Removing a Crossover from a poweramp

[Coconuttopdrop]

Hi guys

I'm trying to MOD a Kustom X11 Bas amp. It has a crossover in it (passive i guess) I would like to take it out and use only the 2 of the 3 power amp sections for the signal (left and right).

There is a dedicated board for the crossover that receives the direct signal from the inputs and also has +12V and -12V connected so i'm not sure if the crossover is passive or if the signal is being preamplified at that stage, or something.

I measured the signal voltage at the input of the cross over and at the output (full gain). At the output the signal was a few mV stronger.

My question is, if i take the direct signal from the input and connect it directly to the amplifier stage, might i be doing something that i shouldn't be doing? Can the +12V and -12V rail be disconnected from that rail without affecting the rest of the amp (these lines are also connected to the power amp section)
What should i be looking at to have more insight in what i what to do and how to do it?

 

[31697B]

usually the cross-over would be to seperate the bass from the rest of the tones so that only the bass frequencies get amplified. if you remove the cross-over, you might not like the sound and you might as well be using an amp that is for a lead guitar or similar. You can try a temporary jumper from cross-over input to output and see what it sounds like?


-RM

 

[rigtec]

Hi guys

I'm trying to MOD a Kustom X11 Bas amp. It has a crossover in it (passive i guess) I would like to take it out and use only the 2 of the 3 power amp sections for the signal (left and right).

There is a dedicated board for the crossover that receives the direct signal from the inputs and also has +12V and -12V connected so i'm not sure if the crossover is passive or if the signal is being preamplified at that stage, or something.

I measured the signal voltage at the input of the cross over and at the output (full gain). At the output the signal was a few mV stronger.

My question is, if i take the direct signal from the input and connect it directly to the amplifier stage, might i be doing something that i shouldn't be doing? Can the +12V and -12V rail be disconnected from that rail without affecting the rest of the amp (these lines are also connected to the power amp section)
What should i be looking at to have more insight in what i what to do and how to do it?

Hi Coconut'..

What R N Marsh said is correct, and a very good idea. I too am a bass player (many yrs), and would like to know what's the reason for this modification? I'm using a bi-amp'd system e.g., two 2k watt Crown power amps, one DBX active stereo 2 way or mono 3 way x-over, 8 tens and 2 eighteens in W-bins. The cross-overs are very good at preventing huge power losses through the "overfeeding" of your speaker system, dividing properly, the power needed for each particular frequency range. Is it that you would rather go with some full range drivers; which (imho) can sound fantastic. Or, is there some other reason? Just curious.

rigtec, cheers!

 

[Coconuttopdrop]

I'm adapting the amp to use as a studio monitor amplifier.
The speakers I have are full range and I need a full range amp for it, and this is a good amp.
It's a really old design with stereo bass and mono treble (really... two outputs for bass speaker and one output for treble speaker)

I'm trying to figure if i can feed the signal through a potentiometer (atenuate the input) to the amp (bypassing the crossover) and not blowing anything up.

But my main question is, can the +12V and -12V rail be disconnected from that rail without affecting the rest of the amp (these lines are also connected to the power amp section)????

I guess i'll just follow R N Marsh advice and jump it, see if the thing doesn't blow!