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How is "tube sound" even audible in modern headphone amps? - Page 19

post #271 of 370
Quote:
Originally Posted by wuwhere View Post
 

This is what I don't understand. If vacuum tubes are rolled off at high frequencies then how did they transmit at kHz and MHz for AM and FM before there were even transistors?

 

For Ham radio, they still use vacuum tubes.


Well, most tube power amps for speakers have output transformers to couple high voltage/low current to lower voltage/higher current for speakers.  That among other things accounts for it.  You also have to remember audio covers 10 octaves, while most RF uses cover a fraction of an octave.  They are resonant circuits.

post #272 of 370
Quote:
Originally Posted by esldude View Post
 


Well, most tube power amps for speakers have output transformers to couple high voltage/low current to lower voltage/higher current for speakers.  That among other things accounts for it.  You also have to remember audio covers 10 octaves, while most RF uses cover a fraction of an octave.  They are resonant circuits.

 

It doesn't really matter. The speaker's and/or headphone's frequency rolls off faster than any well designed tube amp.

post #273 of 370
Quote:
Originally Posted by wuwhere View Post
 

 

It doesn't really matter. The speaker's and/or headphone's frequency rolls off faster than any well designed tube amp.


Of course it matters.  If the speaker rolled off 6 db at 10khz and 12 db at 20khz with a flat amp, you then substitute a tube amp that is down 3 db at 10khz and 6 db at 20khz.  The overall system response is -6 and -12 db with the flat amp, with -9db and -18 db for the tube amp total system response.  Obviously these would sound different.  They would sound different because the tube amp has an audibly different response.  These aren't typical numbers for such equipment, but illustrate why it does matter. 

post #274 of 370
Quote:
Originally Posted by esldude View Post
 


Of course it matters.  If the speaker rolled off 6 db at 10khz and 12 db at 20khz with a flat amp, you then substitute a tube amp that is down 3 db at 10khz and 6 db at 20khz.  The overall system response is -6 and -12 db with the flat amp, with -9db and -18 db for the tube amp total system response.  Obviously these would sound different.  They would sound different because the tube amp has an audibly different response.  These aren't typical numbers for such equipment, but illustrate why it does matter. 

 

Ha! A tube amp that is down 3db at 10kHz? No amp designer in there right mind would design an amp like that. You are citing extreme cases. I said a well designed tube amp.

post #275 of 370
Quote:
Originally Posted by wuwhere View Post
 

 

Ha! A tube amp that is down 3db at 10kHz? No amp designer in there right mind would design an amp like that. You are citing extreme cases. I said a well designed tube amp.

 

Most modern tube amp have quite flat response in to a resistive load often times well beyond human hearing range both top & bottom. Speakers are not resistive loads however. Tube amps typically have a higher output impedance than transistor amps & in some cases can actually flatten the acoustic response of some speakers, especially tweeter drivers as their response deviation is frequently caused by inductive reactance as frequency goes up. As frequency goes up so does the impedance of the driver as a result & since the two impedances being the output impedance & the impedance of the driver including the inductive reactance forms a voltage divider network the voltage drive to the tweeter goes up along with the inductive reactance cancelling some of the acoustic amplitude loss from the tweeter that was caused by the inductive reactance so the tweeter instead of being down 3db  20KHz may only be down 2db instead so the tube amp would actually represent a flatter acoustic response in this case than a solid state amp driving the same tweeter.


Edited by germanium - 7/4/14 at 11:06pm
post #276 of 370

Since speakers have to be equalized anyway to correct for room acoustics, the most important thing about an amp should be consistency from amp to amp. That way, if an amp burns out, you can replace it without having to re-balance the EQ. Solid state amps are much more consistent.

post #277 of 370
Quote:
Originally Posted by madwolfa View Post
 

 

You contradict yourself. If the main factor is transducer, then why do you care about the amp technology at all?

 

Because of the way it sounds combined with the nostalgic factor, and being winter for me right now....the perfect solution for mild heating.  Serious.

Quote:
Originally Posted by esldude View Post
 


Yes, usually tube amps are less high fidelity to the source (though they don't have to be).  Good SS amps can fully and transparently pass on the sound of tube amps.  The reverse is usually not the case.

 

Now with pairings that work, and with particular preferences you may prefer a tube amp. But that is preference not to be confused with fidelity.  No reason to apologize for that, but do recognize what sounds best to you isn't automatically highest fidelity.  That is where things can get very confused.

 

"A crap tube amp on good speakers that pair well is still going to sound better, more hifi than a solid state TV speakers for instance".

 

While perhaps true it really tells one nothing.  It has no useful information.  A good tube or good solid state amp on good speakers will also sound better than TV speakers.

 

No one who loves the sound of tubes is ever confused about fidelity.  Thats not the issue.  When I started modifying speakers...I needed a solid state amplifier for an absolute reference, I anly had a KT88 push pull ....I bought a solid state with 4 channels and adjustable low pass and high pass.  I love it, it sounds awesome.  The KT88 sounds almost exactly the same, it sounds awesome, but slightly different, not fequency balance related as far as I can hear.  The treble sounds smoother and different, not rolled off.  The SS amp is more incisive up top and down low.

post #278 of 370
Quote:
Originally Posted by bigshot View Post
 

Since speakers have to be equalized anyway to correct for room acoustics, the most important thing about an amp should be consistency from amp to amp. That way, if an amp burns out, you can replace it without having to re-balance the EQ. Solid state amps are much more consistent.


 Feeling that now.  The tubes need checking on my amp and a check for bias drift is due.  Not playing up in winter, now, but before winter when it was warmer it squeeks, before it never used to do that.  My tube hybride amp is now also doing the same.  Its been several years of headach free operation, untill now.  At least, unlike a solid state amp, when a tube amp starts farting around you know new tubes will fix it.

post #279 of 370
Quote:
Originally Posted by SP Wild View Post


 Feeling that now.  The tubes need checking on my amp and a check for bias drift is due.  Not playing up in winter, now, but before winter when it was warmer it squeeks, before it never used to do that.  My tube hybride amp is now also doing the same.  Its been several years of headach free operation, untill now.  At least, unlike a solid state amp, when a tube amp starts farting around you know new tubes will fix it.

In the 60s no housewives had tube testers at home so they would take their tubes from the TV and check them when they purchased groceries at the market. If the first set tested good on the machine they would then bring another handful to the market the next day. The odds were after checking 10 tubes, the housewives usually could find the bad tube.

This was just normal tube tv life in the 1960s in America. Women did not work outside of the home and the husband did not have time during the week to go to the market to test tubes. The interesting part of this was the machine that tested the tubes also had a stock of tubes below for sale to replace the bad one. You would take your new tube and put it in the cart and pay during check-out just like buying a light bulb. The remainder tubes would be put into a small paper bag and put in the gals purse. When they got home the moment of truth was to put all the tubes back where they went and turn on the tv. If there was still issues that's when the repair man was called.

TVs had a plethora of knobs and buttons to adjust stuff and at the risk of having to drive back to the market these amazing housewives got really good at keeping track of putting back the taken out tubes and adjusting the 5 to 10 levels you needed to get a great picture. All this before the man of the house came home for his dinner waiting, drink and tv in perfect running condition.

The folks who made the tubes and were kind enough to let those housewives use that exotic and giant tube testing machine and subsequently found out that if they put more electricity into the tube testing process they could burn out the tubes faster and sell more tubes. And remember the only way was to basically check every tube in the TV. Some housewives actually got good and learned which tubes did which to the picture or sound of the unit.
post #280 of 370

Sub.

post #281 of 370
Quote:
Originally Posted by wuwhere View Post
 

 

Ha! A tube amp that is down 3db at 10kHz? No amp designer in there right mind would design an amp like that. You are citing extreme cases. I said a well designed tube amp.


I didn't cite any case.  My final sentence was "these are not typical numbers for such equipment, but illustrate why it does matter".  So if you understand illustrate and that it was showing why all response issues combine regardless of the source you might have gotten it. 

 

Bottom line, tubes are far, far more likely to alter the response of what they are hooked up to play with than solid state.  If you like the result fine.  You could get much the same with a resistor in series for the output impedance bump, and a little EQ. 

 

What you find with many typical tube amps is flat enough response into a resistor at low power.  The treble tends to roll some with power increases or distortion increases or both.  Many tube amps spec some nice looking response without specifying power.  Some do specify the power and quote two responses.  Right off the top of my head Conrad Johnson amps often have something like 20-20khz at 1 watt or 10 watts +/- .3 db.  Then full rated power at something like 1.5% thd and bandwidth of 30-15 khz.  That is fairly typical conventional push-pull transformer coupled tube power amp behavior.  Maybe CJ amps are not well designed. 

post #282 of 370
Quote:
Originally Posted by Redcarmoose View Post

In the 60s no housewives had tube testers at home so they would take their tubes from the TV and check them when they purchased groceries at the market. If the first set tested good on the machine they would then bring another handful to the market the next day. The odds were after checking 10 tubes, the housewives usually could find the bad tube.

 

I experienced what you're talking about there, and the tube tester wasn't at the market. It was at the drug store or hardware store. And it wasn't the housewives. It was the dads given the chore to do on the weekends. My dad would fill a sack with tubes and take them down to Thrifty Drug Store and gripe and complain. Finally, he was doing it so much between the TV, radio and his ham radio rig, he bought some sort of home tester. It was a royal pain in the ass. I remember he had to install a little box fan on the back of the TV set because it kept overheating. We'd turn on the TV and it would go WHOOOSH! and blow out the smell of burning dust. Those sure weren't the good old days!

 

By the way, I can totally see a tube amp with a 3dB dip at 10kHz. Not a high end audiophile one perhaps, but an average one. And I'm sure there are ones that are much worse than that.


Edited by bigshot - 7/5/14 at 11:43am
post #283 of 370
Quote:
Originally Posted by bigshot View Post

I experienced what you're talking about there, and the tube tester wasn't at the market. It was at the drug store or hardware store. And it wasn't the housewives. It was the dads given the chore to do on the weekends. My dad would fill a sack with tubes and take them down to Thrifty Drug Store and gripe and complain. Finally, he was doing it so much between the TV, radio and his ham radio rig, he bought some sort of home tester. It was a royal pain in the ass. I remember he had to install a little box fan on the back of the TV set because it kept overheating. We'd turn on the TV and it would go WHOOOSH! and blow out the smell of burning dust. Those sure weren't the good old days!

By the way, I can totally see a tube amp with a 3dB dip at 10kHz. Not a high end audiophile one perhaps, but an average one. And I'm sure there are ones that are much worse than that.

We were lucky as my Dad was into the latest stuff so around 68-69 we purchased two Hitachi solid state TVs. They were really amazing for the day. The comparison to tube TVs was night and day. The Hitachi sets ran flawless with zero maintenance.

I gave away my personal tube tester in 2010. I just buy new tubes.tongue.gif
post #284 of 370
Quote:
Originally Posted by Redcarmoose View Post


In the 60s no housewives had tube testers at home so they would take their tubes from the TV and check them when they purchased groceries at the market. If the first set tested good on the machine they would then bring another handful to the market the next day. The odds were after checking 10 tubes, the housewives usually could find the bad tube.

This was just normal tube tv life in the 1960s in America. Women did not work outside of the home and the husband did not have time during the week to go to the market to test tubes. The interesting part of this was the machine that tested the tubes also had a stock of tubes below for sale to replace the bad one. You would take your new tube and put it in the cart and pay during check-out just like buying a light bulb. The remainder tubes would be put into a small paper bag and put in the gals purse. When they got home the moment of truth was to put all the tubes back where they went and turn on the tv. If there was still issues that's when the repair man was called.

TVs had a plethora of knobs and buttons to adjust stuff and at the risk of having to drive back to the market these amazing housewives got really good at keeping track of putting back the taken out tubes and adjusting the 5 to 10 levels you needed to get a great picture. All this before the man of the house came home for his dinner waiting, drink and tv in perfect running condition.

The folks who made the tubes and were kind enough to let those housewives use that exotic and giant tube testing machine and subsequently found out that if they put more electricity into the tube testing process they could burn out the tubes faster and sell more tubes. And remember the only way was to basically check every tube in the TV. Some housewives actually got good and learned which tubes did which to the picture or sound of the unit.

 

No wonder so many of the older generation complain about the good old days.  Imagine having a wife today that would set up your home theater, equalise them correctly for response and tune the flat screen, then have a lamb roast ready for when her man came home...I'm totally in love with this imaginary woman already!

post #285 of 370
Quote:
Originally Posted by Redcarmoose View Post
DSPs are coming along and for guitar players making a tube amp sound while recording out of an effects box then USB to a computer is what it is all about. Around 1999 we saw wide popularity of digital reverb and amp simulations digitally. Still in 1999 the amp simulators sounded wet and digital. Every year they get better and better. Zoom has an effects box called the G3 and it emulates the sound of tube amps and guitar cabs being recorded. All this with more choices than you could choose, along with multi-effects all at the same time. What guitar players have always liked about tube distortion has been the compression. The signal is amplified thus the sustain is noticed longer because it is compressed and louder.

And with this super advanced art of tube amp emulation you have some guys leaving their amps at home and plugging in the effect box emulator straight to a PA system. Still this is not the norm and the purists are totally against doing it. It does seem that DSPs could be integrated into solid state headphone amps to color the sound. I could take two G3 amp simulator effects units and try to slightly distort the signal before it reached a solid state headphone amp like the totally clean sounding Asgard by Schiit Audio. It would take two units as they only accept a mono signal in. The trick here is that the amp simulators can be dialed in so little. You could have them at maybe setting 1 and they could maybe replicate the harmonic distortion your getting from a SET 300B tube headphone amp. The other crazy thing in regards to doing this is that the signal is affected by the order in which the amp simulators are placed in the chain. This theorist standpoint is that you could effectively have the DSP tube effect after the headphone amp or before the headphone amp and the placement completely changes your sound. Thus before the headphone amp one sound and after headphone amp another sound all together even though your tube amp DSP simulator has the exact same settings. Amazing Huh?

The G3 is relatively cheap at about $200 USD. ZOOM sells a lot of G3s so they get their development investment back by selling volume. It may be cost inhibited to have headphone amp designers put elaborate tube emulation DSP sections into their headphone amps. The other reason I think is that it is slightly opposed to the way they are thinking. Most of the time amp designers are attempting to take distortion out not design it into a companies headphone amp. I feel we will see it in our lifetime as DSPs have come so far in the last 14 years. The natural distortion you get from tube amps is just part of the process of taking a line level signal and creating volume.


That said I'm still waiting for my CD player to test the Asgard One and write a mini review here. Trying different stuff I settled not using a USB DAC but believe it or not going straight out of my 5th Generation iPod Touch playing both ALAC files and 16 bit X 44.1 FLAC files with the VLC FLAC player. So far the Asgard is blowing me away. More to follow. Warning: Spoiler! (Click to show)




ZOOM G3

The distortion/overloading and sustain sought by guitarists is not what is sought by a listener with audio gear. If you're really looking for this, you can get a pair of G3's and wire them into your listening chain. :D I doubt that this is what you'd really want,even if you could dial it down.

I believe that most of the tube amps that are favored produce distortion levels that are not humanly perceivable. On the other hand I doubt that audiophiles would favor the sound of a cheap distortion hobbled tube amp.

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