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Audio Research - should I replace the valves?

I have a AR Ref 110 power amp and AR Ref 3 preamp. Both have done about 3,800 hours. They both work but I wonder if should be replacing the valves.

How can you tell if they’ve had it? Does the sound quality deteriorate & what happens if you don’t replace them?

i don’t think they sounds as good as they did but no pops or whistles or any other strange noises etc - just a bit flat sounding. But perhaps this is just my ears?

 

pp

willmarchant
fsonicsmith's avatar
fsonicsmith
987 posts
 

Yes, you seat the tubes and then bias. As a long term ARC owner, trust me please and invest in a decent Fluke. As in Fluke meter. And don't sweat it. Except that finding a reliable source of tubes particularly for your amp is not so easy anymore. 

ghdprentice
8,128 posts
 

Tube replacement is simple. Do not touch the tubes with your fingers… use a clean cloth. Biasing is easy… here is a copy of the manual in case you don’t know where it is.

Do this once and you’ll be a pro. It sounds much harder than is.

 

Fluke meters are good and come in vastly different cost ranges. You do not need to spend a lot. I always have a multimeter around, there are hundreds of brands. 

 

https://audioresearch.com/wp-content/uploads/2021/06/REF110_Manual.pdf

willmarchant OP
11 posts
 

Thanks, I do have a Fluke. I’m going to use KT120 valves in my 110. Is it the same settings? I looked at the manual and it says you should use 120v AC to adjust the bias. Obviously in the UK we have 240v AC or am I being dim?

noromance's avatar
noromance
10,198 posts
 

240v in UK is fine. What they mean is the wall voltage should be at 120/240VAC as the preferred voltage to set bias. This is because the internal amplifier voltage varies if the wall voltage varies. 

curiousjim's avatar
curiousjim
5,388 posts
 

So my preamp used 6922’s and they should last about 5,000 - 10,000 hours, but most power tubes should be replaced every 2000  - 2500 hours. 

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