Craig Sawyers

Boy am I feeling dumb! Been totally fooled by where the emoticons were. Then just happened to notice the smiley on the reply toolbar. Then click show all on the popup. Of course you all knew that. I can sometimes be a little slow on the uptake

Ah - there's the problem. For your preferred listening levels, and source output voltage you definitely need attenuation to centre the -12dB point of your Goldpoint. And yes, I guess that the gain of the amp could be changed. But going to say 40dB from 60dB has to done with a little care to make sure it is still stable at the lower gain, or at least has not picked up any overshoot.

FWIW the T2-clone also has a gain of 1000. My D-A has an output of 3Vrms and that puts the DACT at pretty much centre travel at the typical loud level at which I listen. Takes maybe three clicks each way to compensate for recording level differences. Half way on a DACT is -28dB, and the steps are 2dB over most of the range.

Classic! James May in a 500hp go kart that the New Stig threw around the track faster than anything else they have tested. Richard Hammond in a 1 mile race between a VW Beetle and a Turbocharged 911 - the beetle having been dropped vertically from 1 mile and falling under gravity. Oh yes!!

Just latching onto this thread - but if your friend can phone international call Russ Andrews. They recable K701's with Kimber stuff. I have a pair with that cabling - and they do it themselves. Phone them on +44 1539 797302 which is John Armer's personal line and mention my name - I'm sure that they will tell you the secret methods of disassembling the beast.

No - they are precisely the same as in your photos - absolutely no closure of the vent. Now, courtesy of your blu-tak idea, they have exactly the same sound as the Lambdas when you push the cans closer to your ears (what you describe as squeak/fart).

Yes - SZ3-1487. What is the relevance of that? And what am I missing with earpad height? Yeah - I know you're going to say it is already in this thread somewhere

I'll have to have a browse though those - looks good. And sorry to be a smart ass (well, not sorry at all really) but I looked it up and - I was right. CMB at 160.4GHz

Much more solid and tactile low and mid bass. Kick drum really kicks now. But it goes beyond that - the whole voice thing sounds cleaner in some way too. Maybe there is a helmholtz thing going on between the large void between the ear and the diaphragm, and the little (leaky) void that colours the midrange in some way.

Um - blackbody radiation with a peak at 160GHz. Cosmic microwave background?

Had a real panic yesterday. Took the SR007's apart to do the blu-tak port mod. Got them back together and plugged them into the T2 - bad distortion on RHC. Serious panic sets in. Turned out to be a dead 2SJ79 that was causing one output to be at -250V. Just blew coincidentally with the blu-tak mod. The astonishing thing is that with a dead driver transistor for the grounded grid output EL34, the damned amp was still working - all that happened was that the output clipped and distorted - and of course the headphone diaphragm was biassed one way. J79 replaced and all is sweetness and light again.

Interesting. Distortion on right channel, at high-ish listening levels. Well actually very high levels. Got it on the bench - One of the RHC outputs was sitting at -250V. Took about three minutes (after the endless fixing screws had been extracted) to find a dead J79. I suspect that it must have been weakened as a result of the earlier C3675 saga. Anyway, all sorted now. Just reset the batteries, and button it up again.

Have a great one Mike!

Snakes in a pool.

Well, that depends on the money. If you pay relatively little, you will have to spend some money fixing them. If you buy a pair that has been restored, you will pay much more. I bought mine for £300 and then spent another £250 and a lot of time to bring them completely up to original specification. Bear in mind that these are very old loudspeakers, and like a classic Ferrari need restoration and TLC. Mine are 1964 built.

Indeed - the ESL57 has a horrid impedance curve - with a big 35 ohm peak at around 70Hz and then falling to less than 2 ohms at 20kHz. It seems that tubed amps (which is all there were when the speaker was launched) cope with this better than semiconductor ones, which can sometimes run into current limiting and self oscillation. The idea of damping factor, which is important with coned loudspeakers to control their motion, is not really relevant to electrostatics (where the moving mass is only a few milligrams) - so the much higher output impedance of tubed amps is not a disadvantage. FWIW I use a second hand Audio Research D125 to drive mine, set to the 8-ohm taps.

It is the ESL57, of which I own a pair. If they have not been reconditioned, the main problems are: 1. Burnt out mid/treble panel 2. Defective voltage multiplier 3. Leaky bass panels 4. Resistors and capacitors in the crossover wildly out of tolerance But spare parts and reconditioned panels are easy to get - I used http://www.onethingaudio.net/ for mine, which is an hour drive from where I live. Two mid/treble panels, bass panel dust cover kit, mid/treble protection kit (to stop the new ones burning out!), new internal wiring and a kit of components for the crossover. Stunning - there are things the '57 does that no other speaker does - particularly voice.

I'd certainly be interested in such a trial. The perception is that the difference between a Russ Andrews/Ray Kinber power cable and a regular kettle lead IEC is remarkable and non-subtle. The same is probably true of other cables based on more than smoke and mirrors, like Cardas. If that perception (and by implication the 97% who keep these expensive cables and don't return them in the 60 day trial period) is correct, it should be possible to hear by doing a high quality comparison. I might weill set up a simple test using a pair of high current relays, arranged so that the cables are paralleled for a fraction of a second so that there is no perceptible changeover click. If I get around to this, I'll post a few first impressions. But alas this is not the game the Advertising Standards Authority play. And they are immeasurably more used to ruling on a second hand car dealer who is misrepresenting his wares.

Did 5 miles in studded fell shoes on a very boggy section of the Ridgeway.

It certainly does require a significant time committment, and very careful set up and analysis. Listener fatique and the skew that this introduces into the statistics has to be taken into account. We used ABX testing during loudpeaker development when I was CTO of Wharfedale, with an acoustically transparent curtain between the listeners and the speakers, so I'm certainly not against the technique. But the ASA case has nothing to do with being able to tell what the subjective differences, or otherwise, are. You have to look at the ASA website - an ABX test would simply be an "opinion" and hence not "robust" evidence - their italics. Russ Andrews promotional materials were judged to breach CAP code 3.1: "Before distributing or submitting a marketing communication for publication, marketers must hold documentary evidence to prove all claims, whether direct or implied, that are capable of objective substantiation." and CAP code 7.1 "No marketing communication should mislead, or be likely to mislead, by inaccuracy, ambiguity, exaggeration, omission or otherwise." The only response to which is hard technical measurements - their case is down to objectivity, not subjectivity. I really don't want to get into a tussle about this, because that is a no-win situation all round. But to put the data here, this a typical graph of rf attenuation (well it not technically attenuation - what does not get through is reflected) vs frequency.

It is all to do with the wording of promotional material as defined by the ASA. Russ's 2006 document that is being objected to makes the claim that the improvement in sound quality by using one of his mains cables is down to its ability to attenuate mains borne rfi. It fortunately (for Russ Andrews Ltd) does not mean that he has to cease manufacture of any product, nor are their any punitive damages if he complies. Rather, Russ has tackled this from the perspective of fairness - that a complaint to the ASA from a single individual can trigger a three year battle by a tiny company frankly just ain't right. Whether there is actually an improvement in sound quality is of course open to all the usual ugly discussions on the various general audio forums out there, and I don't comment on that. But the ruling means is that you have to couch every statement you make with "We believe", "In our opinion" and so forth. You cannot say "It sounds better than a conventional mains cable", you have to say "In our listening tests, we believe that it sounds better than a conventional mains cable". To make a stronger claim, the ASA demands "robust" evidence to support that. The difficulty arises in that there is no formal definition of "robust", and the ASA has complete freedom to subjectively interpret it as they like. In fact they reinterpreted it at least twice during the last three years, each time after each submission of information from Russ Andrews. So, although having shown that both DM and CM conducted RFI are reduced as compared with a conventional mains cable by rigorous measurement, and measured an increase in harmonic distortion of an audio amp when RFI is injected into the mains using a full Audio Precision test set, and supplied endless reports and data to the ASA in support of that, they still find that the evidence is insufficiently "robust". The ASA's powers are being extended to much more comprehensively cover web advertising, starting on March 1st, opening a whole new can of worms. If you browse around in the Russ Andrews website, you'll see that they have already expurgated the strong statements and worded everything much more loosely in anticipation of the next individual complaint. Or the same individual complainant coming back for another pop. Now there are opinions one way and the other about Russ, which is fine. But helicoptering above all that, what we have now is a precedent regarding the claims made by the Audio industry at large. The safe hands (irony) that the ASA decisions are made by can be found here http://www.asa.org.uk/About-ASA/ASA-Council.aspx . As I said previously, there is not one single technical bone in any of their bodies, as you can see from their on-line CV's.

Getting a low ground impedance is harder than you might think, and depends on the soil resistivity where you are. In good wet ground it can be as low as 500ohm-cm. In sandy or gravelly soil it can be up to 10,000ohm-cm Assuming the worst cast of 10,000 ohm-cm, and a 1" diamter rod buried 20 feet deep has a ground impedance of 18 ohms. 6" diameter buried 100 feet deep (and try driving that in!) gets down to 3.4 ohms. So it is very difficult to get a low impedance to ground with a single rod. One way to go for a prectical set up is to use an array of rods. 20 rods half an inch diameter buried by 8 feet and with a rod-rod spacing of 8 feet gives a (theoretical) 4ohms in 10,000 ohm-cm soil. You can buy rods like that easily. All this stuff is from Grounding and Shielding Techniques in Instrumentation, 3rd Ed, by Ralph Morrison.

And that is looking really good! What resistors are you using, and from where did you get them?

That is strange, if the spec sheet for the device is taken as being correct. From the transfer characteristics, figure 4, for 20mA drain current, the Vgs is about 2.25V. Reading that voltage off on figure 5 gives an unreadably small gate current at 25C, and only rises to about 50mA at 175C.

There are two yahoo groups that are excellent for this sort of stuff. The first is Tekscopes (with 5000-odd members) and the other is hp-agilent-equipment (2200 members). What scope should I buy? is a very frequent question. However, HP had great strengths in many electronics instrument products, but not really in scopes. So join just Tekscopes and ask the question - we're a helpful bunch and the combined might of the group will help as best we can.