Variax Acoustic 700 intermittent output from battery and clipping sound

[Mavril]

Hi,

i may be a little late to the Variax party but I was finally convinced by the tuning capabilities to dive in and pick up a well looked after Accoustic 700.

I know these are obsolete products now and i've had a bit of a blow off from Line 6 saying that I can send it across the country to be looked at and maybe it could be fixed...

Anywho, My acoustic did not work straight out of the packaging and I thought I'd been dudded by the seller. I checked it out through the 1/4 inch battery powered option and I got nada... no LEDs and no sound.

 

I then checked it via the RJ45 port through my xt live... surprise surprise it came to life. i gave it a good work out and it didn't miss a beat.

Went back to the battery and nothing...

I measured the voltage to the board, changed batteries and thought that that power cct must be knackered...

 

Left for a business trip and returned a week later, thought I'd give it one more crack and it has now come to life! except that it sounds like a dying battery, all crackly on strong plucking. This isn't there through the VDI. I don't run two supplies concurrently after reading about it on here.

 

What I am looking for is any service tips, schematics on this instrument in order to make sure i get a decent life out of this unit. i stumbled on a few threads from the archives which relates to power but hte links are all broken and hard to search.

 

Is there anyone here that still dabbles with my model instrument?

 

I'm capable with schematics and with an iron if necessary.

[Mavril]

oh and can you retrofit a current battery pack to this device without damaging the supply? That would be way better than becoming a AA distributor.

[Charlie_Watt]

You need to find out where the bad connection is.  The 1/4 inch jack has a power switch that connects the battery to the board when you plug in the guitar cable.  I would start looking there for a bad switch.  Next look where the switch goes to the board inside.  if it powers fine from the VDI jack, then your electronics are ok.

    I use rechargeable NiMh AA batteries - 2500 mAH.  I have two sets and they last around 6 hours a charge.  If you are not using the VDI, I would go that route.  One thing to be very careful of:  When you plug in the battery carrier make triple sure that you connect the connector the right way.  If you even touch it the wrong way you will blow a diode on the board.  That may have happened on yours but I doubt it since you got it sort of working.

   You can't use the JTV battery unless you are willing to find the battery box and route out the guitar to make it fit.  I would go the rechargeable way.  It has worked fine for me over the 10 years I have owned Variax guitars with AA batteries.

[Mavril]

Thanks for the reply Charile_Watt,

 

I'll follow the switch path and the supply path but it sounds more like a capacitor is not loading the supply rail correctly (which is about right for the age of an electrolytic).

 

As for the blown diode, that sounds like a horrible design! Has anyone had any joy correcting this with a suitable protection diode?

 

Was hoping to get a little bit of a lesson learned from you guys that have played, before I jump into this thing and snoop around.

 

I'll look into the rechargeable thing with eneloops I guess. Although I may just build myself a VDI cable for the road... with a 1/4 inch backup. does anyone have the spec/ pinouts for what VDI requires? Which pairs of the 8 are used?

[Charlie_Watt]

VDI cable is a standard Cat5 Cable with special shells on the ends.  Buy a good one.  They are not that expensive.  I got mine from Best-Tronics www.ptpa.com and it is very nice.  Don't buy the Line6 one.  I doubt very much that it is a cap problem if you don't have it with the VDI.  The power path is basically the same.

[Mavril]

Ooh and I should ask you CW if you use nickel or phosphor bronze strings? what did the 700 acoustic come with standard?

[Mavril]

Thanks again for VDI recommendation.

[Charlie_Watt]

I use Elixir strings on mine.  .012 to .053  I don't know what they came with.  I got mine on Ebay used.  I always run mine on batteries.

[leesteel]

Just curious Charlie, why don't you like the Line6 VDI cable? I have 2 of them and they seem to be very good.

 

Also want to point out that your link is incorrect. Here is the right one to Best-Tronics: http://btpa.com/Line-6-Variax/

[Charlie_Watt]

Thanks for fixing my link.  My previous experience with the Line6 cable is that it was inferior to the others out there.  Stiffer and not as well made.  Maybe they have improved it.  Anyway, the Besttronics cables are great.  I have several guitar cables from them as well as my VDI cable.

[Mavril]

FYI, I found the fault in the end and it appears to be a little bit common with the old packs.

It is an issue with the design of the 6 battery pack lugs contacting the conductive paint in the cavity. By looking at the area it seemed to be very unlikely but a few tests and it proved to be the case. Unsure why the battery compartment needs to be Faraday caged but it doesn't need to be conductive. I will be building the cavity up with a silicone or something that will insulate and hold the pack more securely (currently rattles a little).

 

Also wondering if anyone knows of a good source of flexible, shielded Ethernet cable in Australia? Us based suppliers cost too much in shipping

[Charlie_Watt]

One option is to find and buy the correct connector shells and make your own cable.

[Mavril]

That's the idea CW, but the ethernet cable flexibility is crucial as has been commented. There are only a couple of wholesalers around me and a bunch of online sellers. If anyone has feedback on a brand or model of cable that has proved to be good, I'll hunt it down online and then order the neutrik shells to fit up. Also helps cusotmise length which I do with the rest of my leads.