This is an SM57.  Are you listening, class?

I’m sure everyone out there has at least heard the number ‘57′ in respect to recording gear.  It is a VERY widely used microphone and has been around for a long time.  But this isn’t a history lesson.  This is a modification lesson.

Today, I’m going to remove the transformer from this 57.

“Are you mad?  It’s an SM57, it’s supposed to sound like an SM57!”

I know.  I’m not modding this microphone to make it ‘better’.  I’m modding it to make it different.  I’m creating a different tone to use, a different brush with which to spread the paint across the canvas.  I’m actually modifying two because I have an OCD complex when it comes to stereo pairs of things.

Removing the transformer has been claimed to make the modded SM57 susceptible to phantom power damage, so beware.

Please read all steps before attempting to do this yourself.

1.  Unscrew XLR pin structure toward the ‘bottom’ of the mic using a tiny .4mm screwdriver.

This is what happens after you carefully pull it out:

2.  Unscrew the hollow portion from the diaphragm portion of the microphone, at this joint:

This is what happens after you carefully do this:

3.  Desolder the 4 points, 2 at the XLR connector end and 2 at the diaphragm end.  The result will be 2 wires coming up one side of the hollow portion and 2 wires coming down the other side of the hollow portion:

You can clearly see the transformer suspended in some goo.  Our goal is to remove that transformer.

3.  Boil the hollow portion.  Seriously.  This will melt the goo and allow you to dislodge the transformer.  Keep in mind I am modding 2, that’s why there are 2 hollow portions in the boiling water.  DO NOT PUT THE DIAPHRAGM PORTION IN THE WATER, LEST YOU CARE TO END UP WITH A BROKEN SM57!

4.  When enough of the goo has dissolved and the rest is soft, pick up the hollow portion while it is still hot, using tongs or some other device so as not to burn yourself on boiling-hot metal, and using pliers or a similar tool, grab that transformer and carefully slide it out.  You do NOT want to fling molten goo on your skin, so be gentle.  Once the transformer is freed, this is what it looks like.  Remember, I removed 1 transformer from 2 different microphones.  Now, let the hollow metal portion cool off.

5.  Make new wires and solder!  I used hot and cold leads from a short length of microphone cable – they were the perfect size.  It is easiest to solder the XLR connector first, connecting the wires to the cups.  You may have to add some solder for a secure connection.  Then, feed the wires through the hollow portion of the microphone and screw the XLR connector back into place, from the first picture above.  Now, solder the 2 wires to the 2 eyehole pins on the diaphragm portion of the microphone.  One is clearly marked with a + and that pin should be connected to the hot pin of the XLR connector.  The XLR connector is also labeled clearly.

Remember (for most modern applications):

Pin 1 = Ground/Earth

Pin 2 = Hot

Pin 3 = Cold

This is the result:

6.  Cram the wire (gently) into the cavity and screw that mother back on.  Clean up any excess goo that ended up on the chassis of the microphone and then JUBILEE!  You’ve successfully modded an SM57!  That is, IF it works.  Here is what the final result should look like (duh):

Now test it!  You should notice a few tonal changes (the reasons for doing the mod in the first place):

-The frequency response goes a little further in both the low and high frequencies

-That carefully sculpted midrange ‘presence boost’ should be smaller

-The overall frequency response should be a little flatter

Something to note as well:

-The output of the microphone will drop dramatically, about 10-12dB which means it probably won’t be suitable for quiet sources (not that the 57 is great for quiet sources anyway) and it will require more gain from the preamp it is used with, so noisy preamps probably won’t work out so well

Overall, the tonality changes are subtle, but if you are looking for a little spice in your SM57, this mod is great.

Let’s Record.

-Mitchell

Pushing forward with modifying the console, I tinkered with some input channels next.  The Dynamix 3000 by design has a warm, ‘vintage’ sound, imparted mainly through the input transformers and less-than-modern opamps.  This is something that we cherish at Kilo – it has so much more character and depth than modern comparable products.  However, I was curious to see how an input channel reacted sans the transformer.

The process was painfully easy.  I just desoldered the transformer, took it off (with a little coaxing from a flathead screwdriver – there was some old glue), made little jumper wires, soldered those into place, and I was done.  I wish there was more of a process to write about, but it really was stupidly simple.  So simple, that I decided to do an opamp swap to kill some time.  A Burr Brown OPA134 took the place of the classic 5534 opamp.  This was done in a flash.  I was pouring excitement, ready to hear a world of difference.  The comparison test was a very technical one…

…which consisted of an SM57 on a snare, through the same channel, before and after the removal of the transformer and opamp switch.  I recorded some snare hits and patterns into ProTools with both configurations.  I was literally blown away.  Not at how different they were, but by how similar they were.  Sure, there were absolutely some differences, but on a single track of snare drum through an SM57, it sounded just like an SM57.  Then it hit me.  It sounded just like an SM57.  I know, I know, you can’t REALLY say something sounds like a specific microphone because of all the variables, but stick with me.

I tried out several other microphones.  The results were similar: more characteristics of the microphone were shining through.  That meant that the channel was far more transparent.  Excited, I modded three more channels in about as many minutes (I told you, it was an easy mod).  Now the Dynamix has 4 channels of transparent preamps as well as 12 channels of warm goodness.

Hurray!

-Mitchell

There are so many great and endearing aspects of the Dynamix 3000 that we have at Kilo.  The vintage design lends so many pleasant characteristics to not only the audio, but the general vibe of the studio as well.  Paired with an ‘industry standard’, modern, Pro Tools HD system, it says it all about what we strive for at Kilo – the best of both worlds, both old (and vibey) and new (plus clean).

Master Channels

I was determined to tinker and improve the console by way of minor ‘modernization’ of certain components.  I swapped an old 5532 opamp with a brand new opa2604 opamp in one of the two master channels and did an A/B listening test.  The result was noticeable right away – the modified channel sounded ‘better’ to me initially.  After listening for a while, these words came to mind: cleaner, more robust, better stability…

Admittedly, before the switch there was some dirt on the floor.  The new opamps were like a consumer-grade vacuum cleaner and cleaned all of the obvious mess, but couldn’t necessarily get every little bit of dust up.  In other words, the noise floor was more existent before the swap – not that the noise floor is completely absent now, though.  

The audio from the console would start to break up and distort at about +6 dB (on the meters) but the new opamps make the distortion less apparent – not that I would run program at +6 dB – but it translates to better headroom.  There is less stress on the amplifier and the resulting sound becomes open and takes on some life, as opposed to the ever-approaching-flat-topped-plateu-of-dynamic-range thing that was going on before.

This is good news because not only are we hearing more of the actual audio now, but when we record the two track output of the console, it prints with these ‘new and improved’ characteristics.  

Pro Tools Sub Channel Returns

I decided to experiment further.  The Pro Tools outputs come back to sub channels 3 and 4 on the console.  I wondered what would happen if I replaced the opamp in each of these channels with a modern one…  

Again I did an A/B listening test, and the results were far from subtle.  I was shocked, actually.  I was hearing things I literally hadn’t heard before in the songs I was so…  scientifically…  using for the test.  It’s like I was listening with cloth over the speakers before.  The high end of the frequency spectrum extended so much further!  The lows were less conspicuous, but extended a little further and had a stronger constitution.  The mids sounded much flatter and more uniform, especially between about 800 Hz and 2kHz, and the low mid mud was mopped up.  More detailed harmonics made the instruments sound more realistic and I was hearing super minimal reverbs and delays that just weren’t there before.  The transient response was astoundingly faster with the new opamp, too.  

Such great improvements can be made in such small ways – all of these things from a simple component substitution!  Swapping an older 5532 for a new opa2604 in 2 different places worked wonders for the Dynamix.  All this was possible because of the custom power supply that we had built, of course, so…  don’t try this at home *without a little bit of research*.  After that, have fun!

Let’s Record.

Mitchell