I guess I'm the newest member of The Kustom Club.
My first experience with Kustom was in the 1970s, using a borrowed stereo Rickenbacker, running one channel into each of a twin set of Kustom dual cabs, Tuck 'n Roll, also borrowed. However, as it was 40 years ago and borrowed that doesn't really count.
Yesterday, for the price of a bottle of rye, I acquired a Kustom KBA40.
Granted, this is not high end or high power as bass amps go. However, since I've been without any sort of proper bass amp since selling my Marshall stack [damn fool that I was - should have sold one of the kids for medical experiments] some years back, this is a step in the right direction.
I was a little dubious about this amp - it's missing one knob, the gain pot was noisy-dirty, and the pilot light doesn't work. None of those are serious problems - a shot of contact cleaner, a pilot lamp, and a knob from the spare parts drawer.
However, when I plugged in my beloved Peavey Milestone (the Gibson EB0 is still undergoing rebuilding), it rattled every window in the house and scared the birds off of the neighbor's chimney. Holy Smokes! Talk about LOUD! And clean - no problems with distortion or lack of sound! Everything else worked, including the basic 3-band equalizer, so one crock of rye changed hands and the beast was mine, hernia and all. [Some people scoff at the Milestone IV and III - I've never played a bass with a nicer neck, regardless of price].
It says KBA40 on the front, and says Max Power Out 80 Watts on the back. On the front by the power switch there's a jack for a line to a 2nd cab. There's no user guide/manual/schematic with the amp., and I've found only one reference on the 'net. I don't know how old it is - nothing on Kustom's web site, and the owner was vague about when he'd bought it. My best guess is mid-90's, but it could be late 80's or early 2000's - I've found no dates on it anywhere so far. I'm kind of surprised that there's almost no mention of this model on the net, as it seems pretty rugged and sounds decent.
On the Vintage Kustom forum, there's a discusssion of a guy who blew up his KBA40's bridge rectifier after plugging in a second cab. I've not yet had time to disassemble it, but the jack for the 2nd cab appears "factory", not kludged in. The 2nd cab connection is a bit of a mystery at this point. I'm not sure what impedance is wanted, if I'm working with 80 Watts all the time, or 40 Watts with just the internal speaker, or 80 Watts with both the main and an external cab. Once I throw a meter on the output I'll know a bit more.
However, as it stands its a solid and clean, loud combo amp. A very bad cellphone shot is below - I'll add more pics when I get the camera charged up. Since I've been practicing on a 5 watt shoebox, this is a definite improvement. Once the minor repairs are done and its been given a bath , it looks like it'll be pretty solid - good for practice or jams, anyhow. Might do for a small room gig.
So I've come full circle - the very first bass amp I gigged with was a Kustom, and 37 years later I've got another. No Tuck 'n Roll this time around, more's the pity.
Jim Baritone
A "P.S." Update Oct 14, 2012. Still have not found a user manual or, more importantly, a schematic for the KBA-40. The amplifier chassis is labeled as having a maximum power output of 80 watts.
Having done some testing, I've determined the following:
1) it appears that if you plug a bass cab into the "External Speaker" jack, the internal speaker is disconnected.
2) the output power of the audio amp into an 8 ohm dummy load with a 500 Hz signal generator input is over 60 watts RMS (my homebrew wattmeter from years back doesn't go higher)
3) there are two inputs, "High" and "Low". The "High" input wires go straight to the preamp (or would, if they weren't broken). The "Low" input is connected in parallel with the "High" input, connected through 68K resistors. The two jacks are also both switched - putting a plug in one jack disconnects the other, so no "dual input" capability.
3b) The High input is not working, apparently because the wires are broken at the jack solder lugs. Also it's plastic front panel nut is missing. Not having any of the correct-size plastic nuts, I found that the nut that secures the lamp switch/socket in a gooseneck lamp fits perfectly. Nuts from normal 1/4" jacks are a hair too small. Have yet to get into this further. Probably just needs to have the wires re-soldered.
4) the 3-band equalizer seems to work OK.
5) the headphone jack works, and cuts off the speaker. I suspect it also turns off the main power amp - the headphone signal is probably taken off at the preamp output.
6) there is a "line level" output to connect to another amp input, sound board, or whatever. Haven't measured the level yet, but it's probably whatever is standard, in terms of signal level.
Even using the "Low" input and passive pickups, the output volume is astonishingly loud for a relatively small combo amp. Clean, too.
