Amps that Need only One Tube v.s. Amps that Need more than One Tube?
Jul 11, 2013 at 3:15 PM Thread Starter Post #1 of 15

darkarn

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Hi guys, I am now tube amp-less and thus am planning for my next move (i.e. should I buy back same model or...?)
 
I noticed that the market has amps that need only one tube (e.g. 12AU7) and amps that need more than one tube.
 
Is there any difference between them and what should I (not) care about those cases?
 
Thanks!
 
Jul 11, 2013 at 3:31 PM Post #2 of 15
Generally amps with only one tube are hybrid amplifiers, but choosing an amp is not a five minutes job, what headphones will you use ? what headphones did you plan to buy ? and what is your source (DAC, CD player, mp3 player, etc..) ?
 
Jul 12, 2013 at 2:47 AM Post #3 of 15
Ah I see, so if I really want the tube sound I have to go for those pure tube amps that need more than one tube?

Also, silly me, I forgot to mention my setup. I am currently using my laptop's optical out to a Fiio D03K Taishan (which has RCA outputs and 3.5mm output). I am using my Beyerdynamics Custom One Pro and might go for HD650/AKG702 in the near future.
 
Jul 12, 2013 at 6:57 AM Post #4 of 15
Quote:
Ah I see, so if I really want the tube sound I have to go for those pure tube amps that need more than one tube?

Also, silly me, I forgot to mention my setup. I am currently using my laptop's optical out to a Fiio D03K Taishan (which has RCA outputs and 3.5mm output). I am using my Beyerdynamics Custom One Pro and might go for HD650/AKG702 in the near future.

 
There's no really "tube" sound, some amps can have a 100% tube sound and can have a very lean and neutral sounding and some SS or transistor amps can have a really warm sound, if you're interested only in power hungry cans like HD650 the best bet is an tube OTL design, but i think that hybrid amps are more versatile and allows you to own several kind of headphones (vintage AKG, Grado, HD-650, 600 Ohm Beyer).
 
Jul 12, 2013 at 10:54 AM Post #5 of 15
I see, so once again it's a matter of what my ears approve the most at the set price? :X
 
I don't get how hybrid amps can be more versatile though; is it something about too much/little gain?
 
Jul 12, 2013 at 12:05 PM Post #6 of 15
Quote:
I see, so once again it's a matter of what my ears approve the most at the set price? :X
 
I don't get how hybrid amps can be more versatile though; is it something about too much/little gain?


OTL is most of the time high volts and low current. While it's good for 300 ohms and 600 ohms cans, it's current output isn't enough for low sensibility 50 ohms cans.

Hybrid uses most of the time tube as input and solid state as output to push massive amount of current. Thus, this type of design will be able to drive a wider variety of headphones.
 
Jul 12, 2013 at 12:23 PM Post #7 of 15
hd650 require higher V drive - not particualrly "power hungry" though
 
the K701/2 are lower efficiency which is measured in dB/mW, and lower Z - they require more current and power but a little less V than the HD650
 
single tube dual triode hybrids are the cheapest if you want any tubes in the circuit
 
all tube amps often use stepdown transformers - good audio output stepdown transformers cost OEM $50-100 for 2  - so don't expect good ones in amps selling less than $500
 
Jul 12, 2013 at 2:56 PM Post #9 of 15
Quote:
OTL is most of the time high volts and low current. While it's good for 300 ohms and 600 ohms cans, it's current output isn't enough for low sensibility 50 ohms cans.

Hybrid uses most of the time tube as input and solid state as output to push massive amount of current. Thus, this type of design will be able to drive a wider variety of headphones.

 
Ah I see... And I thought you will need less current for those 50 ohms cans :X
 
Quote:
hd650 require higher V drive - not particualrly "power hungry" though
 
the K701/2 are lower efficiency which is measured in dB/mW, and lower Z - they require more current and power but a little less V than the HD650
 
single tube dual triode hybrids are the cheapest if you want any tubes in the circuit
 
all tube amps often use stepdown transformers - good audio output stepdown transformers cost OEM $50-100 for 2  - so don't expect good ones in amps selling less than $500

 
Errr sorry, what's a stepdown transformer? Is it in the supplied PSU?
 
Quote:
Sounds like a good hybrid is in your future. 

 
Hmmm... Very likely... :wink:
 
Jul 12, 2013 at 4:01 PM Post #10 of 15
tube amps need at least one line power transformer and then may have an output transformer/ch - often all are of similar size, appearance when bolted in view on the top of a "classic" tube amp chassis design
 
some add power filter chokes of near the same size, external appearance as the other transformers
 
the audio output transformers take the I,V tubes may be happy operating at - say 100 V, 20 mA rms and transforms it to say 10 V, 200 mA rms  that would drive many headphones better
 
but to do so over the whole audio range, with low added distortion, good quality audio output transformers use much more expensive materials and assembly techniques than line power transformers
 
Jul 12, 2013 at 4:33 PM Post #11 of 15
If you want great DAC/Amp combo with tube amp for HD650 get Woo Audio WA7. I know it's not cheap but it really good pairing with many other headphones such as T90 and t1
 
Jul 13, 2013 at 7:55 AM Post #12 of 15
Quote:
tube amps need at least one line power transformer and then may have an output transformer/ch - often all are of similar size, appearance when bolted in view on the top of a "classic" tube amp chassis design
 
some add power filter chokes of near the same size, external appearance as the other transformers
 
the audio output transformers take the I,V tubes may be happy operating at - say 100 V, 20 mA rms and transforms it to say 10 V, 200 mA rms  that would drive many headphones better
 
but to do so over the whole audio range, with low added distortion, good quality audio output transformers use much more expensive materials and assembly techniques than line power transformers

 
Any examples of them? :X
 
Quote:
If you want great DAC/Amp combo with tube amp for HD650 get Woo Audio WA7. I know it's not cheap but it really good pairing with many other headphones such as T90 and t1

 
That's really out of my budget! :O And I prefer optical out over USB out...
 
Jul 19, 2013 at 6:17 AM Post #13 of 15
I'm also looking to try a tube amp for the first time and am having to read up on what is available. I don't have the ability to demo before purchasing so it is going to be pot luck I guess.  Here are a couple of options that I'm investigating and you may also find the links helpful:
 
  1. Analog Squared Paper is a one person Japanese business that currently makes two beautifully constructed amps: TU-05 and the smaller in dimensions hybrid TUR-06.  There is a very active thread on Head-Fi which gives heaps of information and the participants are real enthusiasts.  http://www.analog2p.com/index.html
 
  1. These are DIY hybrid tube amps but they also provide the opportunity to purchase them fully assembled at reasonable cost. For a beginner like me they look like a good option to find out what all the fuss is about tubes. Part of the fun is rolling / trying different tube(s) combinations.  I'm seriously thinking about their latest "Project Ember" amp as it allows you to roll dozens of different tube types and the amp handles the biasing automatically.  http://www.garage1217.com/index.html
 
Good luck with finding something suitable for you.
 
Jul 19, 2013 at 6:56 AM Post #14 of 15
Quote:
I'm also looking to try a tube amp for the first time and am having to read up on what is available. I don't have the ability to demo before purchasing so it is going to be pot luck I guess.  Here are a couple of options that I'm investigating and you may also find the links helpful:
 
  1. Analog Squared Paper is a one person Japanese business that currently makes two beautifully constructed amps: TU-05 and the smaller in dimensions hybrid TUR-06.  There is a very active thread on Head-Fi which gives heaps of information and the participants are real enthusiasts.  http://www.analog2p.com/index.html
 
  1. These are DIY hybrid tube amps but they also provide the opportunity to purchase them fully assembled at reasonable cost. For a beginner like me they look like a good option to find out what all the fuss is about tubes. Part of the fun is rolling / trying different tube(s) combinations.  I'm seriously thinking about their latest "Project Ember" amp as it allows you to roll dozens of different tube types and the amp handles the biasing automatically.  http://www.garage1217.com/index.html
 
Good luck with finding something suitable for you.

Thanks for the heads up for the Analog Squared Paper, now that's what I call a portable tube amp! I am not sure if I want it now as I am still trying to figure out the tubes it can use.
 
And yes, I am strongly considering the garage1217's amps too; if I don't see any good second-hand deals locally (Singapore), I will most probably get one of them.
 
Jul 19, 2013 at 7:06 AM Post #15 of 15
Quote:
I'm also looking to try a tube amp for the first time and am having to read up on what is available. I don't have the ability to demo before purchasing so it is going to be pot luck I guess.  Here are a couple of options that I'm investigating and you may also find the links helpful:
 
  1. Analog Squared Paper is a one person Japanese business that currently makes two beautifully constructed amps: TU-05 and the smaller in dimensions hybrid TUR-06.  There is a very active thread on Head-Fi which gives heaps of information and the participants are real enthusiasts.  http://www.analog2p.com/index.html
 
  1. These are DIY hybrid tube amps but they also provide the opportunity to purchase them fully assembled at reasonable cost. For a beginner like me they look like a good option to find out what all the fuss is about tubes. Part of the fun is rolling / trying different tube(s) combinations.  I'm seriously thinking about their latest "Project Ember" amp as it allows you to roll dozens of different tube types and the amp handles the biasing automatically.  http://www.garage1217.com/index.html
 
Good luck with finding something suitable for you.

 
imo if you don't need autobias, strong power and preamp output imo the best option is the Project Starlight..
 

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