Has anyone replaced the internal speaker in the KX-2? I was using it today and I couldn’t pick out a voice in the noise, turned up the volume to try and hear them. The next contact was strong and loud and the speaker massively distorted and it took a second for me to figure this out. This has pulled me up a few times over the last fortnight, holidaying in the Vosges mountains. It’s the first time I’ve really put the KX-2 through its paces, and its a rig I intend to use more often from now on, but the speaker is going to bug me.
As a starting point, does anyone know what the final audio stage in the rig is designed too; what’s the max power (watts) and what is the impedance of the current speaker? Has anyone sourced a good quality replacement?
I am seriously considering dumping the internal battery and using the space for a larger speaker, and possibly an amp too, if required, which I would drive off / piggyback the normal external battery barrel port. I typically use or at least carry and external battery anyway.
I’m also toying with the idea of getting a boom mic headset. I’ve also taken to using Ham2K POLO, but I’ve found I really could do with three arms! One to hold the mic, one to hold the phone and one to type the data in! More than once I’ve had to ask people to repeat callsigns as I couldn’t swap hands fast enough to get it all in the logger. I have to admit learning new tech is getting harder as the years add on. It seems there are so many out there, I’ll have to go into ML&S and try some, but make sure I fully understand my ceiling, otherwise I’ll end up buying another rig .
The AF speaker output is one of the few weak points of the KX2. The low audio and rear speaker encourages you to use the preamp to compensate, resulting in a lot of distortion with strong signals. For CW on headphones, it’s just about loud enough preamp off on near full volume.
Replacing the speaker won’t help unless the one you have is damaged.
The internal speaker is not great. Use headphones. Another option is to get an external speaker that is amplified - I have one like this that works well:
The speaker used in the KX3 is even worse, the solution is to get a self-powered external one, the Anker Soundcore Mini is ok-ish (the Soundcore 2 might look tempting but it introduces latency in the audio processing chain making impossible to send CW).
Yes headphones are better, but they add to the weird person operating strange devices factor, beeps and boops coming out of a speaker contributed to starting conversations with curious passers-by, even shy hams might come out of the group to chat.
For years, I’ve been using a speaker from an unknown manufacturer that I bought on ebay.de. You can find several replacement speakers on Aliexpress.com with very similar dimensions. Unfortunately, I can’t offer a specific recommendation.
73 Chris
Use light weight headphones or ear plugs. That even makes people around you at the summit happier without the radio noise and helps greatly detecting weak signals. Real advantages!
The speaker cables in my KX2 have broken recently after 1,000 activations with 1,000 times opening/closing it for battery charging, but I don’t miss anything with my good and comfy ear plugs.
I remember one standard modification for the FT817ND was to replace its speaker with one designed to go in a model railway sound unit!
By the way - before you go ripping out the speaker - check that you have not accidentally turned off AGC; that will cause received signals to sound distorted, as some stages of the receiver are overloaded.
I had AGC on ‘Slow’ at the start of the holiday and changed it to ‘Fast’ on day 2 of using it, but it’s not enough.
I’ve got some bits around the shack I’m going to experiment with. I’m sure I can improve things!
I’ve read that the KX-2 is set to output 300mW max to the speaker, so the final stage gain might have been reduced to match the speaker? I’ll take a poke around and see if I can up the gain from the stage (if indeed it is set to output at 300mW). I have used a 1w audio amp built from an LM386 before; it still might be underpowered but I have one kicking around. There are plenty of 3w and 5w amps available from the Pi Hut and similar outlets, but will need the DC in dropping to 5V via a buck circuit to power them.
I don’t like using headphones as a rule and earbuds give me serious pain, but I’m going to bob into ML&S next weekend and have a look at some headsets.
I have an FT-857 if I want load up my backpack. In reality, I’m talking about less than 100g of weight delta with any mod I’d be doing.
I’m back home now, after two weeks in the Vosges and has re-inspired my need to get out more often. I’ll consider some weekends in South Wales, as the nearest reasonable SOTA area.
Plus 1 for earphones rather than a speaker Dave (in ear/over ear is down to personal preference). It cuts down on wind/external noise helping with weak signals and it reduces any disturbance for other people nearby (they just think you’re weird talking to yourself. But then my wife would agree with them ).
Earphones indeed! Yes it adds to the aforementioned factor, but really the internal speaker is not very useful.
For external amplifier boards from the Pi Hut and other similar sites selling Pi and Arduino “accessories”, a word of caution is due as more often than not these are class D amps, which may introduce QRM from their switching unless properly shielded (and maybe filtered too).
The internal speaker isn’t great and I normally use headphones in the field. That said, because the speaker is bottom firing with an open grill, if you set it down on the ground or on a workbench you also use for metal projects, the speaker’s magnet can pick up metal bits that make it sound like it has failed. remove the speaker from the bottom of the radio and make sure the diaphragm is clean and clear of debris. Mine wasn’t and after cleaning it carefully, it sounds much better.
I discovered this on one outing when the cable to my headset was damaged and I had to rely on the internal mic and speaker to complete my activation. It sounded like a blown speaker and I thought I was going to be replacing it, but when I removed it from the radio, I found the problem was actually a bunch of “stuff” attracted by the magnet all over the speaker.
Another vote for earphones. I just started using a KX2 after years of delighting in my KX1. For CW I use the cheap earbuds that airlines now give away on each flight. On my first CW activations with the KX2, the earbuds worked fine at a relatively low setting of the audio gain control. As a plus, the weight they add to the kit is so negligible that I typically carry a spare set “just in case.”
Me too. I did need them once when the speaker wire broke. Mine are Samsung ones that came with a phone. After getting a hot ear one day, I wrapped the cable a few times around a snap-on ferrite and the problem didn’t reoccur.
I have used in-ear headphones for years. They make activations far more comfortable for me, and they also spare other visitors to the summit I’m activating. Indeed, even the manual notes that headphones give better audio than the built-in speaker, and recommends them to save battery power. Whether to use in-ear or over-ear headphones is a matter of personal preference, but in-ear ones take up far less space and weigh much less. One thing is certain, though: it will never be high-end audio.
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