kevin gilmore

not really sure what the point is. you took one of my layouts, and removed all the resistor values making it harder to stuff and verify. you also took off the acknowledgements of kerry gerontianos and james lin please take my name off the board

stax is certainly not the only company doing this. krell in a whole bunch of its products puts in a custom microprocessor chip that looks at line frequency, so if you have a usa unit at 60hz it won't even turn on at 50hz. and of course a few have developed plug and play circuits to fake the 60hz.

12v filament version posted pretty sure the original was done the way it was to accomodate the 6dj8 tubes for those that wanted to do that edit: the filaments of the output tubes are tied to -450v on the board

the conversion to 12V filament for the small tubes is easy and I should be able to get that done tomorrow, too many other things got in the way today.

1 ) yes 2) yes 3) the 4 tubes in the middle can either float or tie to -vcc yes the front end tubes are 6.3v, so 1.2 amps

no on the 3 terminal regulators. each output tube is 1.5 amps so that is 4 x 1.5 amp windings and 1 x 6 amp winding all the input tubes are in parallel, so 12V at 600ma

228.0 x 228.0

that looks a fair bit different than the first units

why no one tell me I got the wrong hole size... updated goldenreference6d file.

probably close to 50 milli ohms with a voltage gain of 10

highly unlikely the board is bad maybe you are connecting the transformer to the wrong place, center tap of transformer goes to the middle pin and for single bridge the other 2 wires go next to the center pin if there is no raw dc voltage on either of the main power caps, the bridge is toast or not the correct type for this board

joamat did this on a T2

OH boy is he taken!

I have never tried to get it to work that low, highly likely you have to use the 7V reference chip. Then it should work

i don't remember ever picking elna caps, definitely did pick the wima caps will look when i get home

I have seen ground loops do the 50(60) and 100(120) bumps, but never that amount of wideband noise. a missing ground wire between the pot and board ground could do it.

very noisy input fets or fakes, and volume pot of too high impedance. original was 10k pot.

i was wondering how you were going to do 3 layers in your kitchen, now i know

Definitely return it if you can otherwise get a scope and see if you get clock to the d/a outputs both before and after the opto isolators then see if you get any data etc.. My guess is that the input board is in trouble and I can't imagine anyone actually be willing to troubleshoot something that old filled with obsolete parts. check the +/-15 at each d/a board, same thing with the 5v

this definitely looks like NoNoNoNoNoNo class work. I have a few of his dead attempts in the basement, Jacob will remember. better question would be why you would want to put any more money into this in an attempt to fix it

warning: DO NOT DO THIS Mikhail did this with his "high voltage option" and zapped a number of people if you really must switch secondaries, use high voltage relays rated for 1kv or more isolation and even then, the inrush current might weld the contacts shut.

Outstanding

where did you get the delay board?

I bought one from headroom the first day they went on sale and it was $1399

soren also wanted buffers and a place for the attenuator on the board, which makes the board a fair bit bigger, and thus more expensive. if people think that is a good idea, or have other ideas i am certainly willing to modify. But i think that the smaller board is a better idea