RE: MD: headphones impedance vs battery life / yet another MS722 review
Francisco Jose Montilla wrote: I meant (sorry, english isn't my native language) that what excite the headphone transducers is a variable (AC) electrical signal. I don't have the mathematical demonstration handy, but if you go in a little deeper, you'll notice that with higher loads (i.e. impedances) peak voltage rises. Those equations assume a constant (i.e. DC) voltage. The voltage across the load will increase in proportion to the impedance if it is fed by a current source. Most amplifiers act as (effectively) VOLTAGE sources, in which case the current in the load falls as the impedance rises. My doubt is, if a 200 Ohm headphones with higher sensitivity than a 32 Ohm headphones snip which will drain more battery. I'd bet the 200 Ohm, but am not sure... I'd try to reproduce the equation development to prove the voltage raise. Good luck ! I'll be glad to see Herr Ohms' outdated law exposed for the fraud that it is :-) simon - To stop getting this list send a message containing just the word "unsubscribe" to [EMAIL PROTECTED]
Re: MD: headphones impedance vs battery life / yet another MS722 review
=== = NB: Over 50% of this message is QUOTED, please = = be more selective when quoting text = === [EMAIL PROTECTED] wrote: On Thu, 23 Mar 2000, Ralph Smeets wrote: Hi! than a year...) The only portable that won't break and that is Sony is my CMC-Z1+ portable GSM phone... (of which most consumer magazines write you that the flip-down microphone will break very quickly...) BTW, I don't see http://home.worldonline.dk/~isl366/md/md.htm listed on the construction projects section on minidisc.org (although I'd swear I got that link from somewhere related to minidisc.org. It's a pretty good idea: recycle old GSM phones mics, have done something similar and it actually perform great for speech recordings! The only unexpected mis-feature I have found is the headphones sound; even when people said sharps sound greatly, i found the headphones to have a very harsh and unpleasant sound. Mids are unsanely boosted, and I (I know that is a very subjective area) don't like that at all. Is the only drawback I found on the sharp. I hate earbuds commonly found on other portables, so I don't mind too much, sony's would be worse. I tossed them away after 1 day. I replaced them with the 888's of Sony. Are they sold as a separate product? My impression is that Sony isn't very good with transducers... Here's were my question comes: Sharp headphones are 32 Ohm, I have an old walkman Aiwa headphones whose sound I like too much (in fact i tried lots of walkmans back then to find the better sounding ones). But they're 200 Ohm. My electronic knowledge have some dust on top, and I was wondering if the battery life will be shorter. My mind says that as impedance is higher, AC current *voltage* will actually be higher, and battery life will be shorter. Higher impedance: higher energy loss also... Well, U=I*R. U can't change!! So if you increase R, you decrease I. P=U*I, U doesn't change, but I get's smaller. Thus lower power consumption. Not with variable AC... Wait! I have remembered someone posted a site devoted to headphones (www.headwize.com)! Have just checked it and that's what they say (http://headwize.com/articles/hguide_art.htm#imped): --- Impedance: A measure of headphone load on an amplifier and stated in ohms. This factor is less important with solid state amplifiers, which can drive most headphone impedances, but can be significant with tube amplifiers, which are more sensitive to load impedances. Both consumer and professional headphones generally have impedances of less than 100 ohms. There are professional models rated at 200 ohms or more to minimize loading effects on distribution amplifiers which are often drive a whole bank of headphones at one time. Be aware that very high impedance phones may require more power - on the order of Watts instead of milliWatts. - mine aren't pro's, that's sure. But it seems I was on the right direction... Off course you NEED higher power to drive high quality headphones. Why? Higher quality headphones (like speakers) tend to be less efficient with the energy put into them. Ie, to get the same sound-level out of them as with normal headphones, you need to drive them with more power. However, if you connect these headphones to a portable player, you'll notice that the sound isn't as loud as a normal headphone. A 5mW amp can't put out more than 5mW! Cheers, Ralph -- === Ralph SmeetsFunctional Verification Centre Of Competence - CMG Voice: (+33) (0)4 76 58 44 46 STMicroelectronics Fax:(+33) (0)4 76 58 40 11 5, chem de la Dhuy Mobile: (+33) (0)6 82 66 62 70 38240 MEYLAN E-Mail: [EMAIL PROTECTED] FRANCE === "For many years, mankind lived just like the animals. And then something happened that unleashed the powers of our imagination: We learned to talk." -- Stephen Hawking, later used by Pink Floyd -- === - To stop getting this list send a message containing just the word "unsubscribe" to [EMAIL PROTECTED]
Re: MD: headphones impedance vs battery life / yet another MS722 review
Francisco Jose Montilla wrote: BTW, I don't see http://home.worldonline.dk/~isl366/md/md.htm listed on the construction projects section on minidisc.org (although I'd swear I got that link from somewhere related to minidisc.org. THis set up will only record mono. The one I designed is just as easy to build, and gives stereo results http://www.tir.com/~liteways/Mandolin.html#Microphone If you wanted to use old cell phone mikes, in it,it would probably work. -- Jim Coon Not just another pretty mandolin picker. mailto:[EMAIL PROTECTED] If Gibson made cars, would they sound so sweet? My first web page http://www.tir.com/~liteways - To stop getting this list send a message containing just the word "unsubscribe" to [EMAIL PROTECTED]
Re: MD: headphones impedance vs battery life / yet another MS722 review
Francisco Jose Montilla wrote: Well, U=I*R. U can't change!! So if you increase R, you decrease I. P=U*I, U doesn't change, but I get's smaller. Thus lower power consumption. Not with variable AC... Ok, here is the problem You are driving the head phone through an output stage that has an internal resistance.. The battery voltage comes through the output transistor(s), through the headphones and back to the battery. So, if the unit was designed for 32 ohm headphones, and you put 200 ohm phones on it, you have changed one leg of a voltage divider, and more of the battery voltage will develop across the headphones However, you have changed the operating point (bias) of the transistor output stage, and that can lead to clipping and distortion. You have to remember that you are dealing with a battery voltage of 4.5 to 6 volts or less, not a headphone distribution amp. Wait! I have remembered someone posted a site devoted to headphones (www.headwize.com)! Have just checked it and that's what they say (http://headwize.com/articles/hguide_art.htm#imped): --- Impedance: A measure of headphone load on an amplifier and stated in ohms. This factor is less important with solid state amplifiers, which can drive most headphone impedances, but can be significant with tube amplifiers, which are more sensitive to load impedances. Both consumer and professional headphones generally have impedances of less than 100 ohms. There are professional models rated at 200 ohms or more to minimize loading effects on distribution amplifiers which are often drive a whole bank of headphones at one time. Be aware that very high impedance phones may require more power - on the order of Watts instead of milliWatts. - mine aren't pro's, that's sure. But it seems I was on the right direction... I'd try to contact this guys to see if the can clear it. *---(*)---**-- Francisco J. Montilla System Network administrator [EMAIL PROTECTED] irc: pukkaSevilleSpain INSFLUG (LiNUX) Coordinator: www.insflug.org - ftp.insflug.org - To stop getting this list send a message containing just the word "unsubscribe" to [EMAIL PROTECTED] -- Jim Coon Not just another pretty mandolin picker. mailto:[EMAIL PROTECTED] If Gibson made cars, would they sound so sweet? My first web page http://www.tir.com/~liteways - To stop getting this list send a message containing just the word "unsubscribe" to [EMAIL PROTECTED]
Re: MD: headphones impedance vs battery life / yet another MS722 review
On Sun, 26 Mar 2000, J. Coon wrote: Hi, BTW, I don't see http://home.worldonline.dk/~isl366/md/md.htm listed on the construction projects section on minidisc.org (although I'd swear I got that link from somewhere related to minidisc.org. THis set up will only record mono. The one I designed is just as easy to build, and gives stereo results http://www.tir.com/~liteways/Mandolin.html#Microphone If you wanted to use old cell phone mikes, in it,it would probably work. Yes, I'm aware of it! that will be the second one I build. I'm looking for good spec'ed capsules from typical PC (dirty cheap) equipment such as standalone mics or headsets, as here there is no Radio Shack nor Maplin. I'll keep you and the list reported of whatever I discover... greets, *---(*)---**-- Francisco J. Montilla System Network administrator [EMAIL PROTECTED] irc: pukkaSevilleSpain INSFLUG (LiNUX) Coordinator: www.insflug.org - ftp.insflug.org - To stop getting this list send a message containing just the word "unsubscribe" to [EMAIL PROTECTED]
Re: MD: headphones impedance vs battery life / yet another MS722 review
On Thu, 23 Mar 2000, Ralph Smeets wrote: Hi! than a year...) The only portable that won't break and that is Sony is my CMC-Z1+ portable GSM phone... (of which most consumer magazines write you that the flip-down microphone will break very quickly...) BTW, I don't see http://home.worldonline.dk/~isl366/md/md.htm listed on the construction projects section on minidisc.org (although I'd swear I got that link from somewhere related to minidisc.org. It's a pretty good idea: recycle old GSM phones mics, have done something similar and it actually perform great for speech recordings! The only unexpected mis-feature I have found is the headphones sound; even when people said sharps sound greatly, i found the headphones to have a very harsh and unpleasant sound. Mids are unsanely boosted, and I (I know that is a very subjective area) don't like that at all. Is the only drawback I found on the sharp. I hate earbuds commonly found on other portables, so I don't mind too much, sony's would be worse. I tossed them away after 1 day. I replaced them with the 888's of Sony. Are they sold as a separate product? My impression is that Sony isn't very good with transducers... Here's were my question comes: Sharp headphones are 32 Ohm, I have an old walkman Aiwa headphones whose sound I like too much (in fact i tried lots of walkmans back then to find the better sounding ones). But they're 200 Ohm. My electronic knowledge have some dust on top, and I was wondering if the battery life will be shorter. My mind says that as impedance is higher, AC current *voltage* will actually be higher, and battery life will be shorter. Higher impedance: higher energy loss also... Well, U=I*R. U can't change!! So if you increase R, you decrease I. P=U*I, U doesn't change, but I get's smaller. Thus lower power consumption. Not with variable AC... Wait! I have remembered someone posted a site devoted to headphones (www.headwize.com)! Have just checked it and that's what they say (http://headwize.com/articles/hguide_art.htm#imped): --- Impedance: A measure of headphone load on an amplifier and stated in ohms. This factor is less important with solid state amplifiers, which can drive most headphone impedances, but can be significant with tube amplifiers, which are more sensitive to load impedances. Both consumer and professional headphones generally have impedances of less than 100 ohms. There are professional models rated at 200 ohms or more to minimize loading effects on distribution amplifiers which are often drive a whole bank of headphones at one time. Be aware that very high impedance phones may require more power - on the order of Watts instead of milliWatts. - mine aren't pro's, that's sure. But it seems I was on the right direction... I'd try to contact this guys to see if the can clear it. *---(*)---**-- Francisco J. Montilla System Network administrator [EMAIL PROTECTED] irc: pukkaSevilleSpain INSFLUG (LiNUX) Coordinator: www.insflug.org - ftp.insflug.org - To stop getting this list send a message containing just the word "unsubscribe" to [EMAIL PROTECTED]
RE: MD: headphones impedance vs battery life / yet another MS722 review
On Thu, 23 Mar 2000, Simon Barnes wrote: Hi, Francisco Jose Montilla wrote: (in reply to Jim Coon) That doesn't happen in the amp/transducer world, AFAIK. Here weren't working with DC, is variable Hz AC, and what Sorry Francisco, I'm having a lot of difficulty in understanding what you are trying to say. Jim's equation works with AC or DC. actually happens if my memory serves me well is that current voltage increases, and power decreases. (hence my doubt). What is "current voltage" ? Power = current * voltage. I meant (sorry, english isn't my native language) that what excite the headphone transducers is a variable (AC) electrical signal. I don't have the mathematical demonstration handy, but if you go in a little deeper, you'll notice that with higher loads (i.e. impedances) peak voltage rises. Those equations assume a constant (i.e. DC) voltage. That's why amps tend to produce better sound when using higher impedances. I'd like to see some evidence for this. I suspect the impedance only really affects the volume (More impedance = less power) Not exactly. Less intensity (the I in Power = Voltage * Intensity, dunno what are the variable names used in english). Higher impedance, less distortion (i.e. less intensity), more definition and sharper sound (more Voltage). My doubt is, if a 200 Ohm headphones with higher sensitivity than a 32 Ohm headphones (I mean, so that with a given volume setting, you perceive equal volume level pluging anyone) which will drain more battery. I'd bet the 200 Ohm, but am not sure... I'd try to reproduce the equation development to prove the voltage raise. greets, *---(*)---**-- Francisco J. Montilla System Network administrator [EMAIL PROTECTED] irc: pukkaSevilleSpain INSFLUG (LiNUX) Coordinator: www.insflug.org - ftp.insflug.org - To stop getting this list send a message containing just the word "unsubscribe" to [EMAIL PROTECTED]
Re: MD: headphones impedance vs battery life / yet another MS722 review
On Wed, 22 Mar 2000, J. Coon wrote: Hi, Here's were my question comes: Sharp headphones are 32 Ohm, I have an old walkman Aiwa headphones whose sound I like too much (in fact i tried lots of walkmans back then to find the better sounding ones). But they're 200 Ohm. My electronic knowledge have some dust on top, and I was wondering if the battery life will be shorter. My mind says that as impedance is higher, AC current *voltage* will actually be higher, and battery life will be shorter. Higher impedance: higher energy loss also... The basic equation is V = ZI where V is the voltage, Z is the impedance, and I is the current. Power = I^2 * Z Increasing the impedance will lower the current, decrease power consumption, and the volume. That doesn't happen in the amp/transducer world, AFAIK. Here weren't working with DC, is variable Hz AC, and what actually happens if my memory serves me well is that current voltage increases, and power decreases. (hence my doubt). That's why amps tend to produce better sound when using higher impedances. greets, *---(*)---**-- Francisco J. Montilla System Network administrator [EMAIL PROTECTED] irc: pukkaSevilleSpain INSFLUG (LiNUX) Coordinator: www.insflug.org - ftp.insflug.org - To stop getting this list send a message containing just the word "unsubscribe" to [EMAIL PROTECTED]
Re: MD: headphones impedance vs battery life / yet another MS722 review
[EMAIL PROTECTED] wrote: Hi! I'm the happy owner now of a Sharp MS-722. All other MD equipment I have is Sony. But this time I saw very clear that Sony wasn't competitive in this area; first, slot-in mechanism is far more robust than the clam-shell one, second battery life can't compare. I'm also very fond of Sony pointless attitude, marketing lies, and prepotent behaviour. I've got a 702... main reason was the problems I had with Sony portables (4 walkmans -tape... yuks-, 1 discman. All lived just a little bit longer than a year...) The only portable that won't break and that is Sony is my CMC-Z1+ portable GSM phone... (of which most consumer magazines write you that the flip-down microphone will break very quickly...) I read a lot of reviews of almost every portable unit I came across. People cleared out that the typical 7xx problems (TOC problems, etc) were only on earlier models. Got my 702 for two years now. No problems at all. Discs recorded on my MDS-S38 can be edited on my 702 and visa versa. Sharp has done it's marketing rigth. They've integrated all electronics into one chip (that's what you call LSI) and that cut's the cost. So the 7xx was cheaper than it's equivelent. Result: more units where demanded than Sharp could deliver. Thus a production increase, less quality control and Sharp found themself with a lot of units returned. Finaly they got their stuff back together and the quality is good again. (This is MY analysis of the UTOC problem after beening for more than two years on this list! It's like the Malysian build 510 of Sony!) The only unexpected mis-feature I have found is the headphones sound; even when people said sharps sound greatly, i found the headphones to have a very harsh and unpleasant sound. Mids are unsanely boosted, and I (I know that is a very subjective area) don't like that at all. Is the only drawback I found on the sharp. I hate earbuds commonly found on other portables, so I don't mind too much, sony's would be worse. I tossed them away after 1 day. I replaced them with the 888's of Sony. Here's were my question comes: Sharp headphones are 32 Ohm, I have an old walkman Aiwa headphones whose sound I like too much (in fact i tried lots of walkmans back then to find the better sounding ones). But they're 200 Ohm. My electronic knowledge have some dust on top, and I was wondering if the battery life will be shorter. My mind says that as impedance is higher, AC current *voltage* will actually be higher, and battery life will be shorter. Higher impedance: higher energy loss also... could anyone clear that? I'm lost... greets, Well, U=I*R. U can't change!! So if you increase R, you decrease I. P=U*I, U doesn't change, but I get's smaller. Thus lower power consumption. Cheers, Ralph -- === Ralph SmeetsFunctional Verification Centre Of Competence - CMG Voice: (+33) (0)4 76 58 44 46 STMicroelectronics Fax:(+33) (0)4 76 58 40 11 5, chem de la Dhuy Mobile: (+33) (0)6 82 66 62 70 38240 MEYLAN E-Mail: [EMAIL PROTECTED] FRANCE === "For many years, mankind lived just like the animals. And then something happened that unleashed the powers of our imagination: We learned to talk." -- Stephen Hawking, later used by Pink Floyd -- === - To stop getting this list send a message containing just the word "unsubscribe" to [EMAIL PROTECTED]
