Hello guys, it’s me again...
I decided to replace the the valve in the preamp of my valvestate head today, while it was open I used a good amount of contact cleaner too. Fairly liberally, left it all day to make absolutely sure it was dry (dry to the touch within a minute or so). Valve glowed correctly when I powered it up before I screwed it back together.
thing is, the clean channel is now significantly quieter than it was. The overdrive channels are a huge amount louder at the same relative setting.
Sounds good and it’s loud enough still but is this just a ‘new valve’ thing or is something wrong?
https://ibb.co/hrBN3STheres the old valve snd the box of the new one if that helps.
As ever, any advice is very much appreciated
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Dave
Comments
Spraying contact cleaner randomly over the whole circuit board is not a good idea either - some types can leave a conductive residue.
"Take these three items, some WD-40, a vise grip, and a roll of duct tape. Any man worth his salt can fix almost any problem with this stuff alone." - Walt Kowalski
"Only two things are infinite - the universe, and human stupidity. And I'm not sure about the universe." - Albert Einstein
In the VS series (and the older 80 series - although the valve is only on the dirty channel in those so I assume it's not one of them), the valve is used as a 'cathode follower', which some valves have a problem with... including some JJs.
If it's an AVT it's more complicated - I'll need to look at the schematic
"Take these three items, some WD-40, a vise grip, and a roll of duct tape. Any man worth his salt can fix almost any problem with this stuff alone." - Walt Kowalski
"Only two things are infinite - the universe, and human stupidity. And I'm not sure about the universe." - Albert Einstein
https://ibb.co/gEXjYS
One of the the older ones I think. So does the valve only ‘do things’ on the dirty channels? For some reason I thought it was the other way round..! I can buy another valve if that’s the likely issue (hoping it’s not overly liberal contact cleaner spraying..)
Try the old valve first, anyway - if it doesn’t fix it the problem is somewhere else. The old valve is Chinese-made, which don’t have the cathode-follower problem.
"Take these three items, some WD-40, a vise grip, and a roll of duct tape. Any man worth his salt can fix almost any problem with this stuff alone." - Walt Kowalski
"Only two things are infinite - the universe, and human stupidity. And I'm not sure about the universe." - Albert Einstein
http://www.karltone.co.uk/shuguang-12ax7-ecc83-707-p.asp
For cathode-follower positions you need to avoid all Russian-made and usually JJ valves, which is most of the rest unfortunately. TAD and Ruby also do some good Chinese-made valves.
"Take these three items, some WD-40, a vise grip, and a roll of duct tape. Any man worth his salt can fix almost any problem with this stuff alone." - Walt Kowalski
"Only two things are infinite - the universe, and human stupidity. And I'm not sure about the universe." - Albert Einstein
"Take these three items, some WD-40, a vise grip, and a roll of duct tape. Any man worth his salt can fix almost any problem with this stuff alone." - Walt Kowalski
"Only two things are infinite - the universe, and human stupidity. And I'm not sure about the universe." - Albert Einstein
Using a cloth can still be a good idea when you're changing a hot valve in a hurry though
A spare valve is not a foolish thing to have, anyway.
"Take these three items, some WD-40, a vise grip, and a roll of duct tape. Any man worth his salt can fix almost any problem with this stuff alone." - Walt Kowalski
"Only two things are infinite - the universe, and human stupidity. And I'm not sure about the universe." - Albert Einstein
"Take these three items, some WD-40, a vise grip, and a roll of duct tape. Any man worth his salt can fix almost any problem with this stuff alone." - Walt Kowalski
"Only two things are infinite - the universe, and human stupidity. And I'm not sure about the universe." - Albert Einstein
volume back to how it should be
"Take these three items, some WD-40, a vise grip, and a roll of duct tape. Any man worth his salt can fix almost any problem with this stuff alone." - Walt Kowalski
"Only two things are infinite - the universe, and human stupidity. And I'm not sure about the universe." - Albert Einstein