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What is a good preamp and mixer for heil pr 781 and questions about interconnections with the 6500

Just wondering. I just ordered the pr781 with the correct cabling for the 8 pin connector on the front of my flex 6500 (xlr to 8 pin with TRS for footswitch). I would very much like to add external amplification to the mic so that I do not have to use the 20DB boost feature. So I would like to purchase an external preamp mixer combo but can not for the life of me think how I can interface it with the cable supplied by Heil. Most of the preamp/mixers that I see have an XLR input but a TRS output. The cable that I have from Heil is XLR to 8 pin for the front of the radio (along with a TRS for PTT). Do they make preamp mixer boards that have an XLR output? Or am I missing something. What would the interconnections look like to necessitate this setup?

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Answers

  • Mike NN9DDMike NN9DD Member ✭✭
    edited June 19
    I use a PR 78 through the XLR and great reports on the 6500 using the EQ. No need to spend the extra money unless you really want

    Mike
  • Jim Bryce W5HFSJim Bryce W5HFS Member ✭✭
    edited July 2016
    Exactly. I've been using the 781 with my 6700 and only the 6700's audio equalization and receiving outstanding reports.
  • Jim GilliamJim Gilliam Member
    edited June 2016
    I'm using the 781 with Romac with a USB to XLR interface on my remoting computer. Romac provides plenty of preamplification as well as 10 band equalization. That way I can use my dynamic microphone and remote the radio.
  • Al K0VMAl K0VM Retired Member ✭✭
    edited November 2017
    You could use a TRS to TRS cable from the output of the preamp/mixer to the TRS input on the radio. ( The TRS input is in the center of the dual function XLR/TRS connectoir on the 6500/6700 back panel..)

    AL, K0VM
  • Paul BradbeerPaul Bradbeer Member
    edited June 2016
    Tony,
    I have a 6500 too; at times I use a Heil PR22, and it sounds truly superb, including the 6500's internal equalisation. I'm really not sure what advantage your proposed sytem offers...it requires another (unecessary) box, and if you're not careful you'll lose the advantages inherent in the balanced XLR input to the 6500. Is there a specific reason for the outboard amplification? Might be worth trying the PR781 direct in to the 6500's XLR input first? Good luck. Paul M0CVX
  • Tony C kc2disTony C kc2dis Member
    edited May 2017
    Firstly thanks for all the responses. I guess the reason I am thinking about it was to avoid using the 20 DB boost feature by providing some pre amplification for the microphone as well as adding the option for other input sources and mixing. I also like playing with knobs! Thanks to all.
  • Corey/ KC0YNSCorey/ KC0YNS Member
    edited February 2017
    Tony, If you really want something, I've had good luck with the W2IHY system, All the cables are available...Used it with my 6300 for awhile but have since taken it off, Now just using the the 6300 eq......Good Luck!!
  • Jon_KF2EJon_KF2E Member ✭✭
    edited July 2018
    The PR781 is a balanced microphone and should really be plugged into the balanced input of the Flex for best performance and mitigation of RF interference. I personally use the internal 20DB amp but if you prefer an external one be careful as it is another point where RF can get into your signal.

    Jon...kf2e
  • Ken - NM9PKen - NM9P Member ✭✭
    edited June 23
    Tony, I have a PR22, which has about the same output as the PR781. I am able do drive it to full output with the 20+ Boost ON, and Mic gain at about 85. I talk only an inch or two from the Mic. If you want to go a foot or two away, you might not be able to do it. But that isn't what that Mic was designed to do anyway. (Some guys still try with that mic and others, and sound like they are in a barrel, unless they have lots of pyramid acoustical foam tiles all over the shack to reduce echo.) Until last weekend, I had a Behringer Q802USB mixer in line that functioned as a preamp and distribution hub, sending Mic audio to my 6500, a 1500, and my computer USB port because I was making radio broadcast spots on the side. After I sold my 1500 and ended my contract for radio spots, I found that the mixer was extraneous equipment on my desk and was packed up and sent to the closet. Ken - NM9P
  • Tony C kc2disTony C kc2dis Member
    edited May 23
    Thank you for everybody who replied to this question. I think for now I'll just stick with the PR 781 on the correct cable for input on the front of the radio. Thank you very much.
  • James Kennedy-WU5EJames Kennedy-WU5E Member ✭✭
    edited December 2016
    I use a Behringer MIC2200  with my Heil PR-20

    Jim
    wu5e 
  • Ken - NM9PKen - NM9P Member ✭✭
    edited December 2016
    BTW, I use a balanced cable from the PR22 to the rear BAL port on the 6500. You can use either a XLR or 1/4" TRS connector wired for balanced input on the BAL port. It is a dual-function professional connector. Nice!
  • k0eook0eoo Member ✭✭
    edited December 2016
    Very good, that's exactly how I have my 781 connected and I get great reports.....
  • k3Timk3Tim Member ✭✭
    edited December 2016
    - 0R - one could get a tube based preamp  

    http://www.sweetwater.com/store/detail/TubeMPps

    which is balanced audio in/out using the XLR. Several folks are using a tube preamp for a smoother sound.

    _..--
     TiM 
  • Tony C kc2disTony C kc2dis Member
    edited September 2016
    Tim THANK YOU this is just the sort of thing I was looking for! I came so close to ordering it tonight but I will wait to see how the microphone set up works then if I am not satisfied with the drive levels the 20DB boost on the radio gives.. I will try it.. Now if they made something like that with those XLR input and outputs with an eq on it! That would be a real winner! Thanks again. Ive got the page bookmarked!
  • Tim - W4TMETim - W4TME Administrator, FlexRadio Employee admin
    edited March 2017
    I highly recommend the StudioProjects VTB1
  • Mike_VE3CKOMike_VE3CKO Member ✭✭
    edited April 2019
    My opinion is not to use the front panel 8-pin mic input as when you introduce a pre-amp to the mic input that already has internal pre-amp/processing you will be forced to turn your external preamp down, defeating the purpose of the external pre-amp and possibly introduce artifacts into your audio. More susceptible to RF as well. Use the balanced input (XLR) in the rear. So the PR-781 into the XLR input of your pre-amp, the XLR output of the pre-amp to the XLR input of the 6500. Use ferrites and short cables. I also have a 6500 and use a PR-40 with a Behringer MIC2200, it has 2 preamps so unless you plan on having an alternate mic, look at the stand alone version. I can tell you the MIC2200 and ground loops is an issue and had to fight a lot to eliminate the hum. Tim, I like that StudioProjects VTB1, maybe I'll try it.
  • Tony C kc2disTony C kc2dis Member
    edited May 2017
    interesting...My Mic (PR 781) arrived and I hooked it up to the 8 pin connector and have been getting fantastic audio reports. Interestingly enough... the connector cable is labeled as a balanced connection to the 8 pin connector.. yet  I have read in other posts that the 8 pin connector was not a BALANCED input. I was concerned about connecting a BALANCED to an UNBALANCED connection but it does seem to be working fine. I have found several nice preamps on sweetwater and others like the StudioProjects VTB1 that look like they would fit the bill. I also understand that they would need to be fed into the balanced input on the back of the radio, but in that case how would you key the radio? What would the PTT be?
  • Mike NN9DDMike NN9DD Member ✭✭
    edited October 2019
    Use the PTT port on the back and plug the foot switch or trigger into that depending on which you use Mike N9DFD
  • Tony C kc2disTony C kc2dis Member
    edited May 2017
    OK right silly me I forgot thanks
  • Mike_VE3CKOMike_VE3CKO Member ✭✭
    edited April 2019
    The 6500 has an PTT RCA connector on the back panel. I have a hand held trigger going into the video input of a 4-way video switcher box (unpowered), have the 4 video outputs going to 4 different radios PTT connector, then I use the switches to select what radio I want to used the hand-held trigger. I do the same with my footswitch to another 4-way switch box.

  • k3Timk3Tim Member ✭✭
    edited May 23
    One can also trip the MoX from the SSDR or even on the Maestro. I have plugged the provided mic in the front panel, routed XLR from the tube-preamp to the back panel and used the handheld mic PTT. 
    Best,
    TiM
  • edited November 2018
    Watch eBay for a Symetrix 528E. They can be had for around $200. Probably the best **** for the buck out there for a preamp / processor. Used in conjunction with the SSDR audio processing, it is a winning combination. I've tried a number of setups - W2IHY boxes, Wheatstone DSP, and others - they are all good, but I found that the Symetrix 528E is hard to beat for the price that's they can be had for used. Better yet, watch for the later 628, which has 128 user presets for instant "profile" recall. Eric K2CB
  • Tony C kc2disTony C kc2dis Member
    edited May 2017
    I will have a look for them. Thanks Eric!
  • Tim - W4TMETim - W4TME Administrator, FlexRadio Employee admin
    edited December 2016
    The 8-pin Foster connector is a pseudo balanced input.

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