kevin gilmore

paid

actually all I have is the original above. this thing is a real fucked up mess designed by an idiot on lots of really bad drugs. using the tube filament as a load for the output transistor is all sorts of fucked up.

if you are using a .5 inch heatsink bracket, you have to use the other hole because the part is too big.

picture attached

so the 700s power supply voltages are exactly the same as the 717 and 727 from the transformer yellow,green,yellow go to full wave bridge rectified and regulated to +/-15 blue black blue (the filament supplies on the 700t) rectified and added to Vh- to make the - boost supply white red and brown orange are the 2 high voltage windings full wave rectified into CRC making +/-350 output boards identical to the t8000 each board has 3 x 2sc6127 and 1 resistor vas boards have 4 x 2sc6127 (2 x Darlington pair) and 4 x 150k/2W current source (on main board) vas is driven from dual low voltage n-channel jfet. (red heat shrink) (previously dual npn transistors) front end identical to 717/727 with dual n-channel jfet so about 99% identical to srm717 with non-obsolete parts and change of vas stage driver from bipolar to jfet on the D50 the front end jfet is known to be sourced by linear systems. So likely the k170 are also sourced by linear systems. so the 700T absolutely identical in every way to the srm-007t (and srm-t1 etc) with 2 x 6sn7 replacing 4 x 6cg7 plenty of room for replacement constant current sources to replace the mills load resistors both are priced the same, between $2895 and $2995

just because its a great amplifier does not mean that it likes to drive pure transformers. decca ribbon tweeters, quad esl56 and 63, klh 9 etc are all considered very hard to drive loads. transformers for electrostatics are much harder to wind than you might think, not a standard thing

Not the diodes

With those diodes is there any unregulated voltage on the first big cap?

Yes the opto just provides the on/off switch you need to use a timer circuit, or a seperate switch and a rolex

Ok, the stax mafia has spent quite a bit of time with the kse1500 first the headphones are 200v bias. The kingsound must have been modified to lower bias voltage otherwise these headphones will eventually pop. yes the kse1500/kse1200 is an extremely low power classAB amplifier with significant distortion. But great battery life. The kingsound is a chip amp driving transformers. Might actually sound better, but definitely not stax mafia approved. A really good battery powered portable electrostatic amp is harder than you might think. The stax d10 is another example that has issues.

its not a soft start. its a delayed high voltage turn on. For tubes that don't like voltage before the filament. no reason to use it except for tube or tube hybrid

ok, this scares the shit out of me. hennyo level of quality here. Second pic, the power supply in the upper right is an ebay high voltage switcher that's $7 I know its $7 because I bought some for the up and coming stax mafia portable, and its actually a pretty decent supply but can handle only about 5 watts of output power. You can see two more under the fan. Fan is required because those things get hot especially when you try to push them over 8 watts. And according to people at diyaudio that use them for tube preamps, the main diodes blow up at 10 watts. No way is this a kgsshv-carbon in terms of power. Barely 10% if that. Also limited to about 400v A pair of switchers on either side of the pot drive the HV supplies. So Switchers driving switchers. Not the most quiet of things. And the rest of it, yikes power supply pics here

Nope, you need the common ground.

the dht version is for the emission labs directly heated triodes. Expensive and requires 4 separate 5v filament windings on the transformer.

power supply is version 1.8 copyright 2015 however it shows both boards the same, and that is definitely not the case. although you can do it that way, but then you need a grlv power supply in addition one board has the bias voltage, the other board has the low voltage regulators amp is version .6 copyright 2015 I think this is the latest I released. There is a .61 version which I may or may not have released, don't know the differences

that one is indeed 3 layers, extra complete ground layer in the middle. forgot about that one.

its a 2 layer board. not sure why it is being detected as 3 layers

easy, low cost, no adjustments, only hv supplies etc.

thermal grease lasts forever. I have a jar with original Newark part number on it, and its 50 years old. Still good. the stuff contains aluminum oxide or silicon oxide, or various other compounds in silicone and for voltages less than about 2.5kv its an insulator. Although it can have more capacitance than you might think.

v- is actually -370v and vref3 is -350v take a closer look at the original schematic

history lesson (unless birgir says otherwise) As far as I can tell the first stax amplifier to use differential cascode circuit is the srm-1 first introduced in 1979 long before hifiman was even a company

The srm-001 is an opamp driving a fet that drives a transistor (cascode) into a load resistor and is cap coupled to the output. (cascode differential) The jade2 is an opamp driving a transistor that drives a mosfet (cascode) into a load resistor and is cap coupled to the output. The calculation of output capacitance is flat out wrong as the middle of the cascode is AC ground. (cascode differential) Just about identical. Obviously the jade2 consumes a bunch more power and puts out a bunch more power. I own 2 hifiman products. Both are built like shit. I'm unlikely to buy hifiman products ever again.

uberamp2 in single ended form. then you don't need the resistor box.

The circuit is more like the srm-001 blown up by a bunch. So opamps input, solid state version of grounded grid output stage, resistor loaded, and capacitor coupled output. Positively ancient design by any standard. Did not even replace the power resistors with current sources. Saying that the output capacitance is that low because the two devices are in series clearly shows no understanding on how that design works. And the series output inductors are not a great idea either. The headphones may be decent, I don't know because I have not heard them, but there are so many decent headphone amps out there that buying the hifiman version seems like a waste of money.

2 grhv, 2 grlv78xx,2 grlv79xx, 1 main board, 1 mini t2 please