Tube (valve) amp really works!

On Mon, 19 Dec 2016 15:12:12 -0800, John Larkin
<jjlarkinxyxy@highlandtechnology.com> wrote:

On 19 Dec 2016 13:26:19 GMT, default <default@defaulter.net> wrote:

On Sat, 17 Dec 2016 10:10:03 -0800, John Larkin wrote:

On Fri, 16 Dec 2016 12:42:10 -0800, etpm@whidbey.com wrote:

Some time back I posted a question or two about this tube headphone amp:
http://oatleyelectronics.com/files/K272X.pdf . Anyway, I built the thing
and while it did amplify it did not seem to color the sound,
despite the good reviews about the thing I found online. So it sat on my
desk until a couple weeks ago when I happened to read about another tube
amp and how the amp was left on by the reviewer to break in the tubes.
This made sense to me because tubes do eventually wear out so some sort
of physical change must be happening inside the things. So I powered up
the little headphone amp and left it on for about 28 hours.
I then tried it out with some good earbuds and as a pre-amp for my
Pioneer SX-434. It now changes the sound. Not as much as I expected,
but maybe it's not supposed to. For some music I like using it better
than just plugging my digital sound source into the Pioneer. I suspect
that when I get some good headphones there will be even more difference
that I can hear.
Eric

Tube burn-in is probably a psychological effect, not a physical one.

Tube sound, ditto.

The sound engineers who make the files and CDs already have a zillion
options to add distortion, tweak frequency response, mix signals, add
noise and echoes and other DSP effects, and they put a lot of time and
money into making things sound "right." Why would running their signal
through a dumb tube amp make it sound better?

Placebo effect - Nothing sounds as good as the distortion you're used to?

Double-blind testing makes a lot of acoustic effects disappear.

Greetings John,
I bet you're right about the double blind thing. That's part of the
reason why I was surprised about hearing a difference after the tubes
were burned in. In fact, I'm thinking about buying a couple new tubes
online and trying the whole burn in thing again but this time actually
measuring the output before and after with a 'scope as jurb suggested.
I'm curious though about something you said. When asked by jurb for a
schematic I provided a link and you found that laughable for more than
one reason. How about, since this is an electronics basics group,
letting me know what was so laughable?
Cheers,
Eric

 

[Lucifer Morningstar]

On Mon, 19 Dec 2016 21:53:26 -0800 (PST), jurb6006@gmail.com wrote:

>>"When asked by jurb for a

You need to quote more than that.

schematic I provided a link and you found that laughable for more than
one reason. How about, since this is an electronics basics group,
letting me know what was so laughable? "

The first part of that paragraph is missing.

>The damn thing wouldn't open for me.

--
I call shenanigans on all theistic religions

 

[George Herold]

On Monday, December 19, 2016 at 2:12:34 PM UTC-5, Tim Wescott wrote:

On Sat, 17 Dec 2016 10:10:03 -0800, John Larkin wrote:

On Fri, 16 Dec 2016 12:42:10 -0800, etpm@whidbey.com wrote:

Some time back I posted a question or two about this tube headphone amp:
http://oatleyelectronics.com/files/K272X.pdf . Anyway, I built the thing
and while it did amplify it did not seem to color the sound,
despite the good reviews about the thing I found online. So it sat on my
desk until a couple weeks ago when I happened to read about another tube
amp and how the amp was left on by the reviewer to break in the tubes.
This made sense to me because tubes do eventually wear out so some sort
of physical change must be happening inside the things. So I powered up
the little headphone amp and left it on for about 28 hours.
I then tried it out with some good earbuds and as a pre-amp for my
Pioneer SX-434. It now changes the sound. Not as much as I expected,
but maybe it's not supposed to. For some music I like using it better
than just plugging my digital sound source into the Pioneer. I suspect
that when I get some good headphones there will be even more difference
that I can hear.
Eric

Tube burn-in is probably a psychological effect, not a physical one.

Either that or he's knocked the edge off of the batteries' charge, and
the thing distorts more at a lower plate voltage and/or higher source
resistance in the 'B' battery.

Re Audio and "burn in".
I was looking at teflon caps some time in the past.
I couldn't find any except on Audio sites. Caps were something north of $50 each!
And for the best sound the caps needed to be "burned in" by sending white noise
through them for several weeks.

George H

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

I'm looking for work -- see my website!

 

[default]

On Mon, 19 Dec 2016 09:30:36 -0800, etpm wrote:

On 19 Dec 2016 13:26:19 GMT, default <default@defaulter.net> wrote:

On Sat, 17 Dec 2016 10:10:03 -0800, John Larkin wrote:

On Fri, 16 Dec 2016 12:42:10 -0800, etpm@whidbey.com wrote:

Some time back I posted a question or two about this tube headphone
amp:
http://oatleyelectronics.com/files/K272X.pdf . Anyway, I built the
thing and while it did amplify it did not seem to color the sound,
despite the good reviews about the thing I found online. So it sat on
my desk until a couple weeks ago when I happened to read about another
tube amp and how the amp was left on by the reviewer to break in the
tubes. This made sense to me because tubes do eventually wear out so
some sort of physical change must be happening inside the things. So I
powered up the little headphone amp and left it on for about 28 hours.
I then tried it out with some good earbuds and as a pre-amp for my
Pioneer SX-434. It now changes the sound. Not as much as I expected,
but maybe it's not supposed to. For some music I like using it better
than just plugging my digital sound source into the Pioneer. I suspect
that when I get some good headphones there will be even more
difference that I can hear.
Eric

Tube burn-in is probably a psychological effect, not a physical one.

Tube sound, ditto.

The sound engineers who make the files and CDs already have a zillion
options to add distortion, tweak frequency response, mix signals, add
noise and echoes and other DSP effects, and they put a lot of time and
money into making things sound "right." Why would running their signal
through a dumb tube amp make it sound better?

Placebo effect - Nothing sounds as good as the distortion you're used
to?
Which is not the placebo effect. The placebo effect is expecting
something to happen and it you think it does even though nothing has
changed to cause that something to happen. If I expect the music to
sound better and there is no change to the sound but I think it now
sounds better then that is the placebo effect.

I know what the placebo effect is; I was making two separate statements.

We have any number of ways and the means to measure any deviation from
the original signal. "Fidelity" in this case is: "the reproduction of
sound with little distortion, giving a result very similar to the
original."

I have nothing against the idea of coloring sound to make it more
pleasing (subjectively) to the listener, but it is very subjective and
there will always be someone that will disagree with me.

Ultimately, when you've gotten the sound source as good as it gets, you
have to start looking to the listening room, because more money can't
improve the fidelity of the equipment by a noticeable margin. The law of
diminishing returns takes over, and it is healthy to start questioning
your own sanity IMO. (I've been there - I've pair of Crown linear
kilowatt range amps for the bass, and home-brew 100 watt Mosfet amps for
the mid and treble) Sounds damn good too, but then reality steps in and
I do most of my listening while kayaking with earbuds....

 

[John Larkin]

On Mon, 19 Dec 2016 17:47:36 -0800, etpm@whidbey.com wrote:

On Mon, 19 Dec 2016 15:12:12 -0800, John Larkin
jjlarkinxyxy@highlandtechnology.com> wrote:

On 19 Dec 2016 13:26:19 GMT, default <default@defaulter.net> wrote:

On Sat, 17 Dec 2016 10:10:03 -0800, John Larkin wrote:

On Fri, 16 Dec 2016 12:42:10 -0800, etpm@whidbey.com wrote:

Some time back I posted a question or two about this tube headphone amp:
http://oatleyelectronics.com/files/K272X.pdf . Anyway, I built the thing
and while it did amplify it did not seem to color the sound,
despite the good reviews about the thing I found online. So it sat on my
desk until a couple weeks ago when I happened to read about another tube
amp and how the amp was left on by the reviewer to break in the tubes.
This made sense to me because tubes do eventually wear out so some sort
of physical change must be happening inside the things. So I powered up
the little headphone amp and left it on for about 28 hours.
I then tried it out with some good earbuds and as a pre-amp for my
Pioneer SX-434. It now changes the sound. Not as much as I expected,
but maybe it's not supposed to. For some music I like using it better
than just plugging my digital sound source into the Pioneer. I suspect
that when I get some good headphones there will be even more difference
that I can hear.
Eric

Tube burn-in is probably a psychological effect, not a physical one.

Tube sound, ditto.

The sound engineers who make the files and CDs already have a zillion
options to add distortion, tweak frequency response, mix signals, add
noise and echoes and other DSP effects, and they put a lot of time and
money into making things sound "right." Why would running their signal
through a dumb tube amp make it sound better?

Placebo effect - Nothing sounds as good as the distortion you're used to?

Double-blind testing makes a lot of acoustic effects disappear.
Greetings John,
I bet you're right about the double blind thing. That's part of the
reason why I was surprised about hearing a difference after the tubes
were burned in. In fact, I'm thinking about buying a couple new tubes
online and trying the whole burn in thing again but this time actually
measuring the output before and after with a 'scope as jurb suggested.
I'm curious though about something you said. When asked by jurb for a
schematic I provided a link and you found that laughable for more than
one reason. How about, since this is an electronics basics group,
letting me know what was so laughable?
Cheers,
Eric

Token tubes driving opamps is laughable. The resistor values on the
output amp are optimized to make noise.

The datasheet of that PT2308 chip is silly too. A few bullets and no
specifications!

The board layout, the red thing, is really ugly.



--

John Larkin Highland Technology, Inc

lunatic fringe electronics

 

[John Larkin]

On Tue, 20 Dec 2016 07:41:56 -0800 (PST), George Herold
<gherold@teachspin.com> wrote:

On Monday, December 19, 2016 at 2:12:34 PM UTC-5, Tim Wescott wrote:
On Sat, 17 Dec 2016 10:10:03 -0800, John Larkin wrote:

On Fri, 16 Dec 2016 12:42:10 -0800, etpm@whidbey.com wrote:

Some time back I posted a question or two about this tube headphone amp:
http://oatleyelectronics.com/files/K272X.pdf . Anyway, I built the thing
and while it did amplify it did not seem to color the sound,
despite the good reviews about the thing I found online. So it sat on my
desk until a couple weeks ago when I happened to read about another tube
amp and how the amp was left on by the reviewer to break in the tubes.
This made sense to me because tubes do eventually wear out so some sort
of physical change must be happening inside the things. So I powered up
the little headphone amp and left it on for about 28 hours.
I then tried it out with some good earbuds and as a pre-amp for my
Pioneer SX-434. It now changes the sound. Not as much as I expected,
but maybe it's not supposed to. For some music I like using it better
than just plugging my digital sound source into the Pioneer. I suspect
that when I get some good headphones there will be even more difference
that I can hear.
Eric

Tube burn-in is probably a psychological effect, not a physical one.

Either that or he's knocked the edge off of the batteries' charge, and
the thing distorts more at a lower plate voltage and/or higher source
resistance in the 'B' battery.

Re Audio and "burn in".
I was looking at teflon caps some time in the past.
I couldn't find any except on Audio sites. Caps were something north of $50 each!
And for the best sound the caps needed to be "burned in" by sending white noise
through them for several weeks.

People burn in RCA cables too. The signal direction matters.

And power cords. Soaking them in liquid nitrogen has stunning acoustic
effects.




--

John Larkin Highland Technology, Inc

lunatic fringe electronics

 

On Mon, 19 Dec 2016 22:24:14 -0800 (PST), jurb6006@gmail.com wrote:

Is this it ?

http://diyaudioprojects.com/Tubes/6418-Tube-Preamp-Headphone-Kit/

If that is it, I see no reason for it. you got OP AMPs on the end of triodes, if the OP AMPs can deliver the nuances of the sound from triodes they should be able to do it by themselves.

Of course it is a pentode, but wired as a triode. And the way it is showing it is a directly heated cathode which means one channel has bias and the other does not.

What you are probably hearing is an anomoly due to the input coupling cap charging to make for some badly needed negative bias. I have seen other amps like this and when I see them I think Madman Muntz. If what I found there is actually the print for it, I would never buy it.

These no bias people can sit there and say all day that "The audio biases it", sure does, now when it comes down to half the conduction where you should have biased it in the first place it shifts DC level on the output. I could design better than that at fifteen years old. If I am looking at the right thing of course.

The thing here is cheap. Sure, use a DC filament supply, but if a directly heated cathode you don't put them in series. You need that positive voltage, and in STEREO, remember there are two identical channels, you need the same bias on each channel. Not for one to be biased by the power supply and the other to be self biased like the horizontal output in an old TV set.

Not not be mean, but if the link I put up is of that thing, it is not high fidelity, it is not worth shit by any metric. If you like it then that is because you like a certain type of distortion, because that has it Man. No bias ?

Probably designed by a millenial.

That is my opinion. It affects nothing else.

I believe they got you fooled because of that grid current biasing system. It probably makes the soundstage sound a bit different because of the delay in output of one of the channels. The other channel has bias.

I have seen shit like this before.

No, that isn't it. I don't understand why you can't get the other link
to work because it works fine for me. Would you like me to email you
the pdf? I would appreciate you critiquing the circuit. I know very
little about tube circuits.
Eric

 

>"No, that isn't it. I don't understand why you can't get the other link "

I got it now. I had to switch browsers, I won't "upgrade" FF because I want 23, not the new version. Not sure I even want to go that new actually. Every new version takes away features, some of which I like. Same way with Adobe reader, downloaded DC at work, what a nightmare. Hand cursor switches to select after a few seconds and I could not find a way to turn that off. What kind of brainiacs figure this shit out anyway ? So I had to use (egad) IE8.

Looks like the print I had was the old version. I seem to have been corrected about the bias, as long as one end of the filament is connected to a positive supply. Also, as they said, the operating points of the tubes are now the same.

I say this : Whatever you're hearing is probably even order distortion, which some people like thus the "SET" crowd. (single ended triode) Not sure but I think Audio Asylum has a group just for that, but I take to mean the output to the speakers.

What I think makes the tube sound is the interaction between the high impedance plate(s) of the output(s), the transformer and the speaker. Even in guitar amps I see no reason to use tubes in the input stage(s). In the old days, some musicians used to take a small tube amp, literally put it in a box with a microphone when they got up on stage.

When tubes are used as outputs into an inductive load they got something that no solid state device has - it is a diode first. That means any inductive kickback from the speaker is allowed to just happen, whereas in a solid state amp it would be clamped. People have told me this is nothing, but then why do they have to take steps to keep protection relays in high power amps from welding themselves on when they go into DC protection ?

You can do it with solid state but you have to be using an output transformer, then you put a diode in series with the anode, collector or drain of the output devices.

So of course they also have guitar amps with solid state inputs sections and a tube output section. some are quite powerful with three pairs of 6L6. Then you don't use that amp for practice if you want the sound, and a power soak is not the same because it decouples the speaker. And full power is out of the question usually because you get too much feedback. Some also from the neighbors or even police.

One things you also may be hearing is a real sort of damping factor to the headphones. Most amps and receivers do not have dedicated headphone amps, they just take the speaker output through a resistor. That means the frequency response will vary with the impedance curve of the drivers in the phones.. This doodad drives directly, being a voltage source. You might hear an improvement because of that but IMO that has nothing to do with the tubes. Anything you hear out of those tubes is going to even order distortion.

And I see nothing that would make it anything other than flat frequency response, those tubes are small so their response is most likely good up into the RF. The coupling caps are huge (in value) for the impedances involved, but not the output caps. Most headphones are greater than eight ohms, but a 1,000 uF to feed eight ohms is not enough. You lose quite a bit of low end.. That's why some of the early AC coupled SESAPP solid state amps had that cap within the global feedback loop. Of course phase comp was required or the thing might oscillate. I had that happen once when I was trying to upgrade one. If it is in the feedback loop then frequency response could be smooth but power bandwidth drops off at the low end.

Best headphone sound I even heard was Sony MDR-CD5. The frequency response ruler flat from 2-22,000 Hz. NOT 20 to 22,000, TWO. You could feel the air rush in or out when the stylus landed on the record groove. They were 45 ohms, so running off a receiver or amp that just had the sound resistored down from the speaker outputs they were much louder. They would probably not be louder on your doodad.

I calculated by the sensitivity and the maximum power rating that they were capable of 126 dB. I jumped the resistors. But they were not the loudest phones I had, those were the Sansui SS-10. They required a modification to the foam surrounds to get them to sound good which involved cutting some of the inner part away and get it so your ear gets right up to them. I did that after I heard my buddy' Koss that had them cut that way. What a difference ! And loud ? Let me put it this way, with the resistors jumped, on a Stereotech 1200 (McIntosh red headed bastard child receiver) I could use them as speakers. I mean, they were louder than some table radios.

What I would really like is a very low power tube amp that uses an output transformer. There are several problems with such a design. First of all the calculations, and then getting a transformer company to wind it. You are not going to want to pay $100 for a transformer that can only do one watt or so. But this, with an appropriate dummy load, I mean really built to emulate a real speaker, Fender or whatever, and EQ after to reproduce that old guitar amp speaker sound, I think there may be a market for that. However they come pretty close it seems using a DSP so it might be another futile idea.

Bottom line, I think the improvement you hear is due to damping factor. Anyone who doesn't think damping factor matters is welcome to take eight ohm resistors in series with their speakers and turn it twice as loud.

 

"
People burn in RCA cables too. The signal direction matters."

Now that is audiophoolery.

>And power cords. Soaking them in liquid nitrogen has stunning acoustic effects. "

Do you mean the nitrogen boiling or the cable insulation breaking into little pieces ?

they got tubes they say are dipped in liquid N as well. Phil (it may have been over in SED) pointed out the difficulties with doing that, mainly having to do with differing thermal expansion coefficients. So obviously if true it must be done before the elements of the tube go into the bottle. Even then, if you want to throw money away, put a bigger getter in it so it lasts longer. I had some 6550s had three getters in them. I sold them to a guy in Chicago ad he was worried about the looks of one of them. I sent him pictures of the other getters and he sent the money.

 

[Tim Wescott]

On Mon, 19 Dec 2016 22:24:14 -0800, jurb6006 wrote:

Is this it ?

http://diyaudioprojects.com/Tubes/6418-Tube-Preamp-Headphone-Kit/

If that is it, I see no reason for it. you got OP AMPs on the end of
triodes, if the OP AMPs can deliver the nuances of the sound from
triodes they should be able to do it by themselves.

Of course it is a pentode, but wired as a triode. And the way it is
showing it is a directly heated cathode which means one channel has bias
and the other does not.

What you are probably hearing is an anomoly due to the input coupling
cap charging to make for some badly needed negative bias. I have seen
other amps like this and when I see them I think Madman Muntz. If what I
found there is actually the print for it, I would never buy it.

These no bias people can sit there and say all day that "The audio
biases it", sure does, now when it comes down to half the conduction
where you should have biased it in the first place it shifts DC level on
the output. I could design better than that at fifteen years old. If I
am looking at the right thing of course.

The thing here is cheap. Sure, use a DC filament supply, but if a
directly heated cathode you don't put them in series. You need that
positive voltage, and in STEREO, remember there are two identical
channels, you need the same bias on each channel. Not for one to be
biased by the power supply and the other to be self biased like the
horizontal output in an old TV set.

Not not be mean, but if the link I put up is of that thing, it is not
high fidelity, it is not worth shit by any metric. If you like it then
that is because you like a certain type of distortion, because that has
it Man. No bias ?

Probably designed by a millenial.

That is my opinion. It affects nothing else.

I believe they got you fooled because of that grid current biasing
system. It probably makes the soundstage sound a bit different because
of the delay in output of one of the channels. The other channel has
bias.

I have seen shit like this before.

Not to minimize the rest of the rant, but these little 1.2V filament
tubes are almost universally designed so that if one end of the cathode
is grounded and the other is positive, the 0.6V (average) voltage on the
cathode makes for a pretty good biasing. 'cuz -- toobs.

I think you're probably correct for the rest of it -- sometimes you build
a toob amp because you think it'll do something for you, and sometimes
you just build one so you can say "I got toobs!".

--
Tim Wescott
Control systems, embedded software and circuit design
I'm looking for work! See my website if you're interested
http://www.wescottdesign.com

 

[Tim Wescott]

On Tue, 20 Dec 2016 08:47:47 -0800, John Larkin wrote:

On Tue, 20 Dec 2016 07:41:56 -0800 (PST), George Herold
gherold@teachspin.com> wrote:

On Monday, December 19, 2016 at 2:12:34 PM UTC-5, Tim Wescott wrote:
On Sat, 17 Dec 2016 10:10:03 -0800, John Larkin wrote:

On Fri, 16 Dec 2016 12:42:10 -0800, etpm@whidbey.com wrote:

Some time back I posted a question or two about this tube headphone
amp:
http://oatleyelectronics.com/files/K272X.pdf . Anyway, I built the
thing and while it did amplify it did not seem to color the sound,
despite the good reviews about the thing I found online. So it sat
on my desk until a couple weeks ago when I happened to read about
another tube amp and how the amp was left on by the reviewer to
break in the tubes. This made sense to me because tubes do
eventually wear out so some sort of physical change must be
happening inside the things. So I powered up the little headphone
amp and left it on for about 28 hours.
I then tried it out with some good earbuds and as a pre-amp for my
Pioneer SX-434. It now changes the sound. Not as much as I
expected, but maybe it's not supposed to. For some music I like
using it better than just plugging my digital sound source into the
Pioneer. I suspect that when I get some good headphones there will
be even more difference that I can hear.
Eric

Tube burn-in is probably a psychological effect, not a physical one.

Either that or he's knocked the edge off of the batteries' charge, and
the thing distorts more at a lower plate voltage and/or higher source
resistance in the 'B' battery.

Re Audio and "burn in".
I was looking at teflon caps some time in the past.
I couldn't find any except on Audio sites. Caps were something north of
$50 each!
And for the best sound the caps needed to be "burned in" by sending
white noise through them for several weeks.


People burn in RCA cables too. The signal direction matters.

And power cords. Soaking them in liquid nitrogen has stunning acoustic
effects.

Whacking someone upside the head with the cable when it's still below
100K would have even more stunning effects, I bet.

--
Tim Wescott
Control systems, embedded software and circuit design
I'm looking for work! See my website if you're interested
http://www.wescottdesign.com

 

[George Herold]

On Tuesday, December 20, 2016 at 11:42:07 AM UTC-5, John Larkin wrote:

On Mon, 19 Dec 2016 17:47:36 -0800, etpm@whidbey.com wrote:

On Mon, 19 Dec 2016 15:12:12 -0800, John Larkin
jjlarkinxyxy@highlandtechnology.com> wrote:

On 19 Dec 2016 13:26:19 GMT, default <default@defaulter.net> wrote:

On Sat, 17 Dec 2016 10:10:03 -0800, John Larkin wrote:

On Fri, 16 Dec 2016 12:42:10 -0800, etpm@whidbey.com wrote:

Some time back I posted a question or two about this tube headphone amp:
http://oatleyelectronics.com/files/K272X.pdf . Anyway, I built the thing
and while it did amplify it did not seem to color the sound,
despite the good reviews about the thing I found online. So it sat on my
desk until a couple weeks ago when I happened to read about another tube
amp and how the amp was left on by the reviewer to break in the tubes.
This made sense to me because tubes do eventually wear out so some sort
of physical change must be happening inside the things. So I powered up
the little headphone amp and left it on for about 28 hours.
I then tried it out with some good earbuds and as a pre-amp for my
Pioneer SX-434. It now changes the sound. Not as much as I expected,
but maybe it's not supposed to. For some music I like using it better
than just plugging my digital sound source into the Pioneer. I suspect
that when I get some good headphones there will be even more difference
that I can hear.
Eric

Tube burn-in is probably a psychological effect, not a physical one.

Tube sound, ditto.

The sound engineers who make the files and CDs already have a zillion
options to add distortion, tweak frequency response, mix signals, add
noise and echoes and other DSP effects, and they put a lot of time and
money into making things sound "right." Why would running their signal
through a dumb tube amp make it sound better?

Placebo effect - Nothing sounds as good as the distortion you're used to?

Double-blind testing makes a lot of acoustic effects disappear.
Greetings John,
I bet you're right about the double blind thing. That's part of the
reason why I was surprised about hearing a difference after the tubes
were burned in. In fact, I'm thinking about buying a couple new tubes
online and trying the whole burn in thing again but this time actually
measuring the output before and after with a 'scope as jurb suggested.
I'm curious though about something you said. When asked by jurb for a
schematic I provided a link and you found that laughable for more than
one reason. How about, since this is an electronics basics group,
letting me know what was so laughable?
Cheers,
Eric

Token tubes driving opamps is laughable. The resistor values on the
output amp are optimized to make noise.

Now John, you've claimed to have a tin ear, so you can't
really appreciate the warm and fuzzy sound of a tube amp.

Eric, I'm no audio guy, but I hear tubes clip more gently
than opamps. A lot depends on what type of music you are
listening to.
As far as burn in it could be that your ear/ brain adapts
to the source.

George H.

The datasheet of that PT2308 chip is silly too. A few bullets and no
specifications!

The board layout, the red thing, is really ugly.



--

John Larkin Highland Technology, Inc

lunatic fringe electronics

 

[John Larkin]

On Tue, 20 Dec 2016 18:32:00 -0800 (PST), George Herold
<gherold@teachspin.com> wrote:

On Tuesday, December 20, 2016 at 11:42:07 AM UTC-5, John Larkin wrote:
On Mon, 19 Dec 2016 17:47:36 -0800, etpm@whidbey.com wrote:

On Mon, 19 Dec 2016 15:12:12 -0800, John Larkin
jjlarkinxyxy@highlandtechnology.com> wrote:

On 19 Dec 2016 13:26:19 GMT, default <default@defaulter.net> wrote:

On Sat, 17 Dec 2016 10:10:03 -0800, John Larkin wrote:

On Fri, 16 Dec 2016 12:42:10 -0800, etpm@whidbey.com wrote:

Some time back I posted a question or two about this tube headphone amp:
http://oatleyelectronics.com/files/K272X.pdf . Anyway, I built the thing
and while it did amplify it did not seem to color the sound,
despite the good reviews about the thing I found online. So it sat on my
desk until a couple weeks ago when I happened to read about another tube
amp and how the amp was left on by the reviewer to break in the tubes.
This made sense to me because tubes do eventually wear out so some sort
of physical change must be happening inside the things. So I powered up
the little headphone amp and left it on for about 28 hours.
I then tried it out with some good earbuds and as a pre-amp for my
Pioneer SX-434. It now changes the sound. Not as much as I expected,
but maybe it's not supposed to. For some music I like using it better
than just plugging my digital sound source into the Pioneer. I suspect
that when I get some good headphones there will be even more difference
that I can hear.
Eric

Tube burn-in is probably a psychological effect, not a physical one.

Tube sound, ditto.

The sound engineers who make the files and CDs already have a zillion
options to add distortion, tweak frequency response, mix signals, add
noise and echoes and other DSP effects, and they put a lot of time and
money into making things sound "right." Why would running their signal
through a dumb tube amp make it sound better?

Placebo effect - Nothing sounds as good as the distortion you're used to?

Double-blind testing makes a lot of acoustic effects disappear.
Greetings John,
I bet you're right about the double blind thing. That's part of the
reason why I was surprised about hearing a difference after the tubes
were burned in. In fact, I'm thinking about buying a couple new tubes
online and trying the whole burn in thing again but this time actually
measuring the output before and after with a 'scope as jurb suggested.
I'm curious though about something you said. When asked by jurb for a
schematic I provided a link and you found that laughable for more than
one reason. How about, since this is an electronics basics group,
letting me know what was so laughable?
Cheers,
Eric

Token tubes driving opamps is laughable. The resistor values on the
output amp are optimized to make noise.
Now John, you've claimed to have a tin ear, so you can't
really appreciate the warm and fuzzy sound of a tube amp.

http://phys.org/news/2016-12-scientists-uncover-stradivarius-violins-special.html

Another psycho-acoustic illusion:



Halo effect

One study in 2011 asked professional violinists to compare violins
made by Stradivari and Guarneri with high-quality new instruments
while playing blindfolded in a room with relatively dry acoustics.
Contrary to all expectations, the researchers found that the
most-preferred violin in the test set was a new one and the
least-preferred had been made by Stradivari. They also found that most
players seemed unable to tell whether their most-preferred instrument
was new or old.



The same thing happens in wine tastings: people prefer expensive wines
only when the know which are expensive.


--

John Larkin Highland Technology, Inc

lunatic fringe electronics

 

[George Herold]

On Tuesday, December 20, 2016 at 11:57:57 PM UTC-5, John Larkin wrote:

On Tue, 20 Dec 2016 18:32:00 -0800 (PST), George Herold
gherold@teachspin.com> wrote:

On Tuesday, December 20, 2016 at 11:42:07 AM UTC-5, John Larkin wrote:
On Mon, 19 Dec 2016 17:47:36 -0800, etpm@whidbey.com wrote:

On Mon, 19 Dec 2016 15:12:12 -0800, John Larkin
jjlarkinxyxy@highlandtechnology.com> wrote:

On 19 Dec 2016 13:26:19 GMT, default <default@defaulter.net> wrote:

On Sat, 17 Dec 2016 10:10:03 -0800, John Larkin wrote:

On Fri, 16 Dec 2016 12:42:10 -0800, etpm@whidbey.com wrote:

Some time back I posted a question or two about this tube headphone amp:
http://oatleyelectronics.com/files/K272X.pdf . Anyway, I built the thing
and while it did amplify it did not seem to color the sound,
despite the good reviews about the thing I found online. So it sat on my
desk until a couple weeks ago when I happened to read about another tube
amp and how the amp was left on by the reviewer to break in the tubes.
This made sense to me because tubes do eventually wear out so some sort
of physical change must be happening inside the things. So I powered up
the little headphone amp and left it on for about 28 hours.
I then tried it out with some good earbuds and as a pre-amp for my
Pioneer SX-434. It now changes the sound. Not as much as I expected,
but maybe it's not supposed to. For some music I like using it better
than just plugging my digital sound source into the Pioneer. I suspect
that when I get some good headphones there will be even more difference
that I can hear.
Eric

Tube burn-in is probably a psychological effect, not a physical one.

Tube sound, ditto.

The sound engineers who make the files and CDs already have a zillion
options to add distortion, tweak frequency response, mix signals, add
noise and echoes and other DSP effects, and they put a lot of time and
money into making things sound "right." Why would running their signal
through a dumb tube amp make it sound better?

Placebo effect - Nothing sounds as good as the distortion you're used to?

Double-blind testing makes a lot of acoustic effects disappear.
Greetings John,
I bet you're right about the double blind thing. That's part of the
reason why I was surprised about hearing a difference after the tubes
were burned in. In fact, I'm thinking about buying a couple new tubes
online and trying the whole burn in thing again but this time actually
measuring the output before and after with a 'scope as jurb suggested.
I'm curious though about something you said. When asked by jurb for a
schematic I provided a link and you found that laughable for more than
one reason. How about, since this is an electronics basics group,
letting me know what was so laughable?
Cheers,
Eric

Token tubes driving opamps is laughable. The resistor values on the
output amp are optimized to make noise.
Now John, you've claimed to have a tin ear, so you can't
really appreciate the warm and fuzzy sound of a tube amp.

http://phys.org/news/2016-12-scientists-uncover-stradivarius-violins-special.html

Another psycho-acoustic illusion:



Halo effect

One study in 2011 asked professional violinists to compare violins
made by Stradivari and Guarneri with high-quality new instruments
while playing blindfolded in a room with relatively dry acoustics.
Contrary to all expectations, the researchers found that the
most-preferred violin in the test set was a new one and the
least-preferred had been made by Stradivari. They also found that most
players seemed unable to tell whether their most-preferred instrument
was new or old.

Right, I remember hearing some violinist playing different violins
on the radio... They liked the newer ones too.
(I couldn't really hear much difference....)

George H.

The same thing happens in wine tastings: people prefer expensive wines
only when the know which are expensive.



--

John Larkin Highland Technology, Inc

lunatic fringe electronics

 

>"I wonder how much of that sound you could get with a small tube and a choke for a plate load, with the audio from the plate applied to a clean solid-state amp. "

I am surprised they don't do that. You should see the complexity of some of these amps.

If it is just a choke it would be single ended but then how many of those little amps were single ended.

Where is Les Paul when you have these questions ?

 

[Tim Wescott]

On Tue, 20 Dec 2016 14:22:16 -0800, jurb6006 wrote:

What I think makes the tube sound is the interaction between the high
impedance plate(s) of the output(s), the transformer and the speaker.
Even in guitar amps I see no reason to use tubes in the input stage(s).
In the old days, some musicians used to take a small tube amp, literally
put it in a box with a microphone when they got up on stage.

I wonder how much of that sound you could get with a small tube and a
choke for a plate load, with the audio from the plate applied to a clean
solid-state amp.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

I'm looking for work -- see my website!

 

[Tim Wescott]

On Wed, 21 Dec 2016 12:27:41 -0800, jurb6006 wrote:

> Where is Les Paul when you have these questions ?





--
Tim Wescott
Control systems, embedded software and circuit design
I'm looking for work! See my website if you're interested
http://www.wescottdesign.com

 

[Jim Thompson]

On Wed, 21 Dec 2016 14:54:01 -0600, Tim Wescott <tim@seemywebsite.com>
wrote:

On Wed, 21 Dec 2016 12:27:41 -0800, jurb6006 wrote:

Where is Les Paul when you have these questions ?

Les Paul who ?>:-}

...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| STV, Queen Creek, AZ 85142 Skype: skypeanalog | |
| Voice480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

 

>"Les Paul who ?>:-} "

I am going to assume you were being sarcastic because of the smiley thingie.. But Les Paul practically invented electric guitar, and he also taught many other things. Taught Buddy (Charles Hardin) Holly about overdubbung. He also gave my Uncle guitar lessons.

When people hear the name Les Paul they think guitars, but he was a bit more than that, recording techniques and all that, he was a pioneer.

I am not sure how close to truth it is, but the movie The Buddy Holly Story is a pretty good watch. A tape got to a radio station and they did not know they were not signed and went and played it on the air. By the time they got ahold of him "That'll Be The Day" made him $70,000. this is before I was born. This not just pay cash for a house and car money, this was damnear retirement money back then.

He goes to (I think Norman Petty at) the studio and gets all this about he has to meet the producers and all that and says he has been through all that, forget it, if your producers could do this you would owe him $70,000.

If the movie is up to snuff truthwise, he also was one of the few Whites who performed at the Apollo theater, which was supposedly strictly Black. The owner, upon hearing the music sent a telegram, be here this date, pay is X.. They get there and he sees they are White and says he can't let them go on, so Buddy says "OK, give us the money and we'll go home" citing the exact wording of the telegram. Well the owner acquiesced and they went on and the audience had people dancing in the aisles.

I also believe that the record company which owed the seventy grand thought they were Black and figured they could get over on them, like for releasing the song without authorization and copyright agreements. But they found this White boy from Texas who could really fuck with their world.

The plane crash that killed him, the Big Bopper and Richie Valence, I think maybe they wanted that, or at least welcomed it. Copyright laws in this country are really funny right now, but they were kinda funny then too.

In fact entertainment is one off the US' biggest exports, and that only works because most other countries respect out copyright laws.

Well them days are over, and the useless motherfuckers who get paid more to play act than to do real work are coming to an end. Look at the media. I do not have a TV but I do see TV sometimes. When I was a kid we had three channels. We had to talk about what to watch on Friday night. Most of the time the TV was off. Then UHF came out and there were five channels.

Now there are 300 channels and really there is nothing worth watching. My Mother watches TV, she has been through all the Hoarders, My 600 Pound Life, it is down to cop shows now. And those are so far from reality it is ridiculous.

They want you to think that every crime is investigated by ten cops and computer experts and nobody can get away with stealing a CR2032. But in reality, if someone blows your head off there is on;y a ten percent chance they will even investigate. They might look at camera footage if any and put up a picture, but the face is that well over half the murders in this country go unsolved. But then the people murdered are not complaining, or voting.

 

[John Larkin]

On Sun, 18 Dec 2016 22:57:41 +0000 (UTC), asdf <asdf@nospam.com>
wrote:

On Fri, 16 Dec 2016 12:42:10 -0800, etpm wrote:

Anyway, I built the thing and while it did amplify it did not seem to
color the sound despite the good reviews about the thing I found online.

If it colored the sound it wouldn't be HiFi and would not deserve
good reviews anywhere.

Read some audiophile reviews!


--

John Larkin Highland Technology, Inc

jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com