kevin gilmore

if you want an all tube amplifier with no output capacitors or inductors then get someone reputable to build you a megatron. large voltage swings, and thd < .02%. absolutely flat 20 to 20khz. Bonus points for the all tube power supply. large and heavy to be sure. when you talk to people ask for frequency response and thd #.

the lta unit is something different entirely. and has 1% distortion and switching noise due to the square wave oscillator, diodes and high frequency transformer. The eddie current electra is a center tapped inductor with capacitors on the output. No distortion specs ever published. The original woo audio wes is a pair of inductors with capacitors on the output. No distortion specs ever published. The malvalve has an output transformer and in electrostatic mode the headphones are run off the transformer primary. The new es8 finally has a center tapped inductor and output capacitors. Low power output tubes. The palatauf is highly similar to the es8 with lundahl center tapped inductors ($100 each) and output capacitors. None of these amps have enough voltage gain to have enough feedback to reduce the distortion to reasonable levels. None of these amplifiers have inductors or transformers specifically designed to drive electrostatic headphones which result in various phase and frequency response issues. if i knew of a company that would be willing to correctly wind me some transformers i might be willing to make an amp like this. Even if i wanted to wind my own transformers, availability of the cores i want and the rest of the parts are impossible to find. And there would be 1 more tube gain stage. re: birgir's baked goods. seriously you people have no idea.

front end fets are definitely available. measure the resistance of the plate resistors first. put it on the bench and measure the dc output levels after 30 minutes.

they are the big resistors and they are labeled. 4 or 8 of them depending on model all in a row.

replace all the plate resistors. this is the most likely failure.

too much music that will never ever end up on commercial music services. the teac app works 100% reliably. via smb. wireless even. the nas drives are western digital4100 and have been 100% reliable over the last 10 years. the denon receiver in the home theater room also plays via smb just fine. apple and amazon boxes also work fine via smb. dlna is a massive pile of crap and i refuse to use it. whoever thought to limit a database length was a moron.

teac nt-505 driven native usb up to dsdx8 from laptop. and ethernet for which the app sucks. waiting for the new app before i get the nt-701. playing physical discs with more than 15000 total (more than 5000 sacd and 10000 cd) is just no longer practical. There is media literally all over the house.

i think one of those is coming, under the esoteric label, its going to be $20k+. makes no sense when you can get a sacd ripper for $300 and then put it on a nas drive. then you rip the disc once and you are done. i've done that over 5500 times in the last 12 years. 18 terabytes of playable dsd files...

i've been saying that the switches in a r2r dac were a real problem for many years now. especially the ttl versions. the teac ud-701n is the cheapest ($4k) of the esoteric dacs that use custom and hand matched switches. I expect that better switches will be the new big deal in the next couple of years.

amir using his AP measured the koss amp directly which promptly went into power supply overload at about 100 volts into the 100k input impedance of the AP. then he measured one of the stax tube amps and came up with equally useless graphs. refusing to build an input attenuator he continues to believe in his measurements. if he had tried to measure a kgsshv-carbon without an input attenuator he would have blown the AP to crap, as the kgsshv-carbon is more than happy to put 900 volts peak to peak stator to ground into a 100k load. amir is as i have said before is just another idiot with an AP. and continues to find a way to represent an amplifier as 1 single number. which purrin has correctly labeled as amirNAD. simmconn on the other hand did correctly build a 10x attenuator and has been measuring and posting graphs. and knows what he is doing.

the original larger boards were compatible with amb's lcduino with no software changes. the smaller board i did with the color touch screen programming thing from australia.

probably not. glich is too fast. try it and let us know.

you get a dc glitch in the output. not enough to cause damage to the headphones.

i have bigtime problems with their cables. for cables with a cable shield the shield has to be at ground potential, not 580vdc. with 2 wires on each stator, the cable is double the capacitance that it needs to be. really messes with the frequency response and high frequency load presented to the amplifier. 6aq5 output tubes paralleled, so maybe 5 watts into 8 ohm speaker tap. e180cc as input tube. medium gain. circuit highly similar to early dynaco, pentodes driven as tetrodes with ultra linear transformer taps. unregulated power supply is a bad joke.

that person is a moron. the orpheus has 3 capacitor coupled stages. the BH is completely dc coupled.

surface mount version of the 47uf cap

opa551 is a cheaper opamp that is good to 60 volts opa445 is good to 90v. at least that is what the pricing used to be

As many of you know i have been searching high and low for the world's best headphones. I have finally found them.

well it was designed for 450v power. but really we are talking about only a couple db of difference. a minimum of -100db thd+noise. if you swap the transformer then you have to go with higher voltage rated power caps.

ttc004 might now be a better replacement, different package.

simmcon, first graph not shown. are you measuring balanced? and what additional attenuator are you using?

those resistors are output stage bias set.

no idea, have to look where those resistors go. if those are the input resistors, anything over 50 ohms is fine.

there are gerbers for the k489/j689 and the 2sc3381/2sa1349 pretty sure the 2sj109/2sk389 is compatable with the 2sc3381/2sa1349 board you are looking for that340.zip

the inductance is going to be really low in any case.