Looks doable, i believe i got all the parts.
Not sure why others are criticizing safety when its cap coupled. Besides, tube guys here work with 400VDC minimum.
Btw, that 10uF output cap seems rather small. Are you sure its not 10mF?
Interesting, just looked up Electrostatic headphones.
Rather stylish things at first view. I am ignorant on the technically performance.
And the voltages/current involved with them.
I would assume a off the shelf high voltage opamp with current buffer would work fine.
Like hundreds of other headphone amp designs.
Rather stylish things at first view. I am ignorant on the technically performance.
And the voltages/current involved with them.
I would assume a off the shelf high voltage opamp with current buffer would work fine.
Like hundreds of other headphone amp designs.
If a amplifier has 10u in the front it is "too big" and then if it is on the output it is " Too small"
At the end of the day with 10k impedance the cutoff frequency still remains 1.59 Hz
More than fine for audio bandwidth.
Being 10u the most generic value ever used with opamps.
Far as " 40 watt" transistors needed for " SOA"
The bad news for the experts is IC's never have or never will use 40 watt transistors
for 10k loads or usually higher
If anybody tossed in a few diodes for crude anti latching and flyback / current limiting
it would be vaguely impressive and likely all that is needed to power whatever imaginary audio application
needs 300 volts of small signal other than a tube amp. using a basic triode with absolutely no magical nonsense.
Using some mystical magical unknown 600 volt capacitor that existed sine the 1900's
100 years gone !! what should we doo doo oh no !!
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The LM3886 uses 40 watt transistors. More than 80 volts and poof.
And 300 volt 8 pin DIP (or SOIC) op amps aren’t available in every corner dime store in the country either. Just think how much money they would want for one, too.
160 to 180 volt opamps will range from 3 to 22 dollars in 8 pin package.
300 volt and higher will typically be 24 to 32 pin packages with a very tiny thermal pad.
We are talking 30 to 45ma IC at most.
Depending on what your doing the whole frontend can be 15 volt transistors exceeding
600 to 800 MHz, then the last stage is high voltage.
MicroChip technology just released a new 300 volt opamp.
They dont sell to "hobbyists"
Typical 1000 unit reel is 3 dollars per unit.
You shouldn't expect more than 280 volts peak to peak with most 300 volt applications.
around 92 to 98 volts RMS if your lucky. For 10k loads dissipation = 1 watt
10k not even being typical for a 300 volt application.
With any high current application a mosfet buffer would be added.
Assume a full H bridge for a actual application.
Since none of them would be audio at any level.
I think if people really need a audio application TI has numerous 160 to 180 volt opamps
where a current buffer could be added.
Since VI limiters are pretty much ignored in most Diy applications.
As mentioned, any latching protection or current protection included would be vaguely impressive.
Since you cant win in DIY. If you offer current protection " oh my gosh what a sin"
If you leave it out, then everyone says, ohhhh poo poo doo doo, no short circuit magic thingy.
Your 10ma preamp needs " short protection" but a 10 amp power amp does not .....
Seems to be the theory
So there's the cone shape , that makes it special . I tought electrostatics have very thin , lightweight cone that makes them great especially at mids highs.
In theory planars should have better bass ? Heavier lower fs cone.
Always wanted to build a pair , transformers for the audio input and cone material - conductive layer stopped me. I saw a lot of ideeas from conductive spray paint to wood glue mixed with water and graphite.
Could be a fun summer project.
Planars on the other hand , some neo magnets and the cone can be made at a pcb factory , thin flexbile pcb with the traces for the coil itself .
There's a guy on youtube ( forgot his name ) who does full range planar speakers, fun stuff.
Found his channel:
https://youtube.com/@joppepeelen?si=F_owKHW7XUqyN5GT
Just a little trivia: one of the first op amps was the GAP K2-W that ran a pair of 12ax7s and used a +-300v supply; the first op amp patent was for a 3 tube device that ran at +-350v.
When I was in the service dept. of a rather well known musicians parts & distribution Co. = Troy Music,
I was surprised to find a guitar amplifier schematic that used the U.S. mains rectified without any transformer. From memory it was a 40watt amp.
It obviously used very high voltage transistors. Just imagine how much voltage & heat was 'dropped' across the output transistors !!!
For distribution within Australia > it DID have a voltage & isolation mains transformer 🙂
I was surprised to find a guitar amplifier schematic that used the U.S. mains rectified without any transformer. From memory it was a 40watt amp.
It obviously used very high voltage transistors. Just imagine how much voltage & heat was 'dropped' across the output transistors !!!
For distribution within Australia > it DID have a voltage & isolation mains transformer 🙂
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I believe Linn Valhalla PSU for the LP12 turntable did not have a transformer.
The logic chips ran at 9V. You can imagine how hard the poor regulator transistors had to work.
Linn being Linn, they also used cheap electrolytic capacitors. The dropper resistors used were also of an inadequate power rating, so I reckon all original Valhallas that have not been serviced are now safely dead.
The logic chips ran at 9V. You can imagine how hard the poor regulator transistors had to work.
Linn being Linn, they also used cheap electrolytic capacitors. The dropper resistors used were also of an inadequate power rating, so I reckon all original Valhallas that have not been serviced are now safely dead.
You just 'twigged' a thought to me > the guitar amp I referred to probably DID use "dropper resistors" 🙂
Here are two versions of wideband/HV/low-current amplifiers.
I don’t remember which one was actually built and used:
I don’t remember which one was actually built and used: