Hey all,
I am looking for a 2A3 headphone amp project.
It would be difficult for to implement based off of schematic alone, I would need either a PCB or detailed build manual.
Some background: I've built a Bottlehead Mainline which has been my primary amp for a while.
Recently I built the Elekit TU-8600 300B amp for a secondary speaker system. I was intrigued how it would sound with headphones and was blown away. Specifically, the depth of the soundstage, imaging and layering of instruments and tone was something I have never experienced before.
Granted, these 2 are the ONLY tube amps I've ever heard.
Since well regarded commercial amps such as Eddie Current and DNA Stratus are 2A3 based, I have reason to assume that my experience with the Elekit is something that is "typical" of a reasonably designed SET amp.
As the Elekit will move to the speaker system, anyone have relevant recommendations for such an amp?
I am looking for a 2A3 headphone amp project.
It would be difficult for to implement based off of schematic alone, I would need either a PCB or detailed build manual.
Some background: I've built a Bottlehead Mainline which has been my primary amp for a while.
Recently I built the Elekit TU-8600 300B amp for a secondary speaker system. I was intrigued how it would sound with headphones and was blown away. Specifically, the depth of the soundstage, imaging and layering of instruments and tone was something I have never experienced before.
Granted, these 2 are the ONLY tube amps I've ever heard.
Since well regarded commercial amps such as Eddie Current and DNA Stratus are 2A3 based, I have reason to assume that my experience with the Elekit is something that is "typical" of a reasonably designed SET amp.
As the Elekit will move to the speaker system, anyone have relevant recommendations for such an amp?
300B, 45 and 2A3 have similar mu with 300B and 2A3 being similar in Rpi. The 45 has the highest Rpi of the 3 leading to an output transformer with the highest parasitics.
To understand what influences your ranking: what parameters are responsible for perceived "SQ"? Current? Interelectrode capacitances? Transconductance? Headroom considering the bias voltages? Some of which are pretty similar again.
To understand what influences your ranking: what parameters are responsible for perceived "SQ"? Current? Interelectrode capacitances? Transconductance? Headroom considering the bias voltages? Some of which are pretty similar again.
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Why 2A3 ?
Each amp is different, it's not safe to assume that your amp is typical. Until you are comfortable building from a schematic (at which point your options open up) then why not do the obvious thing and build another 300B based Elekit since it's guaranteed to satisfy.
There are 2A3 kits around and even if intended for speakers you may be able to convert for headphone use. It may be worth asking 2A3 amp/kit providers for their advice. I like the look of the Sun Audio kits from Japan - for no technical reason but because I look the look of them !
Originally wanted 2A3 as it seems to be in the same popularity as the 300B and provides less power which is fine for headphones. Also, some of the best regarded headphone amps are based on the 2A3 and it would be a variation from what I have. Not sure but I thought perhaps the tubes are not as expensive. (more on tube choice below)
Good points. I wouldn't build another Elekit since the price was not trivial, and my curiosity pushes me to try something else/new. Obviously this could yield a lesser result... but that is part of learning.
I looked around and seems like I will go for the TSE II for this build. Its very well documented and comes in PCB which helps alot.
After reading on the Tubelab website I think I'm actually going to stay away from 2A3 due to the current requirements and other subjective opinions.
I'm actually leaning towards building 45's as those should have more than enough power for my headphones and prices for a pair still seem slightly cheaper than 300B.
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This sounds like a good choice to me. I'm not one to want to build the same amp twice either.
That is the biggest problem. Finding an output transformer that suits ranges from 35 to 600 Ohm is complicated and can be very expensive.
Yea, seems like it.
I currently own two 300ohm headphones that are staying for a while. Most other headphones that interest me are in the 120-300ohm range, so I think I can scope it down a bit.
Most headphone amps support lo/high settings.
The DNA Stratus has 8ohm and 120ohm output Z.
Does that necessarily indicate the OPT secondaries are 8 and 120?
The main options I can think of now are:
- single 8 ohm secondary
- dual 8 / 32 ohm secondaries
- dual 8 / 120 ohm secondaries.
These options are more from "crowd sourcing" information, rather than actually knowing how to reach the correct values.
I don´t thing so but how knows.
I had thought of an output for 8R, 35R, 120R, 300R secondaries.
But I think this will be very expensive.
If I remember correctly, for example the Leben CX300 uses the 8 Ohm secondary and a 240R resistance in series for the headphone output.
Sowter has a line of output transformers for headphones: HEADPHONE TRANSFORMERS
In the US, electraprint is known to wind custom ones:Electra-Print.com Line Output Transformers
In the US, electraprint is known to wind custom ones:Electra-Print.com Line Output Transformers
I had jack at electraprint wind a transformer for headphones with 2 taps. It was for 45 DHTs Something like 48 and 150 ohm outputs. Basically for low and high impedance cans.
I added a switch to select which tap to use.
It ends up being about turns ratio, so don't worry that if its not exact. I'm sure 300 ohm cans will be fine on he high impedance tap
You can also add a resistor to a lower impedance output.
It was easy to ask Jack questions over email, he responds pretty quickly.
Randy
I added a switch to select which tap to use.
It ends up being about turns ratio, so don't worry that if its not exact. I'm sure 300 ohm cans will be fine on he high impedance tap
You can also add a resistor to a lower impedance output.
It was easy to ask Jack questions over email, he responds pretty quickly.
Randy
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