Mr.Toast Messages: 11 Registered: September 2015 Location: Kent, Ohio
Junior Member
Hi folks. I recently picked up a K100-2 head and 1x15 cab. It's black and in very nice cosmetic shape...just one small cig burn and a few small nicks. It cleaned up great. It looks like the cab originally had a D140f in it but sadly that is long gone and replaced with a Pyle driver. I love the look of this thing and intend on getting it back to it's original glory. I have just a few questions (for now)...
#1 The amp plays and sounds decent but has a hum which seems to be a grounding issue. Will that clear up if I replace the power cord with a three prong or is there another "usual suspect?" I have other vintage two prong amps that don't hum nearly as bad when plugged into the same outlets.
#2 The reverb and tremolo are not working at all. I do not have the original footswitch. Is that needed to get them to work? I have tried a few footswitches I have from other amps to no avail.
Thanks in advance for the help...it seems like the people on this board are cool Kustom-ers.
stevem Messages: 4738 Registered: June 2004 Location: NY
Senior Member
Hello and welcome to the joint!
Your amp and cabinet are not matched as a k100-2 head with the effects for guitar would not have been sold with the for Bass use JBL 140 speaker, so I guess it's good that it has a crap Pyle driver in it!
Note ,that all too many of the drivers that Plyer makes are rated very low in SPL rating so your likely to want to replace it at some point.
The amp only needs the foot switch to turn off the effects on the fly.
If the trem and reverb do not work than atleast the trem section has issues , the reverb not working is likely a dead reverb pan.
If you turn the reverb control down to zero, does the level of hum drop off?
Hum wise are we talking a tone like a low B on the guitar which would be done 120 hz, or more like a buzz?
Have you opened the amp to see if the reverb pan is even there or if the cables are connected to it or just laying inside the unit? Check also to make sure that the tip on the footswitch is actually touching the prong on the jack....on one of my amps, did the same thing you described until I cleaned the jack up and bent the prong to where it was suppose to be.
But he also said he tried using another footswitch and it still didn't work. I don't have the original footswitch for any of my amps but seems that any footswitch with a standard plug on it will work or stereo plug if two effects are wired off of one plug. Just trying to lessen the number of possible variables that might be causing the problem.
You are probably right about what is wrong, but he is describing EXACTLY the same problem I was having with an amp I had bought and I did not have the footswitch, it hummed until I got a generic footswitch. I was then able to shut the reverb off and the hum was gone. The tabs on the reverb pan where the cords connected were not making a good connection. Cleaned them up and bent them back into position and the reverb worked like a charm. The footswitch jack also was not making a good contact until I re-bent the prong that touched the tip of the footswitch plug.
Sometimes the obvious are the simplest fixes......when we're lucky and that doesn't happen very often.
You and Bill are still the experts here when it comes to trouble shooting.
My amp must be wired wrong then.....the reverb will not shut off unless there is a footswitch connected....the pot still controls the intensity but does not turn it off. My 250 works just like you said though.
Mr.Toast Messages: 11 Registered: September 2015 Location: Kent, Ohio
Junior Member
Thanks for the warm welcome and your excellent suggestions. I will have some time this weekend to dig into the head and check things out. I am actually stoked to hear that the head is more of a guitar than a bass head. I am primarily a guitar player so I guess it's time to look for a replacement 15in speaker that is designed for guitar...any suggestions? I have always played thru guitar amps with 12's or tens, never a 15.
Thanks a 1E6.
AL
pleat Messages: 1452 Registered: June 2004 Location: Belding, Mi
Senior Member
Well as far as the hum, replacing the the AC cable with a grounded 3 prong cable and plug will only make the amp safer to operate with other equipment. I think the point was brought up that the hum may be reverb related.
Unless a person has owned an amplifier from brand new, there is no telling who may have tampered in the amp or replaced speakers. That being said, a good visual inspection is always a good thing. Your amp may just have bad reverb cable connections as pointed out in this thread, to perhaps a broken wire inside the reverb tank itself, or a broken reverb spring, to a missing tank or replacement tank that won't work.
I tend to think you have larger problems since both reverb and vibrato are not working. All kustom amps with the exception of the K200A series amps, the effects work without a footswitch. The footswitch as StevenM said, you only need the footswitch to remotely turn off the effect.
The early versions of the K100-2 head had reverb so thick that even with the reverb gain turn down there was still a trace amount. I think Kustom did at least three revisions to that series of amp over the years.
Again after 40+ years, your K100-2 amp head could have been originally sold with the single 15 JBL D140F speaker. Music was a lot different back then and a guy could have been both a bass and guitar player so he chose the effects head with the bass speaker cabinet. Dealers were more interested in selling product. I remember country players would double up and a bass player and rhythm or lead player would buy a 2x15 cabinet and a K200B-2 effects head. Bass player would use the normal channel and the guitar player would use the reverb channel.
Mr.Toast Messages: 11 Registered: September 2015 Location: Kent, Ohio
Junior Member
Well a visual inspection reveals that the reverb tank has been removed completely. There is just a brown and gray wire left hanging. I will need to find a picture of the guts of a working K100-2 to see how mine should look in there. I guess I will need to do more than I had hoped to get it back up and running, but I only paid $100 for the amp and cab so I still feel like I got a bargain. This head is so light when you pull it out of the box, it wouldn't cost much to ship, so I may need to send it off to someone. Is there a tech that you guys use or could recommend?
Thanks again.
AL
ChicagoBill isn't that far from you, maybe if he's not busy he can do the repairs for you......Stevem is in New York. Like I said, Stevem and Bill are two of our tech genius's on this site. If they can't fix it, it can't be fixed period.
Are the cables still connected to the board? If so and they are touching the case, that's probably where the hum is coming from.
stevem Messages: 4738 Registered: June 2004 Location: NY
Senior Member
Take care of him Bill, he sounds like another great Kustom nut case, lol!
Mr Toast, does the amp atleast still have the two top mounted aluminum cross bars that the reverb pan use to hang off of?
Thanks much for the kind words Iowa Boy, but Bill on the solid State genius level not me, I am still working on it.
Speaker wise your best bet for a driver that would not blow a hole in your wallet would be a Jensen C15N.
Mr.Toast Messages: 11 Registered: September 2015 Location: Kent, Ohio
Junior Member
There are two top mounted cross bars, but they are at the ends of the chassis and seem to be there just for the structure of the chassis. I will post a picture of the guts when I earn enough Kustom board cred to have that option. Thanks for the speaker recommendations. What ohm rating should I be looking for? I would not trust that the speaker in it now is matched correctly.
AL
The crossbars or supports are where the reverb tank hung below them by four bolts. Unit hangs on the right end of the amp chassis.
The speaker cabinet probably had originally since it was just one speaker, an 8 ohm speaker. I don't remember ever hearing of Kustom using a single 4 ohm speaker in any of there equipment but I could be wrong. Pleat will be the one to tell you for sure what was originally in there.
If you decide to rebuild your cabinet, you might want to consider going with 2-12's or even better yet 4-10's or 4-12's wired in series parallel. Any combination of 8 ohm speakers will get you to the total 4 ohms load that Kustom designed there amps to run best at. The more speakers you have the more air movement you get and more distribution of sound. I personally think the sound quality out of a speaker smaller than a 15 inch is better but have no documentation to prove it.......just my ears.
pleat Messages: 1452 Registered: June 2004 Location: Belding, Mi
Senior Member
Your K100-2 amp head is an 8 ohm amplifier. So if your going to replace the speaker, order the speaker of your choice in 8 ohms.
You could make up a new baffle board with 2 12" cutouts and then you would want to order the 12" speakers in 16 ohms.
The cabinet isn't large enough to make it a 4x10" set up. If your not decided on what you want to use, single 15 or something else. You could trace the 15" speaker diameter and bolt pattern on a piece of 1/2" plywood. Mark the center point of the 15" and then cut out a opening for a 12" speaker cone. Bolt the 12" speaker to the donut you made and bolt the donut to the 15" speaker bolts. Basically making a reducer ring. This would give some other options as to brands and sizes of speakers with minimal work. Speaker size and tone is more personal preference.
The reverb tank mounting rails are missing. They are the same size and material that the end bracing tubes are. You will see the 4 mounting holes on the top of the chassis. There should be one more hole on the back top side of the chassis which was used for the grounding wire of the reverb tank.
Have you unplugged the brown and gray RCA cables and tried the amp to see if the hum is gone?
I have really nice K100-2 head in black in perfect working order for sale on this site and on CL in Grand Rapids that has a clean bill of health. Just got it out of the repair shop for a check up. http://grandrapids.craigslist.org/msg/5187006872.html
Sorry...misread your thread and thought you were thinking about building a new cabinet all together not just replacing the 15. Pleats right the 4-10's won't fit in your present cabinet. Now 4-8's will work that are 8 ohms. 16 ohm speakers are kind of limited and not sure what is available other than Eminence Delta's 15's at 16 ohm if your thinking of going more than one speaker. You'd have to make a new baffle plate of course......just matters how much work your wanting to go to and how much you want to keep it original.
Now if you want, you could put another D-140 bass speaker back into the cabinet to keep it original. They are still available (sometimes re-coned) on Ebay. Sound quality, I doubt that you would notice that much difference other than the frequency range will be different. At least you could then use your amp for guitar as well as bass or keyboards without worrying about damaging the speaker. I know Pleat will cringe when I say this, but you could also put a couple of super tweeters in the cabinet to increase you high end......put them inside your bass ports if you have them and decide against using bass speakers. Just an option.
stevem Messages: 4738 Registered: June 2004 Location: NY
Senior Member
Just unplugging the reverb cables may not be enough to stop any 60 hz hum from the power transformer that may be coming thru.
Try this.
With both cables plugged into the board turn the reverb control up and tap each end of each cable.
On one cable you will hear a buzz when doing that, and that will be the cable that you want to short out across itself.
If the cables are not the thick gray stock ones but are thin replacements then just cut the cable off, strip it and twist the wire together. This will short the input to the recovery amp and may be kill off some hum.
When doing this with the amp on stay clear of any of the wires with the wall outlet voltage on them near the on/ off switch and the fuse area!
C4ster Messages: 686 Registered: June 2001 Location: Mukwonago, WI (Milwaukee...
Senior Member
As far as JBL D series speakers are concerned, the D140 was a bass speaker that had a 40 to 2500 Hz frequency response while the D130 was 50 to 6000 Hz. If you like a full guitar sound, the JBL 15's can't be beat. I have JBL's Jensens and CTS speakers in various cabinet configurations, and the 140's in the 1x15 cabs are really great for bass but are lacking the highs for that shimmering guitar sound.
Conrad
Thanks for the input Conrad.......didn't realize there was that much frequency difference in the two speakers. I'd definitely opt out then for the D-130 or another cabinet that was made for guitar.
I could only find 12 inch guitar speakers made by Eminence that are either 8 or 16 ohms. Delta's yes in 15's. Jensen's only found 12 inch in 8 or 16 ohms, 15's only in 8. Steve.....does Weber make a 15 in 16 ohms in the event he would want to go with two speakers in the cabinet? Just doesn't seem like they make many 15 inch speakers for guitar.....mostly bass. Come to think of it, I've never came across a JBL 15 inch that was 16 ohms, all I've seen are 8 ohms. Surely at one time or other they were made at 16 ohms weren't they?
Mr.Toast Messages: 11 Registered: September 2015 Location: Kent, Ohio
Junior Member
Thanks for the speaker knowledge. I am searching eBay and CL now for a decent 8 ohm D130, it will cost more than i paid for the whole stack, but they hold their value so well that it really is a good investment...at least that's what I am telling myself. Can you put a price on great tone? I think not.
Thanks again.
AL
Also keep your eyes open for a cabinet that might be beat to hell but still has good speakers in it. Usually you can pick them up for a song as well. I am constantly scanning the Midwest for deals. If I see something that has anything that might work for you, I will post it to you. If your patient, you can find anything thanks to the internet. Yeah JBL's aren't cheap and the "knowledgeable" people in our business know what they are worth. Sometimes you get lucky and find someone who doesn't have a clue what they have and basically give it away. Those are the real finds.
There's a D-130 listed on Ebay for $199 or best offer. See if he'll bite for $150. You just never know. There is also a set up for sale there too and current bid is $138 and I'll bet they will go for about $300. You could bid on them and if you win sell the other. Just thought I'd give you a heads up.
Mr.Toast Messages: 11 Registered: September 2015 Location: Kent, Ohio
Junior Member
Thanks, I have been watching eBay for D130's as well. There have been two that went Buy-It-Now for around $150 in the last few days. I just need to pull the trigger next time I see one in that range.