If the DC servo fails in just exactly one certain way, the amplifier melts your headphones.
Similarly, if the output coupling capacitor fails and becomes a short circuit, the amplifier melts your headphones.
Similarly, if the output transformer fails by shorting the secondary to the primary, the amplifier melts your headphones.
Similarly, every transistor power amp you've ever owned can melt your loudspeaker, if one of the output transistors fails and becomes a short circuit (to the supply rail).
The possibility of catastrophic failure is very real. It is present in just about every circuit ever built. Thanks for pointing this out!
Similarly, if the output coupling capacitor fails and becomes a short circuit, the amplifier melts your headphones.
Similarly, if the output transformer fails by shorting the secondary to the primary, the amplifier melts your headphones.
Similarly, every transistor power amp you've ever owned can melt your loudspeaker, if one of the output transistors fails and becomes a short circuit (to the supply rail).
The possibility of catastrophic failure is very real. It is present in just about every circuit ever built. Thanks for pointing this out!
For all the reasons Mark gives, an output cap is your Friend. Don't lose your friends.
270uFd or 470uFd at 10V is not a "giant" cap.
> I havent done the google
Oh??
Try "Tori amp". The original site is lost but it may be elsewhere. Yes, it involves an op-amp. You want DC precision, you can NOT beat a 19 cent opamp.
> how low in inductance it could be and still give good bass at headphone amp wattage. Might a line level 600:600
Not "wattage", Impedance. Logically you want something aimed at 32 ohms. Which is an odd value. Given the low Z, a "16" winding may be OK. A 600r winding is liable to have 30 Ohms self-resistance, which in 32 Ohm load is not good power efficiency. Hammond 125ESE's highest secondary tap will work great, but that IS a giant lump. The 125ASE may work, a smaller giant.
And I do not understand what you want from a transformer. If it has "good bass response" then it will pass turn-on/turn-off thumps fine and loud. It is never compact, light, or dead-clean.
270uFd or 470uFd at 10V is not a "giant" cap.
> I havent done the google
Oh??
Try "Tori amp". The original site is lost but it may be elsewhere. Yes, it involves an op-amp. You want DC precision, you can NOT beat a 19 cent opamp.
> how low in inductance it could be and still give good bass at headphone amp wattage. Might a line level 600:600
Not "wattage", Impedance. Logically you want something aimed at 32 ohms. Which is an odd value. Given the low Z, a "16" winding may be OK. A 600r winding is liable to have 30 Ohms self-resistance, which in 32 Ohm load is not good power efficiency. Hammond 125ESE's highest secondary tap will work great, but that IS a giant lump. The 125ASE may work, a smaller giant.
And I do not understand what you want from a transformer. If it has "good bass response" then it will pass turn-on/turn-off thumps fine and loud. It is never compact, light, or dead-clean.
You can also operate two identical amps in "balanced drive" mode where one amp is connected to +ve of voice coil and other amp to -ve of voice coil. Adjust the bias so that the DC level leading to phones is same on both amps (doesn't have to be zero) for net zero flow into phone. Drive amps with differential balanced drive and it will have +12dB more dynamic range and twice the power. Add a coupling cap if worried about DC.
Interesting suggestion! I will try both yours and Marks approaches. Probably will use a cap. : ) .
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