kevin gilmore

Good luck with that problem. But remember... Its portable... It has a handle on the top. (actually 2 on that one)

Neither of those are going to work. You need a 1000 volt or more depletion mode mosfet that likes to work at a couple of milliamps. Use the 2sa1968 with +/-450 volt supplies, or use the ixys parts. Same thing with the required ixys parts in the power supply.

At least around here, you have a very good idea that you are going to get tenure or not way before you generate the application packet. As long as you have published enough and have enough references, it should be a snap. Too many WW2 professors finally dying off, and competent new blood is needed. Good luck Jim...

i spec'd 100 ma per high voltage winding, just in case you want to turn the bias up a bit.

Whether you run the output at 450v or 500v, you still need about 625 vdc unregulated for the bias regulator. So 485 vac (center tap is better but not required) is the target input voltage.

No ferrite beads on the original. No evidence of oscillation in my unit, now about a year old. andy has a problem in one channel of static that comes and goes, he has a scope, so will see if there is any oscillation... A ferrite bead might not be a bad idea.

So here is my comment on the "fake" parts. I've been stocking up on lifetime supplies of the semiconductors i may need in the future. When you get them in large bags, the bags have a label on them that says where they were diffused, and where they were packaged. The diffused is always japan, and the packaging is taiwan,korea,china... So the parts could be the real silicon, but just packaged inside of less than adequate lead frames.

there seems to be a growing interest in the phono section... http://gilmore.chem.northwestern.edu/kgphonoservo.pdf not counting the power supply, this is no more than $50 in parts if you use the lsk389, a lot less if you use 2sk170's... With the servo, matching is virtually unnecessary. I'm trying to find the moving coil schematic i did way back when...

Erno was one of the masters for sure. here is that article http://www.tkhifi.com/div/Erno_Borbely_fet_articel_2.pdf and part 1 http://www.tkhifi.com/div/Erno_Borbely_fet_articel_1.pdf

I think that andy's remaining problem is that the entire chassis is not fully grounded together in one piece, and a couple of star washers should fix that problem. But it does make music.

So here is a little historical fun. Back in 1975 and 1976 while in college i was building and selling world class phono sections and preamps. (sound familiar...) Virtually all of which are still in use today. So while some things like good circuit design seem to be timeless, other things like double sided circuit boards with heavy ground coverage are new. These days i would add a servo to the thing to make sure there was no DC on the output, something that really did not matter back then, as there were no fully DC coupled power amplifiers. I don't actually remember which of the riaa sections i ended up with, there were at least 3, so i showed the one from Robert Linsey Hood The original fets were ct134, which i replaced with 2sk170 in this schematic. http://gilmore.chem.northwestern.edu/kgphono.pdf this was one of the first boards without a solder mask. http://gilmore.chem.northwestern.edu/opampfront.jpg http://gilmore.chem.northwestern.edu/opampback.jpg

Well yes, but show me another audio product that uses this scheme. Then again, there would be virtually no reason most audio products would need to do something like this. Old tube Tek scopes did this in a few places mixing solid state and tubes.

Added an extra mounting hole for the power supply board. May add one or two more if i move a few parts around. The turn on thump is mostly due to the size of the transformer. The T2 actually pulls a bunch more power, but since there are 2 transformers, the thump only lasts about .5 second.

i've tried to get information on the tubes before. did not get anything useful. On my unit which by now has at least 800 hours on it, i have 2 6dj8's that went massively noisy. One happened at cj. But i am using old stock tubes pulled from tek scopes. The two tubes that went bad, i put on the side and recently put one of them back in, and sure enough it was definitely toast. But it still tests good on the tube tester. I'm still on the same set of output tubes, the chinese junk that i put in at CJ. On some of the original production T2's, stax put shields connected to ground around the tubes. Birgir's had the shields. I have a picture of another unit without the shields. The center pin of the tube socket is connected to ground, and the chassis is ground, so it should be easy to make tube shields. The T2 uses the input tubes in a way that i have never seen before, and i'll never likely see it again.

i'm sure c11 and c14 are correct. Q16 and Q14 may be in backwards, will look at that soon. D3 and D4 are 1n4746 which are 18v zeners D1 and D2 are 1n4737 which are 7.5v zeners This version has to run as a moving coil unit. Reason, the .1uf 1% cap and 750 ohm resistor at the output of the first part are one of the 3 riaa filters. Another version has the input resistor and pot replaced with a 47k resistor, and then the gain of the input stage reduced by 20db or so by changing around a bunch of resistors. a couple of other things fixed too.

try again 6 Band Resistor Color Codes or 5 Band Resistor Color Code Calculator

Brown Black Black Yellow Brown Red ==== 1 Meg 1% 50ppm ??

I love it when a plan comes together.

The important fets are super glued together back to back. I don't want to mess with it and risk destroying it because there are no replacements. The others have no markings on them other than the part number and that typically means the BL... It sure seems that each and every unit had different resistors to adjust gain and DC balance. I may have found suitable replacement parts, but i have to build and test... But first i have to order a bunch of them. The klyne are an all opamp design with the opamps made from discrete parts. Really the same thing as the vendetta, and many others. Only way to get the noise down is with discrete parts.

First power supply working and tests at a total of noise of 300 nanovolts peak to peak. (under slightly more than full load of 200ma) I was hoping for better, but this is measured outside of a screen room, so it may actually be lower.

I predict that blubliss should be listening to a wonderful staxmass very soon. Both channels now adjusted to the right numbers. (servo's are a wonderful thing when they work)

A pair of lm317 3 terminal regulators feeding fets as current sources feeding pass fets. Cheap and effective. $20k blowtorch does exactly the same thing. You can certainly do much better these days including tracking regulators to reduce the pumping of the servo's. And much lower noise. I saw a schematic for the klyne a while back, no idea if it was accurate or not, the modules are just discrete fet opamps. The sutherland is an expensive joke. The ayre is much more my style these days

fixed... If you are building it yourself, the xono is going to be easier. But the xono has coupling capacitors between the stages and at the output. So if you want DC coupling... (required riaa network is always going to require capacitors) Its a shame no one has done the input stage as balanced. Makes all the sense in the world for reducing hum.

this should raise a few eyebrows a christmas present for all head-casers... taken from an actual device, so if i did it right, it should be 100% correct, and the only known complete schematic (not including a pair of lm317 pre-regulators) http://gilmore.chem.northwestern.edu/vendetta.pdf

I should have a working "supersillious" power supply for this thing in the next couple of days. Hybrid voltage controlled current source feeding a dual tracking shunt regulator.