Vibrational effects on vintage hifi components

[stevehertz]

In the 80s - probably in search of something 'new' to offer, or as part of the whole audiophool move towards snake oil, voodoo, smoke and mirrors effects and solutions - manufacturers started to introduce hifi components that were build to combat vibrational effects as they were popularly said to blur the purity of the audio signal as it passed through components (my words, to be taken in context). We're taking special chassis, mountings, feet etc etc.

Ok, I can see the point of this when considering a record deck, the more isolated the better, clearly. No need to discuss that. But did it really make that much difference to stop PCBs and their components vibrating minutely? - and unless listening at Deep Purple concert hall levels - the effect would me minuscule in the home setting.

BTW, I personally don't 'buy' this! but I'm just interested if anyone thinks there was, even a small case for it (anti-vibration solutions) or was it, 101%, really, honestly, just another soother dummy for the audiophool to suck on? With all these things (capacitor and cable types etc etc) it is often possible using laboratory level test gear to 'identify' that there is such an effect, but quite simply, when taken in context of the overall distortion levels due to circuit topology, crude speakers etc (best are 2-3% distortion?), then their nett 'effect' is a total non entity. In other words like comparing the weight of one grain of sand amongst a ton of the stuff.

[Edward Huggins]

I do remember quite a move to use very strong chassis fabrication, especially Pioneer, some I believe "Honeycombed".

[Kentode]

Totally agree Steve. My Linn Sondek is wall-mounted as footfall on 100 year old floorboards does not a happy bunny make, but l see big, ugly " isolating" rack systems costing several hundred pounds and think, why?

These systems are usually accompanied by oversized cables and plugs, definitely a rich person's hobby.

My hobby is listening to the music, not looking at the system!

[G6Tanuki]

Some ceramic capacitors are known for their piezoelectric properties: but rather than going to the horrid expense of vibration-isolation systems in an amplifier/tuner it would have been far simpler to use non-piezo-sensitive capacitors!

Vibration of air-spaced tuning-gangs in receivers - this can be a problem (it FMs the local-oscillator) - again, varicap diodes provide a microphony-free solution.

Record decks are indeed susceptible to being shaken [I've run discos in clubs and village-halls with less-than-solid floors: a few hundred teenagers leaping around in such an environment poses a challenge to the best deck]: surely in terms of vibration in the domestic environment though the biggest issue would be direct pickup of sound by the disc itself rather than conduction through the mountings/turntable base?

[Kentode]

G6tanuki , are you saying that the soundwaves from my speakers are impinging on the surface of the LP and affecting the stylus?

If so, that's one-nil to the lid-down brigade! (Awaits rant from lid removing aficionados).

[G6Tanuki]

Of course the soundwaves from the speakers will vibrate the disc directly through the air, and hence modulate what the stylus is picking up from the grooves.

Putting the turntable in a different room from the speakers will minimise the chance of any such 'colouration'...

[Kentode]

Ah, now I understand! I'm putting my deck in the cellar, my preamp in the living room, the amp in the bedroom and the speakers in the loft, all wired with busbar.

[dseymo1]

It's quite possible to experience howlround via acousic coupling of loudspeakers and record, so probably not negligible in terms of colouration at normal listening levels.
We all know that valves in sensitive amplifier circuits are prone to microphony, and are often isolated to mitigate that. Solid state devices are generally less so, but the phenomenon is still not uncommon: even moving a mic cable will sometimes produce a clearly audible signal due to triboelectric effects, so there is perhaps some justification for isolated mounting of equipment. The premium asked for arranging this is another matter...

[Radio Wrangler]

The recurring theme of audiophilia is a lack of any sense of proportion.

The moment some effect is postulated, that COULD affect the sound, steps have to be taken to eradicate it. They don't seem to worry about whether the effect is significant enough to be noticed because their prime belief is that there is no limit to the discrimination of their hearing.

Once you have painted yourself into a corner where everything matters, real or not, then you have to do something to fix everything, real or not. The curse of the fllying Dutchman and the pursuit of the holy grail have nothing on this bunch

David

[Andrew2]

Originally Posted by G6Tanuki

Of course the soundwaves from the speakers will vibrate the disc directly through the air, and hence modulate what the stylus is picking up from the grooves.

Putting the turntable in a different room from the speakers will minimise the chance of any such 'colouration'...

Indeed. We once had a customer who virtually lived in his bedroom (he was a rather strange young man who lived with his elderly parents) and he complained that the hi-fi system we had flogged him - a rather nice set of Technics gear - was 'booming and howling'. So I went around and asked him to demonstrate.
I wish I hadn't. The room was quite small and he had the volume and bass so high that the system was on the verge of 'howl round' feedback from speakers to record deck. Occasionally it would burst into low-frequency flapping that threatened to wreck the loudspeakers.
I had to explain to him that he just HAD to turn it down and reduce the bass (and I'll bet his long-suffering parents were a bit relieved too).

[dseymo1]

The simple, relatively cheap option is to use headphones...

[camallison]

Since the frequency response of my ears is poor at best, I pass on this discussion.

Colin

[Nuvistor]

It doesn’t mean you cannot enjoy listening to music, you will likely get more pleasure than those seeking some holy grail.

I have lost a lot of my audio HF, I listen to music most of the time and get great pleasure from it. Do I hear what the musicians hear, probably not, some are more deaf than I am after years on stage with the amp turned up to 11.

[Craig Sawyers]

I too have been prone to fashionable audio tweaks. So I try to prove things one way or the other.

1. Vinyl and CD's are prone to vibrate in an acoustic field. Vinyl clearly so, particularly to oscillation at the cartridge compliance/arm mass resonance with an increased chance if this is too high in frequency. A lid, counterintuitively, can make matters worse - you now have air resonances in a closed box, and panel resonances in the lid structure to contend with. CD's less obvious; but if you feed the focus servo signal into a headphone amp, you hear a clear and distorted version of the music. This is the remaining error signal in the focus servo. So does regular listening level music have an effect on CD playback? Yes.

2. Valves - yes. Mullard published two papers in 1962 (attached) on the topic.

3. Semiconductors and passive components used in high quality audio. No. Take piece of equipment (a) without a signal going through it. Play music through equipment (b). Look at any evidence, with any test equipment I have at my disposal (audio spectrum analysers, 1uV/cm oscilloscope etc) at the output of equipment (a) and there is no evidence of anything at all. Smoke and mirrors.

The only thing that might be going on is equipment panels resonating and adding acoustic colouration. The old Naim advice of "don't site your system in a room with musical instruments" actually makes sense in the context of resonances.

4. There are certainly effects from other resonant objects in the room. We had an open cabinet with some cut crystal glassware. The trick to finding the effect of this sort of stuff is to stand in the room and clap your hands - and listen. In our case, there was a high Q chorus of glassware ringing. We moved them to another room.

5. Cables. Yes, with provisos. Triboelectric effects have been already raised, but it is easy to check. With no audio going through the system, turn the volume up and wiggle the cable around. Silence is good! and vice versa clearly.

[crackle]

I seem to remember that a long time ago there was an article in Wireless World about a guy who had the idea that in order to get the realism of actually being at an orchestral performance, the kind of power required to create a realistic sound was 1000 watts. So he set about constructing a 1000 watt amplifier.

The transistors were mounted on water cooled heat sinks and I seem to remember the speakers were built into concrete cabinets.

The effect of all this, he suffered a lot from microphony and feedback, and I believe he got through several sets of speaker cabinets..

Or did I imagine the article!

Mike

[stevehertz]

I stated quite clearly in the first post that vibrational effects vis a vis record decks was NOT the issue I was referring to, that is a well documented, well covered phenomenon. As I said, I'm talking about the use of so called specially designed chassis, mountings, dampening devices, feet etc etc wrt the effects of vibration (from speakers, whatever?) on solid state and mechanical components that make up the amp, tuner, CD, whatever, but NOT record decks. Just to clarify as a lot of the responses so far seem to be about record decks! I'd like to keep the thread on track, not about record deck feedback. Thanks.

[sp10mk11]

I see this thread has drifted (like so many others).
But yes in the 80/90s I remember Pioneer (honey combe bases) and Sony (Gibralter bases) oh and yes then came Heavy Copper bases, damped electrolytic capacitors, no heatshrink on cables, gold plated component legs........I dare say it helped sell more units at the time.
As long as there is a market for stuff it will be made regardless

Yours Gary (too old to care)

[Refugee]

I can remember reading about capacitors being microphonic and tried some with my bench amplifier back in the 1970s.
It took about ten of them before I found a grotty looking one of unknown heritage that was indeed microphonic.
I did not apply any bias to them though.
My conclusion was that there was not a problem with them.

[emeritus]

I do recall an April (the first!) WW article about a very powerful amp where cast iron radiators were used for heatsinks, and the initial plop of the needle engaging a record brought down some plaster from the ceiling! Early 1970's I think.

[Craig Sawyers]

Originally Posted by crackle

I seem to remember that a long time ago there was an article in Wireless World ...
Mike

You didn't imagine the article; it was an April fool article.