[Amps] The Pin One Problem

Carl km1h at jeremy.mv.com
Sat Jun 8 16:18:22 EDT 2013 

> > ** You seem to enjoy blaming manufactrurers for all your "perceived"
> > problems.
>
> Another flippant remark from someone who prefers to engage in personal
> attacks rather conduct reasonable discussion about the technology.


** Nothing flippant and just a simple observation. If you cant take the same 
criticism you like to dish out then keep your fingers in your pocket.


> > ** I just wasted several hours looking for those blatant examples and
> > havent found one but with so many radios on the market I could have
> > missed them.
>
> Then you did not look at the Yaesu FT-1000D, FT-1000MP, FT-1000MP MK V,
> FT-990, etc. or the Kenwood TS-480, the Icom 706, 706MKII, 706MKIIG,
> 746, 746Pro, 756, 756ProII, 756ProIII, etc.  Every one of them floats
> the mic return at the jack and ties that line to the "ground" trace
> through an RF choke at the amplifier/preamp.
>
> 73,
>
>    ... Joe, W4TV

** The FT-1000/D, 1000MP, 9000DX, FT-5000 (has a ferrite bead), IC 756PIII, 
IC-7800, TS-930, TS-940, TS-950 family are all without a choke for the 
ground return at the mike preamp. The TS-480 does have a tiny 10uH  choke 
which has negligible DC resistance. Likely there to block any stray RF 
currents.

Ive seen enough to understand:

1. None of these radios have hum problems
2. The mike ground is made at the board with the preamp
3. Discussing this any further is a waste of time, Ive alredy disproven 
enough of your choke claims and the rest of this Pin 1 nonproblem. Sort of 
reminds me of that self styled expert on everything with the none stop ego 
driven web pages where errors either never get changed or are snuck in with 
an edit and no explanation.
4. This is an AMPLIFIER forum and I dont intend to raise Georges ire over a 
ridiculous non issue.

Carl
KM1H






>
> On 6/7/2013 10:34 PM, Carl wrote:
>>
>>>
>>> I am quite familiar with the issue and while Dr. Garland may call
>>> it a "ground loop", the problem with The W8ZR Station Pro is the
>>> same old problem in interfacing with improperly designed amateur
>>> equipment.
>>
>> ** You seem to enjoy blaming manufactrurers for all your "perceived"
>> problems.
>>
>>>
>>> If you bother to look at the schematics for nearly every Yaesu, Icom
>>> or Kenwood transceiver, you will find that the "mic return" connects
>>> to the emitter (discrete transistor preamp) or non-inverting input
>>> (op amp amplifier) of the microphone preamp or amplifier and that
>>> point is connected to the transceiver chassis via an RF choke for
>>> DC.
>>
>> ** I just wasted several hours looking for those blatant examples and
>> havent found one but with so many radios on the market I could have
>> missed them. The ones Ive seen bring the Mic 1 and Mic 2 leads in thru
>> mini coax from the front panel where Mic 1 goes to the active device
>> input thru conventional RC circuitry and Mic 2 is grounded to the boards
>> ground plane and then to the chassis. There is also a chassis ground for
>> the mike connector barrel itself which has several other functons
>> besides audio.
>>
>>
>>> When the mic return is not *tightly bonded* to the chassis, it causes
>>> currents on the return to find their way to the chassis through the RF
>>> choke and in doing so produces a voltage in series with the mic audio
>>> (I^2*Z).  It is not rocket science and not "new."  It is amazingly poor
>>> design - one "designer" coping from another - nobody knowing what they
>>> are doing and why.  A lot like the blind copying of "floating" grids
>>> in common grid triode amplifiers.
>>
>> ** I suspect you have a problem understanding that there is more than
>> one way to do things with equal results and simply prefer to rant about
>> things you dont agree with or understand.
>>
>> ** Ive owned a lot of SS gear over the years going back to the TS-830
>> and have evaluated many others in the contest category for the YCCC and
>> many individuals. This includes outboard digital voice recorders, audio
>> shaping and compressors, SO2R audio switches,  and have yet to come
>> across a hum problem. Nor do I hear them on the air.
>> I also looked thru 30 years of NCJ and find not one mention about this
>> so called major problem, this whole thing seems a bit fishy to me.
>> Getting to commercial audio equipment on the ham bands, and as Ive
>> already mentioned, the Pin 1 nonsense doesnt exist. All it takes is
>> enough of an IQ to wire things up as has been stressed for many
>> decades....maybe that is part of the current problem that a few believe
>> actually exists.
>>
>>
>>>
>>> Quite simply, when a transceiver and an audio processing accessory
>>> - whether it be W8ZR's Station Pro or a microHAM microKEYER II -
>>> are connected to a common power supply (at the power supply), some
>>> fraction of the current drawn by the transceiver will return to the
>>> power supply via the connections (PTT return, Computer control return,
>>> mic shield, FSK return, Key return, headphone return, etc.) between
>>> the transceiver and accessory device.  Unless *all* of those returns
>>> - *including the mic return* - are terminated to the transceiver
>>> chassis that current will appear across the RF choke (remember the
>>> current varies at at an RF rate) which will act like an old fashioned
>>> choke modulator.
>>
>> ** Called Heising after its inventor. Removing the choke and replacing
>> it with a beaded lead is simple and is there to minimize RFI from some
>> the half assed antennas sold to unsuspecting buyers
>>
>>>
>>> It doesn't take much current through that RF choke to generate enough
>>> modulation to be a problem.  Typical audio levels for a microphone
>>> vary from around 5 mV for a dynamic (Kenwood, Yaesu) mic to around
>>> 25 mV for an electret (Icom) element.
>>>
>>> There are a large number of "band aids" for the design problem in the
>>> amateur transceiver mic inputs.  *ALL* of them work by reducing the
>>> current in the returns between the transceiver mic amp and the
>>> accessory.  They are as varied as the designer - including reducing
>>> the resistance in the power supply jack on the rig (multiple pins
>>> in parallel), increasing the gauge of the power cord, bonding the
>>> respective chassis together with wide strap, providing power to the
>>> accessory from an *isolated* power supply or from an aux port on the
>>> rig, etc.  However, none of them really fix the design flaw in the
>>> transceiver which would generally be as simple as connecting the
>>> mic return directly to the chassis at the mic jack and connecting
>>> a jumper across the offending RF choke.
>>>
>>> The amateur manufacturers (except Elecraft, in part) have not learned
>>> what Muncie showed decades ago in professional audio equipment.
>>
>>
>> ** In reality Eleccraft was the biggest offender with the K3 and was the
>> worst sounding SSB radio on the air for awhile. It and their responses
>> soured me on it permanently.
>>
>>> 73,
>>>
>>>    ... Joe, W4TV
>>>
>>
>> Carl
>> KM1H
>>
>>
>>
>>
>>
>>>
>>> On 6/7/2013 11:38 AM, Carl wrote:
>>>> It is obvious that you have drifted off the subject which related to 
>>>> the
>>>> Station Pro which Jim thouroughly explained the ground loop issue.
>>>>
>>>> Carl
>>>> KM1H
>>>>
>>>>
>>>> ----- Original Message ----- From: "Joe Subich, W4TV" 
>>>> <lists at subich.com>
>>>> To: <amps at contesting.com>
>>>> Sent: Friday, June 07, 2013 11:12 AM
>>>> Subject: Re: [Amps] The Pin One Problem
>>>>
>>>>
>>>>>
>>>>> The problem is that it is not a "Ground loop" - there is no issue
>>>>> with multiple grounding if the inputs to the device are designed
>>>>> properly.  It occurs only when the signal return is not correctly
>>>>> connected to the shielded enclosure or bypassed - that also impacts
>>>>> things like VHF/UHF stability, etc.
>>>>>
>>>>> If you continue to call it a "ground loop" it is obvious that you
>>>>> do not understand the nature of the problem.  "Pin 1" problem is
>>>>> as good a term as any since the mechanism for this issue in audio
>>>>> was first identified in professional equipment using XLR connectors
>>>>> and the understanding extended to audio equipment with other
>>>>> connectors (including consumer/prosumer equipment with RCA I/O).
>>>>>
>>>>> 73,
>>>>>
>>>>>    ... Joe, W4TV
>>>>>
>>>>>
>>>>> On 6/7/2013 10:58 AM, Carl wrote:
>>>>>> That would be too easy since ground loops go almost back to 
>>>>>> prehistory
>>>>>> when many discovered the same thing independently at almos the same
>>>>>> time.
>>>>>>
>>>>>> OTOH, before the Brown Theorem it was always called ground loops,
>>>>>> especially in the pro audio industry.
>>>>>>
>>>>>> Carl
>>>>>> KM1H
>>>>>>
>>>>>>
>>>>>> ----- Original Message ----- From: "Alex Eban" <alexeban at gmail.com>
>>>>>> To: "'Ian White'" <gm3sek at ifwtech.co.uk>; <amps at contesting.com>
>>>>>> Sent: Friday, June 07, 2013 5:11 AM
>>>>>> Subject: Re: [Amps] The Pin One Problem
>>>>>>
>>>>>>
>>>>>>> What about plain old ground loops, numerology set aside?
>>>>>>> Alex 4Z5KS
>>>>>>>
>>>>>>> -----Original Message-----
>>>>>>> From: Amps [mailto:amps-bounces at contesting.com] On Behalf Of Ian
>>>>>>> White
>>>>>>> Sent: Friday, June 07, 2013 9:52 AM
>>>>>>> To: amps at contesting.com
>>>>>>> Subject: Re: [Amps] The Pin One Problem
>>>>>>>
>>>>>>> K9YC wrote:
>>>>>>>
>>>>>>>> When you invent, create, or discover something, you get to name it.
>>>>>>>
>>>>>>> Would that would be "Brown's Law"?  I'm sorry, Jim, but it just
>>>>>>> ain't so.
>>>>>>>
>>>>>>> We all understand your personal respect for Neil Muncie, but there
>>>>>>> are
>>>>>>> other
>>>>>>> overriding priorities such as respect for truth and accuracy.
>>>>>>>
>>>>>>> It is only justifiable to call this "the Pin 1 problem" where that
>>>>>>> name
>>>>>>> accurately applies: specifically to Pin 1 of an XLR connector in the
>>>>>>> pro
>>>>>>> audio industry. But this problem extends far beyond the area where
>>>>>>> it was
>>>>>>> originally identified by Neil Muncie. It is no disrespect to insist
>>>>>>> that the
>>>>>>> more generic problem needs a better name.
>>>>>>>
>>>>>>> Calling it the "Pin 1" problem in situations where it simply isn't
>>>>>>> pin 1,
>>>>>>> and even where there isn't a connector at all, is a deliberate
>>>>>>> falsehood
>>>>>>> which misdirects and confuses people. It can only be understood by
>>>>>>> someone
>>>>>>> who is already initiated into the secret. At so many different
>>>>>>> levels,
>>>>>>> that
>>>>>>> is simply A Wrong Thing To Do.
>>>>>>>
>>>>>>> We badly need a short GENERIC name that accurately indicates the
>>>>>>> nature of
>>>>>>> the problem. That won't be easy to find, but it is something we can
>>>>>>> work on.
>>>>>>> Calling it the "Pin 1 problem" simply isn't good enough.
>>>>>>>
>>>>>>>
>>>>>>> 73 from Ian GM3SEK
>>>>>>>
>>>>>>>
>>>>>>> _______________________________________________
>>>>>>> Amps mailing list
>>>>>>> Amps at contesting.com
>>>>>>> http://lists.contesting.com/mailman/listinfo/amps
>>>>>>>
>>>>>>> _______________________________________________
>>>>>>> Amps mailing list
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>>>>>>> http://lists.contesting.com/mailman/listinfo/amps
>>>>>>>
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>>>>>>
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>>>>>>
>>>>> _______________________________________________
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>>>>
>>>>
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>>
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