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New Kustom owner - K-150 repair job [message #26943]

Mon, 03 September 2018 16:17

Gordon Wasabi
Messages: 3
Registered: September 2018

Junior Member

Hi All

After giving up years ago on finding an affordable Kustom in the UK, I just did. Its a blue/green K-150SC8 with celestial speakers in great shape apart from a minor issue, namely that the reverb is just hum.

Basic questions first - am i right in thinking that the orientation of the trem-vibrato pot is reversed (ie to my ears turning it to the left makes it more vibrato-like and to the right more trem-like)?

Also, is there any difference between the inputs on either side of the control panel or are they just multiple inputs sharing the same circuitry? The guy I bought it from seemed to think that the reverb should only work when plugged into the right side but I'm not so sure...

I will be stripping this down over the next few days - any pointers for where to start on the reverb problem would be much appreciated.

Cheers

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Re: New Kustom owner - K-150 repair job [message #26944 is a reply to message #26943]

Mon, 03 September 2018 19:18

chicagobill
Messages: 2006
Registered: April 2003

Senior Member

Welcome to the place!

Your amp has two separate channels, one plain and the other has reverb and trem/vibrato. The plain channel has volume, treble, bass controls and a bright switch. The effects channel has the same controls as the plain channel with the additional reverb and trem/vibrato controls.

If the reverb only hums, there may be a problem with the tank or the connecting wires. If you have an ohm meter, you can test the tank and the wires. If not, then there are a few tests that you can do without a meter.

Again, welcome to the place.

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Re: New Kustom owner - K-150 repair job [message #26946 is a reply to message #26943]

Tue, 04 September 2018 05:57

stevem
Messages: 4775
Registered: June 2004
Location: NY

Senior Member

Hello and welcome!
The inputs are different on those SC series of amps that being one input is normal and one is brite.
So start to narrow down on your reverb issue if you bang the amp around do you hear the reverb crash?

If you do then that atleast proves out that the output side of then reverb pan is working , and the reverb recovery amp section is goo also on that effect channel.

Also many times due to the age of these amps the RCA type connectors on the pan and on the channel board get tarnished and simply do not make connection anymore, unplugging these and spinning them while plugging them back in is all it takes many times to get things working again.

[Updated on: Tue, 04 September 2018 06:02]

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Re: New Kustom owner - K-150 repair job [message #26951 is a reply to message #26943]

Wed, 05 September 2018 06:30

Gordon Wasabi
Messages: 3
Registered: September 2018

Junior Member

Update - I used a different pan from a Vox practice amp to ascertain that it was indeed the pan that was at fault. No obvious problems that could be fixed so have ordered an accutronics 4FB3A1B from Tube Amp Doctor in Germany. I was torn between ordering this one and their own brand equivalent (TAD) which they would have modified on request to insulate the input (at extra cost). Guess I will need to lift the ground on the input jack to the accutronics.

On a related note would there be any benefit (eg less noise) in mounting the new tank in the base of the speaker compartment instead of above the amp itself? Obviously in an appropriate bag etc...I will investigate for myself when the new tank arrives but if it's a definite yes I will order the right parts now.

Thanks for advice on the channels etc. Makes sense. The two sides will come in useful for running organ and synth simultaneously.

I took this to a rehearsal last night and my band mates were quite jealous. Lots of attention from other bands in the place too. Guess I will need to get used to that...!

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Re: New Kustom owner - K-150 repair job [message #26952 is a reply to message #26943]

Wed, 05 September 2018 10:04

stevem
Messages: 4775
Registered: June 2004
Location: NY

Senior Member

Good new to hear there!
Yes, getting the pan even just 8 inches more away from the amps power transformer will lower the amount of 50 HZ hum you get as you turn up the reverb.

You can play around with the distance needed to suite you noise floor needs with long cables, but note that the best mounting position is on a vertical wall and pans can be had to do such and is part oft the pans numbering system to determine such!

You can still find Accutronics info online to read up on such.

Don't toss out that stock pan as they can be fixed with enough effort.

[Updated on: Wed, 05 September 2018 10:05]

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Re: New Kustom owner - K-150 repair job [message #26954 is a reply to message #26952]

Thu, 06 September 2018 14:30

pleat
Messages: 1454
Registered: June 2004
Location: Belding, Mi

Senior Member

I noticed you mention the amp is the K150SC-8. That chassis was sold as either the 4 10" speaker or the two 12" speaker set up. You also mention that the amp has Celestions. If your amp is the two 12" model, the speakers should be 16 ohm and wired in parallel for a total 8 ohm to the amp head. If your amp contains four 10" speakers, each speaker should be 8 ohms and wired in series/parallel for a total of 8 ohms the amp.
pleat

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Re: New Kustom owner - K-150 repair job [message #26962 is a reply to message #26954]

Sun, 09 September 2018 10:45

Gordon Wasabi
Messages: 3
Registered: September 2018

Junior Member

hi
Celestion was a mistake - I meant Eminence, which makes it 1969 if I have researched correctly
I think you are right about the wiring, it's a very neat job.
Cheers

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