开云体育

• replaced failed WX TDA2822 with a NJM2073D pin-compatible chip
• rewired power to put fuse ahead of protective diode
• added QRPGuys keying adapter
• upgraded firmware to KD8CEC v1.01
• increased mic gain by added 47 ohm resistor across R63

Looks good, Mike. ?How are you liking the 2073 replacement? ?I am thinking of putting a regulator in for the TDA, but it would be easier to just replace the IC if the 2073 works OK. ?
I too have a SCAF in the audio line and it makes a huge difference on CW (I'm using the Hi-Per-Mite). ?
As you may note from my earlier message, I implemented an audio pop fix today that works but eliminates the sidetone. ?I want my sidetone back!

73
Howard K4LXY

Mike,

Nice. Did you line the box with copper or just left the plastic as is?

tim ab0wr

On Sat, 17 Mar 2018 06:05:16 -0700
"Michael Aiello" <n2htt.mike@...> wrote:

After about 8 weeks of working on it slowly, a few minutes at a time,
I've finally finished boxing up my uBitX and it's now up and running
FB. The box and mic holder are 3d-printed from a design I found on
Thingiverse and remixed a bit.
I've made a few mods along the way:

* replaced failed WX TDA2822 with a NJM2073D pin-compatible chip
* rewired power to put fuse ahead of protective diode
* added QRPGuys keying adapter
* upgraded firmware to KD8CEC v1.01
* increased mic gain by added 47 ohm resistor across R63

I'm primarily interested in CW, so I tried out my NesCAF switched
capaacitance audio filter with the rig -it works great! The NesCAF
was built from a kit years ago, and has been languishing on a shelf,
but it will get used now daily. I've had a lot of fun with this
little rig already just putting it together, I'm looking forward to
getting on the air with it a regularly. 73, Mike N2HTT

Howard,

?I too have been using the 2073 with much better audio and no more distortion over load at low volume. Got mine from a 1991 tape player :-)

--
David

?N8DAH

Looks great Mike, glad you got the audio fixed. I received my NJM2073D chips last week but haven't needed them yet, maybe never. I really like the compact box you used.

Joel
N6ALT

Hi Howard,
The 2073 seems to beworking fine, good audio and plenty of volume, I've run it turned all the way up to drive the NesCAF, since you lose some volume as you crank down the bandwidth, and it's been fine, no problems at all.
Haven't done a pop fix yet, still mulling over the options. In the mean time I use the old trick of putting the phones just off the ear
73 Mike

Hi Tim,
Just left it as is. I was thinking about copper tape on the top and sides, but given the way the board sits and the way the box goes together, decided it was more trouble that it would be worth. So far I haven't noticed any downside to not having the shielding.
73 Mike

Hey Joel,?

If you have a socket on the board I would definitely switch it out. Sound quality is really very good, although I never actually heard the rig with the 2822 so it's not really a comparison. If the chip is soldered in I don't know if it would be worth the bother, especially if you have everything working now.
Thinking about doing a pop fix but haven't picked one yet.
73 Mike

Since it's an SMD 2822 you might want to get a which is the SMD compatable.
--
John
NQ3RP