Madman_Greg
Joined: 07/12/06
Posts: 707
Loc: The back of beyond
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SM58 / Pre Amp - input requested
#1032429 - 06/02/13 05:08 PM
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I am going to try out the options I have. But wanted get some input as to what to
consider.
Problem, my interface (Mackie Satellite) does not have sufficient
gain to work effectively with my Shure SM58. I end up virtually winding the gain all the
way up.
Now I know I need a pre amp to raise the level of the gain, then to
feed into the Mackie at line level. All I need is to increase the gain. I am not
interested in adding colour to the sound etc….
So I am looking at low cost
options to resolve this.
I have a Yamaha FX500, which I dusted of and tried and
it works OK, but have not tried critically yet. The A2D and D2A are 16 bit, so assume I
would potentially suffer with increased noise floor.
I also have a Tascam 424
Portastudio, which I am going to try for this. Unsure on the quality of the electronics
and the likely hood of noise. But will give it a go. Its quite old !!
There are
a number of low cost microphone pre amps on the market. Are these worth considering.
Thanks in advance for any help / input.
-------------------- Madman_Greg
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Sam Inglis
SOS Features Editor
Joined: 15/12/00
Posts: 1385
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Re: SM58 / Pre Amp - input requested
[Re: Madman_Greg]
#1032434 - 06/02/13 05:14 PM
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Quote Madman_Greg:
I am going to
try out the options I have. But wanted get some input as to what to consider.
Problem, my interface (Mackie Satellite) does not have sufficient gain to work
effectively with my Shure SM58. I end up virtually winding the gain all the way up. .
But do you get sufficient
gain when you do this? If you do and the signal is not noisy, then surely there is no
problem -- the reason the preamp has the range it does is to cope with mics of varying
sensitivities. Also, many budget preamps have much of their gain range bunched up in the
last few degrees of travel, so it's quite normal to need to turn the knob pretty much
right up with dynamic mics.
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Madman_Greg
Joined: 07/12/06
Posts: 707
Loc: The back of beyond
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Re: SM58 / Pre Amp - input requested
[Re: Sam Inglis]
#1032438 - 06/02/13 05:27 PM
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Quote Sam Inglis:
Quote Madman_Greg:
I am going
to try out the options I have. But wanted get some input as to what to consider.
Problem, my interface (Mackie Satellite) does not have sufficient gain to work
effectively with my Shure SM58. I end up virtually winding the gain all the way up.
.
But do you get
sufficient gain when you do this? If you do and the signal is not noisy, then surely there
is no problem -- the reason the preamp has the range it does is to cope with mics of
varying sensitivities. Also, many budget preamps have much of their gain range bunched up
in the last few degrees of travel, so it's quite normal to need to turn the knob pretty
much right up with dynamic mics.
The mic gets microphonic if that the right term and there is little precise
control at that end of the gain knob
-------------------- Madman_Greg
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Sam Inglis
SOS Features Editor
Joined: 15/12/00
Posts: 1385
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Re: SM58 / Pre Amp - input requested
[Re: Madman_Greg]
#1032441 - 06/02/13 05:34 PM
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The mic is supposed to be microphonic! I'm not quite sure what you mean -- do you get hiss
or other noise on top of the signal?
Unfortunately you are unlikely to get more
precise gain control with any other budget preamp. You could perhaps use a fixed-gain
inline preamp like the Cloudlifter.
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Madman_Greg
Joined: 07/12/06
Posts: 707
Loc: The back of beyond
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Re: SM58 / Pre Amp - input requested
[Re: Sam Inglis]
#1032443 - 06/02/13 05:53 PM
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Thanks, reading the clloudlifter blurb it talks about cable length
Is is worth trying a shorter cable, not sure on the actual length I have, but its one I
used to use on stage, so is a reasonable length.
-------------------- Madman_Greg
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Sam Inglis
SOS Features Editor
Joined: 15/12/00
Posts: 1385
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Re: SM58 / Pre Amp - input requested
[Re: Madman_Greg]
#1032448 - 06/02/13 06:29 PM
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Cable length is unlikely to be an issue unless you are trying to send the mic signal a
hundred yards, or something. I'm still not exactly clear on what the problem is here -- in
what way do your recordings not sound good?
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shufflebeat
Joined: 09/12/07
Posts: 2272
Loc: Manchester, UK
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Re: SM58 / Pre Amp - input requested
[Re: Madman_Greg]
#1032451 - 06/02/13 07:11 PM
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When you say microphonic do you mean there's a sound of interference? If there was a dodgy
earth that might account for noise and a low output. Can you try another XLR cable?
-------------------- Ohm's Law states, "Your PA isn't as powerful as you think it is".
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James Perrett
Joined: 10/09/01
Posts: 9660
Loc: The wilds of Hampshire
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Re: SM58 / Pre Amp - input requested
[Re: Madman_Greg]
#1032572 - 07/02/13 02:01 PM
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Looks like you have a problem somewhere as the Mackie preamps should be perfectly capable
of working with an SM58. Yes, you may have to turn the gain control 3/4 of the way up to
get a sensible level but that will be the same with any cheap preamp. James.
-------------------- JRP Music - Audio Mastering and Restoration.
http://www.jrpmusic.net
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Hugh Robjohns
SOS Technical Editor
Joined: 25/07/03
Posts: 18398
Loc: Worcestershire
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Re: SM58 / Pre Amp - input requested
[Re: Madman_Greg]
#1032580 - 07/02/13 02:40 PM
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Quote Madman_Greg:
Problem, my
interface (Mackie Satellite) does not have sufficient gain to work effectively with my
Shure SM58. I end up virtually winding the gain all the way up.
There's nothing fundamentally wrong with
having the gain all the way up.
So what is that actual problem?
What
are you trying to achieve?
What is the source and whreer have you placed the
microphone relative to it?
If you are recording, what peak level are you
achieving and why do you think it is inadequate?
H
-------------------- Technical Editor, Sound On Sound
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Hugh Robjohns
SOS Technical Editor
Joined: 25/07/03
Posts: 18398
Loc: Worcestershire
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Re: SM58 / Pre Amp - input requested
[Re: Madman_Greg]
#1032581 - 07/02/13 02:43 PM
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Quote Madman_Greg:
The mic gets
microphonic if that the right term
Probably not the right term -- Do you mean the mic becomes very sensitive to
external mechanical vibration -- handling noise etc? Do you mean it becomes very hissy? Do
you mean it picks up a lot of ambient room sound?
Quote:
and there is little precise control at that end of
the gain knob
This is quite
normal with the vast majority of budget and mid-price preamps, as others have said. Most
of the gain appears in the last 10 of 15 degres of control rotation, so precise control
will always be difficult.
H
-------------------- Technical Editor, Sound On Sound
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Madman_Greg
Joined: 07/12/06
Posts: 707
Loc: The back of beyond
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Re: SM58 / Pre Amp - input requested
[Re: Hugh Robjohns]
#1032669 - 08/02/13 12:09 AM
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First let me say thank you to those that replied, or read and considered replying. And let
me apologies if I have wasted your time.
As I do not have a problem
Not used a lot of my gear since late 2010, due to being a bit ‘Moby Dick’ and
taking a while to get to the point where I can confidently make music again.
Basically unplugging and replugging everything improved the situation, but I still need
to wind the gain up a long way, but this is expected. But not all the way now !
And to reply to some of the comments
Do you mean the mic becomes very
sensitive to external mechanical vibration Do you mean it becomes very hissy? No
Do you mean it picks up a lot of ambient room sound? Yes
This is
quite normal with the vast majority of budget and mid-price preamps, as others have said.
Most of the gain appears in the last 10 of 15 degrees of control rotation, so precise
control will always be difficult. – Yes this is the case
Edited by Madman_Greg (08/02/13 12:11 AM)
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ef37a
Joined: 29/05/06
Posts: 5628
Loc: northampton uk
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Re: SM58 / Pre Amp - input requested
[Re: Madman_Greg]
#1032684 - 08/02/13 06:49 AM
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A few numbers OTTOMH Greg,
If I try to record acoustic guitar with my NI KA6 I
need the gain knob on the end stop using an SM57 at about a foot. For picked notes this
puts the level just about perfectly at -20, -18dBFS.
If I be quiet(and my
"playing" demands that!) the basic noise floor is around -75dBFS. If I replace the mic
with a 150R load in an XLR plug noise is -80dBfs. Conclusion? My "system" is 5 dB or so
quieter than I can ever get my room!
Re 16bits. I always run 24bits but a
really good 16 bit device such as my A&H ZED10 is still way better than neg 75. I have
not tried it (will if you like) but I doubt the same recording setup via the Z and a 57
would result in a worse noise floor. Also, for ac'git the pre amp gain on the mixer has
to be pretty well advanced tha' knows.
Dave.
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Hugh Robjohns
SOS Technical Editor
Joined: 25/07/03
Posts: 18398
Loc: Worcestershire
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Re: SM58 / Pre Amp - input requested
[Re: Madman_Greg]
#1032703 - 08/02/13 10:07 AM
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Quote Madman_Greg:
And let me
apologies if I have wasted your time.
never a waste of time -- I'm sure others reading this thread will have picked up
some useful pointers too...
Quote:
As I do not have a problem
Pleased to hear it! 
Quote:
Do you mean it picks up
a lot of ambient room sound? Yes
The SM58 is a relatively insensitive mic, and is designed to be
placed very close to the source. So if it's picking up a lot of ambient room sound you are
probably placing it too far from the source and thus having to use too much gain.
hugh
-------------------- Technical Editor, Sound On Sound
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Jim Lockhart
new member
Joined: 03/06/03
Posts: 16
Loc: Menlo Park, California
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Re: SM58 / Pre Amp - input requested
[Re: Madman_Greg]
#1032774 - 08/02/13 06:31 PM
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Another thing you could try in order to reduce pickup of room ambience would be the use of
a portable acoustic screen (e.g. SE Reflexion or Realtraps Portable Vocal Booth), perhaps
along with hanging some duvets. See Sound on Sound October 2012 in the Q & A section.
-------------------- The Sound Physicist
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