kevin gilmore

unlike some other product we have been discussing recently, sure looks built really nice with premium grade parts. especially the output caps. and since this is basically a singlepower extreme done to the extreme, its going to kick ass for high impedance headphones. cathode resistors are visible and are bolted to the heatsinks. betcha no ground loops inside this thing. sure looks to be leaning a bit to the left however. I wonder why that is.

by the way, the newer krell power supply was cloned from this one and only picture http://gilmore.chem.northwestern.edu/newkrellps.jpg no schematics were available, and no one I know actually had one, boozebuttons had the older one

both supplies now fully tested and i'm really happy with each of them. the bigger one easily does 1 amp, so enough to run a pair of boards for balanced. http://gilmore.chem.northwestern.edu/krellsupplies.jpg

yep. the thing gets stinkin hot. because the bias has to be turned way up to compensate for all the extra capacitance it has to drive. even so, its not enough.

that really is the way it arrived. and in a few places on the top, hennyo like balls of solder on the parts. seriously the solder job on this is miserable. also notice NO CONNECTORS. the whole mess is soldered together board to board from the top. Also notice that getting any of the power transistors off the heatsinks is virtually impossible. especially the ones on the triple of small heatsinks. This thing is virtually unrepairable if a part blows. updated schematic with more stuff.

http://gilmore.chem.northwestern.edu/m10.pdf http://gilmore.chem.northwestern.edu/m20.pdf I think its safe to say that even an exstata is better than the kingsound amps.

2sa1486 moar better anyway

definitely. Alex should go into the custom chassis business. I have 3 chassis I need right now, and don't have the time to do myself.

Ksa1156 from mouser Current part

Do a quick calculation noticing that the j176 is 10 times as noisy as the j74 With an amplifier with a voltage gain of 500 and see if you can get the Signal to noise ratio shown in that picture.

Well its a bright and sunny sunday morning and the don of the stax mafia says its ok for me to publish the schematic, so here it is. http://gilmore.chem.northwestern.edu/llmk1.pdf that triple current source at the top of the gain stage with the feedback from the output stage is what alex (knowingly or not) traded 1db of 2nd harmonic for 7db of 3rd harmonic. all the spice models are available, stuff them into ltspice and see for yourself. output transistor pics http://gilmore.chem.northwestern.edu/ll-2.jpg the tough one to take a picture of http://gilmore.chem.northwestern.edu/ll-3.jpg how about that quality way to jumper out a zener http://gilmore.chem.northwestern.edu/ll-4.jpg and a cold solder joint or 3 http://gilmore.chem.northwestern.edu/ll-5.jpg and here are some simple fixes that make the thing sound bunches better with just removing parts and only 2 jumpers http://gilmore.chem.northwestern.edu/llmk1fix.pdf at least alex did learn something from the exstata disaster. The power supply is no longer a shunt regulator. Its actually fairly quiet, and has a temperature stability of about 2% strictly due to the zener reference.

You have seen the singlepower esx rebuilds we have done right? remember this? http://gilmore.chem.northwestern.edu/liquidlightning.pdf well we built it just for fun and it sounded fucking awful. remember what alex said about it... it was a SLOW amplifier well the real thing is virtually identical to this. and its still fucking awful. but we have ways to fix it. at least we think we do. It is kind of a shame, the chassis is actually very nicely done and the power supply is pretty decent. The stax jacks are still way to tight and for no reason. Transformers are very nice. Now all alex needs is a decent amplifier to go inside the box.

there is a grounding error on the zener power supply on the final output cap on the minus power supply. the wrong side of this cap is grounded causing the minus supply to be grounded. simple fix, use a drill bit on the top to un-ground the grounded hole, then add a jumper on the bottom to the other side of the cap to the other cap to ground. http://gilmore.chem.northwestern.edu/dsc_0469.jpg http://gilmore.chem.northwestern.edu/dsc_0470.jpg

you will probably have to adjust the resistor in series with the offset pot, but otherwise everything should work. Since you loose a few volts you can probably go to +/-375v

don't forget that the kingsound has been "mosfetized" also known as "cavallied"

very sweet

moar better now old power supply 1000uf/35v 871-B41041A7108M000 8 4700uf 50v ls10mm 35 dia 598-SLP472M050C5P3 2 1n4750 512-1N4750ATR 2 1n4748 512-1N4748ATR 2 mfj15030 863-mjf15030g 4 mjf15031 863-mjf15031g 4 bridge rectifier 625-G3SBA20-E3/51 2 750 ohm 71-rn60d-f-750 2 562 ohm 71-rn60d-f-562 2 3 pin terminal 651-1729131 2 2 pin terminal 651-1729128 2 .1uf ls 5mm 80-R82EC3100DQ70J 4 heatsink 532-529902b25g 4 thermal washers 8 new power supply 220uf 50v ls 5mm dia 10mm 647-UPW1H221MPD 4 bridge rectifier 625-G3SBA20-E3/51 2 10 ohm 71-rn60d-f-10 1 100 ohm 71-rn60d-f-100 2 511 ohm 71-rn60d-f-511 2 750 ohm 71-rn60d-f-750 2 1k ohm 71-rn60d-f-1.0k 2 2k 71-rn60d-f-2.0k 4 10k 71-rn60d-f-10k 2 op27 use something else 2 4.7uf 505-MKS24.7/63/5 2 3 pin terminal 651-1729131 1 2 pin terminal 651-1729128 2 mfj15030 863-mjf15030g 1 mjf15031 863-mjf15031g 1 zener 13v .5w 78-BZX55B13-TAP 2 lm4040-2.5 926-LM4040DIZ25NOPB 2 .1uf ls .1 too lazy to look up 2 mj15024 863-MJ15024G 1 mj15025 863-MJ15025G 1 pnp mpsw56 1 npn mpsw06 1 heatsink 532-568303B00 2 thermal washer 739-A15038003 2

yep. fix later.

here is the bom for the dual zener regulated power supply less the heatsink which i'm too lazy and tired to look up at the moment. the hole sizes for the zeners are going to be a bit tight. will be fixed on the next rev of the board old power supply 1000uf/35v 871-B41041A7108M000 8 4700uf 50v ls10mm 35 dia 598-SLP472M050C5P3 2 1n4750 512-1N4750ATR 2 1n4748 512-1N4748ATR 2 mfj15030 863-mjf15030g 4 mjf15031 863-mjf15031g 4 bridge rectifier 625-G3SBA20-E3/51 2 750 ohm 71-rn60d-f-750 2 562 ohm 71-rn60d-f-562 2 3 pin terminal 651-1729131 2 2 pin terminal 651-1729128 2

The 2sa1968 is a pnp It is incorrectly listed in a few places as a npn

You cannot use a npn to replace a pnp as the current source as q5,q6 It's either the 2sa1968 or the ixys part.

One person wanted to wire in a toggle switch!

that's a pretty good screwup on mousers part. if you buy them 25 at a time like birgir and I do, you get a tube of them, pretty hard for them to screw that up.

1) those are mosfets and you really should not be putting them on material like that! 2) what are those things on the left anyway? the right thing in the wrong package?

for all those people stuck with a very over priced chassis... in progress. stereo single board about 8.75 x 7.5 designed for +/-400v. But of course you can run it at +/-450v or +/-500v and it needs the +/-15v power supply http://gilmore.chem.northwestern.edu/kgsshvsingleboard.jpg there will be an alternate plug board that's the srm323 version that runs only on +/-400v without the +/-15v power supply