The ultimate DIY? A Stax SRM-T2!

[luvdunhill]

crazy talk I say

[igorst]

Just put baby oil and a fan to move the it... )

Soak Your PC in Mineral Oil: Puget Systems Announces DIY Aquarium Cooling

[grawk]

flourinert is awesome stuff. Buy an old cray waterfall to cool it

[Guest sawyers]

Large Hadrons Collider – LHC consumes 1% of liquid nitrogen produced in the whole world to induce its superconductors.

Well not quite. The liquid nitrogen is just used to pre-cool the beam line and during helium filling to cool the helium to 80K. The nitrogen liquefiers (8-off) each provide 600kW of cooling power.

The real bitch is the helium liquefiers. Each of the eight plants provides 18kW of cooling power at 4.5K, for which they require 4MW of electrical power. So the helium system consumes 32MW of electrical power - that produces 16,000 litres of liquid helium *per hour*.

The LHC helium system doubles the world capacity in helium liquefaction.

All this is necessary since the "cold mass" of LHC, which is at 1.8K, is nearly 40,000 tons.

[kevin gilmore]

We have a helium liquifier here. Its a pain to keep running.

Soon we will have a liquid nitrogen generator. Just hook it to power and it makes

about 200 liters of N2 a day. Its probably also going to be a pain in the neck.

Fluroinert has too much capacitance for high voltage audio amplifiers...

Besides which if you do manage to set it on fire, bad things happen.

That chassis pictured above is now mine

Its 11 x 12 x 3.5 inches inside...

Was thinking of putting a single opamp in it and

taking it to CJ as the heaviest CMOY ever built.

But really something nice should go in there.

Any ideas??

Edited March 26, 2010 by kevin gilmore

[Guest sawyers]

that produces 16,000 litres of liquid helium *per hour*.

Got my factoid wrong - it isn't 16,000 litres per hour, it is 40,000 litres per hour!

[Guest sawyers]

We have a liquid helium liquifier here. Its a pain to keep running.

Soon we will have a liquid nitrogen generator. Just hook it to power and it makes

about 200 liters of N2 a day. Its probably also going to be a pain in the neck.

Yeah - I can relate to that. I worked for 12 years at Oxford Instruments, and we installed a chunky Linde helium liquefier so we could recycle our own helium. Linde techs were a semi permanent feature. N2 is a lot more straightforward, unless water vapour gets in an gums up the works. Which means it will.

Was thinking of putting a single opamp in it and

taking it to CJ as the heaviest CMOY ever built.

or an emitter follower

[kevin gilmore]

Well if you worked for oxford, you will surely recognize this.

http://gilmore.chem.northwestern.edu/birdbath2.jpg

From a round bottom 300mhz magnet.

Oxford even sent me one of their machined name plates saying

Oxford Instruments Avian Aquatic Interface serial No. 1

and with the added stairs for the small animals

http://gilmore.chem.northwestern.edu/birdbath4.jpg

In a couple more years i'm going to trash a 600mhz round

bottom magnet... Perfect for the middle of the back yard.

Not sure how i'm going to get it home..

Edited March 26, 2010 by kevin gilmore

[Guest sawyers]

Well if you worked for oxford, you will surely recognize this.

http://gilmore.chem.northwestern.edu/birdbath2.jpg

From a round bottom 300mhz magnet.

Oxford even sent me one of their machined name plates saying

Oxford Instruments Avian Aquatic Interface serial No. 1

and with the added stairs for the small animals

http://gilmore.chem.northwestern.edu/birdbath4.jpg

In a couple more years i'm going to trash a 600mhz round

bottom magnet... Perfect for the middle of the back yard.

Not sure how i'm going to get it home..

That is absolutely priceless! I laughed so much I almost fell of my chair. You should have sent them the photo and said that the magnet wasn't working because of water in the OVC!

Seriously, we had a UHV deposition chamber for manufacturing thin film devices (SQIDs, transition edge detectors etc). The guys came in one morning and something was obviously badly wrong. Looked though one of the chamber ports - looked fine, but everything was dead. It *looked* fine because it was full to the gunnels with water. The cooling loop had ruptured overnight and filled the whole thing up. Took weeks to sort that out.

Back when the magnet cryostat bottom in the photo was made, Oxford Instruments was divisionalised - those instruments came from the NMR division at a place called Osney Mead a mile or so from Oxford town centre. I worked for the Research Instruments Division, a few miles further out - we made wierd custom magnets, and ultra low temperature fridges that got down to 1mK.

After I left they went through a patch when the website was your typical corporate markets/investors thing where it was difficult to tell what they actually manufactured. Seems like they have got their act together much better now; the bit I worked for is at least now identifiable Low Temperature and High Magnetic Field: . All 12 years in the past now.

[kevin gilmore]

two quickpics...

http://gilmore.chem.northwestern.edu/pszener.jpg

there are 8 glass diodes, all are 30 volt zeners.

the crossed resistors in the servo

http://gilmore.chem.northwestern.edu/resistorcross.jpg

[kevin gilmore]

updated schematics with amphenol plugs suggested pin wiring and wire colors

http://gilmore.chem.northwestern.edu/t2schem.pdf

http://gilmore.chem.northwestern.edu/t2schempower.pdf

[kevin gilmore]

I think i've died and gone to heaven.

After 8 hours of listening...

While cooking up a batch of chicken soup for the matzoh balls

and brisket tomorrow...

In one room all at the same time...

My original all triode ac coupled tube amp.

My original KGSS

My original KGBH

An assembled by me Aristaeus from a complete set of parts from justin

An original KGBHSE prototype half assembled by justin and half by me (my half sounds better )

My T2 with REAL NOS Mullards (yep i'm that sure its 100% solid)

A built by me exstata (solid state) with a modified KGBH power supply

Omega headphones

Omega2 headphones

Lambda pro's

SR003

koss esp950

sennheiser he60

The T2 is just more fun to listen to than the rest of them. The presentation

is more different from the BHSE than i had thought after listening for quite

a while, its hard to put into words. I have to listen some more...

Unlike the original, This T2 has absolutely NO noise, and NO humm.

Especially NO humm. If i did not know better i would never know this

is a tube amp.

(Actually NONE of my tube amps humm at all...)

After about 4 hours, the heatsinks stabilize at about 120F for the amp and

about 105 for the power supply.

(unfortunately, NOT hot enough to cook eggs according to birgir)

One interesting thing the sr-003 sound very different across the range

of amplifiers. Not sure why.

The exstata needs work. Sounds thin and sterile.

Note to people that want to build the exstata, get the output transistors NOW

because farichild just put them on final lifetime buy. After that

you can use 2sc3675's which i'm going to try in a day or two. I expect

that it will sound better with them instead. But the heatsinks will

be electrically hot or you have to use insulators.

Humor mode on!

I have a lot of respect for alex, but after all he is a physics professor, and they

are almost as bad as structural biology professors at designing audio gear.

You want it right, stick with a chemistry professor, we work at the micro level,

not the macro level.

BOM updated again, this time the screws are right for sure

Edited March 28, 2010 by kevin gilmore

[luvdunhill]

Try the 3676 instead. It kills on the kgss...

[kevin gilmore]

Don't have any of those. Yet... But twice the capacitance...

But twice the current... I know where this is going...

A KGSSHV is in the works anyway... Runs on +/- 425...

with the T2 supply with 3 of the supplies unpopulated...

[Bidoux]

The exstata needs work. Sounds thin and sterile.

Lack of Kaboom ?

[kevin gilmore]

after a bit of morning cleanup...

electrostatic porn

http://gilmore.chem.northwestern.edu/statpron1.jpg

http://gilmore.chem.northwestern.edu/statpron2.jpg

[deepak]

Very nice Decca classical collection too

[mrarroyo]

Kevin, I do not see Leporello, Giovanni, and friends! You are not concerned they will chew up some of the cables?

[nattonrice]

BAHAHA I see safety first is a number one priority for that BHSE psu

[spritzer]

I love the fans on the BH and the BHSE "chassis"

[kevin gilmore]

Fans only on the original BH chassis... It was 3 shelves down due to other stuff there and needed

some ventilation. No fans on the BHSE.

The dogs are not allowed in the media room. Ever.

[dBel84]

I think i've died and gone to heaven.

congratulations, this project has been quite the DIY epic.

he is a physics professor, and they are almost as bad as structural biology professors at designing audio gear.

You want it right, stick with a chemistry professor, we work at the micro level, not the macro level.

glad to see we can all laugh at ourselves , life is too short

..dB

[Duggeh]

What the huge cask plugged into the mains for?

[kevin gilmore]

That is a 2kw high isolation transformer. Only way to get rid of ground noise is to fully

isolate every single part of the system.

This is due to American stupidity where on 110 vac power, neutral and ground are similar

but not the same. Except they start out the same where they enter the house.

Sure would be a lot easier if everything in the usa was wired for 220/240v

[Craig Sawyers]

That is a 2kw high isolation transformer. Only way to get rid of ground noise is to fully

isolate every single part of the system.

This is due to American stupidity where on 110 vac power, neutral and ground are similar

but not the same. Except they start out the same where they enter the house.

Sure would be a lot easier if everything in the usa was wired for 220/240v

We've exactly the same system on UK 240V. Neutral is grounded (ie connected physically to the soil) at the electricity substation, and at regular intervals underground. Only two wires come out of the ground to the electricity meter (live and neutral), with the domestic ground wire attached to neutral at that point. Since the neutral wire inside the house takes the return current, it floats an unspecified and usually horribly distorted ac voltage above house ground as a result of wiring resistance and ac impedance.

I've been thinking about a balanced isolation transformer for the audio system for some time, so interesting to see that you have gone a similar route.

Craig