kevin gilmore

needs t2 style power on delay for the high voltage. Or separate switch, one for filaments, one for high voltage. 150ma on the power supplies. about right with 1k resistors. room heater for sure. 135 watts of high voltage plus about 85 watts of tube filament power. no front end tube distortion, no limited output frequency response due to limited size center tapped inductor core etc... plenty of gain, low distortion. yeah baby.

If the power supply voltages are right and the offsets and balances are in the 10 volt Range you are done. Go and listen to the music. Leave the 15 ohm resistors alone for now, let me know The voltage across them. Leave the current limiters off for now. Will have modification soon. Too many projects reaching completion at the same time

yes the servo can be added to the older boards.

speaking of extraordinary http://gilmore.chem.northwestern.edu/dsc_0478.jpg an absolute perfect void free piece of red mallee and a chunk of absolutely black as can be ebony

I know 2 shills for ECP and we are both batshit crazy.

+2 coming soon LLmk3 Seriously this is the major safety issue. And its such an easy and cheap fix. Unless you make it external. (male and female plug with resistors inside) But with the mosfets it still sounds like crap. At least it would be a safe piece of poor sounding crap. I would love to see schiit do an electrostatic amp.

did I see anything about the lack of safety resistors on the outputs of the amp to limit current in fault conditions? I better go and read that again. No possibility of thermal runaway with bjt's in an amp like this, its pure class A, bias is fixed by the current sources! Not possible to build an AB1 amp for electrostats.

hmmm, same post as over there. pretty much same response.

No plans to do that

strange both of my boards go smooth from 120 to 200ma with the 75k resistor and the pot. have not tried the lower value resistor yet. kind of busy. northwestern network down for most of the day due to dns issues.

looking very nice

So let me understand this, you think the pictures are somehow faked? You think the hennyo class soldering job and all the cold soldering joints in a $5k product are somehow acceptable? You think that the screws on the current source triple and transistors are somehow replaceable by someone other than a magician? How about the transistors in the middle of the board? You think that a power dissipation in excess of 80 watts inside a box that size is safe? You think that a posted Thd+N graph that exceeds all possible theoretical calculations by at least 30db with J176 input fets designed for switching (not linear applications) with an input noise of a minimum of 10nv per root hz and an amplifier gain of 50db is real? when alex could have used the real thing instead (2sj74 or lsj74)? You think that the lack of safety resistors between the amplifier and the stax jacks used by every stax amp, every headamp product, every one of my diy products, etc is just a suggestion? Amos, you don't have a fucking clue what it is that you do not know about this. And Alex does not have a fucking clue, because if he did, he would not build a piece of shit like this. Cavalli, Beauty really is only skin deep. At least Mikhail's products sounded really nice when they did work. And when correctly repaired, they work for a very long time. This thing really did sound like a piece of crap. Mosfets don't belong in electrostatic amplifers! It sounds MUCH better now. We are not done yet. When we are done, we will present all the work to everyone including alex. Trust me, he won't do shit about it. Because it won't be liquid anymore.

some of the opamps have horrible offset specs themselves. as long as pin 6 of the opamp is in the range of +/-6v it is doing its job.

depends on which end the pot is at. 1.8k or 2.2k the 500k resistors are really a safety thing. best to simulate the pot for real, but they are ok, just a bit noisy.

although absolutely nothing can compare with Mikhail's build quality (well trevornetwork and hennyo).... The squarewave done right would have been a kickass amplifier. And the klone definitely is. extended use of stock LLmk1 and probably LLmk2 due to heat and other issues is going to definitely cause reliability issues, and out of warranty repairs are going to be nasty. LF are already known to be very hard to repair. Not allowing pictures to be shown elsewhere just makes it worse because the manufacturer has no reason to make better or more repairable products in the future.

1) with both boards connected the temps will drop a bit 2) you should change the 2k resistor to get the voltage to zero before you add the servo

With pot at minimum bias is 120 ma with pot at max it's 200 ma Probably should cut 75k resistor to 50k And 1 meg resistor to 100k. Servo takes 2 minutes to go from 200 mv to .2 mv with 1meg resistor. Thd and noise below baseline of my meter. Slew rate which is already Limited by input filter is very fast. Just great with hd800. Going to add pads to measure bias on next board rev

what I had to do is add an extra inverter on top of the servo to get it to work right, shades of sijosae with that inverter http://gilmore.chem.northwestern.edu/sqwave1-1.jpg http://gilmore.chem.northwestern.edu/sqwave1-2.jpg http://gilmore.chem.northwestern.edu/sqwave1-3.jpg updated schematic http://gilmore.chem.northwestern.edu/squarewaveproduction.pdf

If you are using the central semiconductor metal can fets on the square wave boards They have to be flipped from the plastic parts so put them in backwards. And the servo does not work and will need to be rewired so pull the opamp and you Should get about 200 to 300 mv of offset. Fix coming.

you could be right that one of the hunks of iron on top is a choke. and I do see 4 large power diodes and a CRC in the middle so that would be the DC filament. Just like mikahil. Except done right. 5u4 filament would be AC anyway. In any case, its still really nicely done.

I finished my singlepower squarewaves last night. pictures when I get home. really sounds nice with hd800.

two transformers topside one transformer on the bottom (blue thing) 2 chokes (E/I core black things) 2 large poly caps (white/silver things) 2 power resistors (gold things)

Its just not worth the labor to do what birgir did to that board. And its a HUGE improvement. much more awsum New replacement board about $42 (quantity 10, 3 oz copper, alex's board was 1 oz copper) (about 7 x 9 inches) the parts a bit cheaper than a pair of kgsshv amp boards (16 large heatsinks total) using the new lsj74 input fets, 2sa1968 or ixys current source, 4686 or new Fairchild parts ... so about $500 fully stuffed. boards will NOT be black, and WILL be twice as thick

I was making a joke about the weight distribution

I know for a fact that the liquid fire was built every bit this bad, and also not repairable, and i'm guessing that the liquid gold is also not repairable given the way its assembled. Another pretty chassis with crap inside. by the way, very few of you will ever see this, so have a good laugh, the cavalli packaging http://gilmore.chem.northwestern.edu/wca.jpg