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Help! - Kustom Lead V -Distortion on E string only [message #18282]

Wed, 27 February 2013 00:24

oddeddie
Messages: 7
Registered: February 2013
Location: Portland Oregon

Junior Member

I aqquired a late 60s(?). Kustom Lead V amp. Repair a shorted wire & every thing seems to be fine except when I hit the Low E string with any force the sound craps out, like a blown speaker?. Everyone told me it was a blown speaker, I didnt think it was. I replaced the Celestion G12S-50 with a suitable match, It still does the same thing. Can the bass control knob have anything to do with it? Any help is appreciated!!

[Updated on: Wed, 27 February 2013 00:54]

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Re: Help! - Kustom Lead V -Distortion on E string only [message #18283 is a reply to message #18282]

Wed, 27 February 2013 01:02

chicagobill
Messages: 2006
Registered: April 2003

Senior Member

Welcome to the place. Low frequency buzzes like that can be caused by a bad speaker, something loose and vibrating in the case, or in the chassis.

Seeing as you've replaced the speaker that will rule that out. Try and touch different parts of the cabinet as you play the note that causes the vibration, the handle, the baffle board, each side panel, etc.

Also check for loose screws on the chassis and check for loose parts on the circuit boards.

If you have access to a stethoscope, you can try and pinpoint where the buzz is coming from. I use a paper tube from a roll of paper towels to do this as well.

It may also help to retune the e string up or down a little to really get the buzz going strong.

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Re: Help! - Kustom Lead V -Distortion on E string only [message #18284 is a reply to message #18283]

Wed, 27 February 2013 01:10

oddeddie
Messages: 7
Registered: February 2013
Location: Portland Oregon

Junior Member

Thanx for the quick reply! I didnt think to check the obvious as it really does sound like the speaker :/ I did run it through my pioneer home speaker as I know its a "secure" system, it still had the distortion. Another thing I didnt mention was there is no back on it, I believe they came sealed? Also would like to date this thing, best I can figure is late 60s. Its solid state,tolex covered, made in Chanute Kansas, model "VL", seial # 149801
Thanx again!!

[Updated on: Wed, 27 February 2013 01:29]

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Re: Help! - Kustom Lead V -Distortion on E string only [message #18285 is a reply to message #18284]

Wed, 27 February 2013 01:27

Kustom_Bart
Messages: 601
Registered: October 2010
Location: Greenville, MichiGUN

Senior Member

Kustom started with Tuck and Roll in appr. 64 and ended in 73-74 when Kustom was sold to Baldwin Piano Company and then they went to Tolex. So yours was built 74-75 or after, Pleat can tell you more about the time it was built. You can build a back for it easy enough with a piece of plywood and screw it on. It will make a huge difference in sound. You can always take it off if you like it better without too.

[Updated on: Wed, 27 February 2013 01:36]

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Re: Help! - Kustom Lead V -Distortion on E string only [message #18286 is a reply to message #18285]

Wed, 27 February 2013 01:34

oddeddie
Messages: 7
Registered: February 2013
Location: Portland Oregon

Junior Member

Great!! I apprently didnt have good info on the history of Kustom. Getting late here but I'll try a few things tomorrow. & let you know. Im excited to get this amp up & running! I had planned on making the back...I heard they really thump when enclosed
Cheers!, Ed

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Re: Help! - Kustom Lead V -Distortion on E string only [message #18287 is a reply to message #18286]

Wed, 27 February 2013 01:54

Kustom_Bart
Messages: 601
Registered: October 2010
Location: Greenville, MichiGUN

Senior Member

I am not real up on the tolex models and have never owned one. I am not sure when they made what models etc.

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Re: Help! - Kustom Lead V -Distortion on E string only [message #18291 is a reply to message #18282]

Wed, 27 February 2013 09:39

stevem
Messages: 4774
Registered: June 2004
Location: NY

Senior Member

I would check that the machine screws on top of each of the two main filters at the wire lug connection points are tight.

Check that the speaker output jacks are tight to the chassis.
Check that all the White Molex connectors that the amp uses inbetween circuit boards are tight as over the years these connection points can get flacky. Also these aluminum pins ( male and female) become tarnished and make for a poor coonection.
If they fit tight sometimes just plugging them in and out a few times is enough to clean some tarnish off.

When circiuts start to be driven hard and call for alot of
current an poor connection can sound just like a bad speaker.
It could also just be that your two main power supply filters that I posted before on are shot, but I would check thses other things out first.

[Updated on: Wed, 27 February 2013 09:41]

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Re: Help! - Kustom Lead V -Distortion on E string only [message #18330 is a reply to message #18282]

Wed, 06 March 2013 13:15

oddeddie
Messages: 7
Registered: February 2013
Location: Portland Oregon

Junior Member

Thanks to everyone for the help. I tinkered with this thing for a few days & it still makes that sound. I did realize that it starts "crapping out" after it warms up. It sounds fine for about 5-10 mins, then starts distorting. Got my meter out this morning & will start testing circuts etc.
Thanx!!!!

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Re: Help! - Kustom Lead V -Distortion on E string only [message #18331 is a reply to message #18282]

Wed, 06 March 2013 16:23

stevem
Messages: 4774
Registered: June 2004
Location: NY

Senior Member

It sounds like its a thermally related problem so if you get out to a radio shack or electronics supply house, pick up a spray can of freeze spray then with a hair dryer set to low you can heat up circuits to speed up the ocurence of the problem and then cool it down with the spray and repeat the heat application to confirm the problem.
Just make note that transistor/IC chips and diodes should not be heated much above 120F or they can go south so if you have or can get a friend to lend you a IR thermal gun you can put it to good use.
Also note that each output transistor that is mounted to the bottom of the chassis has a 2 pin slip on connector on its other side and if these pins get tarnished and make a poor connection then most times just sliding these connectors up and down can make for a good connection again.
Also note that in the center of each pair of slip on connector you will find a metal cased diode in a small clip, be very carefull around the leads of the diode, on both the diode side and the circuit board side as these leads can be broken off sometimes without much movement and if one lead brakes off and you power up the amp you will blow the whole output stage.
If you find you need to track down a intermitant circuit board connection the use of a wood chop stick makes a great non-shorting probe to tap around with.
Good luck!

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Re: Help! - Kustom Lead V -Distortion on E string only [message #18454 is a reply to message #18282]

Mon, 18 March 2013 15:56

oddeddie
Messages: 7
Registered: February 2013
Location: Portland Oregon

Junior Member

OK, after much poking around (trouble shooting) I stumbled across what I think is the problem. I seperated the speaker from the amp & put it about 10ft away.....no distortion, even when the Bass is turned up & strummed hard. By accident I found what appears to be the problem. There is a metal rectangular box with 2 prongs on each side, suspended by 4 springs.If this is bummped the sound completely falls apart (distortion) I think the speaker was vibrating this component making it distort. Can this be stablized or does it need to free float? I decided to keep the the speaker seperate from the amp anyway as I built a speaker cab & amp housing. I tried toattached a pic of the componenet & the new set up (first two pics in the album)
Cheers & Thanx!,Ed

https://www.facebook.com/media/set/?set=a.1332222675466.2039 284.1528001552&type=1

[Updated on: Mon, 18 March 2013 16:00]

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Re: Help! - Kustom Lead V -Distortion on E string only [message #18455 is a reply to message #18454]

Mon, 18 March 2013 17:03

Kustom_Bart
Messages: 601
Registered: October 2010
Location: Greenville, MichiGUN

Senior Member

Looks like a reverb tank to me. DO you use the reverb? If not simply unhook it and remove it, but save all of the pieces in a zip-lok and label it so you can always put it back in and make it so it is usable.

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Re: Help! - Kustom Lead V -Distortion on E string only [message #18456 is a reply to message #18455]

Mon, 18 March 2013 17:32

oddeddie
Messages: 7
Registered: February 2013
Location: Portland Oregon

Junior Member

Hi Bart
yes I do use the reverb. Everything seems to be OK so I'll leave it as it is. Interesting that part is the reverb tank, I actually thought it had something to do with the reverb at first but a friend convinced me otherwise :/
Everyone on this site has been GREAT, nice to see helpful people out there!
Cheers!, Ed

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