Tube vs. Solid State Preamp
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From: Phil Hobbs on 1 Apr 2010 09:32 On 4/1/2010 4:33 AM, Adrian Tuddenham wrote: > George Jefferson<George(a)Jefferson.com> wrote: > >> "Adrian Tuddenham"<adrian(a)poppyrecords.invalid.invalid> wrote in message >> news:1jg8ngr.1g7xp3le9s3eyN%adrian(a)poppyrecords.invalid.invalid... >>> �Leo�<leo2100(a)gmail.com> wrote: >>> >>> [...] >>>> This happens so because the transistors are more ideal amplifying >>>> devices than tubes are...so the signal that comes in is the one that >>>> comes out, with as little distortion as possible. Since the tubes are >>>> less ideal, they add different components to the original signal... >>>> this have turned out to be more pleasant to the human ear. >>> >>> I would disagree with this statement. The curvature of the transistor >>> characteristic is much sharper than many valves and the harmonics >>> generated are much nastier-sounding. Valve stages with no feedback are >>> quite common and the distortion they generate with moderate signal >>> voltages is quite tolerable, but transistor stages with no feedback are >>> virtually unusable for audio. >>> >>> Transistor amplifiers can contain more devices in less space for the >>> same price and that allows them to employ much more feedback than valve >>> ones, not just overall but within individual stages; this is what gives >>> the improvement in overall linearity which you have erroneously >>> attributed to the devices themselves. The down side is that when they >>> eventually overload, they do so much more sharply and generate higher >>> harmonics, which sound vile. >> > [...] > >> A tube circuit can never beat a properly designed solid state circuit for >> distortion free sound. > > The big difference is that those valve circuits generally achieve their > performance with far fewer active devices and far less feedback, which > was the point I was trying to make. Valves are not 'less ideal' as > amplifying devices; you can achieve good results with fewer of them than > if you tried to achieve the same thing with transistors. > > If you pile more and more transistors into a circuit with more and more > feedback you will get a lower THD figure than with any practical valve > amplifier. That is not because of the inherent 'betterness' of the > transistors themselves but because they are cheap enough and small > enough to allow circuit topologies that wouldn't be worthwhile to > produce with valves.. > You do need an alternate universe to allow complementary symmetry outputs, though. ;) Cheers Phil Hobbs -- Dr Philip C D Hobbs Principal ElectroOptical Innovations 55 Orchard Rd Briarcliff Manor NY 10510 845-480-2058 hobbs at electrooptical dot net http://electrooptical.net
From: Adrian Tuddenham on 1 Apr 2010 10:09 Phil Hobbs <pcdhSpamMeSenseless(a)electrooptical.net> wrote: > On 4/1/2010 4:33 AM, Adrian Tuddenham wrote: > > George Jefferson<George(a)Jefferson.com> wrote: > > > >> "Adrian Tuddenham"<adrian(a)poppyrecords.invalid.invalid> wrote in message > >> news:1jg8ngr.1g7xp3le9s3eyN%adrian(a)poppyrecords.invalid.invalid... > >>> �Leo�<leo2100(a)gmail.com> wrote: > >>> > >>> [...] > >>>> This happens so because the transistors are more ideal amplifying > >>>> devices than tubes are...so the signal that comes in is the one that > >>>> comes out, with as little distortion as possible. Since the tubes are > >>>> less ideal, they add different components to the original signal... > >>>> this have turned out to be more pleasant to the human ear. > >>> > >>> I would disagree with this statement. The curvature of the transistor > >>> characteristic is much sharper than many valves and the harmonics > >>> generated are much nastier-sounding. Valve stages with no feedback are > >>> quite common and the distortion they generate with moderate signal > >>> voltages is quite tolerable, but transistor stages with no feedback are > >>> virtually unusable for audio. > >>> > >>> Transistor amplifiers can contain more devices in less space for the > >>> same price and that allows them to employ much more feedback than valve > >>> ones, not just overall but within individual stages; this is what gives > >>> the improvement in overall linearity which you have erroneously > >>> attributed to the devices themselves. The down side is that when they > >>> eventually overload, they do so much more sharply and generate higher > >>> harmonics, which sound vile. > >> > > [...] > > > >> A tube circuit can never beat a properly designed solid state circuit for > >> distortion free sound. > > > > The big difference is that those valve circuits generally achieve their > > performance with far fewer active devices and far less feedback, which > > was the point I was trying to make. Valves are not 'less ideal' as > > amplifying devices; you can achieve good results with fewer of them than > > if you tried to achieve the same thing with transistors. > > > > If you pile more and more transistors into a circuit with more and more > > feedback you will get a lower THD figure than with any practical valve > > amplifier. That is not because of the inherent 'betterness' of the > > transistors themselves but because they are cheap enough and small > > enough to allow circuit topologies that wouldn't be worthwhile to > > produce with valves.. > > > > You do need an alternate universe to allow complementary symmetry > outputs, though. ;) ....I had wonderd if a device using positive ions might work... -- ~ Adrian Tuddenham ~ (Remove the ".invalid"s and add ".co.uk" to reply) www.poppyrecords.co.uk
From: Phil Hobbs on 1 Apr 2010 10:14 On 4/1/2010 10:09 AM, Adrian Tuddenham wrote: > Phil Hobbs<pcdhSpamMeSenseless(a)electrooptical.net> wrote: > >> On 4/1/2010 4:33 AM, Adrian Tuddenham wrote: >>> George Jefferson<George(a)Jefferson.com> wrote: >>> >>>> "Adrian Tuddenham"<adrian(a)poppyrecords.invalid.invalid> wrote in message >>>> news:1jg8ngr.1g7xp3le9s3eyN%adrian(a)poppyrecords.invalid.invalid... >>>>> �Leo�<leo2100(a)gmail.com> wrote: >>>>> >>>>> [...] >>>>>> This happens so because the transistors are more ideal amplifying >>>>>> devices than tubes are...so the signal that comes in is the one that >>>>>> comes out, with as little distortion as possible. Since the tubes are >>>>>> less ideal, they add different components to the original signal... >>>>>> this have turned out to be more pleasant to the human ear. >>>>> >>>>> I would disagree with this statement. The curvature of the transistor >>>>> characteristic is much sharper than many valves and the harmonics >>>>> generated are much nastier-sounding. Valve stages with no feedback are >>>>> quite common and the distortion they generate with moderate signal >>>>> voltages is quite tolerable, but transistor stages with no feedback are >>>>> virtually unusable for audio. >>>>> >>>>> Transistor amplifiers can contain more devices in less space for the >>>>> same price and that allows them to employ much more feedback than valve >>>>> ones, not just overall but within individual stages; this is what gives >>>>> the improvement in overall linearity which you have erroneously >>>>> attributed to the devices themselves. The down side is that when they >>>>> eventually overload, they do so much more sharply and generate higher >>>>> harmonics, which sound vile. >>>> >>> [...] >>> >>>> A tube circuit can never beat a properly designed solid state circuit for >>>> distortion free sound. >>> >>> The big difference is that those valve circuits generally achieve their >>> performance with far fewer active devices and far less feedback, which >>> was the point I was trying to make. Valves are not 'less ideal' as >>> amplifying devices; you can achieve good results with fewer of them than >>> if you tried to achieve the same thing with transistors. >>> >>> If you pile more and more transistors into a circuit with more and more >>> feedback you will get a lower THD figure than with any practical valve >>> amplifier. That is not because of the inherent 'betterness' of the >>> transistors themselves but because they are cheap enough and small >>> enough to allow circuit topologies that wouldn't be worthwhile to >>> produce with valves.. >>> >> >> You do need an alternate universe to allow complementary symmetry >> outputs, though. ;) > > ....I had wonderd if a device using positive ions might work... > > The mass ratio between even a proton and an electron is about 1800:1, which makes holes in silicon look very speedy! Cheers Phil Hobbs -- Dr Philip C D Hobbs Principal ElectroOptical Innovations 55 Orchard Rd Briarcliff Manor NY 10510 845-480-2058 hobbs at electrooptical dot net http://electrooptical.net
From: Adrian Tuddenham on 1 Apr 2010 10:46 Phil Hobbs <pcdhSpamMeSenseless(a)electrooptical.net> wrote: > On 4/1/2010 10:09 AM, Adrian Tuddenham wrote: > > Phil Hobbs<pcdhSpamMeSenseless(a)electrooptical.net> wrote: > > > >> On 4/1/2010 4:33 AM, Adrian Tuddenham wrote: > >>> George Jefferson<George(a)Jefferson.com> wrote: > >>> > >>>> "Adrian Tuddenham"<adrian(a)poppyrecords.invalid.invalid> >>>>wrote in message > >>>> news:1jg8ngr.1g7xp3le9s3eyN%adrian(a)poppyrecords.invalid.invalid... > >>>>> �Leo�<leo2100(a)gmail.com> wrote: > >>>>> > >>>>> [...] > >>>>>> This happens so because the transistors are more ideal amplifying > >>>>>> devices than tubes are...so the signal that comes in is the one that > >>>>>> comes out, with as little distortion as possible. Since the tubes are > >>>>>> less ideal, they add different components to the original signal... > >>>>>> this have turned out to be more pleasant to the human ear. > >>>>> > >>>>> I would disagree with this statement. The curvature of the transistor > >>>>> characteristic is much sharper than many valves and the harmonics > >>>>> generated are much nastier-sounding. Valve stages with no feedback are > >>>>> quite common and the distortion they generate with moderate signal > >>>>> voltages is quite tolerable, but transistor stages with no feedback are > >>>>> virtually unusable for audio. > >>>>> > >>>>> Transistor amplifiers can contain more devices in less space for the > >>>>> same price and that allows them to employ much more feedback than valve > >>>>> ones, not just overall but within individual stages; this is what gives > >>>>> the improvement in overall linearity which you have erroneously > >>>>> attributed to the devices themselves. The down side is that when they > >>>>> eventually overload, they do so much more sharply and generate higher > >>>>> harmonics, which sound vile. > >>>> > >>> [...] > >>> > >>>> A tube circuit can never beat a properly designed solid state circuit for > >>>> distortion free sound. > >>> > >>> The big difference is that those valve circuits generally achieve their > >>> performance with far fewer active devices and far less feedback, which > >>> was the point I was trying to make. Valves are not 'less ideal' as > >>> amplifying devices; you can achieve good results with fewer of them than > >>> if you tried to achieve the same thing with transistors. > >>> > >>> If you pile more and more transistors into a circuit with more and more > >>> feedback you will get a lower THD figure than with any practical valve > >>> amplifier. That is not because of the inherent 'betterness' of the > >>> transistors themselves but because they are cheap enough and small > >>> enough to allow circuit topologies that wouldn't be worthwhile to > >>> produce with valves.. > >>> > >> > >> You do need an alternate universe to allow complementary symmetry > >> outputs, though. ;) > > > > ....I had wonderd if a device using positive ions might work... > > > > > > The mass ratio between even a proton and an electron is about 1800:1, > which makes holes in silicon look very speedy! You might cover the development costs of the new device if you sold it to audiophools as part of an all-valve amplifier for driving sub-woofers. The speed wouldn't matter very much as long as the glow moved in time to the music so they could see they were getting better sound. -- ~ Adrian Tuddenham ~ (Remove the ".invalid"s and add ".co.uk" to reply) www.poppyrecords.co.uk
From: John Larkin on 1 Apr 2010 11:26
On Wed, 31 Mar 2010 18:04:35 -0700, Joerg <invalid(a)invalid.invalid> wrote: >John Larkin wrote: >> On Wed, 31 Mar 2010 13:36:54 -0800, Robert Baer >> <robertbaer(a)localnet.com> wrote: >> >>> John Larkin wrote: >>>> On Tue, 30 Mar 2010 08:56:08 -0700 (PDT), Chris >>>> <christopher.maness(a)gmail.com> wrote: >>>> >>>>> With today's modern technology, is it possible to make a solid state >>>>> preamp that is as quiet as a good tube pre? >>>>> >>>>> I am thinking about building a preamp. >>>>> >>>>> Thanks, >>>>> Chris >>>> Tubes are noisy. >>>> >>>> John >>>> >>> Try running a 12AU7 with a plate supply of 45V and grid-to-cathode >>> voltage of about -1.5V (tweaked for zero grid current). >> >> What are the voltage and current noise densities? >> > >Don't know about the 12AU7 but the 7788 or in civilian E810F could get >to around 1nv/rtHz when rigged as a triode (it wants to be a pentode in >normal life). That's impressive. I wonder what the grid current is like. Roughly 100 nA maybe. Since grid current consists of two mechanisms, which can sometimes cancel at some negative grid voltage, I'd expect it to have above, maybe way above, shot noise. But I haven't worried much about toobs, at least amplifier toobs, in a long time. I'll probably stick with BF862s for the few low-noise things I'm doing now. One of those will operate in a vacuum far better than any toob can maintain! John |