The Audiophoolery Thread.

[Craig Sawyers]

Just looked at the Mk4A connector standard. The rated withstand voltage is 1500V, pin to pin and pin to shell.

Interestingly, the bog standard Bulgin 3 pin miniature power connector is rated for the panel mounting part pole-pole 4.5kV and pole-panel 8.5kV. And for the cable part pole-pole 4.5kV and pole-accessible parts 3.5kV.

Having wired these thing in, I'd say those figures are hopeful!

Of course who can say what happens to Bulgin now:

"Cambridge, England (January 19, 2023) – Bulgin Ltd announced today that it has been acquired by Infinite Electronics, Inc., a global portfolio of leading in-stock connectivity solution brands. Bulgin was previously owned by Equistone Partners Europe, a leading European mid-market private equity firm"

Pass the parcel Jeeves.

Craig

[knobtwiddler]

Looks like I'll be stocking up on a few years' supply of any Bulgin parts tomorrow...


Benchmark Audio - Audio Myth - SMPS are Noisy

Rational logic in the audio game. What are they playing at?

[knobtwiddler]

Some of these things are quite well made

Herein lies the rub. If they marketed them as 'audio jewellery' I wouldn't have a problem. A Rolex isn't as accurate as a Casio, but that's not why you buy one, is it?

I posted a link a couple of pages back to a preamp that costs £70K. Do I think any human could reliably A/B/X it against a Self circuit in a Maplin box, based around a pair of NE5532s? No. If you've got the spare cash to buy the £70K preamp, good for you.

[knobtwiddler]

NB - when the firm I work at got an SMPS EMC tested a few years back, we found that it passed CE levels, but failed on FCC. We had to change the inlet to one with larger Ls. One firm got fined a million USD by the FCC. I tell myself that when the invoice from the EMC lab drops through the door.

[stevehertz]

Originally Posted by knobtwiddler

Herein lies the rub. If they marketed them as 'audio jewellery' I wouldn't have a problem. A Rolex isn't as accurate as a Casio, but that's not why you buy one, is it?

I posted a link a couple of pages back to a preamp that costs £70K. Do I think any human could reliably A/B/X it against a Self circuit in a Maplin box, based around a pair of NE5532s? No. If you've got the spare cash to buy the £70K preamp, good for you.

Good points there.

[Craig Sawyers]

Indeed switched mode supplies can be very quiet. It needs real care to make sure that happens.

When I ran the two week ESA EMC tests on the MIXS instrument (currently doing flybys of Mercury) the multi-output switched mode supply had far too much noise on the supply lines. It was a DC to DC converter by the way. It needed LC filters on each line to make it reach specification. In fairness to the Spanish part of the team that were responsible for supply, one of them immediately flew back (from the UK) and returned with a filter box (containing a custom PCB!) complete with the correct connectors. Only took a couple of days. Must have cost a small fortune at that pace of work and probably an all-nighter.

That was then miniaturized and lightweighted, and incorporated into the flight electronics.

Craig

[dglcomp]

Originally Posted by knobtwiddler

Looks like I'll be stocking up on a few years' supply of any Bulgin parts tomorrow...


Benchmark Audio - Audio Myth - SMPS are Noisy

Rational logic in the audio game. What are they playing at?

Benchmark are a reputable manufacturer of High end audio gear and SOS have reviewed some of their products favourably.

Related, as for companies being fined by the FCC, Pyle "Pro" got in a lot of hit water by selling wireless microphone systems that either used frequencies that didn't match the FCC authorisation, units that transmitted on different frequencies to what was on the box and even worse for some systems they had no idea what frequency they transmitted on.
There's a reason why you don't buy unbranded cheapo wireless systems, better to buy an older compliant system (noting that my 80's TOA system still works perfectly).

The new Sony walkman has arrived in Swaffham!

Guy, (the Audiophool), has bought one and was keen to show it off.

If you're not familiar, heres the official video.

https://youtu.be/nvIL9xhhNwY

I'm particularly impressed that it is assembled using 'Quality Sound Solder Containing Gold' for improved sound localisation and a wider sound stage. I guess SAC305 with silver is not good enough any more.

But beware: with that gold in the solder, a smidge too much will make the joints too brittle, and you'll have to buy a new one if you drop it.

Guy, bursting with pride, asked one of my tech savvy nieces (13) her opinion: she studied it front and back, listened to it for a moment then asked where the tapes went in!

"But it doesn't use tapes" protests Guy.

"Should do, so why does it sound so st?" asked my niece, "...my phone sounds as good!

Never mind Guy, it was less than two months mortgage repayments, so if it doesnt swing it as something that will impress the ladies, perhaps buying it won’t make you homeless.

[ajgriff]

Interesting that the new Walkman includes a so called Vinyl Processor described as follows:

“Give the warmth and character of vinyl back to your digital tracks and get lost again in the richness of the melodies and dynamics of your favourite albums. Enjoy subtle reproduction of the low-frequency resonance, tone-arm resistance and surface noise to deliver an authentic listening experience.”

In other words you get deliberately distorted reproduction and yet there’s no Cassette Processor to give the listener that authentic hiss combined with a severely restricted frequency response. All very disappointing.

Alan

[Craig Sawyers]

Originally Posted by G.Castle

T
I'm particularly impressed that it is assembled using 'Quality Sound Solder Containing Gold' for improved sound localisation and a wider sound stage. I guess SAC305 with silver is not good enough any more.

But beware: with that gold in the solder, a smidge too much will make the joints too brittle, and you'll have to buy a new one if you drop it.

In space grade electronics, all gold coatings are verboten. Because of the brittle intermetallics formed between gold and (tin/lead) solder

In fact there is a de-golding process used to remove gold coatings in flight electronics. And there is no solder resist or silk screen either on circuit boards, because they degrade as a result of radiation in space. Apart from potentially screwing up the electronics, the resulting gooey volatiles can find their way onto optical surfaces and cause serious problems.

If Sony were really savvy, they could say that no gold had been used at all because of the compromise in sound quality from brittle joints.

Craig

[Radio Wrangler]

I've said for years that true audiophiles should use 'Mithril' from 3M, the Moria Mining and Metals Corporation.

David

[Craig Sawyers]

What's it got in its electronics, precioussss

Craig

[emeritus]

I seem to remember that the gold intermetallic compounds that caused problems with early integrated circuits were referred to as the "purple plague" on account of their colour.

The gold thing is just what I'd picked up on, better electrical and mechanical qualities could be imparted to the finished item by soldering it together with an old Solon with an unplated bit and acid tallow flux.

Best thing is that Guy is happy, and the person who imported it for him from Japan is £800+ better off.

[Craig Sawyers]

Originally Posted by emeritus

I seem to remember that the gold intermetallic compounds that caused problems with early integrated circuits were referred to as the "purple plague" on account of their colour.

Yup https://en.wikipedia.org/wiki/Gold%E2%80%93aluminium_interme...n%20as,to%20that%20of%20pure%20gold.

There is even red plague in silver plated wire

https://en.wikipedia.org/wiki/Red_plague_(corrosion)

Bad news for audio nuts who insist on silver plated wire.

Another less well known issue is stress corrosion cracking https://en.wikipedia.org/wiki/Stress_corrosion_cracking

Craig

[knobtwiddler]

Apologies for the source of the link, but the product's relatively new and I can't find much about it elsewhere: What Hi-Fi Link for New Denon Amp

Taken from link:

One neat feature is Analogue Mode. This disables the digital inputs and Bluetooth, so the unit can work as a purely analogue amp. By cutting out the high frequency digital influences, it plays analogue sources with greater clarity and fidelity.

It'd be very easy to hook the outputs of said amp to an FFT in realtime and see the 'analogue mode' switching on / off. But it begs the question: why wouldn't a major OEM throw enough resources at its ground structure / track layout / conducted EMC / radiated EMC, in order to render nasty digital artefact immeasurable even when switched on? There are numerous DACs that have digi junk below -120dBV now - even affordable ones.

I would say that digi artefact, be it toothcomb harmonic distortion from clock junk getting into grounds, or HF hash due to switching converters, should be below -100dBV if the design engineer's done their job correctly. In 2023, above that would be an amateur job. Maybe it is below -100 and 'analogue mode' kills it entirely. But what does this say about the amp's performance solely for digital sources? Vinyl is better? Maybe they could have a dedicated input for cassette? And considering even the quietest RIAA amps leave a blanket of hiss when combined with their source impedance, one would like to think that digi nasties should be well buried under that blanket, even if profoundly visible on line I/Ps.

[Radio Wrangler]

Originally Posted by knobtwiddler

But it begs the question: why wouldn't a major OEM throw enough resources at its ground structure / track layout / conducted EMC / radiated EMC, in order to render nasty digital artefact immeasurable even when switched on?

Ah, but this is a sop to audiophiles and it's the thought that counts. You must not let objective data get into such considerations. Where would be the advantage in having golden ears?

Real audiophiles can tell by listening whether a genuine high priest has made the right arcane gestures over the product and whether the holy water wasn't just from a tap. So something flaunting it on the box can only be targetting the wannabe audiophile market. If real audiophiles ever doubted their ears, they could always just check the price.

David

Purple plague corrosion in CMOS ICs was their cold running not driving out moisture as TTL/ECL did, and the moisture leached phosphorus out of the glass passivation, and the phosphoric acid slowly etched away the exposed aluminium metal interconnection layer. No gold involved.

[knobtwiddler]

My understanding is that Denon no longer builds in Japan and is not even Japanese-owned these days. However, much like a fashion label, where this year’s collection might be ‘flannel with earthy colours’, Japanese OEMs have long had a tradition of releasing ‘this year’s collection’ with a pseudo-scientific gimmick, but underpinned by R+D integrity under the bonnet (often unrelated to the theme or claim of the year’s collection).

As we know, there are obvious and expensive ways to ensure that HF switching signals do not get into sensitive analogue paths: metal shrouds, multiple PCB layers, extra power rails to funnel junk away etc. A clever designer will have tricks up their sleeve to do this without doubling the build price. If Denon’s amp range needs a mechanism to turn off digital nasties, it strikes me as an admission of failure on behalf of the R+D team. Not to mention the inference that digital audio is somehow ‘dirty’ and unsanitary.

[The Philpott]

Interesting info about intermetallics. I associated purple plague and white plague with Al-Au intermetallics, but with plagues there's seemingly always another that you've never heard of..

With pukka galvanizing of steel (as opposed to zinc dipping, presumably) the intermetallics may actually be an advantage- distinct strata of different proportioned Zn-Fe alloys form on the steel.

Dave

[kalee20]

Originally Posted by G.Castle

The new Sony walkman has arrived in Swaffham!

Guy, (the Audiophool), has bought one and was keen to show it off.

...

Guy, bursting with pride, asked one of my tech savvy nieces (13) her opinion: she studied it front and back, listened to it for a moment then asked where the tapes went in!

"But it doesn't use tapes" protests Guy.

"Should do, so why does it sound so st?" asked my niece, "...my phone sounds as good!

Never mind Guy, it was less than two months mortgage repayments, so if it doesnt swing it as something that will impress the ladies, perhaps buying it won’t make you homeless.

It certainly didn't seem to impress that lady, Greg!

And yes - gold in solder is bad news. I reckon they skimped on the production, used contaminated solder, a salesman got to hear of it and decided, if it's too late to fix it, he'd make it a feature!