I know this thread has been dead for a while, but since it comes up so high on some search engines, I thought I would respond.
Short answer:
How close is it to the API sound:
kind of; but only because, it has transformer in and out for 4 channels. It deosn't the same EQ curve, nor the same type of preamp, so in stock form, and the EQ doesn't help it. So, NO. If MOD'ed, well, maybe. The Yamaha has an IC based preamp and the API has a discrete OP-AMP. The Yamaha has a cool sound, but it requires a lot of corrective EQ in most cases. :'( API does not! 8)
Details to support my claim:
I have worked with some very crappy pres and some very nice pres, from: a spirit folio mixer to an SSL G series console. I have used all kinds of pres in between, so I know the difference when I hear it!
Recently, I went to the 2014 Audio Engineering Society (AES) convention in LA where I was able to sing through about a hundred different mics and preamps. API with a Shure Beta 87 was one of the combinations. ;D
With most preamps, I have a voice that suffers from TOO MUCH sibilance, too many lows, too many low mids, and not enough high mids to sound as exciting without piercing your ears every time I sing a word with an S. De-essers do very little to help, so I must choose a preamp and mic combination that keeps the lows and low mids neutral, but boosts the high mids between 1k-5k, and then drops highs between 6k-8k range, but then boosts the 10k-15k range. Basically, I sound very sweet and airy, even when I am pushing my voice to sound aggressive and even when I sing smooth every "S" will make you suffer. :'(
The Beta 87:
I have a Shure Beta 87, and by itself is not a problem solver for me, it does drop the lows a little, but all of the problems are still there.
The API 512:
Using the Shure Beta 87 with the API 512, 500 series preamp, was amazing. My voice sounded exciting and awesome without EQ or compression engaged. Lively, exciting, forward enough to stand out in the mix! Just Awesome! The API is solid in the lows, but very neutral, maybe even cut a little. The Low Mids are also solid, but cut a little. The hi mids are pushed and boosted slightly. 6k-8k are cut perfectly and the 10k-15k are neutral and natural sounding so the whole thing is ready for mastering without EQ, just add compression to your taste. I wish Classic API was there so I could have demo'ed their pres to see if I would like their offering better, but they weren't.
Now, to the Yamaha 512 mixer:
At home, I have a Shure Beta 87 and a Yamaha M-512. this combination will not solve my problem, even when I adjust the EQ. It has the transformer in and out color like the API 312/512, but not the EQ curve. To get close, I would have to drop the lows 4db, boost the mids 2db and drop the highs 2 db, but even then it is not the same and the "S" sound will kill you when I sing! What does this mean: Well, it means a lot of later corrective EQ! Which is a headache!
Yamaha MOD'ed:
I do not have a MOD'ed Yamaha 512, so I do not know for sure. There are several threads that I recommend if you already have a Yamaha 512 and some skills to MOD, but if you do not, then just buy API, Classic API, Warm audio, etc... This way you can record today rather than wait 10 years to finish acquiring all of the parts, skills and time to MOD a Yamaha 512. It is not worth it! If you are going to MOD one to sound like an API, the lo EQ is close to the right range to cut, the mids seem close, around 1.5k-3k, but the highs are not in the right area to cut or boost.
Yamaha 512 MOD Threads:
Adding Direct outs for 508 (8 channel version) Good ideas:
http://groupdiy.com/index.php?topic=50521.0
Changing the IC's for OP-AMPS or other IC's:
http://groupdiy.com/index.php?topic=51247.0
Calculating the EQ frequencies:
http://groupdiy.com/index.php?topic=51214.0
About other gear at the ARS:
If any one wants to know my opinions about other gear at the AES: Sandhill's Ribbon Mic was BAD ASS, Telefunken's were all so dreamy smooth, and Advanced Audio was the real deal for budget mics if you want great quality. If you have voice like mine: an overly sibilant voice that never seems to sound exciting enough and you are:
on a budget:
I suggest the Advanced Audio CM414. It will be a great work horse mic. It sounded sounded great through a 6 channel 200.00 mixer (Mackie or a Behringer, can't recall) Their CM87 and CM47 and CM48 did not solve my problems, but I did not try them through an API 512. Still, I would say that they are great sounding mics, if their quality at the booth is the quality you receive, if not call them, they will fix it for you.
All of their Tube Mics were good as well, but none worked as well for me as the 414.
Seeking High End:
Finland's company Sandhill produce a Ribbon Mic is BAD A$$. It uses a new material for the ribbon so it is virtually indestructible. It had a very mid forward sound that was totally different than any other mic and completely usable as a work horse or as a solo mic. It solved my problems through an inexpensive mixer. Their mic can handle something like 160 db! You could record a jet engine with it. BUY IT!
BTW, Sandhill were looking for an American and Chinese Distributors, so if you are a distributor, snatch them up now!
The Telefunken mics were awesome, smooth and clear. The C 12 solved my problems pretty well, but all of the 251's were close, too.
LA's "Tree Audio" had a Tube mixer called "The Roots" with an EQ and Compressor that was amazing. It was clear, strong, focused and sweet. The Compressor could be pushed to add color to the instrument, or pushed without adding any color at all. It was totally AWESOME and usable!
Other awesome sounding gear that although did not solve my problems, did sound great:
All of Cathedral Pipes Microphones
All of Burl Audios gear
DW Fearn Microphone Preamps
Josephson Microphones
A-Designs
Avalon Preamp
Microtech Gefell
BAEaudio
Enjoy,
GuitarDick
DP Pearlman Microphones
All of Shinny Box gear
Cloud Mics and their lifter was cool
