Craig Sawyers

My corns are definitely popping

I don't know about anything other than booze in Dubai, but if anything else goes down it has to be absolutely under the radar. Anyone getting caught is going to have a seriously bad day.

Indeed - I was invited when in Dubai to the home of a guy who used to be Secretary General of OPEC. Out came the whiskey. I was pretty shocked, until I clocked that if you are influential you get access to all sorts of prohibited stuff. Provided you are discreet of course.

RIP John Noakes. He is probably only known to Brits of a certain age, but he was one of the presenters on a Children's magazine programme called Blue Peter in the 60's and 70's, and was a must watch (it is still running!) Noakes was known as a high risk guy - on one show he climbed Nelson's column with the pigeon shit cleaning team. Up a set of wooden ladders, including an overhang at the plinth. With no safety gear, harness, hard had etc - and wearing the 70's fashion statement of bell bottomed trousers. Died at age 83 after a battle with Alzheimers. http://www.bbc.co.uk/news/entertainment-arts-40083025 And this has the Nelson's Column sequence.

I have the original mono 1967 first pressing. Bought new when I was but a pre-pubescent lad.

Now that shows solidarity with the injured big time. Particularly since the Queen is now 91 years old. Respect. She did not see, and rightly so, those injured with life changing injuries - massive facial trauma, limb amputations and on life support.

I cut my whiskey teeth on Bushmills Black Bush when I was about 18. http://www.bushmills.com/whiskey/ Must buy a bottle and see what it is like in retrospect. But that Redbreast cask strength was a great shout - well chosen.

Lots of news on the radio about Roger Moore. He was always self deprecating about his abilities - along the lines of "I was lucky. I'm not the best actor, but was lucky enough to be good looking, and got spotted by Hollywood, and so got the romantic movie roles". Always came across as a nice guy, and really not the usual luvvie thesp.

Manchester bomber was the 22 year old son of Libyan refugees. Salman Abedi.

Who can possibly forget the the secret keypad that needed five numbers, and which played the tune from Close Encounters? No Bond before or since has been played for laughs the way Moore did.

RIP Roger Moore, age 89. I recall him saying quite recently that his acting involved "First raising this eyebrow, then raising the other one".

Have a truly great day Brent!

Another possibility (which alas involves a trace cut to try) is to add grid stoppers on the input tubes - about 1k.

Well something is clearly different between his first T2 to his second. Any idea what he should check to find out?

OK - frequency has gone down (not too surprising since C has gone up) and amplitude has gone up a bit. The issue in my mind is that a gross instability around the feedback loop usually builds up to a rail to rail oscillation, whereas this is almost sinusoidal and well below the peak-peak of what this amp is capable of. Next line of attack - cascode circuits are notorious for self oscillation, which would probably limit the amplitude. So first look for differences in layout from one channel to the other - particularly (a) the position of R86 and R87 to U1 and U2. The position and routing of R6/C2 and R5/C1/R92. If there are differences between L and R - and a few cm of track might be enough - they might be significant enough to cause this. Not saying this is the cause - just working the options.

Mine is the original - no idea what the issue number was. Kevin might have that data. There have been various iterations since then

Getting a particular T2 stable can be a bit of a game. The problem arises from the fact that the feedback trace is quite long, physically. It was less long in the original Stax T2 because it was more compact (and as a result ran incendiary hot). Anyhow, the feedback trace has to get all the way from the output tube's anodes/plates all the way back to the input tube's cathodes. Mine used to hoot too - you need to adjust the 15pF value in small increments both upwards and downwards, and possibly add one or both 2.2pF caps, and again be prepared to tweak the value. While looking for oscillation and its frequency. Once it is stable, do a frequency response sweep and look for a response peak - if you find one continue adjusting those caps until it is critically damped. It is interesting to note that 15pF and 100k gives a dominant pole at ~100kHz whereas the oscillation is at 685kHz, which implies that there is a secondary feedback loop, possibly inductively coupling into the feedback trace. I have a vague recollection that I cut a trace and re-routed in some way, or changed the position of the upper feedback resistor, but I'd have to tear my T2 apart to find out what I did.

Yeesh. Last time I looked at this, maybe ten years ago, a 1956 bottle was around £700 - which was waaaay outside my price bracket. They seem to be even more outrageous now. For a superb real-world Glenfarclas at very good price, have a look at Glenfarclas 105 cask strength. Gorgeous stuff. Around UKP50 a bottle.

For something really special, Glenfarclas do a Family Casks range, from which you can buy a bottle from the age of your birth. http://glenfarclas.com/whisky/the-family-casks/ They are probably way outside your price range (mine too), but worth dropping them a mail and finding out.

If it is oscillating you'll find it everywhere. You'll need an oscilloscope to find out though.

One channel isn't oscillating at some high frequency?

Either a battery, or one of the many current sources? Stax block diagram.docx

I initially thought this was a joke - but no. Pay for a cocktail with a cucumber http://gulfnews.com/guides/going-out/restaurants/pay-with-a-cucumber-at-these-35-dubai-venues-on-may-17-1.2024849

An FG502 will do the lot, including sweep (you need to put a sweep signal up the VCF input). It goes from 0.1Hz to 11MHz, square, triangle, sine. http://w140.com/tekwiki/wiki/FG502 . Ebay has one 252934875917 for $25 with no bids yet. To make it work, you need a TM5xx power frame, like the TM501 122498573980 currently $49.99 with no bids yet. Or a TM503 with three slots (so you have some expansion space for other units (eg the RG501 ramp generator to complement the VCF sweep of the FG502) 361964662469 for $40 with no bids yet.