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kustom 250 [message #18097]

Fri, 25 January 2013 01:58

ihwnine
Messages: 5
Registered: September 2012
Location: iowa

Junior Member

hello this is the 2nd kustom 250 I have owned
and they all seem to sag the low notes some other kustom ownwers
told me they sag from the factory and the power light dims right from the factory . .I will say this is the best fretless bass amp I have ever played thats all tc electronics ampeg swr I have been playing for 40 years
(need heavier caps. and filters. bigger tranny)

[Updated on: Fri, 25 January 2013 02:01]

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Re: kustom 250 [message #18099 is a reply to message #18097]

Fri, 25 January 2013 10:11

stevem
Messages: 4772
Registered: June 2004
Location: NY

Senior Member

Hello.
All amps sag during heavy loads and the metal face K150s and 250s do that the least out of all prevous Kustom amps.
Do to the place Kustom puts the pilot lights on the DC side of the circuit, not the AC side you see when the amps 40 volt supply gets pulled down.
changing out the two mail filters for larger ones( 10,000 uf to 15,000 uf) will greatly help the sag/farting out issue, Installing a bigger PT with .200ma of current will help alot also.
Also if you are not powering the amp into a 4 ohm load you are killing of at least 45% of the amps wattage, also higher rated SPL drivers than stock will add another 3 DB of acostic power to hit your ears with along with more clean head room.
You could also tap the module out signal to a power amp and then drive the speaker cabinet as its safe to run all Kustom amps with no speaker load.

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Re: kustom 250 [message #18104 is a reply to message #18097]

Sat, 26 January 2013 11:10

stevem
Messages: 4772
Registered: June 2004
Location: NY

Senior Member

Here`s my electronic rule of thumb for Bass Guitar equipment.
Lets start with basic speaker area. or the wave front of air they move.
Not that these sq in measurements are not rounded off for the real world cone area as the is different from driver to drive, but will not change enough from driver to drive to change the results.
This also assumes that all the drivers have the same SPL rating which they do not, but the compairision is still valid!
Speaker number of drivers
d
10" (1) 6.5sq in (2) 13.09sq in (4) 26.1 sq in
12" 9.2sq in 18.4sq in 36.8sq in
15" 14.7 sq in 29.4 sq in 58.8 sq in
18" 21.2 sq in 42.4 sq in
There`s how to use this chart.
Since your bass is tuned one octive lower than a guitar you need to move twice the amount of air that would be need to match a 6 string guitar at the same volume.
As such if your guitar player was pumping out sound waves thru 2 10" drivers for a wave front of 13.09" you the bass player would need to double that so your choise would come down to 4-10" drivers, 1-15" driver or 1-18" driver.

In terms of amp power, once again since you are tuned 1 octive lower you need a minimum of twice the amount of clean head room as your guitar player, so if he is pumping out thru a 50 watt RMS amp you need to have 100 watts RMS at your disposal.
If you play 5 string bass with a low B string you may need to add another 50 watts RMS to your total power.

My bas rig minimum for playing out with my 5 string with out sound system reinforcement is 2-15" and 150 watts RMS for the average size 100 to 150 person club these days. Bigger venues or gigging out side make me drag along a addtional 4-10 cab, or 2-15 box, and I perfer to use the added 2-15" cabinet when the stage is big enough to let me place it on the other side from where I stand for a nice big wave front of some 58 sq in.
I hope these tips help!!

[Updated on: Sat, 26 January 2013 11:29]

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