APX-8 1/4" connector question

APX series guitars are designed with a focus on playability. Their thin bodies and cutaways that provide greater access to the upper frets, offer smoother switching between electric and acoustic instruments.

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Mimasu
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Re: APX-8 1/4" connector question

Unread post by Mimasu » Tue Sep 11, 2018 9:39 am

So not the same electronics as my APX20 :? .

Perhaps it's a kind of APX20 without the what they call "acoustic sensors" and only having the stereo bridge PU.

You could check that. The 'acoustic sensor' is a little black PU glued from the inside under the bridge.

If the APX is lacking that sensor that would match with the missing blend knob near the neck. In that case I still think the end pin jack is the mono out of the bridge PU and the lower jack is the stereo out.

The 1/4" strap button connector that goes to a 1/8" where the battery is plugged into is the switching connection. One switch in the 1/4" connector switches the battery in when a plug is put in.

Leon
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Re: APX-8 1/4" connector question

Unread post by Mimasu » Tue Sep 11, 2018 2:13 pm

After some testing the final answer on my APX20:

The strap button connector only works with a mono jack connected (using a stereo jack even doesn't engage the battery). The mono jack gives the mono output and choosing one of the stereo modes has no effect at all.

Using a stereo jack in the lower connector gives the stereo output making it possible to choose wich stereo mode you want.

The "acoustic sensor" is mono. By blending in the under bridge PU is gets more stereo. Under bridge PU only is a kind of extreme stereo with some strings panned left and some panned right. I wonder how they do that on the APX8 if that one should be lacking the acoustic sensor.
On my APX20 using only the under bridge PU gives a very trebly harsh sound. You need the acoustic sensor to add some warmth. I wonder how they solved that problem on a APX8.

Leon
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Re: APX-8 1/4" connector question

Unread post by jakeman19 » Tue Sep 11, 2018 5:54 pm

Mimasu wrote:
Tue Sep 11, 2018 2:13 pm
After some testing the final answer on my APX20:

The strap button connector only works with a mono jack connected (using a stereo jack even doesn't engage the battery). The mono jack gives the mono output and choosing one of the stereo modes has no effect at all.

Using a stereo jack in the lower connector gives the stereo output making it possible to choose wich stereo mode you want.

The "acoustic sensor" is mono. By blending in the under bridge PU is gets more stereo. Under bridge PU only is a kind of extreme stereo with some strings panned left and some panned right. I wonder how they do that on the APX8 if that one should be lacking the acoustic sensor.
On my APX20 using only the under bridge PU gives a very trebly harsh sound. You need the acoustic sensor to add some warmth. I wonder how they solved that problem on a APX8.

Leon
I've also tried both mono and stereo cables with the button connector and get no sound. Still stumped on that. But as for the extra blend thing, I don't have any other wires going to the bridge other than 2 going up into the bridge as you can see in the photo below.
IMG_3747.JPG
Jd
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Re: APX-8 1/4" connector question

Unread post by Mimasu » Tue Sep 11, 2018 8:33 pm

jakeman19 wrote:
Tue Sep 11, 2018 5:54 pm
I've also tried both mono and stereo cables with the button connector and get no sound. Still stumped on that. But as for the extra blend thing, I don't have any other wires going to the bridge other than 2 going up into the bridge as you can see in the photo below.
That a stereo cable in the button connector doesn't work makes sense. The same in my APX20. A mono cable should work though. Did you check the battery check button when a mono plug is inserted in that connector? And is your switch on the preamp on mono? What about a stereo cable in the other jack with the switch on one of the two stereo positions?

Leon
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Re: APX-8 1/4" connector question

Unread post by Mimasu » Tue Sep 11, 2018 9:44 pm

Jd,

It's not helping to solve your problem but your APX8 keeps puzzling me. Your type of preamp without the mix knob and without acoustic sensor just doesn't make sense. When looking into that I found something weird:

The (former online) Japanese Yamaha Guitarchive gives oct 1987 till 1994 as production years. The guitar should have a System 15 preamp with vol, bass, treble and.... Mix (?), stereo switch etc.

The US Guitarchive (also offline now) mentiones production from 1993 till 1996, also mentioning the System 15 preamp, no further explanation. Only 3 guitars have the system 15 over a short period: The APX8, 8L (lefthand version), and the 8S (don't know that one) but this one was produced from 87 till 91 and also the Mix knob is mentioned.

Given the above it could very well be that the APX8 started in 1987 with logical (and most usefull) electronics. After starting export of the APX8 in 1993 someone perhaps wanted to save some money and got rid of the acoustic sensor and mix option. My same era (1993) APX8D doesn't have the stereo option, but is has the mix option.

Do you perhaps know the production year of your APX8, or what's the serial number?

Leon
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Re: APX-8 1/4" connector question

Unread post by jakeman19 » Wed Sep 12, 2018 12:05 am

Leon,

Your questions:Did you check the battery check button when a mono plug is inserted in that connector?

Yes, it was giving good battery level

And is your switch on the preamp on mono?

Yes

What about a stereo cable in the other jack with the switch on one of the two stereo positions?

With a stereo cable plugged in the other jack it works as expected in regards to that output, when switch is in mono I get a mono signal, in either of the 2 stereo switch positions, same thing, works like it should.

Just still unsure what the button connect is supposed to do.

Also, I got a response from Yamaha as I sent a message for help on documentation and no luck. They didn't have paper or electronic documentation on the APX-8.

If I read the serial # of the guitar correct it #10212751 (see photo)
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Jd
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Re: APX-8 1/4" connector question

Unread post by Mimasu » Wed Sep 12, 2018 1:49 pm

Jd,

The serial indicates a 1991 guitar.

Based upon the Japanese specs it should have had a Mix control. I give up <->

Good luck solving the problem, I'm out of ideas. But you have at least full functionality through the lower output jack (although it's not my preferred output. I've seen a lot of wood damage around these lover outputs, using the end block is much more solid).

Leon
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Re: APX-8 1/4" connector question

Unread post by Saul » Wed Sep 12, 2018 3:06 pm

Perhaps that connector is only connected at the output but not at the pickup? What I mean is it may "look" connected but isn't.

It does seem really odd that there is no blend feature on the preamp also photos of other APX8's I have seen are different in both headstock style and preamp that is fitted. A very interesting conundrum indeed!
Saul
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Re: APX-8 1/4" connector question

Unread post by jakeman19 » Wed Sep 12, 2018 4:14 pm

Mimasu wrote:
Wed Sep 12, 2018 1:49 pm
Jd,

The serial indicates a 1991 guitar.

Based upon the Japanese specs it should have had a Mix control. I give up <->

Good luck solving the problem, I'm out of ideas. But you have at least full functionality through the lower output jack (although it's not my preferred output. I've seen a lot of wood damage around these lover outputs, using the end block is much more solid).

Leon
Leon,

Agreed about the wood damage around the lover outputs. When I was doing the once over I had a hard time tightening that one up and noticed it's issues.

Thanks to both you and Saul. It's not like the guitar isn't usable just has something extra I never knew about and with the internet, we can now get a lot of this information by searching and asking questions on forms like this. Thanks again gentlemen.

I still love this guitar.

Jd
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