[Boatanchors] OT: A question about using an 'audio mixer' in a ham set-up

Wed Apr 6 22:13:12 EDT 2016

Behringer makes SOME good products.
Their Eurodesk and Xenyx mixers don;t have a great reputation.

You can look at reviews all over the web and then decide based on what your needs are.

> To: boatanchors at mailman.qth.net
> From: ko6bb1 at gmail.com
> Date: Wed, 6 Apr 2016 21:10:58 +0000
> Subject: [Boatanchors] OT: A question about using an 'audio mixer' in a ham	set-up
> 
> Hi All,
> First, sorry about the OT post, but I really don't know where else to 
> ask this question, and I suspect that 'some' of you may use audio mixers 
> and other advanced techniques in your ham stations. Especially if you're 
> into using BCB AM transmitters etc.
> 
> The first part of this message is general info, at the end are a couple 
> questions.
> 
> My 'receiving post' has expanded greatly over what it once was, with the 
> ability to simultaneously use multiple receivers, make overnight 
> recordings of a wide spectrum (192kHz) of the LF band, etc.
> 
> The antenna routing is taken care of with the antenna/rig select witches 
> and 4 port receive multicoupler, but the audio routing is quite 
> primitive, a single 5 position switch to select which receiver feeds the 
> audio filter/headset/speaker etc.
> 
> In addition, routing the computer audio (when listening to the 
> recordings) complicated matters.  In addition, the computer sound card 
> feeds my "Fender Passport 150 Pro" stereo PA system (75W/channel) and 
> with it's decent sized speakers and 150W sub-woofer serves as my 
> "stereo" system
> 
> Well, I just ordered a used Timewave DSP-599zx filter to augment the 
> homebrewed audio CW filter (440Hz CF 8Hz Wide).  So that complicates 
> things further.
> ************************************
> 
> Then while I was working on the churche's mixing board (Behringer 24 
> channel) it hit me.  What I needed was a smaller version of the board 
> for my receiver interfacing and general audio routing!
> 
> An Amazon search for mixers turned up this unit which seems to be ideal 
> for my application.  Yes, it has special effects which aren't useful for 
> ham radio, but I'm also a (church) musician who plays guitar and 
> piano/synth.  SO it just might get some music use in addition to the 
> ham-shack.
> 
> http://www.amazon.com/Behringer-Xenyx-1202fx-Mixing-Console/dp/B000J5Y214?ie=UTF8&psc=1&redirect=true&ref_=od_aui_detailpages00 
> 
> 
> I figure that I'll use channels 1-4 for receiver inputs (using the 'Hi-Z 
> line' input of each channel for the receivers).  That will let me "eq" 
> the receivers, limiting the audio response to reduce any hum or hiss etc.
> 
> The computer sound card will feed one of the stereo inputs.  There 
> aren't any "eq" functions on those inputs, but it's not needed, the 
> computer media player has eq built in, though I normally leave it pretty 
> much 'flat'.
> 
> The Effects "send" control on each of the channels will let me route the 
> receive audio to the effects output where the two audio filters 
> (cascaded) will be connected, then routed back into the board.
> 
> When I want to use headphones the "Control Room" feed will feed the 
> headphone output of the board.  When I want speaker audio the "Main" 
> output will feed the Fender System.
> 
> I'm sure it'll take a bit of playing around to get everything routed and 
> set up just the way I want it, but it'll be a HUGE improvement over what 
> I've been doing. . .
> ***************************************
> I didn't even think to check eHam reviews until after I'd already 
> ordered the board, and I was a bit surprised to see that some people ARE 
> using this exact board in their Ham station, with generally favorable 
> reviews.
> ***************************************
> 
> QUESTIONS:
> While this unit will be used for RECEIVE ONLY, not in the transmitting 
> chain, the receive audio from my Transceivers (IC-7200 & IC-735) WILL be 
> routed through it and in use on the occasional QSO's I have (I listen 
> far more than I transmit).
> 
> 1.  How susceptible is something like this to transmitted audio getting 
> into the system (I only run 100W, no real power)?
> 
> 2.  I have a large number of QUALITY 1/4" TRS plugs (shielded) on order 
> to make up patch cables between receivers and board, audio filters and 
> board, and the Fender Amplifier and board.  I wonder if it'd be 
> worthwhile to put an "RF filter" comprised of a small series resistor 
> (maybe 1/4W) and capacitor to ground on the board end of EACH patch 
> cable as well as the input end of the cables going to the Fender. If so 
> what would be suitable values for resistor and capacitor?  I think that 
> with small enough parts they'll fit right in the plug,   Something like 
> this.  Please excuse the crude ASCII graphics, it's not something I do 
> often. . .
> 
> Input >----^v^v^v---v-------> To board input
>               Res    l
>                    ------
>                Cap ------
>                      l Ground
>                      V
>                      v
> 
> Several things I REALLY like about this board (or think I will ;-)
> 
> 1.  It's fairly compact, NOT like the 24 Channel one we have at church 
> that's nearly 4 feet wide, and which barely fit on my workbench when I 
> worked on it (XLR mic connectors had broken solder joints to the PCB as 
> well as scratchy controls).
> 
> 2.  The Cost, it's REALLY quite economical (though Behringer doesn't 
> have the greatest rep for reliability in rough use).
> 
> 
> -- 
> 73 From "The Beaconeer's Lair"
> Phil, KO6BB
> http://www.qsl.net/ko6bb/  (Web Page)
> 
> PRESENT HF/LF RADIOS:
> Grundigs: S-350 (~2006), G6 (2011) & S450DLX (2014).
> HOMEBREW: 7 Tube+Rect 1v3 Regenerative RX for LF (built 2015)
> Icom:    IC-735 Transceiver (~1990).
> Icom:    R-75, Cascaded 250/125Hz CW-Filt, Panadapter. (~2009)
> Icom:    IC-7200 Transceiver (~2015).
> R-Shack: DX-380 digital portable (~1990).
> SDR:     Softrock Ensemble II LF (built from a kit 2015).
> Zenith:  Royal-7000 Transoceanic Portable (~1968).
> 
> ACCESSORIES: HOMEBREW LF-MF Pre-Amp, MFJ-993B HF Auto-Tuner.
>               HOMEBREW 8 Hz Audio Filter.
> 
> ANTENNAS:  88 foot Long Ladder-line fed dipole, 35 feet AGL for MW/SW.
>             Active Mini-Whip, 36 Feet AGL for LF/MW/SW.
>             37 foot "Low Noise Vertical", 11 feet AGL for LF/MW/SW.
> 
> Merced, Central California, 37, 18, 37N   120, 30, 6W CM97rh
> 
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