KEL34 problems

[RoyB]

Hello to all,
I have a Kel 34 which is rustling and popping. I have changed the valves between channels but it is still there. Is there anybody who can repair and upgrade if for me. I built the amp over 20 years ago and it hasn’t played up at all. I’m in the North London area, junction 25 of the M25.

Thanks in advance

[Richard]

Hi Roy,
Dirty/loose valve base contacts or failing ECC82 anode resistors;
http://www.world-designs.co.uk/forum...read.php?t=134
http://www.world-designs.co.uk/forum...read.php?t=135
Our very own John Caswell lives in the Reading area and may be able to help

[John Caswell]

Hi Roy/Richard,
Yes can do if required.
PM for address etc.

John

[RoyB]

Hi Richard/John

In have the resistors I need, I can see the 35k pair and can make out of the 47k and 150k in parallel on R7 and R20

R19 pair measure 95k and R24 measures 106.7k
what do need to fit in R19 and R24

thanks in advance

[Richard]

Hi Roy,

Yes its sounds like yours are failing. I found mine varied when I checked them hot and cold.

I've attached the original build drawing of the Ecc82 anode resistors.

Make them up using the values as shown but use 1W carbon or metal film resistors rather than 0.6W and try to leave space between and around them. (The W ratings are for free air. There is not a lot of free air in there and they will mutually heat each other hence uprating them.)

Then simply change them. That may need the pcb removing or if you have room to work in there and have some legs left on the old resistors you may be able to snip them out and solder the new ones to the old legs. That needs a quick iron with low temp solder (not lead free pudding) and pre-tin the legs.

[Richard]

Actually Roy I'm not sure why R19/24 is made up that way as 47K is easily available off the shelf so just use a 2W carbon or metal films in there. I'll have a look in the box and see if I've got some.

[Richard]

Yes got some 47K 2W carbon film for R19/24
and 33K 2W with 3K3 2W to series connect for R7/20
will pop in the post if you pm your address