to hear the H 251!!
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Post by reddirt on Jan 15, 2021 19:56:06 GMT -6
Good to see you (and your lovely mic locker) here JJ. Cheers, Ross
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Post by guitfiddler on Jan 15, 2021 21:06:35 GMT -6
Tim Campbell!!! I need one of your 251 capsules! I PM’d you
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Post by Johnkenn on Jan 15, 2021 21:16:48 GMT -6
New to this site. Got a link to this thread, and had to chime in because I am such a 251 nerd. I've spent a bunch of years rebuilding and tweaking vintage and repro versions, and testing an analyzing dozens of vintage 251's and C12's. This is great news. I've gotten the chance meet Eric and talk to him about mics, and his attention to the things that in my experience have turned out to be the important parts of a character of a mic have me excited to hear what he's come up with. I am also happy to see that he's recreated the internal perspex structure of these mics, because I believe that they are part of the sound of a 251. MASSIVE SNIP for reading ease. Welcome aboard! It's been great chatting recently on another site. Your wise words are very welcome here! tskguy Heiserman mdmitch2 and wave are doing amazing work.
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Post by Johnkenn on Jan 15, 2021 21:20:42 GMT -6
JJ, where would you consider your 251 to be, along the brightness spectrum? (bright/neutral/dark) Thanks, Chris P.S. It's cool you're here! Bright is misleading, because bright can be harsh. I like the term "open." I find a CK12 that is "neutral" is dark to my taste. I would call a K47 neutral, and that's not what I want in a 251 or C12. But any 251 or C12 that has been sent to me or passed through here always gets a comparison against this, and I don't know that I've heard any vintage capsules that sound more open than this one. That's where the magic is on a CK12. It achieves high end in a way that my buddy calls "classy." Nothing else can bring the high mids to the front like this in a rich, complex and smooth way. K67s do it in a harsh way, and even the Josephson version lacks the harmonic complexity and smoothness. What's funny though is, as open as the top end on my mic is, it sounds dark compared to a C800G. Now THAT is a bright mic. You’re right on the GE. I have a NOS Mullard 12AT7 in my Upton to darken it a little...I love the darker sound for my voice, but it definitely makes it sound the different than the prototypical 251.
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Post by Ward on Jan 16, 2021 10:52:46 GMT -6
Welcome aboard! It's been great chatting recently on another site. Your wise words are very welcome here! tskguy Heiserman mdmitch2 and wave are doing amazing work. I'll just go stand in the corner and pelt shit at myself now. Sorry. There are no other sites. There are no other sites. There are no other sites. There are no other sites.
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Post by Guitar on Jan 16, 2021 11:31:33 GMT -6
I'm going to have to visit Nashville to sing in some real vintage 251's. What an exciting thread this is. My little mic was too bright so I used 330 pF roll off capacitor rather than the vintage spec of 100 pF. You also have to use a high quality electrolytic in the cathode bypass position because a cheap capacitor will add midrange crunch there. And the output capacitor is obviously critical as well. I have suspicion that my mic might not have as big of a low end as a "real" 251, but this is the shootout I'll keep dreaming of happening some day. It's certainly plausible that the ADK GK-12d "air" is not really the same "air" as an AKG capsule, I would not be surprised at all. These are the hypothetical questions that excite my imagination, even though I'm happy with my microphone.
It's threads like these that remind me of why I loved gear in the first place.
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Post by chessparov on Jan 16, 2021 11:36:06 GMT -6
Most insightful Ward, verging on frightful. (hey this could be my new Rap song with Plush-bound to be an unforgettable Classic! Chris
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Post by jjblair on Jan 16, 2021 12:34:41 GMT -6
I'm going to have to visit Nashville to sing in some real vintage 251's. What an exciting thread this is. My little mic was too bright so I used 330 pF roll off capacitor rather than the vintage spec of 100 pF. You also have to use a high quality electrolytic in the cathode bypass position because a cheap capacitor will add midrange crunch there. And the output capacitor is obviously critical as well. I have suspicion that my mic might not have as big of a low end as a "real" 251, but this is the shootout I'll keep dreaming of happening some day. It's certainly plausible that the ADK GK-12d "air" is not really the same "air" as an AKG capsule, I would not be surprised at all. These are the hypothetical questions that excite my imagination, even though I'm happy with my microphone. It's threads like these that remind me of why I loved gear in the first place. There's two schematics for the 251. The earliest has a 1µ cap in the transformer coupling position. The later schematic is 3.2µ. 251's use a wet tantalum cap, which is a little pricier, but will fit, unlike a mylar of that value. I would avoid electrolytic at all costs. You will hear a difference in bass resonance frequency between 1µ and 3.2µ. The trick with low end in a 251 is that the low mids are more robust than a T14/1 equipped C12, but not so much more that a vocal feels too boomy in a track. I find that a later "deep dish" style CK12 (with the orange paint), when used in a 251, has too much low end in its factory tuning, and does not sound as lean as a 251 should. It makes me want to hi-pass it. I also find that the 12AT7 tube makes the mic sound way too boomy. The resonant frequencies between it and the T14/1 emphasize entirely too much low end. That's not where the elegance of a 251 is, and it doesn't sit in a track the same way.
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Post by Guitar on Jan 16, 2021 12:55:54 GMT -6
I'm going to have to visit Nashville to sing in some real vintage 251's. What an exciting thread this is. My little mic was too bright so I used 330 pF roll off capacitor rather than the vintage spec of 100 pF. You also have to use a high quality electrolytic in the cathode bypass position because a cheap capacitor will add midrange crunch there. And the output capacitor is obviously critical as well. I have suspicion that my mic might not have as big of a low end as a "real" 251, but this is the shootout I'll keep dreaming of happening some day. It's certainly plausible that the ADK GK-12d "air" is not really the same "air" as an AKG capsule, I would not be surprised at all. These are the hypothetical questions that excite my imagination, even though I'm happy with my microphone. It's threads like these that remind me of why I loved gear in the first place. There's two schematics for the 251. The earliest has a 1µ cap in the transformer coupling position. The later schematic is 3.2µ. 251's use a wet tantalum cap, which is a little pricier, but will fit, unlike a mylar of that value. I would avoid electrolytic at all costs. You will hear a difference in bass resonance frequency between 1µ and 3.2µ. The trick with low end in a 251 is that the low mids are more robust than a T14/1 equipped C12, but not so much more that a vocal feels too boomy in a track. I find that a later "deep dish" style CK12 (with the orange paint), when used in a 251, has too much low end in its factory tuning, and does not sound as lean as a 251 should. It makes me want to hi-pass it. I also find that the 12AT7 tube makes the mic sound way too boomy. The resonant frequencies between it and the T14/1 emphasize entirely too much low end. That's not where the elegance of a 251 is, and it doesn't sit in a track the same way. Thanks for the information, JJ! Do you know the "secret" in the Bock 251? I heard he engineered the low frequency to extend all the way down to 20 Hz or something. I'm just assuming you would use a very large coupling capacitor, and it looks like they use an extremely large transformer as well. I didn't like the film caps at all in the tube/transformer coupling position, they were too snappy and bright. I was also told that the resistors right around the capsule have some influence in low frequency extension, and the vintage (small-ish) values might actually tailor off some of that low end a bit. Sorry for not being more specific. Everything right around the capsule is still sort of mysterious to me, and I'm not an EE just a DIY hobbyist.
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Post by the other mark williams on Jan 16, 2021 13:03:09 GMT -6
I'll just go stand in the corner and pelt shit at myself now. Sorry. There are no other sites. There are no other sites. There are no other sites. There are no other sites. First rule of Fight Club...
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Post by chessparov on Jan 16, 2021 13:25:27 GMT -6
There's two schematics for the 251. The earliest has a 1µ cap in the transformer coupling position. The later schematic is 3.2µ. 251's use a wet tantalum cap, which is a little pricier, but will fit, unlike a mylar of that value. I would avoid electrolytic at all costs. You will hear a difference in bass resonance frequency between 1µ and 3.2µ. The trick with low end in a 251 is that the low mids are more robust than a T14/1 equipped C12, but not so much more that a vocal feels too boomy in a track. I find that a later "deep dish" style CK12 (with the orange paint), when used in a 251, has too much low end in its factory tuning, and does not sound as lean as a 251 should. It makes me want to hi-pass it. I also find that the 12AT7 tube makes the mic sound way too boomy. The resonant frequencies between it and the T14/1 emphasize entirely too much low end. That's not where the elegance of a 251 is, and it doesn't sit in a track the same way. Thanks for the information, JJ! Do you know the "secret" in the Bock 251? I heard he engineered the low frequency to extend all the way down to 20 Hz or something. I'm just assuming you would use a very large coupling capacitor, and it looks like they use an extremely large transformer as well. I didn't like the film caps at all in the tube/transformer coupling position, they were too snappy and bright. I was also told that the resistors right around the capsule have some influence in low frequency extension, and the vintage (small-ish) values might actually tailor off some of that low end a bit. Sorry for not being more specific. Everything right around the capsule is still sort of mysterious to me, and I'm not an EE just a DIY hobbyist. This was part of the reason, I asked about the Bock... Chris
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Post by jjblair on Jan 16, 2021 13:55:19 GMT -6
There's two schematics for the 251. The earliest has a 1µ cap in the transformer coupling position. The later schematic is 3.2µ. 251's use a wet tantalum cap, which is a little pricier, but will fit, unlike a mylar of that value. I would avoid electrolytic at all costs. You will hear a difference in bass resonance frequency between 1µ and 3.2µ. The trick with low end in a 251 is that the low mids are more robust than a T14/1 equipped C12, but not so much more that a vocal feels too boomy in a track. I find that a later "deep dish" style CK12 (with the orange paint), when used in a 251, has too much low end in its factory tuning, and does not sound as lean as a 251 should. It makes me want to hi-pass it. I also find that the 12AT7 tube makes the mic sound way too boomy. The resonant frequencies between it and the T14/1 emphasize entirely too much low end. That's not where the elegance of a 251 is, and it doesn't sit in a track the same way. Thanks for the information, JJ! Do you know the "secret" in the Bock 251? I heard he engineered the low frequency to extend all the way down to 20 Hz or something. I'm just assuming you would use a very large coupling capacitor, and it looks like they use an extremely large transformer as well. I didn't like the film caps at all in the tube/transformer coupling position, they were too snappy and bright. I was also told that the resistors right around the capsule have some influence in low frequency extension, and the vintage (small-ish) values might actually tailor off some of that low end a bit. Sorry for not being more specific. Everything right around the capsule is still sort of mysterious to me, and I'm not an EE just a DIY hobbyist. First off, David's mic is not a clone. I think it's more of a tribute, even though it uses the same circuit design. But, given the lack of availability of 6072's, David decided to use a different tube and transformer pairing, as he has in all his mics. He's always concerned in using a very high grade tube that he can supply for years to come. He makes sure he can attain a large supply of an NOS tube, tests its characteristics, and then signs the circuit around that tube, as long as it is deemed suitable, sonically. As for the capsule resistors, he uses a 1gig resistor in the grid position, which is something anybody with a clue does now. Neumann and AKG likely would have, had it been possible to have one that fit back then. Neumann managed with 100MΩ in the 47, and AKG could fit 20MΩ in the 251. But this has more to do with eliminating low end distortion, and not extending the range, from everything I've learned. There might be extension as a result, but that was not how Oliver explained to me the reason for moving to this value. It was about decreasing grid distortion. David has let me test her personal AKG CK12 that the MBHO capsule he uses is based on, and it is more towards the "neutral" tuning than my capsule. I tend to find that David's taste in capsules is more in that direction, so a lot of what you are hearing in his mic in terms of the top end is that particular capsule. They are still wonderful sounding, but it's about 1.5dB shy, if I recall, of the high mids of my capsule. I have a pair of those MBHOP capsules in my CS1's that I use on every drums session at my studio, and they are gorgeous. I've never been tempted to change them for anything brighter, and this is because that light difference makes them more flexible, and works on some sources that my 251 won't work on. But yes, the low end extension of his mic is completely a result of that lar ger transformer. The T14/1 cuts off pretty early. David's ability to use a large output cap has more too do with the complexity and timbre overall to my ears, than to do with the frequency range. The value determines the range.
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Post by Guitar on Jan 16, 2021 14:22:19 GMT -6
Wow, thanks for the masterclass in these microphones, much appreciated! My mic has a 200 Meg resistor in the grid position, I might have to listen to a 1G. I might also have to try to get something going with a larger transformer. Mine has a small-ish Cinemag, the CM-13114.
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Post by jjblair on Jan 16, 2021 14:44:53 GMT -6
Wow, thanks for the masterclass in these microphones, much appreciated! My mic has a 200 Meg resistor in the grid position, I might have to listen to a 1G. I might also have to try to get something going with a larger transformer. Mine has a small-ish Cinemag, the CM-13114. I know he's changed things as time has gone on. The one the build for me had a 1G resistor, but he used a T14/1. The last one I saw was a larger transformer than a T14/1, which is tiny. Like thumbnail sized. This is the transformer I'm used to seeing:
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