kevin gilmore

for the surface mount version which can handle a bit more heat, 20ma per transistor 160ma on each rail per board

the current sources see the tails of the differential inputs. So really its very close to a dc level that does not change with input signal. maybe microvolts if that much, so the current sources really have very little difference. changing the current sources may change the current a bit which changes the output stage current, so you may be hearing that.

there will be a new version of the boards posted when i get home. difference is bigger mounting holes.

the pass transistors go thru the bottom, so you would have to remount them on the new chassis the transformer is 2.04 inches, so the 2.1 inches is right

make sure you use 500v caps, and it will work at 400v. obviously change the zener string and transformer. in other news, kgsshvcarbon boards by joamat posted. mirror images for the truly insane.

massively sweet. definitely needs a wood knob.

this should give you all a headache... certainly gave me one. http://gilmore.chem.northwestern.edu/kgsshvcarbonstereo.pdf

yep, grounded grid. There is much more gain in the output stage, so all the extra parts in the BH are not needed. So the amp is faster because of less parts in the signal path. 3 stages instead of 5. board is 6.3 x 2.75 so it fits on a 3 inch high heatsink. (do I want to do 1500 lbs of aluminum again... highly unlikely)

someone really needs to check this hard. http://gilmore.chem.northwestern.edu/kgsshvcarbonright1.pdf changed to multipage to make it easier.

of course, thats the point, i'm working on adding connector blocks now. joamat did 2 boards, left side and right side, similar to the t2, that way everything is symmetrical. but it also means that there are twice as many boards.

another reason why many of the boards are on sockets is rework. If everything was on one board, and there was a problem, fixes could be tough. this way, one mini board does not work and cannot be fixed, it gets tossed.

joamat is doing the layout on this. all of the stax brain trust use the same software which makes things easier.

http://gilmore.chem.northwestern.edu/kgsshvcarbonright1.jpg ground plane on both sides, surface mount components on both sides.

he also did not address the temperature issues when you use a fixed reference. the reason to use a red led is that it exactly matches that of the transistor so the thermals don't cause runaway conditions. important because at 1kv, 1ma difference is a big deal. there is a way to bump up the impedance by adding one more transistor and another led in series. its also no surprise that the exstata and the idiot that designed it have no clue. for fun you can analyze the llmk1,llmk2,llmk3... given the high capacitance mosfets that replace the transistors, has to be really bad. schematics were posted.

its definitely my favorite amp for hd800 not even close. yep offset currents open input cause trouble.

well it might be ok if the water is 10**14 ohms... otherwise bad. do remember that someone dumped water on my T2 at CJ010 and it still lives 5 years later.

yep, wave a piece of paper over it, the thermals change and the offset drifts. for 18v rails, that is a good current.

someone please check these http://gilmore.chem.northwestern.edu/kgsshvcarbonv2.pdf http://gilmore.chem.northwestern.edu/kgsshvcarbon.jpg

this one, the servo is integral and required. Same as the T2

I like it.

I think if I design it carefully enough you can put 2 boards together, one is double layer, the other a single layer.

just tried it, very little actual ground plane due to all the wires. eventually when we go to all surface mount everything, the board will be at least 3 layers.

I was thinking those other resistors might be the plate resistors, but then what are the ones in between the caps. Anyway with the resistors not lifted off the board, the same thing will happen that has happened to the kingsound amps.

certainly can replace the reference with a to92, current datasheet does not list the pinouts. I did trim the emitter resistors to 25 ohms, so there is still about 9v on the servo. But will change values to the final parts when we all decide what those are. also added a pot in series with the 20k resistor to adjust the dc to exactly zero. the 25 ohms decreases the thd a significant amount at 20khz because of the added gain. let me know which parts and values to change.

no, just 2 transistors for the servo output drive. identical to Kerry's schematic. the final output is the Motorola part because its about 350mw and if you turn the current up, its more like .5 watt