| Kustom model 600-5 PA [message #24396] |
Tue, 19 January 2016 10:23  |
LukeM
Messages: 6
Registered: January 2016
Location: Ohio
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Junior Member |
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Good day, and thanks for this forum. I've always liked the tuck-n-roll Kustom equipment. So far, all I've purchased is one of their US made guitar amps (a KLA-25A, which gets used on a regular basis).
At a recent estate sale, I picked up a model 600 8 channel PA head, and 2 non-Kustom columns. This beast weighs close to 100 lbs!
I took it out of the case (some tears in the material, consistent with the early 70s vintage), took off the metal lid, and looked around.
There are a couple of resistor arrays for the control board (to get + and - 15v from the power supply, and for the lights for POWER and POLARITY). The wires looked pretty burnt, so I replaced the longer runs. I think the zener diodes on the control board are regulating +/-35v down to 15. That seems like a bit of a strain. I may investigate re-configuring the regulator to something a bit more robust. I did shoot some DeOxit on all the controls, and I'll get my friend's 1/4" wire brush to run through all the jacks. Date code on some components reads 1972.
On the power amp boards, I don't see any burnt or stressed stuff. All the TO3 cans look original, with Kustom numbers on them. So far, so good.
Bonus: 2 pages of schematics inside, that may have been glued to the metal top. I tried scanning them, but as old as they are, they didn't come out very good.
No, I haven't powered it up yet.
The column speakers are not tuck-n-roll, and both will need some re-wiring. Looks like both have 2 15" speakers in them. One of the speakers is a Jensen Special Design. The other has a square magnet, and might be a 4 ohm impedance. The other one I haven't been able to look into.
Thanks for letting me babble, and I'll update this as I make progress.
Luke M
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| Re: Kustom model 600-5 PA [message #24400 is a reply to message #24396] |
Tue, 19 January 2016 12:46  |
chicagobill
Messages: 2006
Registered: April 2003
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Senior Member |
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Welcome to the place.
Yes, not a great unit for modern bands, but it would work well for small clubs, churches or as you suggested Karaoke. Remember that these use high impedance mikes.
The preamp and mixer circuits are both running off of the plus and minus 12 volt power supplied by the two Zener diode circuits. If there is or was a problem in any of the preamp circuits, that could cause too high a current draw. That may be the reason for the overheated wires.
As for lifting it onto the bench, we old farts do have a few tricks for handling these things. And compared to an old Ampeg SVT your 600 is a lightweight.
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| Re: Kustom model 600-5 PA [message #24405 is a reply to message #24402] |
Tue, 19 January 2016 20:27 |
LukeM
Messages: 6
Registered: January 2016
Location: Ohio
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Junior Member |
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Can't find the "technical section". NO worries: I'll scan the ones I have and try and clean them up.
I had some time, and examined the speakers in the 2 columns I got with the amp. These are not the tuck-n-roll versions. They probably aren't Kustom at all. All speakers are 15" units. One cabinet has a stamped steel 4 ohm speaker, labeled 1504H20c, 137 739. The other speaker is a Jensen Special Design model C15P, 220743, made in Chicago USA by the Muter Company. I haven't tested these yet, so I need to check for continuity and no tears in the cone or surround.
The other cabinet has another 4 ohm speaker, 1504H20C 1376918, and a Realistic speaker model 40-1315A, presumed to be an 8 ohm unit. All the speakers appear to be 100W units. The cabinets don't appear sturdy enough to handle that kind of power: the back panels are maybe 1/4" thick. There's room for horns in them, but the horns would be at the bottom of the cabinet. Not very efficient.
One of the 4 ohm speakers has the solder tab sheared off. I don't know if I can resolder that and epoxy the tab back on. The money may be in the Jensen and Realistic units.
Here's a link to a Dropbox folder, showing pics of the speakers, and some other bits.
dropbox.com/sh/bus0joz3smnlb2r/AABAgTAcwuW55iNeEdKVXyHYa?dl= 0
Please let me know if that link doesn't work. I haven't been on Dropbox in a while.
So, what do you think: Wire up everything, and run them until they go *POOF*, or sell the contents and just focus on the PA head?\
Luke M
[Updated on: Tue, 19 January 2016 20:38] Report message to a moderator |
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| Re: Kustom model 600-5 PA [message #24406 is a reply to message #24396] |
Tue, 19 January 2016 23:27 |
Iowa Boy
Messages: 767
Registered: June 2014
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Senior Member |
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Sounds like you got a bunch of junk for speakers other than the Jensen. Someone obviously didn't know anything about mixing ohms in speaker cabinets and were just putting in anything they could get their hands on. In my early days and before I knew any better, I tried Realistic speakers in a PA cabinet. Worst sound I ever heard. Cheap, cheap, cheap.....let me repeat....cheap. (I was in 8th grade so I plead ignorance).
1/4 inch for the back panel is pretty thin. If the cabinets are made of particle board......don't waste your money on putting new speakers in them. There's always plenty of old Kustom T&R PA cabinets for sale out there and a lot cheaper than what its going to cost to put in 4 good 15 inch PA speakers. Eminence are going to run you at least $100 each......you'll have more in the speakers than the cabinets are worth.
Shop Guitar Center and Music Go Round or check area music stores for some used equipment. Maybe you'll get lucky and find a pair of JBL cabinets for under $300. Most of them come with horns and have a pretty decent sound. I picked up a pair of JBL Cabarets for $200 and they have an awesome sound. Word of advice, any cabinet you look at, never assume who ever had it knew what they were doing or what was in it. Always, and I mean ALWAYS take a cordless with you and open the backs to see what is in there for sure. Any seller that won't let you look.....walk. Its always a learning experience when it comes to buy used equipment. Let us know how things turn out......got my fingers crossed that the 600 isn't toast.
[Updated on: Tue, 19 January 2016 23:33] Report message to a moderator |
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| Re: Kustom model 600-5 PA [message #24412 is a reply to message #24409] |
Wed, 20 January 2016 10:40 |
LukeM
Messages: 6
Registered: January 2016
Location: Ohio
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Junior Member |
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You can use dis-similar impedance speakers in various connection scenarios.
There are a few caveats, however:
Almost all amplifier equipment is engineered to drive a specific load. Typically, this load varies from 4 ohms all the way up to 32, depending on the speaker configuration. Since amp makers and speaker makers need each other, they tend to line up to follow demand and supply.
My 600-5 unit is set up to drive 2 8 ohm columns in parallel. Following the rule R1*R2/R1+R2, 64/16 = a total of 4 ohm load.
If I were to keep 1 8 ohm speaker and 1 4 ohm speaker in one cabinet, depending on the wiring, I would have 12 ohms if they were wired in series, and 2.66 ohms if they were wired in parallel. Neither of these will safely deliver the most power from an amp designed for a 4 ohm load. 12 ohms would deliver approximately 1/3 the audio power, and the 2.66 ohm load would strain the output devices if driven to full power over a long period of time.
The fun starts when you have more than 2 speaker elements for a load:
Assume 4 4 ohm speakers.
Your options are:
4 all in parallel: 1 ohm load
4 wired in series: 16 ohm load
2 wired in series + 2 wired in series, and those pairs wired in parallel: 4 ohm load
2 wired in parallel + 2 wired in parallel, and those pairs wired in series: 4 ohm load
Be advised that wiring speakers in series represents a point of failure, should a connection be broken = no sound/no load.
Sometimes the math is the funnest part. 
Luke M
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| Re: Kustom model 600-5 PA [message #24417 is a reply to message #24396] |
Wed, 20 January 2016 17:00 |
Iowa Boy
Messages: 767
Registered: June 2014
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Senior Member |
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Lets put this back into perspective: we have two non-Kustom speaker cabinets. Both cabinets have a Jensen 4 ohm speaker in it; one cabinet has an 8 ohm Realistic speaker, the other an unknown assumed 8 ohm speaker as well.
There are only two ways to wire 2 speakers....series or parallel.
An 8 ohm speaker has twice the resistance as a 4 ohm speaker. On a 4 ohm load, the output will be less with an 8 ohm speaker verses a 4 ohm in which case you get the full maximum output.
Anyway you wire two speakers that have dissimilar ohm values, you will NEVER get a balance sound out of the cabinet. The 4 ohm speaker will be the driving one. Doesn't matter how fast the electrons are traveling through the wire, resistance is resistance, and the more resistance the more power loss, and more power loss, less output.
I'm not an electrical engineer but I did take college physics. I see no practical way to use these speakers efficiently. Sure you'll get sound......but really is that the sound you want?
[Updated on: Wed, 20 January 2016 22:36] Report message to a moderator |
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| Re: Kustom model 600-5 PA [message #24444 is a reply to message #24396] |
Fri, 22 January 2016 12:47 |
Kustom_Bart
Messages: 601
Registered: October 2010
Location: Greenville, MichiGUN
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Senior Member |
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For a pa it doesn't it really matter, if you need to get it going? It will work and not hurt anything and sound fine. Even though Steve is correct with the additional draw on the lower ohm rated driver. that goes without saying. You can make it work and when you pick up a driver of the same impedance then change it out. Here is a really nice link to show you about Series/Parallel wiring.
http://www.colomar.com/Shavano/spkr_wiring.html
[Updated on: Fri, 22 January 2016 13:21] Report message to a moderator |
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| Re: Kustom model 600-5 PA [message #24453 is a reply to message #24444] |
Fri, 22 January 2016 19:09 |
pleat
Messages: 1454
Registered: June 2004
Location: Belding, Mi
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Senior Member |
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Not sure if anyone actually checked out the link to the photo's in this post, but talking about speakers, I'd say none are worth much. Once speaker the terminal posts is completely missing, just the wires from the cone showing. the other speakers may be 35 watts at best. I think two of them are CTS according to 137 code. Not sure who was making the speakers for Radio-Scrap.
I also saw burned sections on what appears to be the master control section, so I think the focus should be if the amp works. The K600 has 4 speaker outputs, two for each internal power amp. Each amp wants 3-4 ohm total load per amp. For testing purposes any speaker from 4 to 16 ohms will work. Once the amp is working as it should be, then determine what the amp will be used for and find speaker cabinets that purpose. I know a Large Kustom collector, in fact the largest collector, over 400 pieces of Kustom gear. I know he is going to part with a lot of 4x12 PA columns and some other gear later this year.
pleat
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| Re: Kustom model 600-5 PA [message #24458 is a reply to message #24396] |
Sat, 23 January 2016 06:04 |
stevem
Messages: 4775
Registered: June 2004
Location: NY
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Senior Member |
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The shack up into the 80s used Utah made drivers.
In the 70s they where orange frame with a aluminum dome, then in the late 80s they switched over to Ponneer brand drivers made in where else , China!
The Orange frame drivers sounded very go and most of them went down to 75 hz and they where rated for 40 watts.
You need to watch out with switching over to a different regulator set up as I have never figured out how much current all 6 preamp sections and the EQ/Reverb section eats up and most regulators are only rated at 1 amp.
I understand your wanting to make something better, but in reality I think just replacing the Zeners is all you need to do as I do not think you will ever drive the amps output stage hard enough to change the 12 volt level that the preamps run on that much, but hey it's your time!
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