Andrew
06-18-2009, 02:40 AM
Those of you following the Thrice Blog would no doubt have seen Teppie’s Mic Mod. It’s actually an age old trick of bypassing the cheap transformer in the SM 57 and hooking the signal directly to the XLR Connectors.
You cant either remove the glue which holds the transformer by using a hot glue gun, or by boiling it in water, which is what teppei did.
http://farm3.static.flickr.com/2145/3530576162_f6e2f41e22.jpg?v=0
The Mod is described in an Issue of TapeOp, which I cant find online, but I really want to test it out. Supposedly it turns it into a 300 dolla mic, improving the bass response. The possible downside is the scooped mids, which might mean it would be lost in a mix. Nonetheless, Its high recommended by most audiophiles and I’d like to see how it turns out. So far this is the most detailed description of the process, but seeing that I have no knowledge in electronics whatsoever, I need the noob schematics.
(apparently it kills alot of the level as well, which is kind of a pain seeing that i feel the 57 is pretty dull and not sensitive at all. You could crank the gain, but that in theory would give you alot of noise. eh whatever, kurt ballou uses one, who am i to question?)
When I first saw this in the March/April TapeOp Magazine I thought it was an 'April Fool's' article. This was especially true considering that the magazine's first step was: Put on a pot of water to boil.. really!!
So, I did a little research and finally decided this was indeed a real deal and gave it whirl.
I had two 57's so I decided to sacrifice one instead of buying another. In the event of failure at least I would not have 'invested' any cash.
Observation number 1. This is really easy. The hardest part is soldering the new wire into place. If you can solder at all, you can do this.
OK, here was my procedure, following guidlines in TapeOp Magazine.
a) I opened the 57 at the middle and snipped the two wires that lead to the transformer.
b) I removed the XLR plug, you run down the set screw and pull the connector out, then snip the two wires. I used needle nose pliars to accomplish this.
c) I put the bottom section of the mic, with the XLR connector removed, into a pot of boiling water. I allowed it to heat up for about a minute and a half. Picked up the heated section (with tongs and then held it with an oven mit)..
d) With needle nose pliars I grabbed the two wires at the top end and pulled out the transformer. It's held in place with what appears to be hot glue.
Here's the tranformer, removed from the mic:
At this point, I put in an extra step to distinguish this now modified 57 from it's twin in my mic locker (more on this in a minute).
e) I cut a piece of sheilded audio cable just long enough to reach from the capsule thru the bottom of the mic. I stripped the ends of the wire (fwiw I left the sheild and casing on the cable to fit thru the small hole that is in the middle of the mic).
f) I solderd red to the + side of the capsule, then to pin 2 on the XLR connector. I soldered black to the other side and pin 3. Pin 1 on a newer SM57 is grounded via the connector sheild to the body of the mic.
I reassembled the sections (screw'em back together) and was ready to see just how much damage was done.
OK, backing up just a touch. Before I soldered the connection back together, I grabbed some masking tape and covered all the vital parts of the mod57. I took it out to the garage and painted it with some 'aircraft grey' spray paint.
This will help me distinguish my mod57 from stock at a glance.
OK back to the story. First thing I noticed.. WOW the mic actually works without the transformer!!
I plugged my two SM57's into the same mixer and set up some headphones to listen in on.. BUT I matched gain on the two before listening.
The modded 57's output is lower, but not enough to cause any problems. I was able to match gain relatively easy just using my mixer's gain structure.
The bass is increased noticably on the modded 57 and it's crisper on top. SO if you've ever 'smiley faced' the EQ on a stock 57 for vocals or instrument micing then this mod is for you.
The mic actually sounds more 'open' to me but my initail tests were done using a Samson mixer and some cheesey headphones. I really want to try this thru a couple of good mic pres to see what it sounds like (I think my JoeMeek will be perfect).
I don't know that I can say that the modded 57 sounds like a SM7 or not (alluded to in the TapeOp article), I don't have an SM7 of my own to compare it to. However, my initial reaction is, it's more open with more low and high end. That'd be more 7'ish than it's unmodded brother.
I'm not dissappointed.
Anyone care to look into this more and find proper instructions?
You cant either remove the glue which holds the transformer by using a hot glue gun, or by boiling it in water, which is what teppei did.
http://farm3.static.flickr.com/2145/3530576162_f6e2f41e22.jpg?v=0
The Mod is described in an Issue of TapeOp, which I cant find online, but I really want to test it out. Supposedly it turns it into a 300 dolla mic, improving the bass response. The possible downside is the scooped mids, which might mean it would be lost in a mix. Nonetheless, Its high recommended by most audiophiles and I’d like to see how it turns out. So far this is the most detailed description of the process, but seeing that I have no knowledge in electronics whatsoever, I need the noob schematics.
(apparently it kills alot of the level as well, which is kind of a pain seeing that i feel the 57 is pretty dull and not sensitive at all. You could crank the gain, but that in theory would give you alot of noise. eh whatever, kurt ballou uses one, who am i to question?)
When I first saw this in the March/April TapeOp Magazine I thought it was an 'April Fool's' article. This was especially true considering that the magazine's first step was: Put on a pot of water to boil.. really!!
So, I did a little research and finally decided this was indeed a real deal and gave it whirl.
I had two 57's so I decided to sacrifice one instead of buying another. In the event of failure at least I would not have 'invested' any cash.
Observation number 1. This is really easy. The hardest part is soldering the new wire into place. If you can solder at all, you can do this.
OK, here was my procedure, following guidlines in TapeOp Magazine.
a) I opened the 57 at the middle and snipped the two wires that lead to the transformer.
b) I removed the XLR plug, you run down the set screw and pull the connector out, then snip the two wires. I used needle nose pliars to accomplish this.
c) I put the bottom section of the mic, with the XLR connector removed, into a pot of boiling water. I allowed it to heat up for about a minute and a half. Picked up the heated section (with tongs and then held it with an oven mit)..
d) With needle nose pliars I grabbed the two wires at the top end and pulled out the transformer. It's held in place with what appears to be hot glue.
Here's the tranformer, removed from the mic:
At this point, I put in an extra step to distinguish this now modified 57 from it's twin in my mic locker (more on this in a minute).
e) I cut a piece of sheilded audio cable just long enough to reach from the capsule thru the bottom of the mic. I stripped the ends of the wire (fwiw I left the sheild and casing on the cable to fit thru the small hole that is in the middle of the mic).
f) I solderd red to the + side of the capsule, then to pin 2 on the XLR connector. I soldered black to the other side and pin 3. Pin 1 on a newer SM57 is grounded via the connector sheild to the body of the mic.
I reassembled the sections (screw'em back together) and was ready to see just how much damage was done.
OK, backing up just a touch. Before I soldered the connection back together, I grabbed some masking tape and covered all the vital parts of the mod57. I took it out to the garage and painted it with some 'aircraft grey' spray paint.
This will help me distinguish my mod57 from stock at a glance.
OK back to the story. First thing I noticed.. WOW the mic actually works without the transformer!!
I plugged my two SM57's into the same mixer and set up some headphones to listen in on.. BUT I matched gain on the two before listening.
The modded 57's output is lower, but not enough to cause any problems. I was able to match gain relatively easy just using my mixer's gain structure.
The bass is increased noticably on the modded 57 and it's crisper on top. SO if you've ever 'smiley faced' the EQ on a stock 57 for vocals or instrument micing then this mod is for you.
The mic actually sounds more 'open' to me but my initail tests were done using a Samson mixer and some cheesey headphones. I really want to try this thru a couple of good mic pres to see what it sounds like (I think my JoeMeek will be perfect).
I don't know that I can say that the modded 57 sounds like a SM7 or not (alluded to in the TapeOp article), I don't have an SM7 of my own to compare it to. However, my initial reaction is, it's more open with more low and high end. That'd be more 7'ish than it's unmodded brother.
I'm not dissappointed.
Anyone care to look into this more and find proper instructions?