Waffling on a tube amp

[antcollinet]

It's a known fact any male over 45-50 is incapable of hearing much over 8khz, ....

Why is the phrase "It's a known fact...." always followed by something that is not a fact.

60yo here and can hear test tones up to 13kHz - sensitivity fades to zero from about 13kHz to 13.5kHz. And that is in spite of lifelong right ear tinnitus (thanks Motorhead )

 

[antcollinet]

Actually, not concerned with validation. I have decided to experiment with a tube amp, but I'm not sure if its where I'll be going long term, and was hoping to find someone who'd had a Willsenton and then went for a higher end amp later, just to compare. Not much point in dropping 2Gs on an amp that isn't going to give me a proper taste of tube amplification, I'll just go straight to the Rogue (or a Linn).

Try and get one second hand - then you can sell it for around what you paid - regardless of whether it helps you or not.

 

[Blumlein 88]

That's how my CJ Premier 12s bias - adjusting the screws with the LEDs.

Do you happen to know how accurate that method is for getting decent bias?

I checked a couple of them, and I don't recall fine details. Maybe 3 or 4 millivolts. Of course I liked to have my bias even to a millivolt or so, but that is not really needed. I did find them to drift a bit. I'd bias after having them on for half hour. Play music a half hour and do it again. They might drift a little. Then they seemed stable after the 2nd biasing.

 

[antcollinet]

Seriously now.
My next major undertaking should be a whopper for which I've been collecting rare bits for a few years.
PSU transformer came from a ship-shore transmitter which came up cheap on EBAY (does 2.2KV at 0.6A) etc etc.

The output stage has had some advice from a real cracking guy called Chambers at chambonino who has actually made and sold the 1KW monsters..
Nottinghamshire people tend to be a bit down to earth...

1.5-2kV is not something really to be messed with, cat or no cat.
It tends to make class D look a little tame, with enough go to blow the doors out of your house.

Talking of which I have a spare pair of Hiwatt 200W output transformers.
Now who said guitar amps were rubbish distorting machines that couldn't be hifi?

Dave Reeves who started Hiwatt worked down the road at Mullards, and used no less than Partridge for his transformers. All of them.

references?
David Gilmour, Peter Townsend, Glen Cornick....

Impressive - but not enough polished wood

As you say, 2KV is not to be messed with. For the benefit of the inexperienced thinking of it, high voltage elctrocution (if it does not kill you right off) can cause severe *internal* tissue death. If this is not removed, it decomposes and poisens the body - you die. I've seen reports of people having to have significant ammount of muscle of one or more limbs removed after electrocution. It does not grow back. I've also seen picutures of hands that have been burned away down to the bone. Don't go near it unles you *really* know what you are doing.

 

[MattHooper]

I checked a couple of them, and I don't recall fine details. Maybe 3 or 4 millivolts. Of course I liked to have my bias even to a millivolt or so, but that is not really needed. I did find them to drift a bit. I'd bias after having them on for half hour. Play music a half hour and do it again. They might drift a little. Then they seemed stable after the 2nd biasing.

Thanks!

If I switch tubes I follow the manual - bias after 1 minute on, again after 30 minutes.

To be honest, I'm not even terribly clear on the effects of biasing. I know it's needed if you want to be sure your amp is working right with the tubes, so you are getting the optimum out of the tubes you've put in. But what are the sonic (or other) consequences of biasing...or being out of bias?

 

[Bob from Florida]

Thanks!

If I switch tubes I follow the manual - bias after 1 minute on, again after 30 minutes.

To be honest, I'm not even terribly clear on the effects of biasing. I know it's needed if you want to be sure your amp is working right with the tubes, so you are getting the optimum out of the tubes you've put in. But what are the sonic (or other) consequences of biasing...or being out of bias?

Too low a bias on a push-pull amp may introduce zero crossing distortion which you may hear. Too high bias will wear out your output tubes sooner, but can result in more bass. Stick with the recommended bias range and you should end up operating on the load line the OEM intended that meets specs.

 

[valve_integrator]

Where did you get this "known fact?"**

It doesn't comport with what I've seen on the subject. .... 12k is certainly significantly higher than 8khz, and covers most of what we percieve as "high frequencies" in music playback.

I'm 59 and can hear at least up to 14,000Hz.

I doubt this claim or at least it's fine to be in denial.
I have checked quite a lot of people's hearing.

One of the most concerning I think is the "deafness" being introduced by regular exposure to compressed music.
Some young people who didn't do too much of it can hear suprisingly up to 22khz+

Having masking (via algos) regularly deliberately used, and conditioning auditive education, appears to educate young ears into ignoring certain parts of the spectra, which can't seem to be explained otherwise, with some suprising dips and troughs in children that shouldn't have them.

There is a large body of medical knowledge showing the results of aging.
Here are 2, one of them from the Lancet, which are quite similar.

As you can see, your 59yr old hearing has typically an attenuation of -35 at 6khz, compared with -12 at age 40.
This is enormous, which means basically anything over 6-8khz is effectively masked by anything up to 30dB.
(Ie, you can't hear it).
Women typically by contrast are lucky.
They get a 12dB better hearing at age 70 than you will do, and at age 40 typically are hearing 4dB better than you at those high notes.

MEN A Women B up to 100yo (Lancet survey in JP)

 

[MattHooper]

I doubt this claim or at least it's fine to be in denial.

I test my hearing regularly. Right now I can test it via an iphone tone generator app (heard up to 14,000Hz), I've tested it via my iMac speakers, my stereo speakers etc. It's always around 14,000Hz.

I just did this test yet again:

I close my eyes listening for the tone, and as soon as I hear it I press the spacebar to stop the video. I stopped it several times in a row around 13,900Hz "43 years old."

If you have interpreted the data to conclude I can not hear that high, you have misinterpreted the data.

 

[antcollinet]

I doubt this claim or at least it's fine to be in denial.

Oh, please do Fuck Off.

 

[Bob from Florida]

Oh, please do Fuck Off.

Please don't feed trolls. They lose their natural fear of humans.

 

[MattHooper]

Oh, please do Fuck Off.

I test my ears a lot because I have Tinnitus and sometimes hyperacusis, and sometimes I can for short times lose my high frequency hearing. It's very obvious when it happens, and when I use my tone generator app I literally can't hear above, say, 10 or 11k in one ear. But then it comes back (which I can hear even without testing) and I can then hear up to 14K again.

I started getting Tinnitus when playing in a band in the 90's and quickly adopted good earplugs, and have generally protected my ears since, which is likely one reason I still have good high frequency perception.

 

[MattHooper]

Too low a bias on a push-pull amp may introduce zero crossing distortion which you may hear. Too high bias will wear out your output tubes sooner, but can result in more bass. Stick with the recommended bias range and you should end up operating on the load line the OEM intended that meets specs.

Thanks Bob!

I've found my output tubes to generally last about 6 years of good use. (The input tubes seem to last almost forever...I only recently had to replace some after over 20 years).

 

[restorer-john]

Why is the phrase "It's a known fact...." always followed by something that is not a fact.

Or some other favs:

"it's generally accepted that...."
"current wisdom suggests..."
"most experts agree..."

 

[SIY]

I think there are small disturbing non-linearities with LED bias.

Not even vaguely. LED bias is (assuming done correctly) close to a perfect common-cathode situation. Dynamic impedances are on the order of 2R and the noise is stunningly low (I use them in the first stage of my phono preamps). Now, if your sonic evaluations are done without basic ears-only controls, you can make all sorts of wonderful judgements having nothing to do with sound.

Here's the ultimate in LED biasing.

 

[valve_integrator]

I test my hearing regularly. Right now I can test it via an iphone tone generator app (heard up to 14,000Hz), I've tested it via my iMac speakers, my stereo speakers etc. It's always around 14,000Hz.

I just did this test yet again:

I close my eyes listening for the tone, and as soon as I hear it I press the spacebar to stop the video. I stopped it several times in a row around 13,900Hz "43 years old."

If you have interpreted the data to conclude I can not hear that high, you have misinterpreted the data.

Did you see the graphs above?
Did you check levels against a calibrated source?
Each one of those sources mentioned has different calibration levels, sensitivity, acoustic sources and pinna transfer.
Levels with reference tones?
NO.
What you appear not to understand is relative levels of signal.
All you have there is an arbitrary test to kind of prove something,
ie.winding up the levels so that they reach the level of audibility is a valid test.

I've done quite a few masking tests.
It's fascinating to see what people claim they can hear compared with what they actually can hear.

If you have a sensitivity drop at those frequencies of 20dB they are inevitably masked by louder sounds.
That, sadly is the very principal of mpeg audio,ie. taking out information as compression which they think you can do without because they are masked.
As you can see by the Lancet article, the effects are inescapable.
You called me out on the issue.
I have just proven to you this is well known medical science of well over 30 yrs research.

 

[antcollinet]

Please don't feed trolls condescending twats. They lose their natural fear of humans.

There you go, fixed it for you.

 

[MattHooper]

Did you see the graphs above?
Did you check levels against a calibrated source?
Each one of those sources mentioned has different calibration levels, sensitivity, acoustic sources and pinna transfer.
Levels with reference tones?
NO.
What you appear not to understand is relative levels of signal.
All you have there is an arbitrary test to kind of prove something,
ie.winding up the levels so that they reach the level of audibility is a valid test.

I've done quite a few masking tests.
It's fascinating to see what people claim they can hear compared with what they actually can hear.

If you have a sensitivity drop at those frequencies of 20dB they are inevitably masked by louder sounds.
That, sadly is the very principal of mpeg audio,ie. taking out information as compression which they think you can do without because they are masked.
As you can see by the Lancet article, the effects are inescapable.
You called me out on the issue.
I have just proven to you this is well known medical science of well over 30 yrs research.

You seem to have forgotten your claim:

"It's a known fact any male over 45-50 is incapable of hearing much over 8khz,"

That's wrong. Full stop. Easily debunked (as I just did). If we want to talk about masking effects, that could be another conversation. But you
made a sloppy Absolute claim and that is what's being called out.

(BTW, I did not have to crank the volume at all for that test above. In fact I kept it quite low, as I do not like subjecting my ears to loud, pure tones).

 

[restorer-john]

@MattHooper

Joe'n'tells 'test' is seriously flawed. There are very high HF noise/tones audible from the very first second it starts- probably some form of aliasing (due to the youtube compression algorithm) and that noise 'beats' as the frequency falls. Either that, or I have superhuman hearing. LOL.

 

[MattHooper]

@MattHooper

Joe'n'tells 'test' is seriously flawed. There are very high HF noise/tones audible from the very first second it starts- probably some form of aliasing (due to the youtube compression algorithm) and that noise 'beats' as the frequency falls. Either that, or I have superhuman hearing. LOL.

Interesting. In any case I get the same results from testing at home, or from on-line tone generators like these:

Online Tone Generator - generate pure tones of any frequency

www.szynalski.com

One moment, please...

 

[JustJones]

The last time my hearing was tested I was 64 which was 3 years ago. This was at a physician's office in the isolation booth, calibrated headphones, the whole deal took 2 days. They were checking for more than hearing ability but when I asked they told me I maxed at 11k. I'm pretty sure it's not that good now.