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K3 Popping noise in headphones??

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Jim Bolit

Re: K3 Popping noise in headphones??

Vic,

Thanks.

There is no "tone" that I would associate with what I am hearing. It is
more a burst of noise, but transient in nature.

Jim

W6AIM

.

-----Original Message-----
From: Elecraft [mailto:[hidden email]] On Behalf Of Vic
Rosenthal 4X6GP/K2VCO
Sent: Sunday, October 18, 2015 11:41 AM
To: [hidden email]
Subject: Re: [Elecraft] K3 Popping noise in headphones??

Well, I have an old K3 plus new synths, I have the RX EQ set to zero dB all
across its range, and I hear the noises. I would call them short tone bursts
rather than pops, though.

73,
Vic, 4X6GP/K2VCO
Rehovot, Israel
http://www.qsl.net/k2vco/

On 18 Oct 2015 21:16, Joe Subich, W4TV wrote:

>
> On 10/18/2015 11:46 AM, Wes (N7WS) wrote:
>> As a point of reference, my old K3 with the original synthesizer
>> board pops when changing BW. It's most noticeable going from 150 Hz
>> to 100 Hz and vice versa.
>
> There will be a slight pop when changing bandwidth between 150 and 100
> Hz as the K3/K3S disables the RXEQ at bandwidths less than 150 Hz.
> The level of the "pop" will be related to the amount of EQ in use
> *around* *the center of the passband* (e.g., "pitch"). If for
> example, pitch is
> 500 Hz and bands 4 (400 Hz) and 5 (800 Hz) are 0, there will be little
> or no "pop". However, if one has 400/800 Hz set for significant boost
> there will be a fairly loud "pop" as the level changes.
>
> 73,
>
> ... Joe, W4TV
>
>
> On 10/18/2015 11:46 AM, Wes (N7WS) wrote:
>> As a point of reference, my old K3 with the original synthesizer
>> board pops when changing BW. It's most noticeable going from 150 Hz
>> to 100 Hz and vice versa.
>> This is with normal AF gain and CM500 in rear headphone jack.
>>
>> On 10/16/2015 6:01 PM, jim wrote:
>>> I just got my K3 back from Elecraft. They did the once over and
>>> installed the new SYN boards.
>>>
>>>
>>> I have noticed a "popping" noise in the headphones as I change the
>>> bandwidth control, but ONLY as I transition from 200 Hz, 150 Hz, 100
>>> Hz and 50 Hz. I have only checked this in the CW mode.
>>>
>>>
>>> This popping noise was not there before sending the rig in.
>>>
>>>
>>> I have the 500 Hz and 200 Hz crystal roofing filters installed,
>>> which is the same configuration as I had before sending it to
>>> Elecraft.
>>>
>>>
>>> Any thoughts?
>>>
>>>
>>> Tnx
>>>
>>>
>>> Jim
>>>
>>> W6AIM

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Bob McGraw - K4TAX

Re: K3 Popping noise in headphones??

In reply to this post by Joe Subich, W4TV-4

Thanks for the detailed explanation. I was beginning to wonder when and
if someone would advance a valid explanation.

73
Bob, K4TAX
K3S s/n 10163

On 10/18/2015 1:16 PM, Joe Subich, W4TV wrote:

> There will be a slight pop when changing bandwidth between 150 and 100
> Hz as the K3/K3S disables the RXEQ at bandwidths less than 150 Hz. The
> level of the "pop" will be related to the amount of EQ in use *around*
> *the center of the passband* (e.g., "pitch"). If for example, pitch is
> 500 Hz and bands 4 (400 Hz) and 5 (800 Hz) are 0, there will be little
> or no "pop". However, if one has 400/800 Hz set for significant boost
> there will be a fairly loud "pop" as the level changes.
>
> 73,
>
> ... Joe, W4TV

Lyle Johnson

Re: K3 Popping noise in headphones??

The selection of IIR versus FIR filtering for the narrowest bandwidths
(50 Hz and 100 Hz) may also have some effect on this.

In general, the K3 and K3S switch to a different filtering algorithm for
these two bandwidths. The loading of coefficients and filter settling
time -- and to some extent the difference in "energy" that may be stored
in these filters from the last time they were selected and this time --
may combine to produce a small artifact during filter selection.

I'll state again that using the Rx EQ to provide additional filtering
doesn't work. The K3 creates a single filter that combines the
bandwidth, center frequency, manual notch *and* RxEQ parameters. And in
general it is a good idea to use rx EQ to tailor the audio response
using cuts away from, rather than boosts of, preferred pitches,
especially near pitches you are likely to want to monitor in CW
operation. The intended purpose of the Rx EQ is to help tailor the
radio to your speakers or headphones, not to provide selectivity or
signal enhancement.

73,

Lyle KK7P

> Thanks for the detailed explanation. I was beginning to wonder when
> and if someone would advance a valid explanation.
>
>> There will be a slight pop when changing bandwidth between 150 and 100
>> Hz as the K3/K3S disables the RXEQ at bandwidths less than 150 Hz. The
>> level of the "pop" will be related to the amount of EQ in use *around*
>> *the center of the passband* (e.g., "pitch")...

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Wes (N7WS)

Re: K3 Popping noise in headphones??

In reply to this post by Joe Subich, W4TV-4

I don't use any RXEQ and my pitch is usually between 400 and 450 Hz. Yes,
100->150 is "worse", although not particularly objectionable; a curiosity
actually. But there are other pops too, 750->800 is about the same and there is
also a dependence upon the shift.

On 10/18/2015 11:16 AM, Joe Subich, W4TV wrote:

Jim Bolit

Re: K3 Popping noise in headphones??

In reply to this post by Jim Brown-10

Thanks Jim.

I used the Kenwood TS-480 when the rig was in the shop, and the audio was
better, fewer pops and hiss, and the Noise Reduction was noticeably better
on the Kenwood 480.

Jim
W6AIM

.

-----Original Message-----
From: Elecraft [mailto:[hidden email]] On Behalf Of Jim
Brown
Sent: Saturday, October 17, 2015 9:59 AM
To: [hidden email]
Subject: Re: [Elecraft] K3 Popping noise in headphones??

On Fri,10/16/2015 11:15 PM, Jim Bolit wrote:
> The popping is present as I rotate the BW control back to wider bandwidths
also, but the popping stops once above 200 Hz bandwidth.

Hi Jim,

I also do a lot of digging for weak signals, but I rarely go narrower than
200 Hz because I find the filter ringing on noise takes over. Yes, I'm using
the optimal setting to minimize ringing.

If you're hearing the popping and others are not, perhaps you're using more
AF gain and less RF gain than they are. If so, I suggest adjusting that
ratio in the direction of less AF gain and see if you can reach a happy
compromise. As an OT CW op, I do recognize the virtue of not using excessive
RF gain.

And maybe Wayne can do something about the switching transient in a future
firmware firmware release.

73, Jim K9YC
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