BHK Signature PreAmp Tube Replacement


#1

At approximately how many hours should I replace my PreAmp tubes? I have seen many suggestions of annually but everyone’s usage is different. Thanks.


#2

I’ve always thought 2000 hours of operation was the rule of thumb. Similar to the life span of an incandescent light bulb. That’s a long time if you think about it. A year at work. Paul has said replace tubes annually but that seems like overkill to me. I use my stereo a lot but nowhere near 2000 hours a year.


#3

Small signal tubes can easily last over 10,000 hours.

I suggest purchasing a replacement set and installing them every year or so and comparing to your existing tubes. Once the new set sounds better, toss the old and keep the new tubes in the unit.


#4

I’ve had preamp tubes both 6 volt and 12 volt easily last over five years with no degradation in the sound. There are some preamps that however are famous for eating tubes on a yearly basis or worse. The ones that come to mind are Audible Illusion and CJ.


#5

I am with Elk on this. I bought the BHK300s in August 2015 and I am still running on the original tubes and the amps have played “much longer” than 2000hrs ! I tried a new quad set last August just for comparison and there was no “wow” improvement musically.
They made the amp a tad louder and clearer but the amp wasn’t as sweet sounding - which would have arrived with burn-in. I just reinstated the original valves. I have used original tubes on other amplifiers I’ve owned for 7+ years…! Only when the music suffers, level imbalance and or clicks & pops do I change them… Like I said before on this very same subject, there is a lot of paranoia and audio nervosa when it comes to the life span of amplifier Tubes. Bear in mind they are input tubes !
I have read about owners changing input tubes at 400 hrs … To me that’s just crazy !! Playing 24/7 one would be changing tubes every 17 days…

[ EDIT: ] Been doing some calculations: the original tubes in my 2.5 year old BHK300s have been powered up around the 9000 hour mark… ‘I’ve not played music for that length of time’ - the BHK300 tubes are usually on for 10 hours a day. I never fret about the length of time the tubes are switched on: if music becomes degraded and / or the tubes eventually pack in I will simply go into the cupboard for a new set…


#6

I replace the BHK preamp tubes about every 6 months but then I am also over the top.


#7

That’s how I do it. Once a year swap and listen. One important note is that the tubes should be the same or you could easily think you’re hearing degradation in your old tubes when you’re actually hearing the difference between say a Brimar vs Mullard…