[Elecraft] K3 Audio Upgrade Mod

[Ron D'Eau Claire]

I'm glad to hear the mod went so smoothly for you Jim. 

 

We recognize that K3 owners have a huge range of skills, tools, and
experience working on their rigs, so we work very hard to provide the
easiest way to do any mods that might be wanted.  

 

Sure, anyone can always return a rig to Aptos, but that involves lost time
and costs for what may be a very simple little modification. 

 

So, in writing the procedures, we look at various ways they can be done.
When there are several possible approaches, we often document all of them so
each person has the option of choosing what looks like the easiest for them.

 

For those used to working with SMDs, piggy-backing the new SMDs on the
existing ones is actually easier than using the leaded parts, and some don't
mind cutting a circuit trace to save some disassembly and time. We wanted to
give you and everyone else the option to chose. 

 

Thanks for your encouragement to others. 

 

BTW, you are quite right that the difference in the resistance in the RF
choke is not great, and  the improvement it provides is slight. The
improvement is only apparent on large audio peaks when  maximum current
flows. 

 

These short of improvements based on customer feedback have been a tradition
at Elecraft since the first K2 kit went on the air. 

 

73,

 

Ron AC7AC

 

 

 

From: elecraft-bounces at mailman.qth.net
[mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Dr. James C. Garland
Sent: Wednesday, December 03, 2008 6:47 PM
To: elecraft at mailman.qth.net
Subject: [Elecraft] K3 Audio Upgrade Mod

 

Today I got around to installing in my K3 the audio upgrade kit that arrived
a couple of weeks ago. The first part of the kit involves swapping an RFC on
the main PCB with one that has a lower resistance. (FYI, I measured the
resistance of the original choke as 0.4 ohms, and of the new choke as 0.1
ohms - hard to imagine the new choke would make that much difference!).  The
instructions give a "short" and a "long"  method of installing the choke.
The "short" method involves cutting a circuit board trace. I elected to do
the "long" mod and timed myself. Start to finish it took 15 minutes! I
highly recommend folks do the long method, and also that Elecraft delete the
short method as an option. It just isn't necessary and, besides, who wants
to mess up that beautiful circuit board?

 

The second part of the kit involves shunting two resistors with 51 ohm
resistors,  and here also Elecraft gives two options: one is to solder 1/8w
through-hole resistors onto the IO board, and the other is to solder two
tiny SMT (surface mount ) resistors piggy-back onto existing SMT resistors.
The kit comes with both kinds of resistors.  I elected to do the SMT version
of the mod, and here I'd recommend that owners opt for the other method. I
don't see any advantage to doing the  SMT version. It takes a very steady
hand, a very small-tipped soldering iron, and very good eyesight to
piggy-back the two SMT resistors into the circuit, and I just don't see the
reason for the hassle. It would take five minutes to install the
through-hole resistors, and the result looks quite clean and neat.  I'd
recommend also that Elecraft delete the SMT option from the instructions.
Took me about 30 mins to install the SMT resistors, probably about half that
time to install the through-hole ones.

 

73,

 

Jim W8ZR 

 

 

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