Craig Sawyers

I've been talking to Charcroft, and asked them to quote for a set of Z-foil 10k attenuator resistors in either 2512 or 2010 size. There is a good chance that they can trim down to 6R34 and up to 169K. I've asked them to quote for one set, and ten sets. Basically they hand trim to order in darkest Wales - they buy the basic chips from Vishay. Same game with the leaded Z-foils too. I'll let you all know when I know the awful financial truth.

Happy 50th Ethan! Have a beer on me.

Yeah. I've seen this in Arts and Crafts movement furniture. In that case (a large dining table in Cheltenham's museum) the bowties were of different woods and sizes and used partly as a decorative feature apart from the functional.

Well, yes - the Z-foil resistors with leads from (eg) Parts Connexion are $16 to $17 each. So the SM versions are likely to be about that too. But if this attenuator is to match up to the KG Blowtorch, it's gonna need some pretty fancy resistors. I'll get a quote and see how nuts this option is likely to be.

This http://www.charcroft.com/site/pdf/data/Charcroft.SCAR.04.09.Is2.pdf could be an interesting resistor option - the SM form of the Vishay/Charcroft Z-foil resistors. Not sure about availability though. Unless anyone knows of an easy source already, I'll make enquiries.

Yours too, Dusty? Thought it was just mine. Something something something Dark Side.

The stuff I use on copper is a Kester product called Copper-nu. Actually used in PCB production, but is NASA approved for cleaning copper cooling braids for satellites. Takes oxidised or sulphided copper and very quickly produces pink, chemically clean copper. Also works on brass. Kester also do Nickel-nu, but I've never tried that. Also I tend to use Caig De-Oxit and/or Pro-gold. Deoxit is used/recommended by Tektronix and Fluke for minimising switch contact resistance, which kind of says all you need.

^^^ Now that is some serious lurking - 2 1/2 years on the list and two posts.

It's Cardas, so it needs to be a Golden Ratio length

I've just bought one (with 3G, and natty case with light). I am totally smitten with it - what a bewilderingly marvellous product. Just stuffed on the complete works of Dickens. Next it's Trollope and Hardy.

Just catching up with the threads. Biwiring is a semi-religeous thing - there are strong views for and against. When I had speakers with separate binding posts for bass and treble speakers, I used to biwire, and swore I could hear a difference, although I did not have a physical model to give a remote inkling why. Always troubling. For me anyway. Now I listen to a pair of 1964 vintage QUAD ESL, which have a single pair of connections that go straight into the transformer. So there is absolutely no way that I can frig around with biwiring - which solves the do or don't biwire problem perfectly. I have a semi-stalled dipole sub project to add some oomph to the ESL's, following Siegfried Linkwitz's approach. That definitely needs an electronic crossover. The sub amp is a C-audio GB602 600Wpc professional sound reinforcement amp, courtesy of eBay at £150.

Check back through the thread - I posted some UK suppliers that I used which would have no problems shipping to Denmark

Because of the high cost of 2SC3381, why not replace with two separate transistors during fault finding? Two transistors on the same bit of silicon are only necessary to ensure thermal tracking (ie that the Vbe tracks with temperature)

Well, my latest errors have been (a) a solder bridge that vapourised two tracks on a pro power amp I was fixing. Um, re-fixing as it turned out; and ( missing soldering a component at all in the BH. I was so paranoid about the T2 I did a 100% solder inspection under a magnifier - and I still missed an unsoldered joint (so 99.95% inspection...)

That is bloody wierd. I'd really go back to basics. Pigtail the transformer leads into a bridge rectifier taped to the bench, and measure the rectified (ac) voltage - which will tell you if there is a problem with that particular winding. Connect up a 680uF cap and again see what it measures as smoothed ac. If all is OK, then there could be an interwinding short or something else peculiar in the way the -260V is generated from 300V using a dc offset from the -500V and -60V supplies. But again I'd go back to basics - even take the Tx out, and run each winding into a bridge screwed to a piece of wood (say), then add caps and see what the actual raw dc is from each of the three windings. Then check the voltage between each of the windings - they should be isolated. Birgir - do you have a megohm meter? The windings should be electrically well isolated to a rather high voltage. If there is an interwinding short, or low resistance, it should show up using a megohm meter with the voltage set to 500V. Do your transformers have interwinding insulation barriers?

That is a massive relief - that could have been really ugly in many different ways.

You've got that right Spritzer - tiredness (and booze) are never good partners to HV work

I've got a BH (not SE) and a T2. Anyone want to buy me a pair of SR009's so I can tell you what they sound like?

Jeez - sorry to hear that. I guess I got lucky with the power supply - it just fired straight up and hasn't missed a beat since. The amp - as most of you know - was a different kettle of fish entirely. It's got to be simple though - if the cap is roasting, and the rectifier bridge is OK - then it has to be the cap. Mislabelled and electrically in backwards. If that is the case, make sure the rectifiers haven't got cooked into the bargain. Try pulling the IXYS current limiters temporarily, and isolate the transformer, bridge and capacitor.

Um - how about filling in your profile so we have some idea who the hell you are?

Hey guys - happy birthday!

Al - have a great day! I'm drinking one for you right now.

In the UK they were call a Flexicurve. Green in colour IIRC. Yup still available - in the UK around £5 depending on length (isn't that true of so many things). But they seem to have changed to blue.

I want to live in Rochester! A fifth of a Gigabit per second - I had no idea that was possible. And "Sadly, most of the time I'm in my dorm on 100mbit ethernet" - well boo hoo.

I wondered too - but his profile says USAF, so it looks like he's at the sharp end.