kevin gilmore

somewhere there is a mini board that is a stn9360 to to126 pinout. but bending the pins is something i have also done.

the 2sa1968 is definitely a pnp. there were datasheets that were definitely wrong. for this application you need a 400v pnp.

definitely not. use ksa1156. not sure if its the same pinout. kind of busy at the moment. but you would not know that

going to look at it in a few minutes. should be ground i think. nope, thats the feedback on the output. and the gerber file is correct. not sure where you got that picture, probably here, and likely not done. 3 of the other versions had the same error, all are updated on the google shares. no idea how that happened. someone needs to go thru all 9 versions (or more) to see if there are any more errors. i'm kind of busy waxing my brand new 2025 corvette Z06 3lz htc.

12 volt filament version with pin 6 grounded. for existing boards modification is easy. solder short wire from pin 6 to the ground pin on the .1uf 630v cap nearest to that tube. megatron12vcs - CADCAM.ZIP

will look into the megatron boards and see if the mods are easy. likely they are.

since pin 6 of the tube is a no connect, you can modify the amplifier and tie the 4 pin 6's to chassis ground. then in the adapter, pin 6 to the heatsink.

great idea. but there had better be a tail to ground the heatsink. otherwise not safe.

someone asked for this, so here is the amp board. working on power supply board now need to find a suitable chassis. power supply board in progress. cfaelectrostatschem2-4 - CADCAM.ZIP cfaelectrostatschem2-3.PDF cfaelectrostatschem2-3ps - CADCAM.ZIP

well there are apex chips that do sound good. but they are stupid pricy. and require large heat sinks.

it could have originally been 2 different transistors for the darlington in which case the original diagram might have been correct. since this is 30 years old, any original ideas are long gone.

you are not looking carefully enough. there is much more wrong with this thing. hint: power supply

makes sense.

same push pull stacked circuit with higher voltage all smd parts. also this https://buyee.jp/item/yahoo/auction/d1165787088 ac powered version of stax d10 with the lower voltage apex parts.

this is why i have 4 sets of tires for 2 cars. seriously under 40 degrees F is death for summer only performance tires. besides which the tires will crack and then you have to throw them out.

koss pro4a ? definitely koss

with the sanyo transistors 5v results in about 500ma bias. which was the original design spec for this board.

you need to measure the voltage across q36 should be about 5 volts. if not adjust rv2 and if that is not enough change r36

minimum power supplies +/-24 might have to change a couple of resistors in the bias generator for this output transistor.

what is the name of the gerber file for the output board

super thin traces are never a good idea. just ask cavalli.

yes the distance matters. always put caps as close to the chips as possible. probably need a scope to see whats happening to the power rails. possibly one of the diodes on the input lines is in the wrong direction.

solder on some .1uf caps on the power supply lines on each chip close to the pins. also no diodes that i see across the relay coils.

much better. max sensitivity of the qa403. 60 hz and multiples are very hard to remove, moving wires around in the box and things will change. completely inaudible. the synchronous rectifiers may take out even more noise. mumetal shielding around the transformer is also a good idea. glad that more and more people are buying the qa403. higher quality diy coming soon

might want to try again with a good quality mylar cap say 1uf in series with the power supply outout. you should be able to get better resolution.