I've been spending some time the last several days searching around for an inexpensive but still high quality phone patch for on-air interviews, and found this nice little unit from a company called Re-Tell (www.retellrecorders.com).
What impressed me most is the following page with audio clips to compare the differences in quality between their different connectors.. www.retellrecorders.com/help/connectors.htm
It sounds really good! A BIG difference! The cost for their most expensive connector (Model 650) is £119.99 +VAT which I think is about $150.. plus $10 shipping.. still more than I was wanting to spend, but am seriously considering it.
Years ago I had bought a Symetrix TI101 off ebay for about $90, but never really seemed able to make it sound right - Maybe it was my own errors, or perhaps it was a flawed unit.
I just emailed them with a few inquires. I'm thinking it might be better to spend a little more for this new unit, instead of taking a chance on some old 30 year old ebay bargain..
Any opinions?
Been curious about this.. I see those Heath Kit and other Ham phone patches on ebay for $10-$20 all the time.. Can't help but wonder if they could be utilized in Part15 broadcast.
I suspect not, since I never hear of anyone using them.
Or could they?
The phone patch I am happy with is a modified Radio Shack Duo 101 Speakerphone, which may no longer be in the catalog. I use it exactly as is, but with two add-ons.
The "as-is" part means that anyone here in the studio can hear the caller on the speakerphone and no one needs headphones. But the radio listener is patched in as follows: I ran a cable out from the speaker voice coil and added a capacitor since I think there's DC present for some reason. This cable goes to a 1:1 transformer, from the same Company, and plugs in to the audio mixer. On this line the incoming call is perfectly clear and the local out-going voices have been phased-out, so that our voice is picked up by the normal studio mic.
2nd, the speaker phone has a built-in electret microphone, which I disconnected, and ran the mic line out to my own electret, installed in a plastic tube and projecting from my studio mic where it is attached by a yellow rubber-band (any color rubber band will work). In this way the incoming call hears us close-up.
In the past I installed a Symetrix TI101 for a client, and was surprised how (relatively) poor it sounded. I was afraid the client would think I didn't know what I was doing, but they never complained so I'm not sure what they thought.
Carl, your phone patch creation is pretty impressive. I've heard all four of your Low Power Hours and the sound quality of your phone interviewee's is certainly acceptable to my ears.
Did notice background noise when (some of) your guest speak, but the other interviews sound clean.. It must have to do with what phone they are speaking through on their end.
Would be happy to equal the quality yours produce, and hope it will.
I don't have your knowledge, but at least vaguely comprehend your description, but lose it when you when you say ".....and ran the mic line out to my own electric, installed in a plastic tube and projecting from my studio mic where it is attached by a yellow rubber-band (any color rubber band will work). In this way the incoming call hears us close-up.."
But you don't have to elaborate for me, don't have your talent and wouldn't know what I was doing anyway..
But if I did try to duplicate your patch, would be sure to use a yellow rubber band too, just to be sure it was right!
Still not sure what route I'll end up taking.. it's mostly a matter of dollars. Think it might be time to tighten up for the meantime, -if there was cash to throw around, I wouldn't hesitate.
May go with a less expensive selection for now.. but just not sure.
By chance did anyone check out the audio clips (mentioned above) of Re-Tell's different connectors? Does it impress anyone else but me?
Thank you Rich Powers for noticing how smart I am, but the thrill of it is short because now I'll give credit to an AM radio engineer I knew who really was super smart. He taught me the phone-patch trick, and he also built out of a junk box a 1-watt FM transmitter that I used every Friday night to broadcast to a girlfriend 1-mile away, all comedy material, and she got on the phone and laughed along with me. No one ever noticed the station was there back in 1976 (about 88.1).
I'm planning a Low Power page so that I can list such things as these schematics so that the two circuits I know can be posted.
Well, maybe it wasn't your idea, but at least you know the mechanics of it.. Speaking of makeshift alterations - Perhaps you might be willing to take a look at this and tell me if you know what going on with it..
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=360321994805
It's a modified Gentner Microtel Broadcast Telephone Interface on ebay for only $22.39 each & free shipping (he has 5 available).
He shows large detailed pictures, and describes as such:
..This is a professionally-modified Gentner Microtel - looks to me like the line interfaces are presented on the 4 pin XLR jack and the audio in/out on the 6 pin XLR. I have no more information on what was done or why. I've included a couple of photos of the interior so hopefully you can work out what they've done. There are no battery connectors remaining so powering was achieved through one of the two XLR connections.
My guess is that these were used in some kind of press box or recording studio to allow someone to turn on their mic and to hear cue audio in a pair of headphones.
As this is a modified item with no documentation so I am offering it for sale on an as-is,...
My gut tells me these are usable units, but my experience tells me.. well.. nothing. Bet you could tell..
This could be a real bargain for some of us.
Rich Powers:
I looked at the good pictures and share with you this caution. Although it looks very neatly (professionally modified) it also looks totally baffling as to what is going on with that circuit. Since there seems to be no documentation by the modifying engineer, I doubt whether most people would know what to do with this device. You might end up with a permanent mystery part in your junk box.
By the way, here is a simplified description of the two mods I made to the Radio Shack Duofone 101 to get a phone patch:
1.) Use the speaker phone as intended, it is self powered from the phone line;
2.) Tap the speaker voice coil (2-wires to speaker audio connection), 1uF non-polarizing capacitor on one side of the audio-line out to a 1:1 matching transformer;
3.) Extend the built-in electret microphone to a location very near yourself, careful to observe D.C. polarity.
There I have left off all the odd parts like "tubing," "rubber band" and "tooth-pick."
It is easier than figuring out that think from e-bay.
Dear Rich Powers:
I remember that there is a super easy way to get an instant phone-patch. You start by using a speakerphone of the sort I named, Radio Shack Duofone 101 or similar, and point a microphone directly close to the speaker so the incoming call will actually be "on mic."
Then you also mic yourself, the interviewer, and mix those 2 mics together.
We did that on a public radio station and the owner of shortwave station WBCQ in Monticello Maine does it at the present time.
Easy and quick.
The phone-patch I used when Carl interviewed me for the Low Power Hour consisted of two audio isolation transformers connected to a telephone handset cord. One transformer connected to the earphone line the other one to the telephone microphone line.
The telephone earphone output was fed into my little audio mixer input. My station audio was fed into a second mixer input so I could hear that in the headphones. My local microphone was connected to a third mixer input.
The mixer output went to the telephone microphone line. Some careful adjusting of the earphone signal and mixer output took care of feedback.
This setup allowed me to hear the caller (Carl), myself and my station audio through the headphones connected to the mixer while using the local microphone to talk to Carl. Carl could hear my station audio as well.
The telephone provides the "hybrid" circuit to couple all the audio to and from the phone line. The isolation transformers were both inside a small metal box with connectors and was designed to be used in a car stereo installation.
When asked, Carl said the audio sounded pretty good.
Well, I ended up buying one of these things called a Phone-Jam from ebay for $50, http://www.phone-jam.com/ Says it perfect for on air broadcast.
I could not find any info or reviews about it, except from their own website, which is about 10 years old and contains dead links, and their contact page gets no response..
Because of the lack of info, and the fact that I feel like I've been spending too much lately anyway, I actually started to pass on it, but it stuck in my mind, so I finally bid.. and I was the only bidder, so I won it.
It's got to be worth what I paid - and man, it just looks and sounds like the perfect thing for a telephone radio interview.
I'll let you know more after I receive it
This is the actual item: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&rt=nc&nma=true&item=300511934663&si=JHAWj0jCCPfN3sa7ktzj6GjgIMI%253D&viewitem=