Help with dead bass!!

RicoDirenzo · #1 05-29-2009, 08:50 AM

I need a bass electronics geekazoid to provide some information. Can I actually measure jack voltage at jack connections on an 18 volt system? This my logic: I have a Tune 16 volt active bass that produces nothing at the output side. If I use digital voltmeter, should I be able to read some voltage at the jack. I'm thinking that if I can and I do then I have a bad jack and If I can and can't then the preamp has tanked.

**line6man** · #2 05-29-2009, 09:04 AM

I am not quite sure what your asking.

There should be no voltage at the jack, if there is, you have a problem with the wiring, and the danger of blowing out whatever your bass is connected to.

If you wanted to check the preamp, you can put an amp meter across the ring and sleeve terminals to see whether or not the preamp is drawing any current.

RicoDirenzo · #3 05-29-2009, 10:09 AM

Now I'm really confused...(which shouldn't be a shock)...the preamp puts out a signal right? Volts/amps are the push? Anyway, I'm thinking I'll just call tech support at Carvin and ask one of their geeks in the tech support side of things. I was acturally hoping to isolate the jack vs the preamp before I get involved in buying a new preamp for this guitar. Thanks.

excane · #4 05-29-2009, 10:56 AM

A 16volt pre?

**line6man** · #5 05-29-2009, 11:34 AM

Quote:

Originally Posted by RicoDirenzo

Now I'm really confused...(which shouldn't be a shock)...the preamp puts out a signal right? Volts/amps are the push? Anyway, I'm thinking I'll just call tech support at Carvin and ask one of their geeks in the tech support side of things. I was acturally hoping to isolate the jack vs the preamp before I get involved in buying a new preamp for this guitar. Thanks.

The preamp is putting out a low voltage AC output, not an 18 volt DC output. The 18V (or 16V?) is to power the preamp.
If you are not getting any sound out of your bass, checking with a volt meter will not do you any good.
You can hear an output through your rig just as well as a volt meter could measure it.

RicoDirenzo · #6 05-29-2009, 11:50 AM

Quote:

Originally Posted by excane

A 16volt pre?

18 volt...Doh! Carivn tech helped me out. Test the voltages to the board. If the voltages are good and the jack voltage inputs to the board are at 18 volts then the board is probably fubared. Any sugggestions on a preamp upgrade? The pots on this guitar are integrated so I will have to replace the whole thang!!! Aguilar, Seymore-Duncan others? Thanks. The construction of this Tune bass is really nice and so I will repair it.

RicoDirenzo · #7 05-30-2009, 10:00 AM

Bump: Problem solved. It was the Flush mount jack that was bad. I unsoldered (is that a word?) and soldered a standard jack outside the bass and plugged it in and the preamp did it's thang. Although I remain ignorant about active bass electronics I am relieved it was (will be) a simple fix as the jack is on it's way From MusiciansFriend for $14 shipped. I now pledge to educamate myself about active preamp electronics!

mongo2 · #8 05-30-2009, 10:15 AM

Quote:

Originally Posted by RicoDirenzo

Bump: Problem solved. It was the Flush mount jack that was bad. I unsoldered (is that a word?) and soldered a standard jack outside the bass and plugged it in and the preamp did it's thang. Although I remain ignorant about active bass electronics I am relieved it was (will be) a simple fix as the jack is on it's way From MusiciansFriend for $14 shipped. I now pledge to educamate myself about active preamp electronics!

You say you used a "standard" jack for the external one, did you by any chance use and order a standard stereo jack (3 connectors: tip, ring, sleeve aka TRS)?

The reason I ask is if it's not a stereo jack and you connected the negative side of the batteries directly to the jack ground, your battery will drain quickly since the stereo jack uses the ring connector and jack ground in conjunction with the sleeve contact (cable ground) of a standard instrument plug as a switch to turn the battery on and off.

RicoDirenzo · #9 05-30-2009, 11:38 AM

Quote:

Originally Posted by mongo2

You say you used a "standard" jack for the external one, did you by any chance use and order a standard stereo jack (3 connectors: tip, ring, sleeve aka TRS)?

The reason I ask is if it's not a stereo jack and you connected the negative side of the batteries directly to the jack ground, your battery will drain quickly since the stereo jack uses the ring connector and jack ground in conjunction with the sleeve contact (cable ground) of a standard instrument plug as a switch to turn the battery on and off.

The jack was a three wire flush mount jack (original). Wires were green to the jack case (ground) and red and white (red power and white neutral?). The one I ordered is exactly the same. When I wired the two wire jack I soldered the green to the jack sleve and it worked fire. I immediately took off the jack and it sits waiting for the replacement. All this active preamp stuff is going to be challenging but I'm pretty excited as I am moding a OLP Earnie Ball and adding a 9 volt pre, new tunners. I was going to replce the stock pickup with a Bartolinni Stingray style but some peiple have been dissing Bartolini pickups in another thread. Any suggestions on a new pickup for the OLP??

BTW, the dead base was a newly purchased Tune Casiopea TWX 41. $200 shipped and this bas is georgeous (Black with chrome hardware). http://tuneguitars.com/store/wizmart...501&no=35&lv=2