View Full Version : U-Bass Questions

05-21-2017, 02:41 PM
I am not a bass player, so I'm a little lost - maybe you all can help me out!

I recently bought a U-bass (used) and subsequently picked up a Fender B-DEC 30 bass practice amp at a garage sale. When I play the U-bass thru the B-DEC the bottom string is essentially inaudible. I think this could be due to:
1. String (black pahoehoe) needs replaced
2. B-DEC 30 doesn't sound those notes either because:
a) Speaker is not large enough to sound it
b) B-DEC needs fixed
3. Problem with pickup on U-Bass for lowest string

I tried plugging the U-Bass into my guitar amp (2-12" speakers) and bottom string was not inaudible, but significantly lower volume than the other 3 strings - OTOH, this guitar amp was definitely not designed for bass, so, inconclusive.

Any experience with U-Bass or B-DEC 30 that might help me sort this out? Should I expect full range of U-Bass on the B-DEC 30?

Thanks for any help

Patrick Madsen
05-21-2017, 06:03 PM
Some of the Kala U Bass' needed a preamp.A preamp boosts the signal going into the amp. I own a Chennell Bass that has a Piezo pickup; it needs a preamp or the sound would be very muffled.

I doubt you need new strings. In the least, bad strings wouldn't make an instrument not sound loud. I suggest taking it in to a music store and try it with a preamp and without one. I'm sure you'll hear a big difference.

A person must be very careful not to blow out the speaker on a regular amp playing a bass thru it.

05-22-2017, 03:25 AM
Does the pickup need adjusting? Sounds more like its a problem on the UBass...

Patrick Madsen
05-22-2017, 05:04 AM
I thought the same about my Chennell; the sound was so muffled it must be the pickup. So much so that I inquired about throwing in a new pickup. Once I tried it with a preamp, it sounded almost like a true standup bass. I'm fairly certain yours is built with a passive pickup needing a preamp to power it. You can get used preamps really cheap.

Here's a photo of my bass made in England by Jazzboxukes.com; Toby Chennell

05-22-2017, 05:32 AM
I thought the Kala U-basses have a power preamp. It's very possible the string was stretched too much and might need to be replaced.

All my bass ukes have a powered preamp and all but one have Pahoehoe strings. I also find that from one to another the strings don't amplify evenly. I read on Rondomusic.com that sometimes the pickup does not sit right under the saddle, they suggest loosening the strings and moving the saddle a little. I also read that the kind of saddle Rondo and Kala uses that looks like individual sections under each string, are actually one piece and the suggestion is to take apart the saddle/pickup assembly then cut apart the saddle sections so each string can put pressure on the underlying pickup separately.

05-22-2017, 06:13 AM
So, the U-Bass has a powered preamp, I think. There is a tuner built in with flashing lights, and volume and tone knobs. Maybe I will try replacing the battery and also replacing the strings first.

05-22-2017, 06:47 AM
With my Kala Rumbler with Pahoehoes and Orange Crush 25, I also get less volume out of the E string.

The older U-Bass's didn't have a preamp built in...

Also, there's a Bass thread, that might be better for this question...

05-22-2017, 10:34 AM
I had a similar problem with my Kala UBass. One of the strings was considerably lower in volume than the others. I took it to a guitar repair shop. The first thing they did was to look at the the saddle to make sure it was making proper contact with the undersaddle pickup. After finding that to be OK, they concluded the pickup was defective. We contacted Kala, had a new pickup sent, it was installed by the repair shop, and problem now solved.

05-22-2017, 01:39 PM
You may have already done this, but you should make sure the bass end of the equalizer controllers on both the bass and the amp aren't turned down...

It might also be useful to see if you can find another bass to test out your amp.

05-22-2017, 11:56 PM
I replaced the batteries in the U-Bass and turned the tone all the way down. At this setting, the bottom E string is more audible, but I don't like the tone of any of the strings at this setting. I'll have to think about what to do next. I did order a new set of pahoehoe and I'll try them when they arrive.

Thanks for all your suggestions!

J.P Dedy
07-26-2018, 09:10 PM
Hi, im from indonesia, i have kala rumbler u bass
I have same problems, and i allready fix it,what you need is turn the piezo saddle 180 deggre, thats mean you need drill a new hole on saddle slot to feed piezo cable trough, after that you will see the gap between the piezo and the saddle, (under E strings) , i fill that gap with hot glue to maintain string pressure deliverd to the piezo saddle propperly, after that modifications i have all 4 strings sound at the same level, hope that will help,

And i want to tell 1 more modification on my u bass, are you all not tired changging the battery, yes i talking about thats 2 button batteries, i put 9v battery with no problems on that shadow preamp, no modifications on the preamp, just change that 2 batteries with 1 9v battery

I Hope that will help

07-27-2018, 06:16 AM
On any battery powered uke, the battery dies quickly if you leave the cable plugged in to the uke all the time, when I'm not playing the uke, I unplug the cable. This has happened to me a few times with some of my solid body bass ukes, so I had one of the tone controls changed to a push/pull on/off switch with tone control.

8 tenor cutaway ukes, 3 acoustic bass ukes, 8 solid body bass ukes, 7 mini electric bass guitars

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