BassAdder60 Posted January 18, 2022 Share Posted January 18, 2022 Recently my two month old Ashdown ABM600 started to make a slight humming noise when engaging the drive circuit / tube When new it was very quiet and did its job, I started to notice the hum and gave Dave Green a quick message ( thx Dave ) and he said swop the tube and report back. Did this and it’s back to its original great sound without the annoying hum. My question is how many ABM users have had to drop out the tube ( mine had a Ruby in it ) as I’m somewhat surprised it would need changing only after a few months of regular use. As a drive tube I guess it’s going a fair bit of work perhaps ? I popped in a JJ ECC83 S and I will see how long it lasts It’s an easy job but annoying having to carefully remove the four plastic screw covers and pull out the amp from its wooden case. Hopefully a one off ? Quote Link to comment Share on other sites More sharing options...
Woodinblack Posted January 18, 2022 Share Posted January 18, 2022 I haven't had to do it, but you know, its a glass tube with electrons bouncing between metal plates, its always fairly amazing that it works in the first place! Quote Link to comment Share on other sites More sharing options...
BassAdder60 Posted January 18, 2022 Share Posted January 18, 2022 Just now, Woodinblack said: I haven't had to do it, but you know, its a glass tube with electrons bouncing between metal plates, its always fairly amazing that it works in the first place! In amps where the humble 12AX7 or ECC83 is the pre amp tube or tubes they tend to last years in comparison to power stage tubes. Just maybe they are working this tube hard to get the grind and drive tone ? Quote Link to comment Share on other sites More sharing options...
agedhorse Posted January 18, 2022 Share Posted January 18, 2022 Defective tubes do sometimes occur. Quote Link to comment Share on other sites More sharing options...
BassAdder60 Posted January 18, 2022 Share Posted January 18, 2022 8 minutes ago, agedhorse said: Defective tubes do sometimes occur. Yes that’s true .. A marvellous thing yet so fragile Quote Link to comment Share on other sites More sharing options...
Sparky Mark Posted January 18, 2022 Share Posted January 18, 2022 (edited) 3 hours ago, BassAdder27 said: Yes that’s true .. A marvellous thing yet so fragile I love this film of the history behind the British valve industry. It also shows how they're made in detail. https://youtu.be/GDvF89Bh27Y Edited January 18, 2022 by Sparky Mark 3 Quote Link to comment Share on other sites More sharing options...
Stofferson Posted January 18, 2022 Share Posted January 18, 2022 I got my ABM 600 2nd hand from here like 3 years ago now, like 6 months into me having it i had to change the tube once. It's been awesome since. Quote Link to comment Share on other sites More sharing options...
CJPJ Posted January 18, 2022 Share Posted January 18, 2022 Bought mine off here a month ago or so with the hum on the value. It arrived with Dave today so hopefully will get fixed. Didn't want to attempt it myself although I've changed the valves on my old OTB500 a couple of times to change the tone. Quote Link to comment Share on other sites More sharing options...
BassAdder60 Posted January 18, 2022 Share Posted January 18, 2022 1 hour ago, CJPJ said: Bought mine off here a month ago or so with the hum on the value. It arrived with Dave today so hopefully will get fixed. Didn't want to attempt it myself although I've changed the valves on my old OTB500 a couple of times to change the tone. It really is straight forward but if Ashdown do it then you know they will check it over too Quote Link to comment Share on other sites More sharing options...
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