Aune T1 USB Tube DAC+ SS Amp Discussion Thread ***See first post for FAQ--Updated on 02/14/15***
Mar 26, 2014 at 2:39 PM Post #4,936 of 8,309
What tube do you recommend I get to replace the stock tube? I guess I want something that takes the edge off of the highs, brings the mids forward and expands the sound stage.
The Gold Lion is a nice new-production upgrade from the stock 6922EH. Here's a barely used one on ebay that you might be able to snag up cheap:

http://www.ebay.com/itm/Genalex-Gold-Lion-6922-E88CC-Gold-Pin-Tube-Barely-Used-/271432681647?pt=Vintage_Electronics_R2&hash=item3f32a608af

They run ~$45 new.
 
Mar 26, 2014 at 4:14 PM Post #4,937 of 8,309
The Gold Lion is a nice new-production upgrade from the stock 6922EH. Here's a barely used one on ebay that you might be able to snag up cheap:

http://www.ebay.com/itm/Genalex-Gold-Lion-6922-E88CC-Gold-Pin-Tube-Barely-Used-/271432681647?pt=Vintage_Electronics_R2&hash=item3f32a608af

They run ~$45 new.

 
Do you think this tube would sound similar? The JJ E88CC? 
 
http://www.thetubestore.com/Tubes/6922-E88CC-Tube-Types/JJ-E88CC-6922-Gold
 
Otherwise, I'm just going to try to find the Gold Lion on ebay that ships for cheap to Canada.
 
Mar 26, 2014 at 4:52 PM Post #4,938 of 8,309
Mar 26, 2014 at 10:04 PM Post #4,939 of 8,309
Does the Aune T1 only use 12V towards the tube? From what I read, the 6922 it comes with wants 90V for class A and can handle up to 220V.
 
Doesn't this mean that the tube in this device is more for show? 
 
If that's the case, I'm thinking about saving some money and going with something else, like the Bravo V3.
 
Mar 27, 2014 at 11:45 AM Post #4,941 of 8,309
Are there fake Valvo e88cc's floating around?
 
I got it but it has an A-frame with a solid disc getter, is it a fake?
 
A lot of different type of boxes and all make it confusing for me, should I post some pics?
 
Mar 27, 2014 at 12:49 PM Post #4,942 of 8,309
  Does the Aune T1 only use 12V towards the tube? From what I read, the 6922 it comes with wants 90V for class A and can handle up to 220V.
 
Doesn't this mean that the tube in this device is more for show? 
 
If that's the case, I'm thinking about saving some money and going with something else, like the Bravo V3.

 
There could be charge pumps inside that bump the voltage being sent to the tube to the 220 volts, but I doubt it. In the guitar world, there are quite a few tube pedals that run preamp tubes at around 12 volts, but very few still in production that exert the full voltage available to the tubes. From what I can tell, you won't be able to output 240v from USB and will need a kettle lead and a full-sized transformer. I really can't imagine the Aune T1 has any of these in the way that full-sized amplifiers have that cost ten times the price do.
 
Is it a gimmick? No, not in my opinion. The tubes still impact the sound—to what degree is up to you and your discretion—and swapping them out with NOS variations will alter the sound slightly, for sure. Again, would it be as much in a design that can kill you if you touched the capacitors without discharging them first? Probably not. But don't discredit it yet. I'd recommend seeing how it sounds before making any passive judgements. I've been dismissive of tube pedals that run off 12v power supplies, but some of my favourite designs use either charge pumps or are simply built so well that you don't notice the difference, and sound as good as if not better than the 240v pedals that cost $1000 and are enormous and impractical.
 
Mar 27, 2014 at 2:15 PM Post #4,943 of 8,309
 
There could be charge pumps inside that bump the voltage being sent to the tube to the 220 volts, but I doubt it. In the guitar world, there are quite a few tube pedals that run preamp tubes at around 12 volts, but very few still in production that exert the full voltage available to the tubes. From what I can tell, you won't be able to output 240v from USB and will need a kettle lead and a full-sized transformer. I really can't imagine the Aune T1 has any of these in the way that full-sized amplifiers have that cost ten times the price do.

 


I thought that I understood the role of the tube in Aune T1, but now I am not so sure.

It was said that the gain achieved by the tube is 1, that the tube is used as "buffer". If I am not mistaken, a tube used as "buffer" and with gain 1, then serves the purpose of "distortion" (or "modulation") phase, it is there only to introduce those distortions pleasant for human ear found in preamps/amps built on tube technology. Which is, BTW, great, I want sound that is pleasant for my ears, the measurements and instruments be damned.

But now the quoted chapter indicates that higher voltages can be provided by voltage pumps and that sounds like an amplification stage to me...

Which is it, please? I am considering pairing HD600's with either T1 or O2/amp and am a bit suspicious about the consistency of T1s.
 
Mar 27, 2014 at 2:28 PM Post #4,944 of 8,309
 
   
There could be charge pumps inside that bump the voltage being sent to the tube to the 220 volts, but I doubt it. In the guitar world, there are quite a few tube pedals that run preamp tubes at around 12 volts, but very few still in production that exert the full voltage available to the tubes. From what I can tell, you won't be able to output 240v from USB and will need a kettle lead and a full-sized transformer. I really can't imagine the Aune T1 has any of these in the way that full-sized amplifiers have that cost ten times the price do.

 


I thought that I understood the role of the tube in Aune T1, but now I am not so sure.

It was said that the gain achieved by the tube is 1, that the tube is used as "buffer". If I am not mistaken, a tube used as "buffer" and with gain 1, then serves the purpose of "distortion" (or "modulation") phase, it is there only to introduce those distortions pleasant for human ear found in preamps/amps built on tube technology. Which is, BTW, great, I want sound that is pleasant for my ears, the measurements and instruments be damned.

But now the quoted chapter indicates that higher voltages can be provided by voltage pumps and that sounds like an amplification stage to me...

Which is it, please? I am considering pairing HD600's with either T1 or O2/amp and am a bit suspicious about the consistency of T1s.

 
Higher voltages can be provided by charge pumps or from the wall and an appropriately sized and specified transformer. How this translates to sound is debatable, and is, from my understanding, not set in stone. Amplification can be described as 'gain'. When you turn the gain up on an amplifier, the volume is increased. When that volume surpasses the clean threshold of the design and tubes, distortion and compression is introduced. This is a pleasing and 'modern' sound, depending on your preferences and set-up obviously.
 
So basically, don't worry. Charge pumps are not commonly used in the technology I'm aware of, though I could be ignorant to a vaster, wider use of it. I doubt the Aune T1 has charge pumps. I can't see anything in the photo I have of the PCB that looks like a charge pump circuit. Really I was just being conversational. I don't know that much about the T1, probably as much as you. I hope I didn't create any confusion for your purchase. I'll be buying the T1 as my first headphone amp and DAC. I know a lot about tube technology, but not in the headphone context.
 
Mar 27, 2014 at 2:57 PM Post #4,945 of 8,309
There could be charge pumps inside that bump the voltage being sent to the tube to the 220 volts, but I doubt it. In the guitar world, there are quite a few tube pedals that run preamp tubes at around 12 volts, but very few still in production that exert the full voltage available to the tubes. From what I can tell, you won't be able to output 240v from USB and will need a kettle lead and a full-sized transformer. I really can't imagine the Aune T1 has any of these in the way that full-sized amplifiers have that cost ten times the price do.

Is it a gimmick? No, not in my opinion. The tubes still impact the sound—to what degree is up to you and your discretion—and swapping them out with NOS variations will alter the sound slightly, for sure. Again, would it be as much in a design that can kill you if you touched the capacitors without discharging them first? Probably not. But don't discredit it yet. I'd recommend seeing how it sounds before making any passive judgements. I've been dismissive of tube pedals that run off 12v power supplies, but some of my favourite designs use either charge pumps or are simply built so well that you don't notice the difference, and sound as good as if not better than the 240v pedals that cost $1000 and are enormous and impractical.
The T1 doesn't get it's power from the USB. You can modify a USB cord and cut the +/- power leads and it'll still operate. It's powered by the power supply. USB is just for data transfer. I think there's some internal images of the power supply but can't seem to find it anymore.
 
Mar 27, 2014 at 3:04 PM Post #4,946 of 8,309
The T1 doesn't get it's power from the USB. You can modify a USB cord and cut the +/- power leads and it'll still operate. It's powered by the power supply. USB is just for data transfer. I think there's some internal images of the power supply but can't seem to find it anymore.

 
Yeah, I don't think you can run 240 volts from USB. But I know the T1 doesn't run on 240V so I can see why I was confusing there. :p
 
Mar 27, 2014 at 3:22 PM Post #4,947 of 8,309
 
When you turn the gain up on an amplifier, the volume is increased. When that volume surpasses the clean threshold of the design and tubes, distortion and compression is introduced. This is a pleasing and 'modern' sound, depending on your preferences and set-up obviously.

 


The gain of 1, 0 dB, means no amplification. The amplitude of the signal on input should be the same as the amplitude on the output of the stage.

But the distortion should still be there even without the amplification if I am not mistaken?
 
Mar 27, 2014 at 3:51 PM Post #4,948 of 8,309
That
 
   
When you turn the gain up on an amplifier, the volume is increased. When that volume surpasses the clean threshold of the design and tubes, distortion and compression is introduced. This is a pleasing and 'modern' sound, depending on your preferences and set-up obviously.

 


The gain of 1, 0 dB, means no amplification. The amplitude of the signal on input should be the same as the amplitude on the output of the stage.

But the distortion should still be there even without the amplification if I am not mistaken?

 
You could be right. I guess from my understanding, gain and amplitude are one and the same. Without gain there is no amplitude, and when you think of gain you think of distortion. I think my misunderstanding is that you seem to be saying the amplifier is only 'buffering' the signal and is still relying on the amplitude of the original device. What I'm saying is: When you amplify the signal via the device on the sound source, you are amplifying its set of frequencies. The T1 changes this by bypassing that amp entirely and adding its own distortion via its own amp. So although it states 0dB, there is still amplitude, it's just not higher than the original source.
 
Mar 27, 2014 at 4:53 PM Post #4,949 of 8,309
That
 
You could be right. I guess from my understanding, gain and amplitude are one and the same. Without gain there is no amplitude, and when you think of gain you think of distortion. I think my misunderstanding is that you seem to be saying the amplifier is only 'buffering' the signal and is still relying on the amplitude of the original device. What I'm saying is: When you amplify the signal via the device on the sound source, you are amplifying its set of frequencies. The T1 changes this by bypassing that amp entirely and adding its own distortion via its own amp. So although it states 0dB, there is still amplitude, it's just not higher than the original source.

 


What I am trying to say is that distortion is inherent whenever one is leading a signal through the active component, be it a semiconductor or a tube. The response across the frequency range is, alas, never ideally flat, and some frequencies will be slightly attenuated, some slightly amplified even for circuit that operates in "no amplification" mode.

If Aune T1 is indeed running its tube as a "buffer", the design of the device is ingenious as it is relying on solid-state components to do amplification and the tube is there to introduce the desirable and (for human ears) pleasant distortions inherent to that tech. And whatever black magic happens as a consequence of compound work of DAC+tube.

I like that. I distrust any preamp/amp built on tube technology that sells for ~$200.
 
Mar 27, 2014 at 5:12 PM Post #4,950 of 8,309
 
  That
 
You could be right. I guess from my understanding, gain and amplitude are one and the same. Without gain there is no amplitude, and when you think of gain you think of distortion. I think my misunderstanding is that you seem to be saying the amplifier is only 'buffering' the signal and is still relying on the amplitude of the original device. What I'm saying is: When you amplify the signal via the device on the sound source, you are amplifying its set of frequencies. The T1 changes this by bypassing that amp entirely and adding its own distortion via its own amp. So although it states 0dB, there is still amplitude, it's just not higher than the original source.

 


What I am trying to say is that distortion is inherent whenever one is leading a signal through the active component, be it a semiconductor or a tube. The response across the frequency range is, alas, never ideally flat, and some frequencies will be slightly attenuated, some slightly amplified even for circuit that operates in "no amplification" mode.

If Aune T1 is indeed running its tube as a "buffer", the design of the device is ingenious as it is relying on solid-state components to do amplification and the tube is there to introduce the desirable and (for human ears) pleasant distortions inherent to that tech. And whatever black magic happens as a consequence of compound work of DAC+tube.

I like that. I distrust any preamp/amp built on tube technology that sells for ~$200.

 
I think you're right. All-tube amps, in my experience, require high quality components to function properly, and extremely high quality to function at their best. You could have an excellent circuit design, but if you use cheap capacitors, don't filter the noise properly, don't bias the output tubes correctly, you'll have a poor machine with great potential. With that said, I do think you can make low cost tube amps work, but you will probably have to source production in cheaper countries such as China.
 
A truly 'flat' frequency curve is not usually very enjoyable to listen to. The songs we listen to are mastered on speakers that have a frequency 'balance' more so than a flatness. That's what I've come to learn anyway. It's almost impossible to create a 'slab' of analog sound. Digitally it's more than possible to create a flat frequency, but with analog technology it must be incredibly hard. Which is maybe why we have adjusted and settled on the specific frequency curve that we have now; because technology wasn't advanced enough to perfectly flatten the spectrum and then record excellent music with it. The same goes for the frequency of concert pitch, 440hz. For some reason that's what we settled on. Conspiracy theorists have theories as to why. I read that the Nazi's pumped out music and sound at 432hz to 'pacify' inhabitants as its frequency curve is more in line with human placidness, and it also apparently was used to control. Ha!
 

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