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Author Topic: Any Shure SM7B users?  (Read 1433 times)
K3GM
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« on: April 16, 2019, 12:09:26 PM »

Are there any users of the Shure SM7B microphone? I'm looking to determine if they use any kind of preamplification to boost its low signal output.
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KD0REQ
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« Reply #1 on: April 16, 2019, 02:16:24 PM »

plain old dynamic mike technology. if the -59 dB (1 mV) doesn't do it for you, put it through a mike mixer with gain. that spec looks a good 10 dB down from what I would expect from a dynamic.
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K3GM
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« Reply #2 on: April 16, 2019, 02:55:51 PM »

.......that spec looks a good 10 dB down from what I would expect from a dynamic.
Great mic, notoriously low output...
« Last Edit: April 16, 2019, 03:00:26 PM by K3GM » Logged
K4FMH
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« Reply #3 on: April 17, 2019, 08:27:15 PM »

Are there any users of the Shure SM7B microphone? I'm looking to determine if they use any kind of preamplification to boost its low signal output.
See Cloudlifter...
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K3GM
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« Reply #4 on: April 18, 2019, 05:03:22 AM »

See Cloudlifter...
Thanks.  I'm aware of the assorted mic preamps and processing strips.  I'm looking for actual users of the microphone.  Anyone?...anyone?...
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KB7TT
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« Reply #5 on: April 25, 2019, 10:34:58 AM »

I use my SM7B to feed a FTDX 5000 thru an ART preamp and ART Compressor.
Plenty of output to drive the radio, in fact I have a 20DB pad on the output of the compressor/limiter.  I run the preamp gain about 3/4 full on.

FYI
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K3GM
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« Reply #6 on: April 30, 2019, 01:58:31 PM »

I use my SM7B to feed a FTDX 5000 thru an ART preamp and ART Compressor.
Plenty of output to drive the radio, in fact I have a 20DB pad on the output of the compressor/limiter.  I run the preamp gain about 3/4 full on.

FYI
Could you supply the ART model numbers?
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W9AC
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« Reply #7 on: May 02, 2019, 04:42:42 AM »

.......that spec looks a good 10 dB down from what I would expect from a dynamic.
Great mic, notoriously low output...

I'm an actual user.  The output is so low that I designed my own low-noise mic preamp when using the SM-7B with my transceivers.  It can be powered from a pair of 9V batteries when used portable.  

Info on my QRZ page for anyone interested. Scroll down to the heading: "SHURE SM-7B ULTRA-LOW-NOISE MIC PREAMP."

https://www.qrz.com/db/w9ac

Another low-cost option is to build a common-source (not source follower) preamp built around a low-noise 2SK170 JFET.  It can be easily powered from +8V available on most modern transceivers.  Less than a half-dozen parts needed and the entire circuit can be fit into an XLR connector at the mic end. 
 

Paul, W9AC
« Last Edit: May 02, 2019, 05:02:06 AM by W9AC » Logged
W9AC
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« Reply #8 on: May 02, 2019, 04:58:34 AM »

Are there any users of the Shure SM7B microphone? I'm looking to determine if they use any kind of preamplification to boost its low signal output.
See Cloudlifter...


Doesn't this device require +48V phantom powering? If so, then a separate phantom source is needed for powering the CL-1. 

Paul, W9AC
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K3GM
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« Reply #9 on: May 02, 2019, 07:05:48 AM »

Yes, Paul, the CL-1 requires +48VDC.  The mic of course does not.  Research has led me to believe that the Cloudlifter's gain is still not enough, so additional gain is probably required, perhaps in the form of a strip processor which could supply Phantom Power. It would be helpful if the transceiver manufacturers, in this case a K3, and IC-7610 would list microphone input voltage requirememts, but none are listed.  I'd prefer to choose peripheral equipment wisely, and not just throw money at this project until I got it to work.  But without specs, it seems you kind if have to do that.
« Last Edit: May 02, 2019, 07:10:41 AM by K3GM » Logged
W9AC
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« Reply #10 on: May 02, 2019, 07:38:10 AM »

Yes, Paul, the CL-1 requires +48VDC.  The mic of course does not.  Research has led me to believe that the Cloudlifter's gain is still not enough, so additional gain is probably required, perhaps in the form of a strip processor which could supply Phantom Power. It would be helpful if the transceiver manufacturers, in this case a K3, and IC-7610 would list microphone input voltage requirememts, but none are listed.  I'd prefer to choose peripheral equipment wisely, and not just throw money at this project until I got it to work.  But without specs, it seems you kind if have to do that.

My custom mic preamp has variable voltage gain up to 30 dB (but capable of 60 dB) and when used with the SM-7B and Elecraft K3, the K3 mic level is at "25" without the K3's internal preamp.

The CL-1 and its progeny are interesting devices because if +48V phantom powering is already available, odds are good that the device supplying the phantom voltage already has a high-gain mic preamp that can be used with low-level dynamics and ribbons.  But, I guess there are enough fixed-level mic pre's and channel strips in the field that don't have the necessary gain.

Yet another option is to use an audiophile-grade USB inrerface device like the Presonus Studio 192 Mobile or Behringer UMC2020HD.  That way, you can also port mic audio to USB devices or VAC if ever desired.

Paul, W9AC
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K3GM
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« Reply #11 on: May 02, 2019, 08:31:40 AM »

Thanks for the valuable info, Paul.  The other question I'm wrestling with is whether or not an expenditure of perhaps $750 for the mic and preamp(s) is warranted for the limited frequency range of SSB.  Having alternate uses for a microphone in this price range would certainly help tip the scale in favor of its purchase.  But I have no  other reason except that is has been on my radar for years, and is a precision device.
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N4UE
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« Reply #12 on: May 02, 2019, 12:04:20 PM »

Although this doesn't relate to this model Shure mic, here's what I went through....
I purchased a "Shure" mic (new) on eBay for what seemed to be a 'too good to be true price". While waiting for the mic to arrived, I happened upon a YouTube video about counterfeit mics and how to identify them.
When mine arrived, sure enough, it was a darn good copy.
I returned it and got my $ back.

I did a lot of experimenting with mics like the BM-800 and NW-800 from Amazon, phantom power, amps, etc. At the end, I found it was hard to beat the 219 Icom hand mic and the SM series desk mics.

It was fun...…

ron
N4UE
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If you're not the lead sled dog, the view never changes......
K3GM
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« Reply #13 on: May 02, 2019, 12:22:51 PM »

.....At the end, I found it was hard to beat the 219 Icom hand mic and the SM series desk mics......
Ron, I'm struggling between a plug and play Icom SM-50, and the Shure which in the end may end up costing $500 more.  The problem is a desk mike is a hard to fit item when a keyboard is typically occupying its spot.  I'm currently using a pantograph arm with Heil GM-4 which I haven't cared for since I first plugged it in some years ago.
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N8FVJ
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« Reply #14 on: June 05, 2019, 03:43:25 PM »

Incase you drop the SM7B idea, a seriously good microphone is the Sennheiseer e835. It is very articulate with voice and has a crisp midrange for extra punch on the transmit audio. No amplifier required.
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