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Tweeter issue with GK 700RB (model 1) 115 combo

S

Stakes_Is_High

Apr 14, 2012
19
0
#1
Hey guys,

New member here so I apologize if the post isn't where it should be and for its length. I just bought a used GK 700RB (model 1) 115 combo for $200 and it sounds great as is, but I realized the tweeter does not work at all. I tested the tweeter by muting the woofer/master volume (lowered pot all the way) and played high notes while increasing tweeter volume. There was no sound whatsoever even with the tweeter volume maxed and the tweeter high cut on or off. This amp has two different amps for biamp capabilities, one 50w for the tweeter and one 380w for the woofer. Based on this logic, I slid the head out of the cab hoping to find two fuses with one being burnt, but to my surprise, I only found one fuse and it appeared to be fine. I admittedly do not know much about circuitry or amps but I did find a reddish brown connector prong on the circuit board that had the letters BIAS and p2 labeled near it with nothing attached. I looked for loose or unconnected wires and there was nothing I could find. It isn't worth it for me to bring it to a shop as it does sound good as is but if I could get the tweeter working on my own, why not? I can't tell if the problem is the 50w amp, that connector, the tweeter itself, or the speakon conductors. Any help would be much appreciated (have never done amp repair before so the most basic terms would be best!) Thanks! :p
ps- if it helps I can take the head out again and upload a picture
 
#5
It makes no difference to me, help is help and is much appreciated! Anyway the amps are connected with a speakon connector. I'm not too familiar with the how the speakon connectors are organized as this is the first amp I've owned that uses them. I have taken apart the connector's head and verified that the wires were screwed in properly and they appeared to be fine. How do I get inside the cabinet to test the tweeter with the battery? The only possibility I see with working inside the cabinet is to remove the side handles but that is about it...
 
#7
Stakes_Is_High said:
I didn't even think about removing the grill... I assume that this is the best way to access the horn for removal.
Click to expand...

Only way. If you have some test leads with alligator or push clips you can just attach them to the pins on the speakon labeled "2+ and 2- those connect directly to the horn inside (if the connection in the cab is okay).
The labels on the connector can be pretty small you will need good light to see them.
 
#9
Joe Louvar said:
Stakes_Is_High, you're in luck because B-string is a pro repairman.
Click to expand...

I can see that! I have never done anything related to amp repair so I am quite newbie to this stuff but definitely not afraid to try things.

As far as the battery test goes, I found it to be strangely inconclusive so far. I used leads for a multimeter taped to each pole on the battery with electrical tape, checked to see if the multimeter gave a reading (which it did) and then proceeded to put the other ends on the +2/-2 ends of the speakon terminal wires. Not only did it not make a noise or move at all, I tried the same test on the +1/-1 terminal wires as well which I know for a fact that the woofer is in working condition and got the same result. 1.5 V should be more than enough to move the woofer or horn from what I've heard...
 
#10
Im guessing that you got the pins wrong on the speakon. Since you have a multimeter, do a continuity test all the way through from the speakon pin to the terminal of the horn (thats the one that beeps when you touch the leads together). In fact, while you are in there, get another set of wires or the aligator clips, and do the battery test right on the horn terminals and test it directly, since you don't know if its wiring or the horn. Take note of the color of wires when you do the continuity test.
 
#12
Upon further inspection, I took out the horn and the woofer from the cabinet. I noticed that the horn is definitely not the original part because it is not a paragon 50w RMS it is a P.Audio ht406. Tested the battery directly on the terminals and it made a noise so it is not entirely blown. Second thing I noticed was that both the woofer and the horn wire terminals were not properly connected to the speakon on head as there was a one of the woofer wires on 1 and one of the horn wires on 1 etc. I'm going to rewire these according to GK manual for biamp mode and then see if there is a difference. Only thing I am wondering now is how did the woofer work at all if it was not wired properly in both +1/1- terminals?
 
#14
I don't remember exactly how it was wired because I just rewired it properly but it basically one terminal of the woofer was on the 1 (don't remember +/-) and the other was on the 2 (don't remember +/-). By filter circuit do you mean a built in crossover? I honestly don't know anything about this horn I just looked it up by the labeled brand name not too long ago to see if it even was 50 RMS (which unfortunately it is not).
 
#17
@Kenner Believe me I know it was a steal haha. Got lucky that some guy in NY who barely played any bass was moving to Montana and didn't want to deal with it anymore. Put it up on Craigslist and apparently I was the first serious inquirer coming from Jersey to test it out after it had been listed for months. Even without everything working yet it has a great tone and punch.
 
#18
@B-string that's what I figured. However, I've been pushing this amp pretty hard with the woofer wired as it was and I don't believe that a 50W amp would have been able to keep up with that at all. If it were wired the way you say it might have fried the 50W, I would assume there wouldn't be sound at all from the woofer.

Either way, now that it is wired properly I'll pop the amp back in and test it out fingers crossed. I wouldn't be too disappointed if the horn didn't work at all as it seemed to have pretty decent highs as is.

Anyway thanks for all the help guys I really appreciate that there are still people out there willing to help bass player out! Will report after I put everything back together.
 
#20
Stakes_Is_High said:
@Kenner Believe me I know it was a steal haha. Got lucky that some guy in NY who barely played any bass was moving to Montana and didn't want to deal with it anymore. Put it up on Craigslist and apparently I was the first serious inquirer coming from Jersey to test it out after it had been listed for months. Even without everything working yet it has a great tone and punch.
Click to expand...

I have well over 300 shows on my 700/112...always delivers
 

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