[K2CC] New Equipment

John Robinson johnwesleyrobinson at gmail.com
Tue Nov 18 22:35:41 EST 2014


Greg's proposed circuit will also work even without the second set of transformers. I was originally picturing a very different circuit.

-John

> On Nov 18, 2014, at 9:01 PM, Greg Zenger <n2gz at gregzenger.com> wrote:
> 
> My thought process was that to do it passively, you would need a transformer on the input to separate the grounds (balancing the audio lines) I suppose there is no need for transformers on the output. 
> 
> Here is a sketch of what I am thinking.
> 
> http://oi61.tinypic.com/2wqcumv.jpg
> 
> I have never attempted to build this, but I'm pretty sure it will work if quality audio transformers are selected.
> 
> And then there are ways to do it actively as John pointed out.
> 
> Greg, N2GZ
> 
>> On Nov 18, 2014 7:37 PM, "John Robinson" <johnwesleyrobinson at gmail.com> wrote:
>> Well here is some gory details on how to implement such a phase reversal circuit from one of the audio sites I frequently visit. http://sound.westhost.com/project107.htm . I do not see transformers working in a common ground scheme as the signal needs to be physically inverted in such a scheme as you would be driving the signal to  the ground of the other speaker most likely resulting in undesired results.
>> 
>> I may experiment one day with a variable phase circuit and see if it yields anything beyond a echo... It will probably be based on the Marantz vari-matrix circuit. This is what happens when you dabble in audio circuits for too long and vintage Marantz gear.
>> 
>> -John 
>> 
>>> On Nov 18, 2014, at 4:17 PM, Greg Zenger <n2gz at gregzenger.com> wrote:
>>> 
>>> You know what John, I thought about the whole roll-your-own breakout box idea for phase reversal switch and almost recommended such a thing in my previous email.  However most (maybe even all) headphones share a ground between the left and right channels which means such a breakout box approach would need audio transformers on both the input and output to re-derive the grounds prior to transmission over the common ground conductor in the headphone cable.
>>> 
>>> Greg N2GZ
>>> 
>>>> On Nov 18, 2014 3:03 PM, "John Robinson" <johnwesleyrobinson at gmail.com> wrote:
>>>> I also highly recommend the linemaster clipper foot switch. They are well built, cast metal and made in the USA here in Woodstock, CT. I actually have one currently in front of me on a piece of medical equipment at work.
>>>> 
>>>> I modified a pair of headphones with a in/out of phase switch as Greg had mentioned. The pair I modified is a yamaha CM500 which are about 60$. They are a pretty decent pair and have plenty of room inside for the switch if you wish to add the feature. They also do not sound bad either and receive decent reviews. I suppose you could also roll a switch box which the headphones plug into and make any attached headphones in/out of phase without any physical mods to the headset.
>>>> 
>>>> For mic jack adapters i have picked up a couple W2ENY made adapters off ebay as I was often too lazy to roll my own. They work well and shipped from NY and support an ham in NY. Just a throwing it out there for another source I have used.
>>>> 
>>>> -John
>>>> 
>>>> > On Nov 17, 2014, at 10:53 PM, Ethan Miller - millere <millere at clarkson.edu> wrote:
>>>> >
>>>> > The boom mic is in addition to the heil proset we already have. Good things to note on the other equipment, thanks!
>>>> >
>>>> > - Ethan
>>>> >
>>>> >> On Nov 17, 2014, at 22:45, Greg Zenger <n2gz at gregzenger.com> wrote:
>>>> >>
>>>> >> I'll toss in my two cents here, if you dont mind.
>>>> >>
>>>> >> The PR781 is a great microphone... however consider the environment of the
>>>> >> station.. Im not sure of how things are setup now in the new station, but
>>>> >> back in the late 2000's there was often a lot of 'spectators' hanging
>>>> >> around the radio during contests. And by hanging around, I mean goofing off
>>>> >> and being social. A big boom mike like that is likely to pickup alot of
>>>> >> background noise. Not good.
>>>> >>
>>>> >> I prefer to operate with a headset with a boom mic.  A headset helps put
>>>> >> the sound inside your head; you can hear things that you cant hear
>>>> >> otherwise when you are diggin' out that weak signal under all that splatter
>>>> >> from the guy transmitting a few kc above or below. a headset with a phase
>>>> >> reversal switch is nice. I use the Heil Pro Set Elite 6. Though keep in
>>>> >> mind Its possible to do phase reversal on any headphones if get creative
>>>> >> like K1JR did and build one into your favorite headphone.. A double pole
>>>> >> double through switch installed to reverse the polarity of one of the
>>>> >> speakers is all it takes.  The PowerSDR software might give an option to do
>>>> >> it in software... I don't remember.
>>>> >>
>>>> >> The club should definitely have an adapter like the HLS-AD-1-YM.... I bet
>>>> >> you could build one using parts found around the shack.
>>>> >>
>>>> >> This year we used both an external speaker for spectators to listen, and
>>>> >> had the Heil Pro Set Elite 6 for the operator... it worked well.  Going
>>>> >> forward, I think it might be nice to have a multi channel headphone amp to
>>>> >> allow additional headphones to be plugged in with independent volume
>>>> >> control.
>>>> >>
>>>> >> I do not recommend the Heil foot switch... I bought one once and it felt
>>>> >> cheap and I just didnt like it... Save up and get a a Clipper... (model
>>>> >> 632-SC3)  Here is a decent deal.... though ive seen them cheaper at
>>>> >> hamfests:  http://ebay.to/1AaqcM3  Its cheaper than the Heil, and anyone
>>>> >> can figure out how to wire it in.  Put an RCA connector on it and plug it
>>>> >> into the back of the F3K.
>>>> >>
>>>> >> Best of luck and 73
>>>> >>
>>>> >> Greg N2GZ
>>>> >>
>>>> >>
>>>> >>
>>>> >>
>>>> >> On Mon, Nov 17, 2014 at 9:03 PM, James P. Dapp - dappjp <dappjp at clarkson.edu
>>>> >>> wrote:
>>>> >>
>>>> >>> Hey all, some of our equipment broke this weekend and we are looking to
>>>> >>> buy some new gear. As for the microphone, here are a few to consider:
>>>> >>>
>>>> >>> http://cart.flexradio.com/Heil-PR781-Balanced-Microphone_p_21.html
>>>> >>> http://cart.flexradio.com/Heil-HB-1-Microphone-Boom_p_837.html
>>>> >>> http://cart.flexradio.com/Heil-FS-2-Dual-Foot-Switch_p_836.html
>>>> >>> http://www.dxengineering.com/parts/hls-ad-1-ym
>>>> >>>
>>>> >>>
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