Craig Sawyers

OMG. I'd better start slowly softening my wife up as a long term strategy. I've just got to have a pair of those.

That is just great - I'll bet that kid is never picked on again! My son (many years ago) did something similar when he got fed up with being bullied and broke the kid's nose.

I decided to run the test at work having just downloaded a 530MB CD ISO image in a bewilderingly, jaw droppingly short time.

Check back through this thread for modifications on the power supply. In fact I think I posted a summary of mods, to wich KG added one or two I had forgotten.

Have a great one

Hear hear!

Given the third world speed I get at home, this is what I get at my desk at Leicester University: Zoom....

I'm not sure how many people have now got these running. Last time a poll was done, the count was 5 out of 22 having completed and were listening. Anyone like to volunteer a current number?

From what I've seen in the pics it is a wonder that this amp works at all!

Looks like it for DC http://hypertextbook.com/facts/2000/JackHsu.shtml To drive 100mA through the body at 700V rail to rail of a KGSS would need a body resistance of 7k. Typical hand to hand dry skin resistance can be way below that (a k or two) - and working with high voltage usually gives "sweaty palm syndrome", which makes the hazard even worse. Hence the excellent general advice of keeping one hand in the pocket at all times while taking measurements at modest levels.

I've just had a shudder moment. It looks to me like you are completely new to electronics - and the voltage inside any electrostatic amp is quite lethal. If you get it wrong, you can end up with many hundreds of volts with significant current capability from one hand to another - and that has a very high risk of stopping your heart. Please get someone to fix this for you - Justin already offered to do this if you sent it to him.

Anybody been in touch with Stax to see if they are OK there? They aren't too far from Tokyo, so would have been shaken around pretty badly.

Well, here we are in not-quite-in-the-21st-century England. This is 6 miles from Oxford, so hardly hicksville. The excuse is that we are more than 4km from the BT exchange.

Woof woof! That sounds like a serious way of moving a large volume of air. One of my unfinished projects is a pair of dipole sub woofers to reinforce the output of my ESL57's. Used Shiva X2 drivers http://www.diycable.com/main/product_info.php?products_id=693 which have a maximum power handling of 1kW, although they do a very serious 18" or 21" driver - the Maelstrom, which can handle 1.5kW with a peak-peak excursion of 64mm (2.5"). 'Nuff to blow the windows out. Nelson Pass has done some really crazy things with bass drivers - such as the KleinHorn http://www.passdiy.com/pdf/KleinHorn.pdf and El-pipe-O http://www.passdiy.com/pdf/el-pipe-o.pdf

Have a great one!

I've had only limited sonic success with loudspeaker building over the years, and long ago went for commercial (and sometimes very quirky) options. Magneplanar, Martin-Logan, Podium 1 and now ESL57 among others. However, one thing is clear - cabinet colouration is a major issue. Various high-end manufacturers use constrained layer damping - Wilson and Rockport as examples. Rockport use either fibreglass or carbon fiber inside and outside skins, and fill the gap with an epoxy/ceramic powder filler. Seriously heavy - the Arrakis are 900lbs each (and cost a Jaguar's-worth of dosh from your pocket) - and totally inert. Of course the idea of contrained layer damping is not new. The Wharfedale SFB (sand filled baffle) was there in the mid 1950's, a good account being here http://www.inner-magazines.com/news/28/72/Whaferdale-SFB3/ along with comparisons to the Quad ESL57 and the Klipsch Horn. Oh - and back in the early 1970's I built an irregular pentagon footprint cabinet (to defeat standing waves), and lined the things with an inch of concrete. My parents though I had seriously lost the plot. They were a dangerously heavy two-person lift. They drew the line at an underfloor mounted bass horn firing upwards through an aperture in the floorboards though.

I think that I put the models (simple text) on the thread a while back - check and see what is there Nice thought - but I suspect not. The innards of the original T2 get incendiarly hot - nothing like as much heatsinking and air circulation as KG's clone and *that* gets quite hot enough! I think they just used a method similar to the one I worked out - again on this thread a way back.

Wow - well done sir! The only problem is tracking down spice models for the typical transistors we use in audio - particularly (but not uniquely) of Japanese origin. You can get quite a long way by writing a simple spice description file for the major transistor parameters from the spec sheet. Good enough for DC and low frequencies where the various capacitances can be ignored. There is enough on the web describing how to do this. But a complete Gummel-Poon model needs quite a bit of measurement/guesstimation to put a full description in place if the manufacturer has not made a full Spice model available. Plus the fact that there is a large spread in parameters typically, so to do the full nine yards you need to do a sensitivity analysis over the parameter spread. Not counting layout parasitics...... I did the simple description route to work out a foolproof method for how to set the battery voltage. The graphs (Excel spreadsheet) used to be on my webspace, but they probably got trashed in the ISP debacle. If anyone has a burning desire to get these, let me know and I'll upload them again.

Why not build the T2 (instead of endless spice analysis an what-if's) and then carry out mods using real components so that you can evaluate them by actual measurements and (shock, horror) what it actually sounds like? I've got precisely this problem on my major project at the moment, where the subcontract engineering company insists on only using analysis tools, and pooh-poohing measurement. This is a system for lauch to Mercury in 2014 - and they are studiously missing the point that you don't lauch analysis - you launch actual hardware that must not fall to pieces when subjected to launch loads. They are in the last chance saloon at the moment on this topic. So, jcx - lets see some building and measurements. And does it sound like audio nirvana or a bag of hammers?

OK - just restored it at http://www.tech-enterprise.com/tekstuff/T2deconstruct.pdf Anyone else need any files that I have supplied links for that are now dead, let me know and I restore them. I just don't have a record of what was stored, because my half-assed ex-ISP corrupted the damned folder when they had the fatal crash. Complete wasters that aren't worth the desk they sit at.

Have a virtual beer on me, Nate!

Doh

Thanks one and all! Actually that is a Siemens & Halske T52. Those who know me a bit might have spotted that I restored the world's only known complete Lorenz SZ42 for Bletchley Park a few years back. I can get *really* boring on this topic - please don't encourage me

Nice idea - but Top Gear is a BBC show, and the BBC have never broadcast advertisements. The Beeb is funded by the Television License Fee (£145 per year), which all TV owners have to pay by law http://www.tvlicensing.co.uk/about/legislation-and-policy-AB9/ . Part of which is what is used to pay Clarkson's wage. Massive advantage is of course no commercial breaks - just end to end uninterrupted TV. All other TV channels broadcast in the UK (the many hundreds of them) self fund through advertising or sponsorship.

The ones that Paul wound for me were 93mm OD x 55mm height for the HT ones and 98mm OD x 69mm height for the LT one. All windings had a double thickness insulation barrier between each mainly as a precaution, but essential on the LT transformer since the EL34 heaters sit at -500V. They were centre epoxy filled with a single bolt hole, and the top of the centre fill was below the top of the windings. I used 65mm long dome headed steel bolts with plain washer, lock washer and nut to fix them. If they were conventional fixings with rubber washers and a steel disc, you'd have to think carefully if they would fit or not into the case height.