tube change interval

amplifiers, receivers and loudspeakers
sunderwood
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tube change interval

Post by sunderwood » 12 Nov 2019 04:30

Paul McGowan in his daily post today noted that this is the time of year that he changes out the tubes in his equipment to keep the sound at its best. . These would be the preamp tubes as he has said he finds that is where he feels they sound best. He says he always notices an improvement. For the ones who have tube equipment what is your tube change schedule? Do you change them regularly or just wait till they go out?

aardvarkash10
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Re: tube change interval

Post by aardvarkash10 » 12 Nov 2019 05:55

Direct answer first - I change them when they no longer measure within spec for the circuit they are in. Given that tubes have a very wide latitude and circuits can be designed to allow for that, in a preamp that has been well-designed the life of the tubes would be measured in decades, not months.

Finals in aguitar amp - not so much.

My pick is that either:

he gets his tubes supplied for free and so it makes no difference to him or;
he sells tubes so it makes a difference to him, but not the one he's suggesting.

I note that he is a proponent of "burn-in" as well. The contradiction inherent in holding these two beliefs concurrently is glaring. At what point is a device burnt in sufficiently but not burnt out? Write your response on the back of a blank check and send it in...

vanakaru
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Re: tube change interval

Post by vanakaru » 12 Nov 2019 07:08

There are so many tweaks - some of these rather esoteric - that people swear to make huge difference(improvement) to the sound. Often this is just refreshing your brain. I bet if he puts back the tubes he took out last time he will have the same sensation.

georgesgiralt
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Re: tube change interval

Post by georgesgiralt » 12 Nov 2019 07:14

Hello
Do not change tubes unless they have failed. Period.
In a pre-amplifier, tubes are touched with a feather. So they will last the life long of the equipment.
I own precise measuring instruments build on vacuum tubes. All manufacturer advise against swapping tubes. They have bed in with the others in the circuit and the calibration will go away for a very long time if you change one tube . Meaning what ? Well the tubes are actually better in a circuit when they have run in it for a long time... So your guy seems to prefer the untamed sound of it's equipment than the real sound he will get if the equipment has settled to the specs it was designed for... It is no surprise he hears a difference !
It is just my 2 ¢
P.S. : the situation is different on amplifier for the output tubes. These do wear. But slooooowly... SO often they are exchanged before they are actually due to retire.

rewfew
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Re: tube change interval

Post by rewfew » 12 Nov 2019 15:25

Yes, that sounds like an audio fable. Like, don't touch tubes as your finger oil will damage the 'sound'. People come up with all manner of neurotic reinforcement for their equipment's performance. Unless there's an abhorrent change to the sound from a bad tube, in a preamp you should have decades of service from it's tubes.

sunderwood
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Re: tube change interval

Post by sunderwood » 12 Nov 2019 16:44

For those not familiar Paul McGowan runs P S Audio. I get his daily posts through email. If you go to the P S Audio site under community you can read his daily posts and also watch videos he puts up. I don't think he is trying to con anyone, but just expressing his opinion. He readily recognizes that some disagree with him on various subjects and you can make up your own mind. Concerning my own experience with the subject I have a Vincent 236mk2 integrated. It has three 12ax7 tubes in the preamp section. The last time I changed tubes was about 1 1/2 years ago. The old tubes had about 2000 hours on them, I think. I did notice a very slight improvement in cleanness of the sound. I use gold lion which usually run about $60 each.

Bandit127
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Re: tube change interval

Post by Bandit127 » 12 Nov 2019 19:01

While PS Audio on youtube seems to be more evidence based than some people offering opinions on the web, it looks to me like this is offering the same benefits as changing incandescent lightbulbs in your house once a year. Yes, it brings benefits in reducing the possibility of getting a failure next year and maybe one or two had a dimmer (lower) colour so possibly the quality of your light improved. Alternatively the same light bulbs might last 10 years and be fine.

You pays your money and you takes your choice.

aardvarkash10
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Re: tube change interval

Post by aardvarkash10 » 12 Nov 2019 19:17

sunderwood wrote:
12 Nov 2019 16:44
For those not familiar Paul McGowan runs P S Audio. I get his daily posts through email. If you go to the P S Audio site under community you can read his daily posts and also watch videos he puts up. I don't think he is trying to con anyone, but just expressing his opinion.
No, he's attempting to establish expertise to sell more product or service.
sunderwood wrote:
12 Nov 2019 16:44
He readily recognizes that some disagree with him on various subjects and you can make up your own mind.
If he had data that backed his claim, he'd provide it. He would have easy access to equipment that could do the testing - a simple FFT before and after would show up any change and the extent of the change.He hasn't provided this data because there isn't any.

In the absence of facts, he is doing that thing all the supposed high end of this market do - he's waving his hands and making claims.
sunderwood wrote:
12 Nov 2019 16:44
Concerning my own experience with the subject I have a Vincent 236mk2 integrated. It has three 12ax7 tubes in the preamp section. The last time I changed tubes was about 1 1/2 years ago. The old tubes had about 2000 hours on them, I think. I did notice a very slight improvement in cleanness of the sound. I use gold lion which usually run about $60 each.
Thats fabulous - I'm glad that your $180 or thereabouts has resulted in a change you are enjoying. From my pov as someone who builds their own gear and so has to know why it works, how it works and what measurements indicate its working correctly, there is not enough information for me to understand IF your device is working better, and WHY if it turns out that it is.

There are good reasons your replacement tubes may have made a change to the sound. Tubes in the same production run have tolerances that are often up around 20% - so if you randomly select two tubes there is a chance that they are 20% different in thier performance. Thats a pretty significant range and will introduce a change. There is a 50/50 chance that change is an improvement (its either better or worse, right?). Psycho-acoustics and human behaviour tells us that 50/50 chance is probably more like 90/10 in favour of you percieving a positive effect because thats what you want and expect and you've just spent $180 to get it.

sunderwood
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Re: tube change interval

Post by sunderwood » 12 Nov 2019 20:36

There are good reasons your replacement tubes may have made a change to the sound. Tubes in the same production run have tolerances that are often up around 20% - so if you randomly select two tubes there is a chance that they are 20% different in thier performance. Thats a pretty significant range and will introduce a change. There is a 50/50 chance that change is an improvement (its either better or worse, right?). Psycho-acoustics and human behaviour tells us that 50/50 chance is probably more like 90/10 in favour of you percieving a positive effect because thats what you want and expect and you've just spent $180 to get it.
[/quote]

If you would like to know I get my tubes from Upscale Audio. The reason is they have a good reputation among their customers for selling good quality tubes that have been tested and matched. As far as what Paul McGowan or any other retailer does their goal is to sell their product. You can't blame him for that. You can make your own decision what you buy or who you buy from. Also he only sells 6922 tubes which are what goes in his amps. I would like to ask a favor. To anyone who wants to respond to my original post I only wanted to find out of curiosity what anyone does with their equipment. I did not mean for this to become a p*****g contest. Please read what I originally said.

georgesgiralt
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Re: tube change interval

Post by georgesgiralt » 12 Nov 2019 20:52

Sunderwood,
Not to try to assault you, but I have an AMC 3030 integrated amplifier which is solid state except for the EL34 push pull output tubes.
The factory soldered the tubes to the circuit... This proves you do not have to change tubes that often. One died on me because I moved and let the amp fall while running. The fall cut the filament. The amp was bought in the 90's and is still preforming great on the channel with the original tubes in place. And this amplifier is used a lot every day.
I also use a Grundig radio (with stereo FM ) and it is still in its original tubes set since 1962 (I checked the date of manufacture). This radio is used everyday for 3 to 4 hours a day. I own a Ducretet Thomson radio from 1957 with it's original set of tube except the output EL84 which died on me. This set runs around 7 to 8 hours a day since 1989 when I bought it second hand.
So replacing preamplifier tubes is IMHO a waste of money and more importantly of precious resources (these tubes are filled with rare earth material and precious metal)...

sunderwood
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Re: tube change interval

Post by sunderwood » 13 Nov 2019 04:15

georgesgiralt wrote:
12 Nov 2019 20:52
Sunderwood,
Not to try to assault you, but I have an AMC 3030 integrated amplifier which is solid state except for the EL34 push pull output tubes.
The factory soldered the tubes to the circuit... This proves you do not have to change tubes that often. One died on me because I moved and let the amp fall while running. The fall cut the filament. The amp was bought in the 90's and is still preforming great on the channel with the original tubes in place. And this amplifier is used a lot every day.
I also use a Grundig radio (with stereo FM ) and it is still in its original tubes set since 1962 (I checked the date of manufacture). This radio is used everyday for 3 to 4 hours a day. I own a Ducretet Thomson radio from 1957 with it's original set of tube except the output EL84 which died on me. This set runs around 7 to 8 hours a day since 1989 when I bought it second hand.
So replacing preamplifier tubes is IMHO a waste of money and more importantly of precious resources (these tubes are filled with rare earth material and precious metal)...
Thanks for your response. That is the type of response I am interested in reading.

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Re: tube change interval

Post by lenjack » 13 Nov 2019 06:22

You hear what you want - expect - to hear. The placebo effect is all powerful, as is the b*lls*it effect.

sunderwood
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Re: tube change interval

Post by sunderwood » 13 Nov 2019 14:34

lenjack wrote:
13 Nov 2019 06:22
You hear what you want - expect - to hear. The placebo effect is all powerful, as is the b*lls*it effect.
That is true too much of the time in a lot of areas of life. At 68 I have learned that in order to really solve problems we have to be as honest and objective about what is going on around us as we can. In audio and music collecting which is my favorite hobby I have in the past bought an accessory, tweak or new piece of equipment and then try to convince myself that I was hearing an improvement. In reality what I was really doing was trying to justify spending the money. I finally started reading both positive and negative consumer reviews and overall doing as much investigating as I could. That has so far worked out pretty well. I do not like to waste money.

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Re: tube change interval

Post by lenjack » 13 Nov 2019 15:44

The advocates of frequent tube changing, are the same people, who will give you 20 reasons, why double blind, or ABX tests, are invalid.

rewfew
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Re: tube change interval

Post by rewfew » 13 Nov 2019 19:30

sunderwood wrote:
12 Nov 2019 20:36
I would like to ask a favor. To anyone who wants to respond to my original post I only wanted to find out of curiosity what anyone does with their equipment. I did not mean for this to become a p*****g contest. Please read what I originally said.
And.
sunderwood wrote:
13 Nov 2019 14:34
I have in the past bought an accessory, tweak or new piece of equipment and then try to convince myself that I was hearing an improvement. In reality what I was really doing was trying to justify spending the money. I finally started reading both positive and negative consumer reviews and overall doing as much investigating as I could. That has so far worked out pretty well. I do not like to waste money.
Well. Isn't that what we have conveyed, since you wanted opinions? We don't like wasting money either. And changing out preamp tubes once a year because better sound is accomplished is just what our opinion points to. No p***ing contest involved. If you take the point of view of the gentleman you refer to, then by all means load up on preamp tubes for regular refreshment at whatever interval appropriate.

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