Sennheiser E835 and 6500 - preamp?

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I've been using the electret microphone on my Yamaha C500 headset for my limited SSB activity with my 6500 and that's worked just fine.  I recently acquired a Sennheiser E835 dynamic mic and today connected that via XLR cable to the 6500.  It appears that the output of the E835 is just too low to drive the 6500 to full output.  With the mic gain all the way up and the TX equalizer turned up far as possible while still maintaining the desired response curve, and speaking very closely into the mic, the best I can achieve is -10 dB on the Level meter.  Processor turned off at this point.  So, it would seem that I'm in need of an external mic preamp to raise the level of the mic output.

Have other E835 users had this same problem?  If so, what mic preamp did you use?  Not interested in an elaborate mixer/equalizer/preamp, just need some more gain. 

73, K8AC
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K8AC

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Posted 3 weeks ago

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Hector W2NPR

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Hello K8AC,


Which input are you using? The 8 pin on the front or the BAL input on the rear? Did you select the correct input on the P/CW panel? I use the balanced input on the rear and if I am set to a different input, it seems that I do not have enough gain until I select the proper input. My input selection only changes when I use the radio remotely.
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Gayle Lawson

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Have you enabled the radio's internal 20 dB mic preamp?  

Gayle K0FLY
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Gene Duprey

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I assume you are using the XLR connector on the rear of the 6500.  If so you must select that microphone input on the P/CW panel to get enough gain.

Gene, K1GD
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K8AC

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I said I used an XLR cable - those only plug into the XLR socket on the 6500 rear panel.  Yes, I selected the correct microphone input.  Yes, I've enabled the 20 dB mic preamp. 
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Hector W2NPR

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The next step you may want to try is the front 8 pin Foster connector. If someone can loan you an XLR to 8 pin cable that is wired for a Yaesu mic (ex: Heil CC-1-XLR-Y-BAL) that should work. That will tell you if the issue is the mic itself or the rear BAL input on the radio. The aforementioned cable is $36.95 at HRO unless you find another at a musical instrument store. Good Luck.
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Larry - WA7LZO

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Hello, Floyd

Well, if you plan on sticking with that very low output mic, I’d strongly recommend using either the Symetrix 528e, or its replacement, the Symetrix Voice Processor 2x. Both are MD’ed, so you can find them on eBay. You can easily snag either piece of kit from eBay for a song-and-a-dance. This will solve all of your problems with low mic audio.

Another good choice would be to get yourself an Electro Voice EV RE27N/D mic. This particular high-quality microphone is famous for its characteristic very high output level (it’s a good 6dB higher than most pro mics, such as the old EV RE20), so it likely will not need a preamp before hitting your 6700, although I have never run it barefoot myself.

A third alternative that may work is the Heil PR-781. While it also is hobbled with a low output level, it may have at least a somewhat higher output level than your Sennheiser E835, so it might do the trick. On the plus side, it is a very inexpensive entry level mic, with a street price of about $150, brand spanking new. I’d guess it could be had off-of eBay for a lot less, too. Keep in mind, though, I have seen huge claims and counter claims re: the PR-781 on this board, and whether it “works” with the 6700, or not, sans a preamp. The opinions are very split on this, with some 6700 users claiming it works OK without a preamp, and then you see tons of posts here saying they have their PR-781 mic gain cranked all the way up to max on their Flex 6700, and the thing is just not cuttin’ it.

Maybe someone else who has used the EV RE27N/D can weigh-in on the pros/cons of going directly into the 6700 with the RE27N/D, versus using a good preamp/processor ahead of the 6700, along with this mic.


Hope this helps.


Br,

Larry

WA7LZO


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Lawrence Gray

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I use a 781 directly into the balanced input on my 6500. I have no difficulty with mic gain and regularly receive unsolicited positive comments about audio quality, even from the AM purists.
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K8AC

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Just to close this out, the real problem here is that the Sennheiser E835 I had was defective - the output was far lower than the specs called for.  Substituting a known good dynamic mic resulted in adequate output to drive the 6500 to full output with a mic setting of around 35.  And this was a mic with lower sensitivity than the E835.  I've ordered one of the new 629 mics from Inrad - you'll note that these are now sold on the Flex website.  If you use a mic boom, you can buy the mic by itself without the desk stand directly from Vibroplex at about half the price.  I'm afraid that for communications purposes, it makes no sense whatever to me to use a mic that absolutely requires a preamp and the associated extra cabling, space, etc.  By the way, once I converted the non-standard way of stating mic sensitivity that Sennheiser uses to what other manufacturers use, the E835 is actually more sensitive than other mics Flex owners are using without preamps.  But, if you really do need a preamp, someone pointed out to me the DM-1 preamp that simply plugs into the XLR socket on a mic and so takes up no space and needs no additional cabling.  Of course, it does need a phantom power supply to power the preamp.  Thanks to all who contributed suggestions.
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Cosmos (Alan KB5CUS)

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I just read this post...  lol...  after I posted below...  FYI..  have friend that ordered that Inrad & it Does Not sound very good....   Maybe his is defective... ?  I'd order an E835 for known dealer..  Also it has a 10 year warr....  Some mics can be damaged from the 5 volt bias.. can magnitize coil... over time..   Oh..  & also Sennheiser has been making mics for 70 years ... & are not from China , I don't think ..  lol   The 2.8 mv is pretty common for 150 - 600 ohm Dynamic mikes...
(Edited)
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K8AC

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It would be nice if Sennheiser stated their sensitivity in the same terms that most other manufacturers use.  After converting their advertised 2.7 mv/Pa sensitivity to dB relative to 1 volt, The E835 comes in at -51.4 dBV, which is more sensitive than the Heil PR-781 (-55 dBV) or the Heil PR-40 (-53.9 dBV) and people here report using those with no preamp.  I trust that someone at Flex tested the Inrad mics with the 6000 series before deciding to sell them in the Flex store. 
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Cosmos (Alan KB5CUS)

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I've used the Sennheiser E835 & E935 for years on my Flex 6500 & the 6600... Did you buy it NEW ?   The Sennheiser has plenty of output ( 2.8mv )  I run mine around 66 mic gain ,,  MAKE SURE  BIAS is OFF,,  +20 Db Boost,,,  Beware that there are fake copies of many high end mics....  Best to buy from known dealer ..exmpl..  Sweetwater...etc...   The Sennheiser's sound quality is very hard to tell difference from other mics costing 3 + times the price.......  So...  you do not need a preamp... Make sure the XLR cable is not some Odd ball  cable...  LOL   I get many comments of my tx sound quality..  Even from the Rack gear yahoo's......
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K8AC

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The mic was purchased new from Amazon and the packaging appeared to be factory fresh.  Of course, that's no guarantee that it isn't a factory reject or a copy.  I generally buy from Amazon due to the ease of return if there's a problem and the free shipping.  I've bought from Sweetwater in the past with no problems, but the day of my trusting ANY U.S. retailer to do the right thing is in the past. 
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KC2QMA_John

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If you want to keep it simple but still have Hi-FI audio here are a few mic that have worked great for me connected straight into the radio.

Heil PR40 Or 781
Electro Voice RE27N/D
Sennheiser MD421
Even a $99 Shure SM58 sounded great.

If you add outboard voice processing you can enhance your transmitted audio even further just be aware of potential RFI issues.

If you are just looking for good narrow DX type audio the stock hand mic or headset with proper EQ works perfect.

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Larry - WA7LZO

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In my experience, the Flex 6700 with an Electro Voice RE 27N/D will perform just fine, at least for purposes of plain ol' SSB QSO's. But, for truly great sounding audio for those late night/early morning AM mode, long winded rag chews, I use my Neumann U67 microphone, running it through a Symetrix Voice Processor 2x. Lots of other great options, of course!
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