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2x15 bass speaker cabinet [message #11194]

Fri, 12 June 2009 23:57

tsprad
Messages: 9
Registered: February 2008
Location: Dallas Texas

Junior Member

I have finally acquired a proper[1] speaker cabinet to go with the K-200 head I picked up nearly a year and a half ago. I have pictures at

I bought it from a rained-out garage sale about half a mile from home, that I found on craigslist. The outside didn't look too bad for a 40-year-old barn find, but the guy I bought it from said he bought it in Mississippi 8 or 9 years ago, put it in a storeroom and forgot about it, and never opened it up or connected a head to it to see if it would play.

The outside was really filthy, but no serious damage. The back was attached with 26 screws of only two different types. But once I got the back off[2] I could see what the DPO[3] had done.

So I'd really appreciate it if someone could direct me to some pictures of what this is supposed to look like inside.

[1] For suitably small values of 'proper'.
[2] I have since learned from this web forum that what I thought was petrified Dr.Pepper was really Kustom Kat Poo, and what I found was only a small trace of what I should have expected.
[3] "Dreaded[4] Previous Owner", borrowed from forums for old guys who waste their time and money on old foreign cars.
[4] This is probably a politically-correct euphemism.

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Re: 2x15 bass speaker cabinet [message #11197 is a reply to message #11194]

Sat, 13 June 2009 05:46

C4ster
Messages: 686
Registered: June 2001
Location: Mukwonago, WI (Milwaukee...

Senior Member

Let's try this again. I had a 13 page response that got lost when I tried to preview it. First off does the nameplate on the front say Kustom Electronics or does it say Kustom by Ross? The Ross cabs are older. They also had the portholes as an option. The Electronics cabs all had ports. The Ross ports were aluminum and the later ones were Chrome. On the back, the speaker jack should say what the original speakers were. The older ones have a large model on it, i.e. D140F. The newer ones had more info on it including the model, Jensen, CTS, D130F, Altec. After removing the back, there should be 2 matching speakers, Jensen’s have the name on the back with a round magnet. On the basket rim it might say C15N or something like that. These speakers were used for guitar. The CTS speakers have a large square magnet and a serial number on the basket rim that starts with 137. These are bass speakers. The JBL's came in either D130F for guitar and D140F for bass. The D130F's can be used for bass. They have a higher frequency response but lack some bottom end. They also have a lower power rating because the voice coils are aluminum for lighter mass. Last on the list of speakers was Altec Lansing. Others more versed in these speakers can add their input here. These are all 16 ohm speakers wired in parallel. Kustom used a red and black #18 gauge wire running to the lower speaker and then to the upper speaker. The entire cabinet except for the speaker baffle has black sprayed fiberglass sound insulation stapled to the inside. Then there is a back board support that is attached between the 2 speakers with lots of staples. This connects only to the back on one side only. We have had many discussion on that. WHY? No one knows. After that all of the back screws should be Phillips oval head screws. Any deviation from this might be attributed to senility, mine, or a mod by a previous owner. I sometimes change out speakers for my own uses or change the impedance for power reasons. All Kustom Frankensteins and K200 series amps were rated for 4 ohm operation. This meant a cabinet needed to be 8 ohms so that 2 cabs could be connected to the amp. 1 cab would run at about 65 watts instead of the rated 100 of the amp. 2 cabs were the maximum you could attach for a total of 4 ohms. The amount of air that could be moved was incredible. I change the speakers to 8 ohms so that 2 speakers would yield 4 ohms and I would get the full output from 1 cab.
Conrad

[Updated on: Sat, 13 June 2009 05:47]

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Re: 2x15 bass speaker cabinet [message #11202 is a reply to message #11197]

Sat, 13 June 2009 11:47

tsprad
Messages: 9
Registered: February 2008
Location: Dallas Texas

Junior Member

Conrad, thank you so much for your help. I see now that the link to my pictures disappeared, so you couldn't have seen them. If you can get to pix.talent-free-studios.com you'll find the pictures in a few mouse clicks.

The front nameplate says "Kustom Electronics Inc." and the back nameplate says "D-140F". The grillcloth has no holes for the portholes, so that suggests that the grillcloth is not original. There are two matching speakers, wired in series. The only markings I have found say "52-19 67-8550" stamped on the round magnets. A Radio Shack special?

The black fiberglass insulation is there, and there's a cluster of bent staples on the right-hand side of the back, near the middle vertically. The ports are blocked off. You'll have to look at the pictures, I can't describe it.

And Mineral Spirits works even better than WD-40 to get the traces of the gasket around the back cleaned off. Shines up the Naugahyde nicely, too, but it didn't get the traces of blue spray paint off.

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Re: 2x15 bass speaker cabinet [message #11207 is a reply to message #11202]

Sat, 13 June 2009 15:22

C4ster
Messages: 686
Registered: June 2001
Location: Mukwonago, WI (Milwaukee...

Senior Member

OK I fanlly got the pictures to load. The grill looks original or at least a very good replacement. The lack of ports does not mean has been modified. But the crappy port closers certainly do. Kustom had many examples of amps that crossed bounderies in production so it's hard to say if that grill is original or not. You are correct, those are not JBL's. I can see where the center support was mounted between the speakers. It needs work and wheels and handles and 2 D140's, well that can come later.
Conrad

[Updated on: Sat, 13 June 2009 15:35]

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Re: 2x15 bass speaker cabinet [message #11214 is a reply to message #11207]

Sat, 13 June 2009 21:40

tsprad
Messages: 9
Registered: February 2008
Location: Dallas Texas

Junior Member

Update: I dragged out my K200 head and plugged it in and it works!

The no-name drivers measured about 6.2 ohms, so they must be 8 ohms nominal, so I rewired them in parallel rather than serial. I still want to open the ports eventually, but ahead of that on my agenda now is to replace some of the caps in the head. It has a lot of hiss and occasional random little pops, so I'm thinking I should replace the electrolytics and tantalums.

And it's missing one knob and one foot and the lamp, and one of the handles on the cab is missing the grip, so I'm off to search the replacement parts forum.

Thanks for your help and encouragement, Conrad!

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Re: 2x15 bass speaker cabinet [message #11217 is a reply to message #11194]

Mon, 15 June 2009 06:16

stevem
Messages: 4733
Registered: June 2004
Location: NY

Senior Member

The 67-8550 drivers stamping means its was made in on the 50th week of 1985 by the 67,Eminence speaker company.
Gain hiss is normal in a kustom as they have a very wide frequency resopnce, but should only be heard in the back ground if you are sitting 6 ft in front of the amp and having a normal converstion level in a quite room.
Little pop sounds could be from a cap leaking or a semicondutor breaking down.
If you open the amp up you will find two blue wires( signal output) going to the rear mounted regulator/driver booard from each front mounted preamp board. if you clip each wire at a time you can drop out each preamp board to see if the popping stops and to detrmine if the coming from a preamp of something on the driver board.
You can use a red type butt splice to reconnect each blue wire bacl together.
The red and green wires carry the + and - 8 volts to power each preamp in a K200B model amp, and this should be checked also and you should find it very close to 8 volts + and -.
The two main power supply rail filter cans mounted on the chassie floor can be checked by site, as they will have a little round dimple on the top which should be flat or somewhat reccessed, if looks like a pimple, than the filters are going bad due to the elctrolite in them drying up and swelling.

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Re: 2x15 bass speaker cabinet [message #11220 is a reply to message #11194]

Mon, 15 June 2009 22:27

tsprad
Messages: 9
Registered: February 2008
Location: Dallas Texas

Junior Member

Eminence, Christmas of '85, eh? Not D-140Fs, but they're more than adequate for my purposes.

And thanks for the advice about clipping the blue wires to isolate noise to one board. Some kind of quick disconnect on those sounds like a good idea. I've already replaced one transistor, and I think I'll be spending some time inside there.

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