|
|
|||||||
| Register | FAQ | Members List | Calendar | Gallery | Today's Posts | Mark Forums Read | Search |
| WAD Problems For questions and answers re older World Audio Design Projects |
 |
|
|
Thread Tools | Display Modes |
|
#1
17th September 2006, 01:33 PM
|
|||
|
|||
KEL84 rustling/crackle noise
Hi Folks,
My kel84 has developed what i would call a rustling/crackle noise from the left channel.  First of all I thought this could of been one of the valves but i've swapped them from left to right and the crackle noise is still there. Volume pot makes no difference either and audio still plays through the left channel. It started yesterday after the amp had been on for about 3hrs. Just tried it again now and its still there although but not as loud...... Does anyone have any suggestions before i get the lid of and start poking around? My first thought is that it maybe one of the ICAR PIO caps i have in the signal path the 0.22uf in c9/c10/c11/c12 (not got the circuit diagram in front of me so the c# maybe wrong). The amp is just coming up to its first birthday so not that old at all. thnx Rich 
|
|
#2
17th September 2006, 02:05 PM
|
||||
|
||||
Re: KEL84 rustling/crackle noise
It could be a dry joint in need of a touch of solder,check all connections first before changing anything.The heating/cooling process can cause poor joints to go high resistance.
__________________
Davy
|
|
#3
17th September 2006, 04:45 PM
|
|||
|
|||
|
Re: KEL84 rustling/crackle noise
thnx dave,
I've had a look over the circuit for any dry joints but none obvious. I've gone over the left channel and dabbed some extra solder on the pcb connections and resoldered all the o/p tx and signal connections, alas no change. i think I was wrong about the rustle sound getting louder after the amp had been on for a period of time - probably due to the alcohol consumption between listening to it last night and this morning  any other suggestions ? thnx
|
|
#4
17th September 2006, 06:08 PM
|
|||
|
|||
|
Re: KEL84 rustling/crackle noise
mmm, i'm at a loss now.
replaced the ICAR caps back with the orange drops , still the noise. It seems to have got worse - previously the noise came in and out, now its a constant hiss........
|
|
#5
17th September 2006, 06:10 PM
|
||||
|
||||
|
Re: KEL84 rustling/crackle noise
Could be a resistor breaking down, check to see if any are showing signs of discolouration.
__________________
Just about everything I say has been in public use since the 1940's so no one owns the copyright on that. If by any chance its not prior art, then the copyright is retained by me.
|
|
#6
17th September 2006, 06:14 PM
|
||||
|
||||
|
Re: KEL84 rustling/crackle noise
Could it be a valve about to pack up?,do you have spares to try swapping,especially the ECF80.
__________________
Davy
|
|
#7
17th September 2006, 08:11 PM
|
|||
|
|||
|
Re: KEL84 rustling/crackle noise
It's quite common, happened on my Kel80s, usually the resistors on the input valves on the way out.
http://www.world-designs.co.uk/forum...read.php?t=135 http://www.world-designs.co.uk/forum...read.php?t=134 Regards
__________________
Gerry 
|
|
#8
22nd September 2006, 07:29 PM
|
|||
|
|||
|
Re: KEL84 rustling/crackle noise
It was the resistors, replaced in both channels and my Kel84 is back to its former sonic glory
 Thnx Rich
|
|
|
|
Similar Threads
|
||||
| Thread | Thread Starter | Forum | Replies | Last Post |
| The Agony of Surface Noise | Primalsea | Sources | 50 | 10th November 2006 10:28 AM |
| noise | vitalstates | Amplifiers | 2 | 12th September 2006 12:42 PM |
| KEL84: Output Transformer Upgrade / Shunt Mod | pete_b | WAD General | 10 | 16th April 2006 07:55 PM |
| Lowering feedback in KIT34 KIT6550 KEL84 | FAQ Team | FAQ - Upgrades and Tweaks | 0 | 6th January 2006 10:22 PM |
Linear Mode
