Yep, that's what we lucky ones have been doing for ages, previously 3 phase 220 VAC, now 230 VAC as is the general European standard grid network value.
Under worst case conditions, my line voltage doesn't drop below 225 VAC.
You have 3 phase transformers and rectifiers on your audio equipment? Is the wiring in your home Wye or Delta?
Its really rare and costly to get three phase in US homes. The HV (usually something around 17KV) on the poles is 3 phase but the step down transformers are single phase.
Running on 240 instead of 120 helps a lot- the drop on the power lines is reduced by 1/2 since the current is 1/2 of what it would be at 120V. For a preamp drawing 10W is not significant but on a bigger power amp it is. The balanced power stuff probably contributes a little. The fact that the computers, TV's printers and phone chargers are on the 120V legs probably contributes more.
Its really rare and costly to get three phase in US homes. The HV (usually something around 17KV) on the poles is 3 phase but the step down transformers are single phase.
Running on 240 instead of 120 helps a lot- the drop on the power lines is reduced by 1/2 since the current is 1/2 of what it would be at 120V. For a preamp drawing 10W is not significant but on a bigger power amp it is. The balanced power stuff probably contributes a little. The fact that the computers, TV's printers and phone chargers are on the 120V legs probably contributes more.
True dat ....240v 2 phase is best i could hope for ...
@DVV, revision , on my telarc Lp , Fredrick Fennel , from a low of .4v - 17v swing ...Reserves boys , who need em ......
Up from 14 to 17V, then - noted, but that only translates to 36/72/144W into 8/4/2 Ohms, WELL within my Centurion's range.
Just as I told you.
IMHO the whole issue of power delivered by current times voltage can mean high voltage and low current or high current and low voltage is overlooked. This plays into the whole valve vs SS amplification thing too.
The 240/120 of the USA is said to be the old Edison 3 wire system adapted . I think it was + , 0 , - DC . When Westinghouse /Tesla won the AC /DC debate it was economical to use the same cables . The problem in the USA is if the load in the house is out of balance the neutral shifts from the centre position . I am told 6 V is not unknown . Using 240 V is like using balanced audio as it no longer requires connection to Neutral . It is hard to say for certain this is the reason . Seems to me to be a good candidate . Also 240 V has lower losses and plugs to suit ( cooker /washing machine ) . In a Mr Wayne amplifier I would imagine this would be appreciated .
Anyone know of an add on switch for 6 mm shafts ? I want to add standby to a pot type as below . I have a shaft extender so can put it anywhere . SPDT would be great . I am using a micro switch and cam . It needs tweaking to work, I have doubt it will stay in adjustment . To have the virtues of a transistor radio pot in stereo is what I want . Audiofool, grade required . I have some ideas for using a comparator . I would like to use the traditional route If I can . If it is 12 mm or 1/2 inch that would be OK .
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I would use a cam and a microswitch. The traditional switch segment for a pot has become difficult to find. You can find cams and other stuff for 1/4" (6mm) shafts in the mechanical breadboarding areas. Manufacturer of Precision Components | Spur Gears | Sprockets | Timing Belts | Timing Pulleys | Miniature Bearings | Shafts | WM BERG Engineered Mechanical Components
Yeah now increase listening level by 6 db ...
So , high voltage low current superior to low voltage high current ..?
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Yeah now increase listening level by 6 db ...
So , high voltage low current superior to low voltage high current ..?
It is possible that non-linear resistive loss mechanisms do less damage at lower current demand, pure speculation. Certainly less power is lost by high voltage transmission lines.
Since year dot I've worked on conditioning caps, but I don't have any thoughts either way on running them near their max rating. The main thing I've found is that they get "lazy", if they haven't had a healthy dose of current flow happening for only a short while then their subjective performance falls off - it does become complicated here because it can be hard to distinguish whether it's the caps, or another part of the circuitry that needs to "stretch its legs" ...
I don't know about dangerous, I've had clipping plenty of times, and as Dan indicates this can be totally inaudible most of the time. At this very moment I'm running the PC setup and plastic speakers at max volume, on a piano compilation, speakers directly facing me about 15 feet away - sounding pretty good, but every now and again the limits of the power supplies are heard, the sound chokes as the amps gasp for energy, but it instantly recovers and all's fine - it's giving me pretty decent sound at the expense of inability to handle the crescendos, but it's a decent trade off - and no harm done ...
All good amps will have more distortion at low power, a nice, straight slope will show every time. But, the volume from the speakers is commensurately lower at these low powers, so no audible problems ...
MBL Reference 9011 amplifiers, probably the most superbly measuring units that Stereophile has tested, http://www.stereophile.com/content/mbl-reference-9011-monoblock-amplifier-measurements, shows the behaviour that I'm talking about - http://www.stereophile.com/images/312MBLfig3.jpg
The lower the power, the "worse" the distortion ...
Edit: An even more 'perfect' version of the curve was got for the Soulution 701, http://www.stereophile.com/images/811Soulfig4.jpg.
The lower the power, the "worse" the distortion ...
Edit: An even more 'perfect' version of the curve was got for the Soulution 701, http://www.stereophile.com/images/811Soulfig4.jpg.
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Your joking right , you need to go back to the beginning of this thread it was all addressed before and discussed, while its not uncommon its not correct , there are others with better i posted graphs etc on that over a year ago. ..
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First, what is high distortion? 1%, .1%, 20%?
The old measurement methods mixed distortion and noise. Sine its easy to separate distortion products and further analyze it to almost ridiculous levels it doesn't really follow to use the old charts except for "backward compatibility". Look at the distortion spectrum. Low order products matter a lot less than high order products. If you look at that amp or even a single ended tube amp with a high res FFT you should get a lot better insight into what its doing. Even at .1W there may be interesting stuff. And, of courde there is the question of what SPL is generated at .1W. At say 90 dB/w (pretty sensitive) for a speaker, .1% distortion levels at 1 Watt would be 90dB-60dB so around 30 dB. The Soulution being substantially lower would be around 90dB-90dB or effectively 20 dB below the ambient noise level in a very quiet space. I'm not sure how far one can hear into the noise but 20 dB would be pretty good I think. The best argument for look at this is 1) the high order harmonics at low levels are a tell-tail sign of crossover distortion and 2) some high order harmonics are not present in musical instruments and can be very dissonant.
The old measurement methods mixed distortion and noise. Sine its easy to separate distortion products and further analyze it to almost ridiculous levels it doesn't really follow to use the old charts except for "backward compatibility". Look at the distortion spectrum. Low order products matter a lot less than high order products. If you look at that amp or even a single ended tube amp with a high res FFT you should get a lot better insight into what its doing. Even at .1W there may be interesting stuff. And, of courde there is the question of what SPL is generated at .1W. At say 90 dB/w (pretty sensitive) for a speaker, .1% distortion levels at 1 Watt would be 90dB-60dB so around 30 dB. The Soulution being substantially lower would be around 90dB-90dB or effectively 20 dB below the ambient noise level in a very quiet space. I'm not sure how far one can hear into the noise but 20 dB would be pretty good I think. The best argument for look at this is 1) the high order harmonics at low levels are a tell-tail sign of crossover distortion and 2) some high order harmonics are not present in musical instruments and can be very dissonant.
Disagreed.
If your 1 or 2 W levels happen to be within the pure class A operation caused by high bias, you WILL see distortion sink lower than at any other point within the amp's range. At such low power levels, current delivery is not an issue.
If this does not happen, you either 1) have got something wrong somewhere, and/or 2) are using very low bias levels. Throughout the 70ies, Japanese amps were almost notorious for using exceptionally low bias levels, typically in the region 15-25 mA, whereas the US and European manufacturers were more in the 50-60 mA range, in general.
Otala recommended that the crossing over from pure class A into class B should occur at around -17 dB of the full nominal output level, that's about 1/7 of the nominal power. Personally, I think he was a bit blinded by relatively low power levels of amps in those days, especially in Europe, where 100W was considered to be a mammoth power level in those days. Besides, it quickly becomes rather inpractical without using some fancy sliding bias circuit.
As I said, my experience is that there is little more to gain above the 110-130 mA of bias current per output device, although I expect that also depends on the actual circuitry used. For example, my venerable HK 680 integrated amp (2x85/130W into 8/4 Ohms) is factory biased at 80 mA per output device pair, for a total of 160 mA. I started adding 10 mA in steps and listening hard. Moving up from 130 to 140 mA brought no change as far as I could hear, so I put it at 130 mA and called it a day. Other amps may behave differently.
@1audio
Good point!
No clear cut answer.
To me, the breaking point between acceptable and unacceptable is arbitrarily the 0.1% point under ANY circumstances. I feel fairly certain that we cannot hear classic THD at any point below that one - but I could be wrong.
No matter how wide bandwidth one's circuitry is, at my control frequency of 50 kHz THD levels WILL be higher. Asking an amp to deliver like 14 Amps at 50 kHz is a tall order, and asking it to do so with less than 0.5% THD is an even taller order. But it can be done.
Then of course there's the matter of harmonic decay. Ideally, it should have a nice order of decay, but life is anything but ideal, so some funnies may be encountered which may blur the overall sonic picture. For example, if one's say 7th harmonic is about the value of one's say 3rd harmonic - something is not quite right there, even if both actually satisfy the 0.1% THD condition. But, that's another story.
Not to even mention that one's settling time is 10 or more times slower than one's rise time, if there's significant ringing despite it being below the 0.1% mark, current delivery, stability, and what not. We try, but don't always make it.
Good point!
No clear cut answer.
To me, the breaking point between acceptable and unacceptable is arbitrarily the 0.1% point under ANY circumstances. I feel fairly certain that we cannot hear classic THD at any point below that one - but I could be wrong.
No matter how wide bandwidth one's circuitry is, at my control frequency of 50 kHz THD levels WILL be higher. Asking an amp to deliver like 14 Amps at 50 kHz is a tall order, and asking it to do so with less than 0.5% THD is an even taller order. But it can be done.
Then of course there's the matter of harmonic decay. Ideally, it should have a nice order of decay, but life is anything but ideal, so some funnies may be encountered which may blur the overall sonic picture. For example, if one's say 7th harmonic is about the value of one's say 3rd harmonic - something is not quite right there, even if both actually satisfy the 0.1% THD condition. But, that's another story.
Not to even mention that one's settling time is 10 or more times slower than one's rise time, if there's significant ringing despite it being below the 0.1% mark, current delivery, stability, and what not. We try, but don't always make it.
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