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Trying to frankenstein some gear

B

Bassvito

Aug 7, 2015
6
1
33
#1
I've got a Kustom KBA65 combo amp which is obviously not loud enough for real gigs.
BUT I absolutely love the tone I get out of it and I also don't want to spend a ton on a new head sooooo:

I was hoping to disconnect the amplifier from its original speaker and hook it up to a separate power amp and then send the signal from that to a cab. It has an external speaker output which (to my knowledge) sends a power-amplified signal while bypassing the speaker. But it's only a 65W amp so I'd need more power, and if I put that into another power amp, I think that would break it? Alternatively, it's got two line outputs (1 xlr, 1 quarter inch) which (to my knowledge) can be sent safely to an external power amp. However, since signal still gets sent the the speaker (and logically therefore also to the internal power amp), I assume that disconnecting the speaker would cause a problem because now power is getting sent to nothing. I'm planning to purchase a 1000W 410.

Am I correct in my assumptions? Regardless, how can I make this work? I'd rather not go through the trouble and expenses of buying a head.
 
#2
Your assumptions are simply incorrect...

1. The solid state power amp will operate perfectly safely unloaded

2. You are happy with the sound of the combo, but a big part of that sound is the speaker (which you propose not to use). The preamp may be voiced to make the most out of that speaker, so using it with another speaker may not produce what you hope.

3. You can use the line outputs to drive an external power amp PROVIDED they are really line outs. I suspect that the XLR output is not line level (I have not confirmed this though).

This is the perfect opportunity to shop for a head to go with your new speaker, one that suits the specific needs and might be no more expensive than buying a power amp alone.

(your assumption that using the ext. speaker out to drive a power amp is correct)

(Edited for i-phone auto-correct!)
 
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#3
Thanks! Really, a lot of this has to do with budget and if I can spend less doing this, I'd rather put off buying a head for the future.

Any brand recommendations for power amps? They seem a bit tougher to search for.

Regardless, I'll be continuing my search for a head because I think you're right that in the long run it will make more sense...


agedhorse said:
Your assumptions are simply incorrect...

1. The solid state power amp will operate perfectly safely unloaded

2. You are happy with the sound of the combo, but a big part of that sound is the speaker (which you prose not to use). The preamp may be voiced to make the most out of that speaker, so using it with another speaker may not product what you hope.

3. You can use the line outputs to drive an external power amp PROVIDED they are really line outs. I suspect that the XLR output is not line level (I have not confirmed this though).

This is the perfect opportunity to shop for a head to go with your new speaker, one that suits the specific needs and might be no more expensive than buying a power amp alone.

(your assumption that using the ext. speaker out to drive a power amp is correct)
Click to expand...
 
#4
I suggest looking through the TB classifieds as a first step. IMO there's some quality gear available at very reasonable prices, especially if weight is not a huge factor in your decision.
 
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#6
Just to clarify: I won't have any transformer problems if the speaker is disconnected from the amp and I'm using a line out?

agedhorse said:
Your assumptions are simply incorrect...

1. The solid state power amp will operate perfectly safely unloaded

2. You are happy with the sound of the combo, but a big part of that sound is the speaker (which you prose not to use). The preamp may be voiced to make the most out of that speaker, so using it with another speaker may not product what you hope.

3. You can use the line outputs to drive an external power amp PROVIDED they are really line outs. I suspect that the XLR output is not line level (I have not confirmed this though).

This is the perfect opportunity to shop for a head to go with your new speaker, one that suits the specific needs and might be no more expensive than buying a power amp alone.

(your assumption that using the ext. speaker out to drive a power amp is correct)
Click to expand...
 
#7
agedhorse said:
a big part of that sound is the speaker (which you prose not to use). The preamp may be voiced to make the most out of that speaker, so using it with another speaker may not product what you hope.

(your assumption that using the ext. speaker out to drive a power amp is correct)
Click to expand...

Post edited for brevity.

You still having trouble with that iPhone Andy?? :D
 
#11
I think you will find it WAY more convenient just to get a head that does what you need it to, rather than kludging together a "sort of" solution.

If you like the sound of the Kustom, why not look at some of their heads?
 
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#12
Bassvito said:
Thanks, super helpful! I'll be taking the in-between route, by the way: I'm going to buy a head that has a power amp input so that I can run my kustom straight though it if I want.
Click to expand...
wait, what?

"power amp input" means an input into the power amp inside the head, it does not mean "plug a power amp output into this"! :eek:

you'd still need to send it a low-level "preamp" signal, not a speaker-driving "power amp" output. (that amp apparently has this, a 1/4" line out and a 1/4" effects send, both of which would work to run an external power amp.)

anyway, there's no point! i'll bet you a quarter that if you buy a real bass head with some real power it'll sound way better on its own than any little kustom hobby practice amp anyway. leave the kustom at home for noodling and stuff, that's what it's meant for.

(OK, if you did manage to score a cheap power amp then yeah, use the line out or effects send to run it, that should work just fine. don't worry about the speaker being unplugged, like @agedhorse said solid state amps don't care about that.)
 
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#14
There were a couple of Kustom KXB 500 heads for sale in the classifieds recently in the $300 range. It's a capable little head and I've found it to cut through well in a live mix. Should go quite loud through any 4 Ohm 410 of reasonable efficiency. I think that you could use the effects send to drive a power amp if you really needed to at some point (though it is a loud little 500 W micro).
 
#15
So, I have a KBA65, too, and I don't like the sound when I crank up the volume. I have it connected to an external speaker that's old and moldy, which is now making fluttering sounds when the volume is cranked up at a gig. I'm thinking of replacing the speaker head in the external speaker. How do I go about getting an appropriate speaker to replace the one I have? I'm told the speaker needs to have an impedance matched to the amp. Is that true? Is the impedance of the KBA65 8 ohms?
 
#16
agedhorse said:
Your assumptions are simply incorrect...

1. The solid state power amp will operate perfectly safely unloaded

2. You are happy with the sound of the combo, but a big part of that sound is the speaker (which you propose not to use). The preamp may be voiced to make the most out of that speaker, so using it with another speaker may not produce what you hope.

3. You can use the line outputs to drive an external power amp PROVIDED they are really line outs. I suspect that the XLR output is not line level (I have not confirmed this though).

This is the perfect opportunity to shop for a head to go with your new speaker, one that suits the specific needs and might be no more expensive than buying a power amp alone.

(your assumption that using the ext. speaker out to drive a power amp is correct)

(Edited for i-phone auto-correct!)
Click to expand...

#2 is the first thing that popped into my head. You aren't hearing just the head. You're hearing the whole package...speaker and enclosure included. There's a chance you could run the same signal into a different amp and speaker and you won't like it at all.

(Andy, you made #2 pop into my head. I hope you're proud of yourself.) :roflmao:
 
Last edited:
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#17
sanjayscorpio said:
So, I have a KBA65, too, and I don't like the sound when I crank up the volume. I have it connected to an external speaker that's old and moldy, which is now making fluttering sounds when the volume is cranked up at a gig. I'm thinking of replacing the speaker head in the external speaker. How do I go about getting an appropriate speaker to replace the one I have? I'm told the speaker needs to have an impedance matched to the amp. Is that true? Is the impedance of the KBA65 8 ohms?
Click to expand...
I was surprised to scroll through this and see my own post a little way up! That's when I realized this was a slightly older thread. Kudos for searching, though.

When you say, "I'm thinking of replacing the speaker head in the external cabinet" do you mean the speaker?

Had a look at the manual, which states:
Speaker out... will disconnect the internal speaker and allow an external speaker cabinet to be employed. Rating is 8 Ohms.​

Based on that, I would go with an 8 Ohm speaker. 4 Ohms might not be safe for the amp. If you can find the same speaker used in the cab (look on the speaker for info or contact the manufacturer), that'll work -- or you might be able to find one with similar parameters that would be a pretty straight up sub. You could likely upgrade but, if you do, make sure the speaker you get is suitable for the box size and tuning of the cabinet (you'll have to ask someone more knowledgeable than I). With 65 Watts on tap, I'd also get the most efficient speaker I could. That will be more important than big power handling in your situation.
 

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