Flex 6000 8-pin Mic connector wiring

Barry N1EU

Are there any issues with connecting pins 5 (GND) and 7 (MIC-) together in the mic connector or do the circuits needs to be kept isolated?  And can the connector shell be tied to cable shield and pins 5 & 7?

Clay N9IO

Keep the grounds separate.  Shell only to pin 5.  Mic is always separate, issues will show their ugly face otherwise.

Clay N9IO

Paul Christensen, W9AC

Ditto what Clay suggests. Try and keep Mic(-) isolated to only mic GND. By placing PTT and any command GND controls on Pin 5, control current isn't shared on the mic GND lead. It's probably less of an issue with Flex. Some rigs use excessively high PTT current that create audible "clicks" when keying the mic.

Paul, W9AC.

Barry N1EU

Thanks guys.  However, I'm using an electret mic powered from pin 2, +5V.  Should I use mic (-) for the bias return instead of pin 5 GND?  

K3ZJ - Dave

To understand this potential problem, see page 5 of K9YC's paper, at:  http://k9yc.com/RFI-Ham.pdf  (the rest of the paper is good too!)

Paul Christensen, W9AC

Barry,

For the electret return lead, you may still use Mic(-). Pins 5 and 7 *should* be tied together to the chassis at one place: the 8-pin Foster jack on the Flex.

K9YC's references the so-called "Pin 1" problem. This relates to the bonding of ground leads to the chassis and not via insulated connectors to a PC board grounding/bonding point.

Hopefully, Flex has tied pins 5 and 7 direct to the chassis at this one location, and in doing so, has avoided any long leads with an impeded path to the chassis. A schematic may show this, but most often doesn't. Knowing for sure requires an inspection of Flex's chassis-mounted mic jack. I've not yet been in that area of my Flex 6700.

Paul, W9AC.

K3ZJ - Dave

Unfortunately FLEX will not provide a schematic for any purpose under any conditions (I've asked) so there is no easy way to figure these things out.  

Burt Fisher

Are there any adapters that will allow a 3 conductor 1/4" phone plug?

Tim - W4TME

Do not bond Pins 5 and 7 together because the mic input is pseudo balanced and this will cause a ground loop.  If you meed the mic bias voltage for the mic element, but enabled it in the SmartSDR software setup.  It really is that easy.

Burt Fisher

Does anyone sell a cable to go from 8 pin to 1/4" 3 conductor mic cord?

Ken - NM9P

Burt, are you referring to using a balanced mike 1/4" TRS to an adapter to plug into the front of a 6300?  Or the other way around an 8-pin from a mike into the 1/4" TRS into the back of a 6500/6700?  

Heil sells a CC-1 XLR Y.  It is an XLR-8-pin Foster connector wired for Yaesu/Flex. But I don't see one for a 1/4" TRS input.  You could probably custom order one if needed.

But they are easy enough to make.  (I still do a LITTLE soldering as my eyes and arthritis permit )

I bodged one of the former together at one point just to see if it would work for a second mike before I got the Behringer mixer.  It worked fine.  It had a pig-tail for a PTT switch, too.  But I cannibalized it to use on a 9-pin DB-9 connector on my 1500 before I sold it.  

Burt Fisher

I have a 6300. I am not very mechanical. I hate abbreviations, TRS? 

KY6LA_Howard

Tip -- Ring--Sleeve = TRS

Ken - NM9P

Correct. For balanced Mike lines...Tip = Mike+, ring=mike-, sleeve=ground shield.

Burt Fisher

Thank you for TRS, now no one makes the adapter?

KY6LA_Howard

Check Amazon. Lots of TRS to XLR Adapter cables.

KY6LA_Howard

Use the Heil CC-1 8 pin foster to XLR Femaile cable plus a XLR Male to !./4" TRS Cable

I am using that combo for a Heil,Mike I have.

Burt Fisher

Where did you get it?

KY6LA_Howard

Amazon

Steve K9ZW

Same place I ordered a quality 6 ft cable with the TRS terminations I wanted and they had five-packs of 8-pin Forsters pretty inexpensively. 

Cut the cable in half, and put on the 8-pins, there we go!

Of course I wanted two (as they say "Two is One, and One is None.")

[Edit] Forgot to share the "Why?" - this way I avoided having the loose Heil 8-pins plugs which are so easy to insert wrong if you are not careful, and have full specification plugs.  I also only had to solder one end on each, which isn't as good as ready-made but not too far off. 

73

Steve

K9ZW

Burt Fisher

The link so I don't **** up?

KY6LA_Howard

This should do the job

8 Pin Foster tFemale to XLR Female

http://smile.amazon.com/Heil-Sound-adapter-cable-bal/dp/B00WTHFJ7G/ref=sr_1_1?ie=UTF8&qid=145221...

XLR Male to 1/4" TRS Adapter

http://smile.amazon.com/Hosa-GXP246-XLR-Male-Adaptor/dp/B000068O4I/ref=sr_1_7?ie=UTF8&qid=145221...

Might find similar on Ham Radio retail sites but searching Amazon is easier.

Steve K9ZW

Amazon links:

5 packs of 8-pin http://www.amazon.com/gp/product/B0125YRWKE
I needed MALE TRS (three connector) plugs - so I used http://www.amazon.com/gp/product/B00IPNR64M

In hindsight I would up spec the cable.

If you need Female TRS you either need adaptors of a different cable.  Female to Female TRS patch cables are uncommon, so you might need to use a Female to Male and lose the male plug replacing it with the 8-pin.

73

Steve
K9ZW

Paul Christensen, W9AC

A physics professor's proverb: "One measurement is worth a thousand words." 

Using a VOM, I verified that the 8-pin Foster mic connector correctly bonds pins 5 & 7 to the Flex chassis.  This is the only location where the two lines should meet.

I probably would not call use of the (-) pin "pseudo balanced."  It's not.  If it were, we would see some resistance from the (-) pin via a series input resistor, shunted by another resistor to ground. 

A truly balanced input typically requires either a transformer, or a 3-stage instrumentation amplifier.  A single op-amp can be configured as a differential input, or "pseudo balanced" input, but I would not consider it a balanced device since CMRR is poor across a wide range of frequencies.   

Use Foster Pin 5 for PTT and control return, and Pin 7 only for the mic lead return.  This results in only audio current on the (-) mic lead and prevents PTT current from causing audible "clicks" in mic audio.

Paul, W9AC 

  

Burt Fisher

What adapter specifically can  I get to get this to work with my 6300?

Duane N9DG

Presumably this will fit the bill as long as that mic is wired the same as the Ten Tec badged EV mics are.

http://www.ebay.com/itm/Mic-Adapter-1-4-Stereo-TRS-Phone-Jack-to-Ten-Tec-Yaesu-8-Pin-Microphone-Plug-/201251371823?rmvSB=true

I know nothing of this seller, but the description for what is needed looks correct.

Burt Fisher

Will the end fit into the 6300?

Ken - NM9P

@Duane,
That is the way a lot of 1/4 inch stereo (TRS) mike plugs were wired in the "old days."  Several CB mikes were the same.  They used the Tip for PTT and the rig for mike audio.   When I asked an old timer why?  his response was that if you had it the other way, every time you plugged the mike in the tip would go across the PTT relay and the voltage would destroy the mike cartridge over time (and sometimes immediately.)  This way, the mike contacts don't connect anything until it is all the way in.

@Burt,
This mike looks like one I have seen on some old Heathkits, a Browning Golden Eagle, and some old Motorola and other brands of commercial base stations.  (police & fire mostly)

The add says it will connect with a Ten-Tec or Yaesu.  The Flex 8-pin connector follows the Yaesu format, so it should be OK.

It would be better if they would give you a pin-out of the 8-pin plug just to make sure.

Good luck, Burt.  I hope it works.

Ken - NM9P