Hi. First, I've also posted this on Head-Fi. If this is bad protocol, let me know and I'll clean up my act. 
I've just gotten an Amiron Home, and am loving it. The rest of my system is:
PiCoreplayer --> Modwright Transporter (EML Mesh rectifier, RCA Grey vt231) --> Sony TA-4650 (which I brought back to life thanks to y'all at diyaudio!)
Time for a headphone amp! (Amirons are 250 Ohm).
If I were buying an amp, I think I'd be looking for something like the Feliks Echo (still researching) , but I'd love to DIY my amp. I'm comfortable with solder, and don't want to go the starter kit route. I'm thinking hybrid/tube design, but not really sure why, except that I think tubes are cool.
I'm learning about the Jonokuchi, Millet Max, Torpedo 3, Tubelab SE, etc. and my head is swimming! I want a high-end amp, but don't want to wait until I'm an old man until it gets built!
Main question: any thoughts that may help me narrow things down?
Minor question: since the Transporter has the volume adjustment, is there any issue with doing without a volume pot on the headphone amp? Would I have to change anything in the design?
Thanks!
I've just gotten an Amiron Home, and am loving it. The rest of my system is:
PiCoreplayer --> Modwright Transporter (EML Mesh rectifier, RCA Grey vt231) --> Sony TA-4650 (which I brought back to life thanks to y'all at diyaudio!)
Time for a headphone amp! (Amirons are 250 Ohm).
If I were buying an amp, I think I'd be looking for something like the Feliks Echo (still researching) , but I'd love to DIY my amp. I'm comfortable with solder, and don't want to go the starter kit route. I'm thinking hybrid/tube design, but not really sure why, except that I think tubes are cool.
I'm learning about the Jonokuchi, Millet Max, Torpedo 3, Tubelab SE, etc. and my head is swimming! I want a high-end amp, but don't want to wait until I'm an old man until it gets built!
Main question: any thoughts that may help me narrow things down?
Minor question: since the Transporter has the volume adjustment, is there any issue with doing without a volume pot on the headphone amp? Would I have to change anything in the design?
Thanks!
You could check this Headphone amplifier:
Build A High-Quality, High-Power Headphone Amplifier | audioXpress
I have some PCBs available for the construction if you are interested.
Build A High-Quality, High-Power Headphone Amplifier | audioXpress
I have some PCBs available for the construction if you are interested.
You can add as many tubes as you want. Just light the filaments and leave the rest of the tube disconnected. It'll give you the subtle glow in the dark with all the benefits of solid state.
If a tube amp is what you want, there should be plenty of designs available. A 250 Ω headphone lends itself well to OTL (output transformer-less) designs, which will lower the cost. If cost is not an object, something like my DG300B (built with 300B, 2A3, or 45) would provide the ultimate glow-in-the-dark experience with good tube sound to boot.
Tom
If a tube amp is what you want, there should be plenty of designs available. A 250 Ω headphone lends itself well to OTL (output transformer-less) designs, which will lower the cost. If cost is not an object, something like my DG300B (built with 300B, 2A3, or 45) would provide the ultimate glow-in-the-dark experience with good tube sound to boot.
Tom
Your headphones are efficient, you don't need much power. The beta22 is complete overkill design imo.
If you want something clean, get a simple opamp+buffer amp. You can make it fancy with balanced inputs, dual mono construction, super-regulators. Tom above has a particularly fine implementation of this.
If you want tubes, I'd look at something like the 6e5p design I've got here. Very similar to the original Torpedo, very clean sound. Could maybe be even cleaner with a µ-follower setup. Two boxes construction is a good idea once you use output transformers at low levels. In the US, you have the chance to have affordable parafeed transformers for headphones. If you want more upscale than Edcor, Electra Print is an option iirc. Or Sowter in Europe.
If you want something clean, get a simple opamp+buffer amp. You can make it fancy with balanced inputs, dual mono construction, super-regulators. Tom above has a particularly fine implementation of this.
If you want tubes, I'd look at something like the 6e5p design I've got here. Very similar to the original Torpedo, very clean sound. Could maybe be even cleaner with a µ-follower setup. Two boxes construction is a good idea once you use output transformers at low levels. In the US, you have the chance to have affordable parafeed transformers for headphones. If you want more upscale than Edcor, Electra Print is an option iirc. Or Sowter in Europe.
> Amiron Home
1 Volt, 4mA, 4mW, takes these to 108dB SPL which is really loud.
4 V 16mA 64mW makes 120dB SPL which is quickly deafening. I have used headphone systems capable of that, but never at full blast for more than a few seconds (on-site recording of loud acts).
A '5532 chip with +/-9V rails will be plenty. Don't even need output buffers.
Many "small" vacuum tubes can deliver >4mA, you don't need a monster bottle.
IMHO the most important considerations are the finish on the case and the "snak" of the headphone jack.
1 Volt, 4mA, 4mW, takes these to 108dB SPL which is really loud.
4 V 16mA 64mW makes 120dB SPL which is quickly deafening. I have used headphone systems capable of that, but never at full blast for more than a few seconds (on-site recording of loud acts).
A '5532 chip with +/-9V rails will be plenty. Don't even need output buffers.
Many "small" vacuum tubes can deliver >4mA, you don't need a monster bottle.
IMHO the most important considerations are the finish on the case and the "snak" of the headphone jack.
Simple enough for first build, hybrid tube / Mosfet, full description :
A Hybrid Tube/MOSFET Headphone Amplifier | audioXpress
Project files: The Borbely Hybrid headamp | theslowdiyer
(incl. free Gerber files for the clone, NOT the original)
Other HPAs from Borbely :
A Battery-Powered Class A Headphone Amp | audioXpress
The Borberly EB602-200 Revisited
(incl. subjective comparison between lateral & vertical FETs)
Cheers,
Patrick
A Hybrid Tube/MOSFET Headphone Amplifier | audioXpress
Project files: The Borbely Hybrid headamp | theslowdiyer
(incl. free Gerber files for the clone, NOT the original)
Other HPAs from Borbely :
A Battery-Powered Class A Headphone Amp | audioXpress
The Borberly EB602-200 Revisited
(incl. subjective comparison between lateral & vertical FETs)
Cheers,
Patrick
Incidentally, the start-up DC offset problem of the tube version can be dealt with using a headphone protection circuit :
The ε12 muting / protect circuit
XEN SHPP -- Simple Headphone Protection
Patrick
The ε12 muting / protect circuit
XEN SHPP -- Simple Headphone Protection
Patrick
Pocket sized SE Class A Headphone Amplifier
Discussion and technical details here:
xrk971 Pocket Class A Headamp GB
Reviews here:
XRK Audio NHB Pocket Amp Review - Headfonics.com
XRK Audio NHB Portable Class A | Reviews | Headphone Reviews and Discussion - Head-Fi.org
Pocket Class A DIY Headphone Amp by XRK971 – Audio Primate
Desktop version capapble of driving 32ohm headphones using same topology here:
xrk971 Desktop Class A (DCA) Headphone Amp
Discussion and technical details here:
xrk971 Pocket Class A Headamp GB
Reviews here:
XRK Audio NHB Pocket Amp Review - Headfonics.com
XRK Audio NHB Portable Class A | Reviews | Headphone Reviews and Discussion - Head-Fi.org
Pocket Class A DIY Headphone Amp by XRK971 – Audio Primate
Desktop version capapble of driving 32ohm headphones using same topology here:
xrk971 Desktop Class A (DCA) Headphone Amp
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