barbaroja
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The SM57 impedance mod - Increase gain <not for me>
I read the article about making an adapter cable for increasing the gain in a SM57 mic. It did not work for me, I am even getting lower gain!!!
Did I make the cable wrong?
I connected pins 2 to 3 with a 680 ohm resistor as i could not fint the 698 one. (Male connector)
I am recording with a konnekt 8 interface, wich produces 62 dB of total gain, so I do not think this would limit me.Why am I doing this? Because I like the SM57 sound and I tend to record quiet sources, not snares.
Thanks in advance.
Maybe making a variable resistance box with a pot would work?
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macflooze
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RE: The SM57 impedance mod - Increase gain <not for me>
2007/03/16 23:14:26
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Can you link the article?
Pmac ToneZone Information spreads at the speed of light, while ignorance is instantaneous at all points in the known universe - Dmitry Orlov
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rumleymusic
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RE: The SM57 impedance mod - Increase gain <not for me>
2007/03/17 01:51:12
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I don't see how an adaptor cable could increase the gain of any mic. You might raise the impedance, but....why? That would weaken the signal. You could always get another cheap stand alone preamp or mixer to double up on the voltage gain with the konnekt
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krizrox
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RE: The SM57 impedance mod - Increase gain <not for me>
2007/03/17 12:40:12
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FWIW - Rode makes a device called the Power Plug (or something like that) which adds an extra 20db of gain to any mic. I bought one through Cascade for my ribbon mic and it works great. No noise. Mucho gain. It's not cheap though (+/- $100) but is a worthy addition to your tool box for those oddball requirements where you need a little push over the edge.
Larry Kriz www.LnLRecording.com www.myspace.com/lnlrecording Sonar PE 8.5, Samplitude Pro 11, Sonic Core Scope Professional/XTC, A16 Ultra AD/DA, Intel DG965RY MOBO, Intel Core 2 Duo E6600 2.4GHz processor, XFX GeForce 7300 GT PCIe video card, Barracuda 750 & 320GB SATA drives, 4GB DDR Ram, Plextor DVD/CD-R burner.
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barbaroja
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RE: The SM57 impedance mod - Increase gain <not for me>
2007/03/17 13:37:07
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Hi guys, this is the link: http://rec.gatago.net/rec/audio/pro/41244004.html Some people in this forum tried it, too: http://forum.cakewalk.com/tm.asp?m=743735&mpage=2&key=SM57 It looks like the impedance actually has to get lower, not higher. The konnekt preamp impedance is rated: Pad "on" 2000 ohm. Pad "off" 1300 ohm. For this people, adding the resistor across pins 2 and 3 really pushed the SM57 sound for better definition AND increased the output gain. When I did this, the input signal got quieter. I did notice an improvement over the sound, specially in higher frequencies (more defined - I liked it). I need higher output to lower the noise. Maybe papa2004 (who said it worked for him here at cakewalk forums) can come here and give us a little light...
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billruys
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RE: The SM57 impedance mod - Increase gain <not for me>
2007/03/19 21:50:42
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The idea of this mod is not to increase the gain of the SM57, it's to change the tone of the SM57. The idea is that most modern mixing desk pre-amps are very high impedance, which is supposedly not a good match for the mic. A resistor across the mic will always drop it's output a certain amount, as you are loading the circuit.
Generally, lowering the impedance will get you a darker tone.
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holderofthehorns
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RE: The SM57 impedance mod - Increase gain <not for me>
2007/03/20 12:54:45
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Eric Anderson HolderOfTheHorns - It's a Viking thing.
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barbaroja
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RE: The SM57 impedance mod - Increase gain <not for me>
2007/03/20 20:49:36
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ok, but how does that affect the recording (preamp related)??? I mean, those guys say it really gave more gain to the mic. How could be that possible?
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Staccato
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RE: The SM57 impedance mod - Increase gain <not for me>
2007/03/21 03:25:38
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ORIGINAL: holderofthehorns
The formula for Parallel Resitance is:
SM57 = 150 Ohms http://www.shure.com/ProAudio/Products/WiredMicrophones/us_pro_SM57-LC_content
Mod = 698 Ohms
Total resistance = 123.47 Ohms with the 698 Ohm mod.
Total resistance = 122.89 Ohms with the 680 Ohm mod.
Lower Impedance yields higher current in Amps (or milliamps).
Yes, an increase in current inside the 680 ohm resistor, which translates to less power available for output. But the perception of the human ear is a different matter.
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holderofthehorns
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RE: The SM57 impedance mod - Increase gain <not for me>
2007/03/22 18:23:12
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I have to agree with Staccato. Notice my edit.
If the lower impedance was on the Pre end, there would be more current flow in the pre.
But since the SM57 is dynamic and generates electricity in a fixed amount, any extra bleed would shunt that limited current supply back into the mike and away from the Pre.
I would also be willing to bet that Shure has engineers with college type letters after their names that have figured and tested and figured and tested, and came up with the all time best configuration for that mic.
They call it the SM57 and time has proven it to be a favorite, just exactly like it is, with no mods.
It's brother, the 58 is in the same boat.
We don't ask "Do you have a 57 or 58?" Instead we ask "How many do you have?"
Eric Anderson HolderOfTheHorns - It's a Viking thing.
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