kevin gilmore

a lot of people were having trouble getting the original parts. you can still use the other parts in that board, just have to bend the transistors a bit.

for the servo cap you really want a film cap. which is why it is that big. ceramics as I have found out have real trouble as integration caps.

anything over 20v is fine for the servo

on that version of the board, the A970 and mpsw56 are labeled backwards. The correct position is the a970's on the left and the mpsw56 on the right. latest board had the silkscreen right, consult that for more info.

I think you have the mosfets and bipolars backwards. all the Motorola parts are current production. all of the ixys parts are current production

Do not jumper the 270V zeners! either install them, or leave the slots empty.

that is how I build mine.

the added zeners for the mosfets and changes in the labeling also the dual transistor option

http://gilmore.chem.northwestern.edu/kgsshvproductiondualmot.pdf you replace Q1,Q2,Q9,Q10 with ixtp05n100m I don't think lil-knight has the latest dual transistor layout. the Motorola transistors are a different pinout on the older boards. most of us like the bipolar transistors better.

nope, you need 2 high voltage windings

yes it looks real. I have not seen 2sc4686a parts as fake yet. I bought extra parts from many ebay vendors recently and all test ok. 2sa1968 are a different story, most are fake.

lots of 2sc4686a on ebay still for cheap. suggest you buy a bunch.

if you have the latest boards with the zener protection you can replace the 3rd stage bottom and top of the 4th stage with 05n100m (latest on board version) or solder the zeners on the back schematic was never updated I have never actually seen 2sc4686. only 2sc4686a which is a 1200v part

something with a pair of 35V windings would be ideal, 40V windings are going to probably overheat the power supply. And you may have to adjust the bias generator to lower the standing current.

the ref102 WILL NOT WORK it cannot operate in 2 wire mode you cannot use all enhancement mode mosfets it will go boom

you have to replace all 4 zeners. the second stage zeners need to be 33V and the first stage need 40V and the caps need to be voltage upgraded

probably any of the lsk389 would work, but never tried it.

yep 120 ohms or even lower

you change R7/R10 to 350 ohms which will give about +/-33V on the power supply.

default for 500v is the same 5ma. you change the emitter resistors at the bottom of the output stage. and you want a lsk389B. the lsk170B is available from diyaudio.com

phil has sent me his schematics a number of times. He asked me not to publish them, so I did not publish them. He definitely got screwed over by larry numerous times. larry's video game addiction... etc...

I'm waiting for birgir to send me a liquid gold

The on board version can only handle so much power because of the heatsink size. The default is 5ma, which at 450V is 9 watts total for the output stage which is 2.25 watts per output device. The off board version is limited by only 2 things, the size of the heatsink and the maximum amount of power the output devices can handle. So yours is 14ma which is 25 watts per channel. The effect of the higher current is to extend the high frequency response well past 50khz. So the amp will definitely sound different. The choice of resistors will likely not make a change that you can ever hear. Except that a few of the trendy and expensive resistors cannot handle the voltage and cause all sorts of trouble. An lsk389 is going to be better than 2 x 2sk170 from an electrical drift standpoint. Not going to make any difference in the sound. Now the pot makes a big difference. RK50 and P&G are definitely the best of the bunch, rk27 and tkd less so. Mainly in channel to channel matching. dact will do better on matching. digital attenuators are even better.

white delrin. turns out there is a .002 taper in the insides of the neutrik jack. will make a couple out of Teflon anyway

final production stax male jacks http://gilmore.chem.northwestern.edu/staxmale5.jpg in case someone wants to have the Chinese make up a batch cheaper than I can http://gilmore.chem.northwestern.edu/staxplug.pdf