Amp Problems. :(

[Exxcell]

Well, I have two problems.
First off is, I own a 70's Kustom B1 solid state bass amp. And it is not loud at all. I mean, sitting in a room by myself, playing, I have to be right next to it. it gets a little hard to hear when your 10+ feet away from it. I dont really have any Specs on it. I've looked around, but no luck. Any ideas on how to fix? I have a basic knowledge on speakers, amps, ect. ( my crappy Behringer that I bought for $30 is louder then the B1...)

Second, I have a Kustom (I'm seeing a pattern. :P) KPM7250, 200Watt 2 channel Powered Mixer. It was working fine to power a cabinet housing a 300W 18'' woofer. Now, when I turn the amp on, I get a soft distorted sound, when when turned past 40% on any volume it clicks, shuts off, immediately turns back on and does this over and over until i turn it down a little. Any ideas?

Also, and specs on the B1 that you have, they would be greatly appreciated.

[Joe Louvar]

Start over - and go buy a bass rig you like!!!

[Exxcell]

Originally Posted by Joe Louvar

Start over - and go buy a bass rig you like!!!

I dont have the kind of money... :P

[Joe Louvar]

EDIT:
Then I don't know - sorry.

[rodl2005]

For prob. 2- the 18"speaker isn't too low impedance for the amp is it? Eg. is the woofer 4 ohm, & the amp needs 8 ohm minimum?

Prob 1 - see Joe's reply. You can pick up 2nd hand combos CHEAP these days.
Might be more expensive to get the amp checked than to buy an ok 2nd hand prac amp.

[Exxcell]

Originally Posted by rodl2005

For prob. 2- the 18"speaker isn't too low impedance for the amp is it? Eg. is the woofer 4 ohm, & the amp needs 8 ohm minimum?

Prob 1 - see Joe's reply. You can pick up 2nd hand combos CHEAP these days.
Might be more expensive to get the amp checked than to buy an ok 2nd hand prac amp.

Prob 2 - lol. Checked that before I built the cab.
Prob 1 - amp worked fine for 7 months. It was a gig amp. It was extremely loud. It just got quieter over time. It's 40 years old. Dirty jams?

[Dekker]

First, if you are not comfortable with electronics, skip everything and just get a new one Most electronics can kill, and capacitors can store a charge for longer than you think...

If you don't have $, you'll have to do the work yourself... Don't have full details on your amp, but this thread has schematics for that series, and it depends on your PCB version:
Kustom 200 schematic

Even without a schematic, it might be as simple as opening up the amp, and looking for obvious problems such as failed electrolytic capacitors (leaking, or with bulging tops), or failed resistors (burn/scorch marks on the circuit board) or blown fuses (visual inspection, or pull them and test with multimeter).

After that, look for wiring that looks faulty (loose, frayed, burnt, etc).

If you have identified an obvious problem, replace the part with the exact same specification (no need for the exact same brand), but keep in mind that many components are "paired", and it is usually best to replace obviously linked components together.

If nothing is obviously wrong, then you can button it back up and sell it for parts :O

[Oobly]

2nd problem sounds like a faulty capacitor to me. If you have the time, patience and skill, it could be worth replacing the caps yourself. I recommend replacing any cap in there that looks even slightly puffy, damaged, leaky or burnt.

1st problem I don't really know. Could also be caps... or a resistor... or a transistor... or whatever.

[Exxcell]

Originally Posted by Dekker

First, if you are not comfortable with electronics, skip everything and just get a new one Most electronics can kill, and capacitors can store a charge for longer than you think...

If you don't have $, you'll have to do the work yourself... Don't have full details on your amp, but this thread has schematics for that series, and it depends on your PCB version:
Kustom 200 schematic

Even without a schematic, it might be as simple as opening up the amp, and looking for obvious problems such as failed electrolytic capacitors (leaking, or with bulging tops), or failed resistors (burn/scorch marks on the circuit board) or blown fuses (visual inspection, or pull them and test with multimeter).

After that, look for wiring that looks faulty (loose, frayed, burnt, etc).

If you have identified an obvious problem, replace the part with the exact same specification (no need for the exact same brand), but keep in mind that many components are "paired", and it is usually best to replace obviously linked components together.

If nothing is obviously wrong, then you can button it back up and sell it for parts :O

Im pretty tech savy. I took it apart yesterday. Turns out. The original 15" sub is gone, replaced with a 10" car sub. They built a box to fit inside the amp box. Which makes my amp now like 100lbs. Could this be my problem?

[Exxcell]

Originally Posted by Oobly

2nd problem sounds like a faulty capacitor to me. If you have the time, patience and skill, it could be worth replacing the caps yourself. I recommend replacing any cap in there that looks even slightly puffy, damaged, leaky or burnt.

I'm not so hesitant to take this one apart, I did and everything looks like new. (except for a small cobweb in the corner of the box.) maybe I'll make a video showing what exsactly happens. I paid $450 for it brand new in 2005. Rather not see it go.

[craig.p]

Originally Posted by Exxcell

Im pretty tech savy. I took it apart yesterday. Turns out. The original 15" [driver] is gone, replaced with a 10" car sub. They built a box to fit inside the amp box. Which makes my amp now like 100lbs. Could this be my problem?

LOL, that's gotta be one of the better hack stories I've read over the years. Yeah, get that ten out of there and put things back to original. You'll have to decide on a suitable 15" driver: Tell us what the internal cab dimensions are, whether the cab is ported, and if it's ported, what the port dimensions are.

[Dekker]

Originally Posted by craig.p

LOL, that's gotta be one of the better hack stories I've read over the years. Yeah, get that ten out of there and put things back to original. You'll have to decide on a suitable 15" driver: Tell us what the internal cab dimensions are, whether the cab is ported, and if it's ported, what the port dimensions are.

At first (for some strange reason) I thought you meant they took out the amp portion, and replaced it with a car amp. But then I read craig.p's comment and it clicked - they replaced the 15" speaker/driver with a 10" speaker/driver!

No wonder it never performed like you thought it should! Craig.p has you on the right path with this one.

Dekker

[Exxcell]

Originally Posted by Dekker

At first (for some strange reason) I thought you meant they took out the amp portion, and replaced it with a car amp. But then I read craig.p's comment and it clicked - they replaced the 15" speaker/driver with a 10" speaker/driver!

No wonder it never performed like you thought it should! Craig.p has you on the right path with this one.

Dekker

Haha. Sorry for the misunderstanding.
But the amps impedence range is 8-16ohmns. The drive was a 4ohm. Could damage to the amp be irreversible now?
Ill also make a vid showing exsactly what it looks like, ect.

[Dekker]

Originally Posted by Exxcell

Haha. Sorry for the misunderstanding.
But the amps impedence range is 8-16ohmns. The drive was a 4ohm. Could damage to the amp be irreversible now?
Ill also make a vid showing exsactly what it looks like, ect.

"could" the damage be irriversible? Yes. Is it? Don't know. By running too low of an impedance, too much current passes through the amp. How well it handles that is up to the amp designer. Could be as simple as a blown fuse, resistor or cap, or could be worse.

[Exxcell]

Originally Posted by craig.p

LOL, that's gotta be one of the better hack stories I've read over the years. Yeah, get that ten out of there and put things back to original. You'll have to decide on a suitable 15" driver: Tell us what the internal cab dimensions are, whether the cab is ported, and if it's ported, what the port dimensions are.

Internal Cab Dimensions:
H/W/D - 19"/18"/10"

Port Dimensions:
H/W - 2"/7½"

I also finally found specs on the amp.
"The I Bass was the "entry level" Kustom, but was still a very serious amplifier.
It features 30 watts and one dual input channel with the following controls:
Volume, Bass, Middle, Treble and Bright.
It has a single 15" speaker with a 38 oz. magnet, 1 1/2" voice coil, 8 ohms.
H/W/D: 26" X 20" X 13" and weighs 71 pounds.
It is a good portable gigging amplifier for clubs."
Source - Early to mid 1970's Kustom Amp Page

[Stumbo]

Originally Posted by Exxcell

Prob 1 - amp worked fine for 7 months. It was a gig amp. It was extremely loud. It just got quieter over time. It's 40 years old. Dirty jams?

I suggest in the future saving money from your gigs to cover repairs and such. Stuff happens. Still, I'm not sure how many gigs can be covered by a 30w combo rig?

If you're not electronically inclined, here's a link to good amp techs all over the U.S., some of which work on solid state amps. Tube amp techs- recommendations

I think that it would cost you more to repair it than to buy a new/used rig.

If you check out Craigs list, I'm sure you can find a good rig cheap that will do a lot more than your 30 watt combo could ever do.

[Exxcell]

Originally Posted by Stumbo

I suggest in the future saving money from your gigs to cover repairs and such. Stuff happens. Still, I'm not sure how many gigs can be covered by a 30w combo rig?

If you're not electronically inclined, here's a link to good amp techs all over the U.S., some of which work on solid state amps. Tube amp techs- recommendations

I think that it would cost you more to repair it than to buy a new/used rig.

If you check out Craigs list, I'm sure you can find a good rig cheap that will do a lot more than your 30 watt combo could ever do.

Haha. It's not like I'm in a rock n roll band. It's just me and a buddy. He's on acoustic and I sing and play bass.
And with the money deal... I'm broke. I have to pay off a hefty ER bill from when I was in a accident. :P

[Exxcell]

Heres a short vid on the amp. Kustom B1 Bass Amp - YouTube

(Sorry if it looks like i recorded it with a brick...)