in the usa at least stax got away with direct ac mains to the transformers because of the polarized ac plug. bad idea. but legal 30 years ago. lots of tube type televisions with hot chassis did the same thing. also a bad idea. but cheap. Zenith was the only manufacturer that used an isolation...

close but no cigar. same input transistors. 2sk216 and 2sj79 which are very obsolete replaced with current production bipolar transistors. also this https://www.audiosciencereview.com/forum/index.php?threads/topping-eha5.42149/post-1948464

like this

early srm313 are identical schematic to srm212. no adjustment pots. for transformer boxes, 5.1k resistors absolutely required. 1/4 watt. you want the resistors to blow first. as far as zeners, anything that adds up to 600v in series and back to back. so a total of 32 x 150v zeners. or 24 x...

the correct answer is to buy both. also found this on the web this morning

david and goliath

500v has more headroom before clipping. some people like it very loud. and the higher you go in voltage the more current you need. the output transistors for the kgsshv are obsolete unless you happen to have a stock of them. carbons are 450v max due to parts ratings. no way to increase the...

warning to all that don't know, a lot of cars keep the brake light circuit active when the car is turned off. then the brake light switch on the master cylinder leaks, and starts the brake fluid on fire. huge issue with many ford vehicles. and bmw. and few others. if you have one of these, get...

i had an original bmw m3. in 19 months it was in the shop 21 times. head came off twice. got rid of it. replaced it with an audi quatro turbo 200. the only thing worse was the jaguar s type r. my father had a 300sel3.5. most amazing car ever. very hard to work on. i begged him to get the 6.3...

how many $300k porsche's burned to the ground when their engines siezed due to piston bolts coming loose? how many porsche's turn into rustbuckets when they are 5 years old. my C8 is rustproof. and 1/3 the price. gotta love the carbon fiber and polycarbonate body. with respect to the picture...

there is a gigantic difference between voltage and current. the koss amp can deliver 2400vppss at 1khz into the koss headphones. it is extremely current limited. it cannot deliver 2400vppss at 20khz into the koss headphone. the power supply will go into protect mode. the koss amp consumes a...

the maximum voltage for the headphones measured in vpss is 4 times the bias voltage of 580v before the diaphram goes negative. so 2320 vppss is max. i'm shooting for 2200vppss. this is why many of the modern amplifiers can destroy old standard bias headphones real easy. the koss esp950 has...

stock megatron is about 1500 volts with 400v power supplies. megatron is 8 output tubes driven by 2 dual 12ax7 triodes. you can push the power supplies to 450v. the new thing for which there is no name yet is 8 x 211 output tubes. driven from 4 x 300b. pre-driver and input section are e80cc and...

no difference. so it goes like this. just about every stax amp solid state or tube uses the same power transformer spec. the transformer makes +350 unregulated and -350 unregulated. in addition there is a pair of windings used for the filament on the tube amps, and on the 717 since there are...

a ccs modified t1 will have about 30 volts less vppss than a 717.

the current source vs the resistors is in the 3rd stage (vas). the output stage on both the 717 and 727 are emitter followers with current sources. same as the 313,323,t8000,500s,700s,d50 and a few more. people need to read and understand the schematics.

the s590 has the mediatek chipset and will rip sacd's out the ethernet port with the appropriate software on a usb stick. then you can get something with a decent dsd dac.

The koss amplifier is not deliberately equalized below 200hz. Its an AC coupled design, and the physical size of the 1kv coupling caps to the output section and the massive amount of open loop gain limit the frequency response of the amplifier. The kingsound m10 is similar in this respect.

no 3rd stage current source in the 700s. reason: no current production >700v pnp transistors. first 2 stages identical to 717. 3rd and 4th stage identical to t8000. lots of current production surface mount transistors in 3rd and 4th stage. tails of the 3rd stage are jfet. first use of jfet in...

anyone with a dead 211 to be used as a physical example? or 845 or 805 or 810... concerned with the quality of the one and only available pc mount socket for 211,845 etc. megatron with 8 x 211 should be a nice thing with +/-750v power supplies. and 4 x 300b as the driver tubes.

real current sources in the 727 at the top of the 3rd stage. as opposed to just resistors. real power is voltage * current * cosine( phase between voltage and current) since the load is a pure capacitor, the phase is 90 degrees. its actually a bit more complicated than that because there is...

The srm717, srm727, 500S and 500T are all the same voltage power supplies, and roughly the same current in the output stage. 500t is a slightly lower voltage swing. a srm727 with the global feedback modification is a better amplifier than the srm717.

turns out i had the simulation for the srm727. in distortion graphs, top trace is 2nd harmonic, bottom trace is 3rd harmonic. the global feedback modification significantly reduces 3rd harmonic distortion. remember to subtract about 57db to get distortion % output stage current source about 8ma.

that is a great deal of work. i already had the t1 simulation done many moons ago. and all the spice models that go with it. for the 717, i don't have a model for the output transistors. and unlikely to find good ones.

with virtual pot adjusted to 5% under clipping. spec on t1s is 320v power supplies, except in the real world its 350. full simulation. too much work, others need to do this. back to your regularly scheduled program. anyone with a scope and a signal generator can do the same thing with the real...