Yamaha APX-6 electronics replacements?

[granz]

Anyone have some advice on replacements for Yamaha APX-6 electronics? I contacted Yamaha and they no longer have them. My APX recently starting popping, making fuzz noises, and then loses most of the output level. Short of finding a damaged guitar that I can acquire cheaply for parts I'm not sure what can be done. Not a huge loss, given the value of the guitar, but I would like to fix it if I can.

[guitaniac]

Hi granz,

Those older APX series guitars are knarly little guitars which amplify well, at least in terms of gain before feedback and clarity of tone. Just last night, I heard an ampified APX-4A at a coffeehouse open mic. I was reminded of what a phat (if somewhat dry and in-your-face) amplified tone they are capable of.

I had two pickups go out on the APX-4A which I once owned. I finally had a Baggs LB6 (in saddle pickup) installed, and it happened to be compatable with the preamp. End of problems.

It sounds like your problem may be with the preamp, although I'm not certain. Bad pickups can behave strangely too.

How is the pickup connected to the preamp? If its with a 2.5mm plug, you can find undersaddle pickups on ebay (Artec and other brands), for $15 or so, which are pre-wired to a 2.5mm mono plug. One can also find replacement preamps (undersaddle pickup included) on ebay, though it may be a task to find one which will fit your guitar's preamp hole.

If it were my guitar, and I really liked its playability or some other feature, I'd try connecting a Fishman replacement film UST ($60 from Elderly) to the Yamaha preamp to see how that works. (It will probably have lower output than with the Yamaha pickup, but I'd be happy with the extra preamp headroom.)

If the Yamaha preamp/Fishman film UST combo worked OK, I'd run the signal thru my DTAR Mama Bear, or my Fishman Aura Spectrum DI, to model some bigger guitar ambiance into the little APX's signal.

If the Yamaha preamp/Fishman film UST combo didn't work well, I'd replace the Yammi preamp with another preamp, or just wire the film UST passively to a strap-jack. (I currently have a passive Fishman film UST in one of my guitars. It works fine, just taking a low impedance 10' cable directly to the Aura Spectrum DI.)


You have plenty of options, if the guitar is worth salvaging to you. Some folks here would try installing a K&K Pure Western mini and wiring it to the Yammi preamp (or simply install it passively, if they were sure the Yammi preamp is faulty).

Gary

[granz]

guitaniac - thanks for the reply and suggestions. I do get the popping with the pickups un plugged from the pre-amp so I'm fairly certain it's the preamp, but I appreciate the suggestions on the pickups. The K&K maybe an option in this case. It's kind of a tough call, I don't care for the "un-plugged" sound of this guitar, but through an amp (UltraSound or Fender Acoustasonic) I could dial in a sound I liked with the balance of the piezo bridge pickup and transducers mounted inside the guitar. I'm not sure I can get this with a single pickup. I do have a cheap barcus-berry outsider that I tried, but didn't like. Again, thanks for responding to my post with your suggestions.

Granz

[guitaniac]

Granz,

If you already have the guitar equipped with extra pickups (soundboard pickups, it sounds like), then why not wire the UST and SBTs directly to a stereo jack (or two mono jacks, if you prefer) and run them passively to an outboard blender like the Ultrasound DI Max.
http://shop.ebay.com/?_from=R40&_trk...All-Categories

Gary

[granz]

Gary,
the apx 6 is standard with multiple pickups, one under the bridge, and two mounted on soundboard, and a blender built in to the preamp. Your suggestion is a good one, I'll check out what it would take to rewire them to a stereo plug and then use an outboard preamp. thanks again for your posts.
Mark

[giurmax]

Hi,

I own an acoustic guitar Yamaha APX-7, which has the same electrical configuration of the APX-6.
I have the same problem, after years of non-use of the PA system, it does not work anymore, and most likely the fault of one of the capacitors in the preamp.

At this point I have two choices :
1. remove the preamp from the guitar, leaving the pickup, and connect directly to the output jack. But I do not know how I can do the connection.
can someone give me a hint?
I have a pre-amp modeler Behringer V-TONE ACOUSTIC DRIVER ADI21 that I could connect to the output.

2. search for spare parts of the original preamp yamaha apx-7

It would be interesting to be able to bypass the preamp yamaha, by connecting to an external preamp like my Behringer, but using the original knobs of volume and mix on the guitar, controlling the two pickups built into the APX-7.

has anyone any suggestions?

Here the Service Manual with electric scheme :

https://www.dropbox.com/s/urf5a6nwg6...21_SM.pdf?dl=0

Thanks!