Listening to hifi in the perfect position?

[Jez1234]

Many years ago I had a customer bring in an Audionote single ended triode zero feedback amplifier. A truly awful thing as are all of the breed and easily beaten by a decent music centre amp. I measured around 8W max output and THD around 16%! At 3W it was still something like 3% THD.

When he came to collect it we got chatting hi fi and he asked about my system so I gave him a demo. It was pretty high end gear of the day (about 1990). I put on a good recording and turned up the wick a bit. After a while he turned to me and said "that's got amazing clarity, dynamics, nice tight bass, it very much reminds me of when I worked for a while in a recording studio and heard the playback on the monitors... No I don't like that at all!"

[stevehertz]

No accounting for taste. I recall back in the seventies there was a very clever guy who I worked in the test department with. He designed and developed speakers in the BBC vein and I don't mean just buying paper cone speakers and using a capacitor to a crossover. He developed Zobels and so on. Anyway, on the subject of valves he said, "They're fine if you don't mind listening to distortion." And of course he was right, most half decent trannie amps have many times less distortion than valved amps. Of course that isn't the full story as we know, but it's a fact.

[Jez1234]

Ah the old valves Vs transistors in audio is a subject with long legs!

I think being single ended, with no negative feedback whatsoever and with all that DC magnetising the tranny core, which needs to be so much bigger to take this (and prob air gapped) so more leakage inductance etc, have more to do with it than the valves per se in this instance

For my ha'porth on the wider subject well it's dead easy with line level and lower signals to get 0.5% THD or less with ye olde generic circuits dating back to the 20's. This was thought more than good enough until around the late 60's into the 70's I guess, so maybe there was little effort to reduce it to super low levels (KISS, bean counters and not re-inventing the wheel no doubt all played a part with the status quo here).

Many more modern units have simply copied these designs, either because they couldn't design their own, or it was still considered good enough, or to try and get some "vintage valve classic magic" into the sound.

If we leave output transformers out of the mix for now then it is perfectly possible to make valve amps using more modern techniques (often one's nicked from Tek and HP valve instrumentation schematics and modified for audio use) that can give very low distortion. Older Audio Research pre amps with phono stage managed about 0.003% and I've designed and built valve stages with similar or slightly better specs myself.

Valved power amps from Radford, Audio Research and Esoteric Audio Research (EAR) amongst others have managed THD around the 0.05% level in spite of output transformers. Obviously if it wasn't for the distortion of the transformers themselves and their phase shift, which limits the amount of NFB that can be used, then they could go much lower. I seem to recall a rare Technics output-transformer-less power amp managed about 0.01% THD and a damping factor of something like 80!

An all valve apart from the mosfet source follower OPS 100WPC power amp I built many years ago managed 0.005% THD and some excellent 20KHz full power square waves.

If you "cheat" and help the valves out by resorting to using solid state devices as current sources and mirrors then THD can be just as low as with all solid state designs

I'm still waiting for the "PNP" valve to be invented

[Radio Wrangler]

Originally Posted by Jez1234

I'm still waiting for the "PNP" valve to be invented

Asimov, 'Positronics' If we ever get it, we may not be so keen on the plague of troublesome robots associated with it.

David

[Phil G4SPZ]

Originally Posted by Viewmaster

...get your ears tested for HF response. You may get a shock...

I was aware that I had HF hearing loss because I'd spent some time aligning my high-speed Revox A77. I could see from the instruments that the machine was recording and playing back at over 17kHz, but I couldn't hear a thing above 12kHz!

However the shock came when I went for an audiogram and discovered that I also have the well-known "4kHz notch" in both ears, a pronounced dip in the response around that frequency. This makes speech particularly hard to decipher in the presence of background noise. The odd thing is that 4kHz notch hearing loss is usually associated with noise-induced hearing damage.

Now while I've been to the odd rock concert (Runrig's was the most painfully loud; it lasted two hours but my ears rang for two days), ran a mobile disco back in my youth and so on, my day job was largely office-based and I never considered that I'd suffered from much noise exposure. The thing is, it's cumulative. It can also have a family link - my father was profoundly hard of hearing, and my sister is more affected than I am - so who knows?

Look after your ears, you only have one pair, and hearing aids, as good as they are nowadays, are no substitute. Audiologists don't correct any hearing loss above 8kHz, so most of the top octave of hi-fi recorded music is sadly lost to me forever

[Joe_Lorenz]

Phil,
you are not the only one who is hard of hearing! Many years of my work life I did "special orders" blasting in the mining business. When you are a young guy you enjoy every big booom but the older you get the more you regret and eventually you become aware what it has done to your ears! My audiograms have shown more and more decay, so I do not need any "High-End" gear any more. A strong 1960s valve amp is all I need!
Joe

[Doghouse Riley]

Another problem with hearing particularly when you're middle age is wax in your ears, it can also affect your balance. Here in the UK you can get it removed free on the NHS if your GP believes it is necessary. If you've had a build up and got it cleared, it still may need doing again in a few years time. A couple of drops of olive a week in each ear, is supposed to help keep them clear, but there are proprietary solutions which are better.

I remember reading many years ago, I think it was Stan Kenton, told his horn section that they weren't blowing loud enough. "We're blowing as loud as we can boss!"
So he got his ears syringed and it cleared the problem.

[stevehertz]

Originally Posted by Phil G4SPZ

I was aware that I had HF hearing loss because I'd spent some time aligning my high-speed Revox A77. I could see from the instruments that the machine was recording and playing back at over 17kHz, but I couldn't hear a thing above 12kHz!

However the shock came when I went for an audiogram and discovered that I also have the well-known "4kHz notch" in both ears, a pronounced dip in the response around that frequency. This makes speech particularly hard to decipher in the presence of background noise. The odd thing is that 4kHz notch hearing loss is usually associated with noise-induced hearing damage.

Now while I've been to the odd rock concert (Runrig's was the most painfully loud; it lasted two hours but my ears rang for two days), ran a mobile disco back in my youth and so on, my day job was largely office-based and I never considered that I'd suffered from much noise exposure. The thing is, it's cumulative. It can also have a family link - my father was profoundly hard of hearing, and my sister is more affected than I am - so who knows?

Look after your ears, you only have one pair, and hearing aids, as good as they are nowadays, are no substitute. Audiologists don't correct any hearing loss above 8kHz, so most of the top octave of hi-fi recorded music is sadly lost to me forever

Phil, I too have suffered HF loss. When I play my test CD with frequency tracks I hear clearly up to 8kz but at 10 it's pretty much gone. But in reality how much of a problem is that? Two things... Firstly at those frequencies it's pretty much harmonics on cymbals, that kind of thing, we're not missing out on fundamentals. Secondly, as I said earlier - and I know it's not perfect - to some extent you can just turn up the treble tone control to compensate. It's not a perfect world we live in, and as we know only too well as you get into older age, lots of compromised 'fixes' can and do help. I put on my test CD and increase the treble until the higher frequencies are more audible, being mindful of course of any unacceptable stress to tweeters. There is life after hf loss!

[stevehertz]

Originally Posted by Doghouse Riley

Another problem with hearing particularly when you're middle age is wax in your ears, it can also affect your balance. Here in the UK you can get it removed free on the NHS if your GP believes it is necessary. If you've had a build up and got it cleared, it still may need doing again in a few years time. A couple of drops of olive a week in each ear, is supposed to help keep them clear, but there are proprietary solutions which are better.

I remember reading many years ago, I think it was Stan Kenton, told his horn section that they weren't blowing loud enough. "We're blowing as loud as we can boss!"
So he got his ears syringed and it cleared the problem.

So true. Also, one shouldn't attempt to remove earwax using cotton buds. Freed up wax will find its own way out once softened using olive oil.

[Phil G4SPZ]

Very valid points, Steve. My wife suffers from very waxy ears and despite using olive oil and other proprietary products regularly, she has narrow ear canals and still needs them syringing now and again. This service has all but disappeared. GP surgeries no longer offer it, and the private sector (if you can find a provider) charges exhorbitantly.

Other areas may differ.

Good to see this topic being discussed as hearing loss seems to afflict many of us!

[Doghouse Riley]

Originally Posted by Phil G4SPZ

Very valid points, Steve. My wife suffers from very waxy ears and despite using olive oil and other proprietary products regularly, she has narrow ear canals and still needs them syringing now and again. This service has all but disappeared. GP surgeries no longer offer it, and the private sector (if you can find a provider) charges exhorbitantly.

Other areas may differ.

Good to see this topic being discussed as hearing loss seems to afflict many of us!

As I mentioned, it is available under the NHS. Here in Trafford there is a NHS clinic where there's a surgery at an NHS clinic devoted to it. But you need a doctor to tell them it's necessary and you can then call and make an appointment. It's not just wax, as you get older you start to get tiny amounts of skin being shed by the ear canals, the wax can attach itself to flakes that are still attached and no amount of olive oil will remove it, even if you use drops on a weekly basis.

Some chemists will do it for you for around £50.

But I'd rather have an experienced nurse with all the specialised equipment.

[Welsh Anorak]

Yes - just had mine done with a sort of specialised vacuum cleaner for £55 from a well-known high street opticians who also offer this service. The syringe method or the water blaster is now frowned upon (though not as much as the cotton bud or worse!).

Once done you will find you need to re-adjust the balance control on your amplifier...

[Pfraser]

I have been fortunate to experience broadcast studio equipment, as well as some very nice kit at a hi-fi exhibition. Back when my hearing was up to the task! Even so, I still preferred a pair of Beyerdynamic (pale grey, oblong) or AKG Professional heaphones. It's not so much about precise positioning in the sound field, or acoustics; more so a sense of immersion in the music.

Not expecting anything near hi-fi is liberating. Simply 'relaxing into' the rich, mellow tone from a valve woodie set brings its own rewards.

[Jez1234]

Yes good point. I realised this many years ago when I'd got into various albums by enjoying them at a friends place on their ghetto blaster or music centre etc and had then bought my own copy only to find when played on my hi fi system that they were atrociously badly recorded to the point of never being played again!