Why ?
Dec 14, 2006 4:38:40 GMT
Post by rickcr42 on Dec 14, 2006 4:38:40 GMT
Maybe I am missing something but would someone please explain to me the purpose of having a tube stage AND an op amp in the same headphone amp ?
Not being a wise guy here but I am truly baffled on this one.I can not in fact think of a single good reason to use a tube fronting an op amp other than to say "tube inside" (or in most cases considering the windows or tube sticking out "lookit me glow") just to do it not for any valid audio electronics reason.
Examples :
first up is a three stage amp that I dunno,seems to have one stage too many
rockgrotto.proboards39.com/index.cgi?board=b&action=display&thread=1165014166
next up is a tube gain stage mated to a unity gain op amp (used as a buffer) which begs the question WTF is the tube for if you already have a device capable of producing BOTH the voltage gain and the current drive in a single device with a simple feedback loop change rather than using an entire extra stage that does no more than complicate the simple ?
www.audioasylum.com/scripts/t.pl?f=digital&m=125137
headwize.com/projects/cavalli2_prj.php
I can fully understand triode voltage gain/solid state current gain hybrids but NOT an Op-Amp following a triode which is in turn followed by a buffer when it seems you could TOTALLY lose the tube and still have the exact same functionality or have a triode gain stage fronting a wideband op-amp fully capable of producing both voltage and current gain without any "helper" circuits so what's the deal here ? Pretty lights ? Piss poor sonics needing to be tamed by a piss poor "warm" triode stage ? FOTM ? (flavore of the month
Am I the one off base on this one ??
I truly don't understand the function in the context of the above applications unless for as visual or aural FX because to me personally it makes zero sense to use a high gain closed loop device (100% feedback !) on the output of a triode when a simple open loop buffer would do the job better and in the case of the Little DOT three stages with one being no more than a "night light" as far as I can tell is just goofy..............
"hey i know gang.Lets do something with a TUBE just because we can"
ummm....OK.....
Chillin' in CT
Not being a wise guy here but I am truly baffled on this one.I can not in fact think of a single good reason to use a tube fronting an op amp other than to say "tube inside" (or in most cases considering the windows or tube sticking out "lookit me glow") just to do it not for any valid audio electronics reason.
Examples :
first up is a three stage amp that I dunno,seems to have one stage too many
rockgrotto.proboards39.com/index.cgi?board=b&action=display&thread=1165014166
next up is a tube gain stage mated to a unity gain op amp (used as a buffer) which begs the question WTF is the tube for if you already have a device capable of producing BOTH the voltage gain and the current drive in a single device with a simple feedback loop change rather than using an entire extra stage that does no more than complicate the simple ?
www.audioasylum.com/scripts/t.pl?f=digital&m=125137
headwize.com/projects/cavalli2_prj.php
I can fully understand triode voltage gain/solid state current gain hybrids but NOT an Op-Amp following a triode which is in turn followed by a buffer when it seems you could TOTALLY lose the tube and still have the exact same functionality or have a triode gain stage fronting a wideband op-amp fully capable of producing both voltage and current gain without any "helper" circuits so what's the deal here ? Pretty lights ? Piss poor sonics needing to be tamed by a piss poor "warm" triode stage ? FOTM ? (flavore of the month
Am I the one off base on this one ??
I truly don't understand the function in the context of the above applications unless for as visual or aural FX because to me personally it makes zero sense to use a high gain closed loop device (100% feedback !) on the output of a triode when a simple open loop buffer would do the job better and in the case of the Little DOT three stages with one being no more than a "night light" as far as I can tell is just goofy..............
"hey i know gang.Lets do something with a TUBE just because we can"
ummm....OK.....
Chillin' in CT