Microphone preamps

March 18, 2019
 by Paul McGowan

As Gus Skinas and we build out the new recording facility we run into the inevitable issues of electronics, in particular, the microphone preamplifiers. There are so many opinions on which preamp topology betters the next you'd think we were back in audiophile land. Maybe worse.

There's transformer coupled designs, transformerless, tubes, transistors, high voltage, low voltage, vintage, and modern miracles to choose from. And, of course, it's us so we will roll our sleeves up and design our own. Heck, it's what we do.

And, like audio electronics, we'll use (gasp) our ears! in the designs.

As we do in our stereo products we'll start with a supposition based on a lot of research. We'll then poke around at what's available and see what floats our collective boats when it comes to capturing the essence and soul of music through microphones. And then we will combine all that we've learned into crafting a new device that perfectly suits our needs.

No, we're not going to worry about making commercially viable microphone preamplifiers for the recording industry. We won't be hamstrung by the needs for differentiating them in the marketplace, the trap of building what we hope others will like and buy.

For our quest to capture music's heart and soul we need only to focus on the results. Like a magician building the perfect trick to elicit gasps of astonishment our only goal is to build what pleases our ears and bags the beauty of voices and instruments.

I cannot imagine a more exciting project.

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36 comments on “Microphone preamps”

  1. Yes sir, the improvement in the recording process will get us closer to the music because I believe there lies your weakest link in the chain.

  2. Paul, I wish I lived in the US because you are currently building the studio that has been in my mind for years. I would be at the PS Audio HQ everyday, until you either had me arrested or gave me a job!

  3. I was also interested to see that you’ve taken delivery of a Studer desk, for modification. I know a couple of guys here in Sheffield (UK) who have done the same thing - modifying vintage Studer broadcast desks. They sound excellent when restored and with some more modern thinking around their internals - although I’m sure you will be able to do a much better job given your resources! I really am very excited to hear the output from all your endeavours, and when my resources allow - would like to bring some of the music I’m working on, over to your studio to make a really great record. Exciting times indeed!

  4. I love posts like these where you are talking about audio with all the problems intrinsic to the subject.

    And I think many love them here too.

  5. Paul,

    Unless it is considered proprietary information, what type and manufacturer of microphones will the studio employ?

    I imagine there is a synergy between the mike and preamp to be considered.

      1. Isn’t this and a similar approach of many masterings what makes the purity concerns of the following HW stages so weired, not to say ridiculous?

      2. Paul, the goal is to sell gear even to those lacking talent! Talent shouldn't be a barrier! Just witness the popularity of AutoTune. Most consumers of poor music, listening on ear buds are wowed by effects and can't recognize or appreciate talent.

  6. If you get to the point of designing a mic preamp that does what you want it too, i hope that even if you don't so into production for the general public, you at least allow those in the industry to buy. Be a pioneer in bringing the entire music industry back to recording the best music it can. Maybe PS Audio can only plant a seed, but seeds can grow into tall, strong oak trees, Sequoia trees, etc. The best things the world has ever seen have started as small ideas. Best of luck!!

  7. Ah, mic pre's - so much choice out there. My personal preference is definitely Millennia Media high voltage pre's. To my mind they give you all the transparency, headroom, performance and reliability expected by the audiophile fraternity. Assuming of course your choice of mic's will be exemplary too 🙂
    p.s. I have absolutely no connection with the company, just a very happy long-term user.

  8. Doug Sax wound up putting the preamp right back in the condenser microphones. The separate preamp was intended for ribbon microphones. The first rule of gain structure is to never allow the signal level to drop below the level it entered the system at. Doug also avoided transformers, the opposite approach to today's hobbyist obsession with "vintage."

      1. Another one to try is a Daking Mic Pre One. It uses the original Trident A-Range console discreet FET circuit only with a Jensen input transformer and a THAT output driver. It comes with an outboard 48-volt single-ended DC power supply. They make larger units but I think they use the same supply for multiple channels. It's really good out of the box and could probably be tweaked to be even better without much of a hassle. I bought one for my wife's streaming shows and been very happy.

        1. But Bob, ALL the great recordings of "the Golden Age" had transformers everywhere, and they suffer from nothing. A properly designed transformers is a joy to behold.

          1. True in a sense however an awful lot of "golden age" records from the '70s used Mastering Labs tube preamps for the vocals and anything acoustic. Armin Steiner's Sound Labs studio employed a fair amount of Sherwood Sax technology and was one of the very best sounding rooms I or any of my friends ever worked in.

      1. Doug tried every way imaginable and wound up finding line level sounded best. He was never into audiophile mysticism. He tried every possible way and went with what sounded best. For example, he was into solid-core copper wiring. Nothing exotic or expensive, just Belden. He was into tubes unless a solid state version sounded as good.

  9. For the mic pre, could you modify the NPC and remove the RIAA EQ adding XLR inputs. Then you could have two output feeds, one digital and the other pure analog.

  10. I don't know how much you've worked with DSP EQ in your playback system, but I've long wondered if anyone ever thought of using DSP EQ for specific microphones on the recording end? Could you make an Oktava MK-012 mic sound like a Schoeps MK4? Or better yet, have it sound like some ideal?

    1. There are a few systems that do that - such as the Townshend Labs Sphere, Antelope Audio Edge Strip and Slate Digital VMS. That stuff has come a long way, but it's more for us broke musician types than a state-of-the-art Audiophile recording chain. Personally, in this application I would not want to let DSP anywhere near the analog front end. There's a reason these mics and pre's are classics, and still get the big bucks.

      1. I'll second that. Any mic in the world that you might want to use can be rented for the session. No reason not to have a good locker of the basic ribbons, dynamics and condensers for instruments but it's better to let someone else own and maintain the really extra special sounding specimens of the Neumans, RCAs etc... for really demanding vocalists.

    2. Interfaces like Universal Apollo and others use dsp in the interface to simulate mics, preamp, compression, eq, tape, reverb, and other effects. I just wish the capacitors and A/D were better. I use an Ifi low noise power supply on my UA Apollo.

  11. I remember talking to Ray Kimber years ago. What he was enthusiastic about then was some sort of filtration or correction system he had devised or latched onto that would remedy the problems associated with the original microphone set ups used in recordings. Was this a real solution or just a bunch of hype?

    1. For the reason of avoiding transformers in the signal path I'm more drawn to high voltage microphones that are usually transformerless whereas phantom powered varieties are generally transformer coupled, any thoughts for/against?

      1. Some transformerless are very prone to RFI problems. A friend's rule of thumb is you must have one transformer in the microphone or in the preamp. The Jensen transformers are a lot less harmful than most. They are useless for coloring the sound which is a good thing.

    2. I seem to remember he talked about using their patented DiAural circuit in line level stages but never saw any demonstrations. It was only used for series passive crossovers in speakers as far as I ever saw them implemented. As promising as all the reviews seemed, it never really took off.

  12. Given the low current low voltage of microphone outputs I'd go for a vacuum tube input stage at the microphone possibly with a transistor buffer and then directly to digital right at the mike. This way there will be no hum, noise, or interference induced in the cable.

    1. I would buy a dual audiophile Mic preamp which doubles as a photo preamp. I can count on one hand the Mic preamp designed for accuracy. One was made by Simaudio (Moon) but was expensive and discontinued. I would also love to buy a premium AD converter to go with them or perhaps included. Affordable like your $1k phono preamp, not as expensive as a Meitner or Burl. Keith Johnson made some premium gear, but again not for sale. Other than big studios willing to pay for the best, there is a huge market of dreamers not willing to pay much, and probably sound better with color. I want to record classical (grand) piano accurately, but the good stuff is expensive. Pueblo audio is on my list of more affordable. Gordon is also well regarded and seems to use a servo to null phantom power rather than a transformer or electrolytic capacitor. Check gearslutz for reviews.

  13. Too late to record this cat, RIP ...

    Dick Dale was born Richard Monsour in Boston (1937) to a Lebanese father and Polish mother. As a child, he was exposed to folk music from both cultures, which had an impact on his sense of melody and the ways string instruments could be picked. He taught himself to play country songs on the ukulele and soon graduated to guitar, where he was also self-taught. He also heard lots of big band swing and found his first musical hero in drummer Gene Krupa influencing his percussive approach to guitar so intense that Dale regularly broke the heaviest-gauge strings available and ground his picks down to nothing several times in the same song. His father encouraged him and offered career guidance, and in 1954, the family moved to Southern California.

    During the late 50s, Dale became an avid surfer and soon set about finding ways to mimic the surging sounds and feelings of the sport and the ocean on his guitar. Dick Dale wasn't nicknamed "King of the Surf Guitar" for nothing, he pretty much invented the style single-handedly and no matter who copied or expanded upon his blueprint, he remained the fieriest, most technically gifted musician the genre ever produced. Dale's pioneering use of Middle Eastern and Eastern European melodies (learned organically through his familial heritage) was among the first in any genre of American popular music, and predated the teaching of such "exotic" scales in guitar-shredder academies by two decades. Dale managed to redefine his instrument while essentially playing it upside-down and backwards, he switched sides in order to play left-handed, but without re-stringing it (as Hendrix later did).

    Dale partnered with Leo Fender to test new equipment later saying "When it can withstand the barrage of punishment from Dick Dale, then it is fit for human consumption." His combination of loud amplifiers and heavy gauge strings led him to be called the "Father of Heavy Metal". Working closely with the Fender company, Dale continually pushed the limits of electric amplification technology, helping to develop new equipment that was capable of producing the thick, clearly defined tones he heard in his head at the previously undreamed-of volumes he demanded.

    Leo Fender and Freddie Tavares saw Dale play at the Rendezvous Ballroom in Balboa, California and after blowing up several Fender amplifiers identified the problem from him creating a sound louder than the audience screaming. The pair visited the James B. Lansing loudspeaker company to ask for a custom 15-inch loudspeaker which became the JBL D130F model and was included in the original Fender Single Showman Amp. Dale's combination of a Fender Stratocaster and Showman Amp allowed him to attain significantly louder volume levels unobtainable by then-conventional equipment.

    Dale's performances at the Rendezvous Ballroom in mid to late 1961 are credited with the creation of the surf music phenomenon. Dale successfully asked for permission to use the 3,000 person capacity ballroom for surfer dances after overcrowding at the local ice cream parlor. Dale's events at the ballrooms, called "stomps," quickly became legendary, and the events routinely sold out.

    Surf music became a national fad, with groups like the Beach Boys and Jan & Dean offering a vocal variant to complement the wave of instrumental groups, all of which were indebted in some way to Dale. But in 1964, the British Invasion stole much of surf's thunder, and Dale was dropped by Capitol in 1965.

    Dale's comeback didn't get into full swing until 1994 when his song "Miserlou" was chosen as the opening theme to Quentin Tarantino's blockbuster film Pulp Fiction.

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