I can think of some really really good reasons for using 2N2222, 2N3904, etc., etc. It is called my pocket book. They make these things by the billions. Lot of people make them and make lots of them. They are dirt cheap. Are they the best? Heck no, but for many applications, they absolutely work. And if they do the job, they will be the cheapest, easiest to obtain, etc.
Run away!
We used to have a cat here that would run for cover every time I played "Eat that Question", on "The Grand Wazoo" by Frank Zappa. We never could figure out why.
Keep that sense of humor!
Back to the point.......
No, I don't care for tubes, but some of my best friends make their living building tube gear.
I have a pair of RCA 810s in my stash. Never used. Carbon plates, grid and plate caps, ceramic socket. Used mainly for modulators in AM transmitters. Would make a nice grounded-grid linear amp for some ham radio types.
Any takers?
We used to have a cat here that would run for cover every time I played "Eat that Question", on "The Grand Wazoo" by Frank Zappa. We never could figure out why.
Keep that sense of humor!
Back to the point.......
No, I don't care for tubes, but some of my best friends make their living building tube gear.
I have a pair of RCA 810s in my stash. Never used. Carbon plates, grid and plate caps, ceramic socket. Used mainly for modulators in AM transmitters. Would make a nice grounded-grid linear amp for some ham radio types.
Any takers?
Re: "What is wrong with what story?"
my sort of humour also can be warped, mischievous, macabre, but in any case humour is not generally compatible , besides that irony requires the receiver brain to have its floating point unit running (let's hope anyone of us has one
), so i care to label my humour, just to protect my environment from me. Has served me well on the web where few have English as mother tongue or seen some Gerhard's or George W's or Aaron's last goofs in the news or the current soap.
You don't like flames? that's great, so do i. Was not sure, to be honest
1st, i am not an amp guru at all (i pester my friend Manfred who is a tube amp guru every other day with questions ), i come from mechanical design. Have a look on my website, it is terribly untidy but there are some nice pictures.
I am a listening animal rather than a measuring one, but i ensure by measuring i do not compare apples and oranges. Andi try to marry my measuring with my listening results to find out which measured parameter has which significance to the amp making music.
Linearity is a static thing, or atleast it is not easy to measure if linearity is maintained dynamically in the presence of more than one frequency.
Music OTOH requires a lot of frequencies to be handled simultaneously and each amplitude change to be processed properly.
To me, dynamic behaviour of an amp is one of the most vital things, correct, lifelike dynamic behaviour, to be particular.
One thing i learned from Manfred: hook a headphone amp with differential AC inputs, high commonmode rejection and adjustable gain to B+ and GND of your amp's PS and let the amp under test play music into an appropriate load. And then listen to the music on the B+ ! Provided enough gain, there always is music. If the music is sounding distorted (the PS then facing a complex load and not being able to handle it), the amp is crap and will sound like crap. Dynamics are wrong then, too.
A very important thing, for tube amps more an issue than for SS amps, is what Allen Wright calls downward dynamic range and some other folks descibe it as blackness of background from the listening point of view. Or should i call it dynamic signal2noise ratio?
An amp should have enough headroom to handle the required signals with ease. Being linear but clip hard 1 W or 1 V above the specified rating is a no show to me.
An amp can have all sorts of nastinesses not or not easily measurable but audible in a way they prevent the listener from enjoying his music, or worse, make the listener escape. Magnetic resistors and capacitors are a cause for such , TME, and that's why i was initially lurking the thread, seeking for other "coiincidences" . I have not yet fully understood how this works, but not understanding doesn't keep me from avoiding magnetic stuff AFAP.
And then there are those completely unmeasurable but clearly audible things like soundstaging, body, air between sound sources, 3D imaging from only 2 speakers. I am a hedonist, i want to feel the vibrating air column of Sonny Rollins' saxophone and to "visualize" the grand piano of Maurizio Pollini playing the 1st Chopin Ballade.
Distortion: a tricky issue. Special sorts of distortion like produced by single ended triode amplifers can sound utterly pleasant and seducing and very open and detailed, but tricky recordings demanding detail resolution just to hear through the material (Coltrane's "Ascension" e.g. or orchestral music from Arnold Schoenberg) show that a SET amp's subjectively experienced detail resolution can be quite a fake; that's why i tend to prefer 1st class PP tube amps.
Exceptions exist, of course, there are exceptionlly good SET amps. I have several vocal recordings demanding in speech understandability. If and to which degree i understand the sung text is a criterium quite easy to distinct for me. Those SETamps mentioned excel in that and i doubt my PP design will reach that level of speech understandability.
Although, if i increase the number of used interstage transformers, maybe!? ooops, they are reputed to be non-linear ..... but ..... hmmmhh ... i don't care they can sound gorgeous!!
I am VERY curious how Hugh Dean's AKSA amp will behave in those respects, ordered it yesterday. Rumours have it that the amp sounds tube-like while maintaining SS virtues.
Several friends of mine prefer their tube amp's sonic colorations to a neutral sound, they are aware of the lack of neutrality and use it to their taste. As we say over here, allowed is what pleases . I doubt this sort of coloration can be measured in a way that we can say "this peak in th FFT spectrum causes the oboe sound like an English horn or a clarinet"
And, to community, sorry for bothering you with tube %age of content in a SS thread
my sort of humour also can be warped, mischievous, macabre, but in any case humour is not generally compatible , besides that irony requires the receiver brain to have its floating point unit running (let's hope anyone of us has one
), so i care to label my humour, just to protect my environment from me. Has served me well on the web where few have English as mother tongue or seen some Gerhard's or George W's or Aaron's last goofs in the news or the current soap. You don't like flames? that's great, so do i. Was not sure, to be honest
1st, i am not an amp guru at all (i pester my friend Manfred who is a tube amp guru every other day with questions
), i come from mechanical design. Have a look on my website, it is terribly untidy but there are some nice pictures.I am a listening animal rather than a measuring one, but i ensure by measuring i do not compare apples and oranges. Andi try to marry my measuring with my listening results to find out which measured parameter has which significance to the amp making music.
Linearity is a static thing, or atleast it is not easy to measure if linearity is maintained dynamically in the presence of more than one frequency.
Music OTOH requires a lot of frequencies to be handled simultaneously and each amplitude change to be processed properly.
To me, dynamic behaviour of an amp is one of the most vital things, correct, lifelike dynamic behaviour, to be particular.
One thing i learned from Manfred: hook a headphone amp with differential AC inputs, high commonmode rejection and adjustable gain to B+ and GND of your amp's PS and let the amp under test play music into an appropriate load. And then listen to the music on the B+ ! Provided enough gain, there always is music. If the music is sounding distorted (the PS then facing a complex load and not being able to handle it), the amp is crap and will sound like crap. Dynamics are wrong then, too.
A very important thing, for tube amps more an issue than for SS amps, is what Allen Wright calls downward dynamic range and some other folks descibe it as blackness of background from the listening point of view. Or should i call it dynamic signal2noise ratio?
An amp should have enough headroom to handle the required signals with ease. Being linear but clip hard 1 W or 1 V above the specified rating is a no show to me.
An amp can have all sorts of nastinesses not or not easily measurable but audible in a way they prevent the listener from enjoying his music, or worse, make the listener escape. Magnetic resistors and capacitors are a cause for such , TME, and that's why i was initially lurking the thread, seeking for other "coiincidences"
. I have not yet fully understood how this works, but not understanding doesn't keep me from avoiding magnetic stuff AFAP.And then there are those completely unmeasurable but clearly audible things like soundstaging, body, air between sound sources, 3D imaging from only 2 speakers. I am a hedonist
, i want to feel the vibrating air column of Sonny Rollins' saxophone and to "visualize" the grand piano of Maurizio Pollini playing the 1st Chopin Ballade.Distortion: a tricky issue. Special sorts of distortion like produced by single ended triode amplifers can sound utterly pleasant and seducing and very open and detailed, but tricky recordings demanding detail resolution just to hear through the material (Coltrane's "Ascension" e.g. or orchestral music from Arnold Schoenberg) show that a SET amp's subjectively experienced detail resolution can be quite a fake; that's why i tend to prefer 1st class PP tube amps.
Exceptions exist, of course, there are exceptionlly good SET amps. I have several vocal recordings demanding in speech understandability. If and to which degree i understand the sung text is a criterium quite easy to distinct for me. Those SETamps mentioned excel in that and i doubt my PP design will reach that level of speech understandability.
Although, if i increase the number of used interstage transformers, maybe!?
ooops, they are reputed to be non-linear ..... but ..... hmmmhh ... i don't care they can sound gorgeous!!I am VERY curious how Hugh Dean's AKSA amp will behave in those respects, ordered it yesterday. Rumours have it that the amp sounds tube-like
while maintaining SS virtues.Several friends of mine prefer their tube amp's sonic colorations to a neutral sound, they are aware of the lack of neutrality and use it to their taste. As we say over here, allowed is what pleases
. I doubt this sort of coloration can be measured in a way that we can say "this peak in th FFT spectrum causes the oboe sound like an English horn or a clarinet"And, to community, sorry for bothering you with tube %age of content in a SS thread
Hey Jocko, YOU SUCK!
Just kidding- just my sense of humor, get it?
Well, anyway... You jumped all over my use of one of these antiquated transistors in my post on a current sourced zen balanced line stage. If you had taken the time to even read through the previous posts, you would have seen that it was only used in the schem. because it was one of the models in my freeware software. The circuit was put together just to learn and see what could be done, and to stimulate conversation.
So, what's my point here? Just that this forum has been a place where people with less experience (such a myself) can go to learn and talk about circuit theory. Why the burden of policing the DIY community for part correctness has been placed on you, I don't know. Maybe it's some kind of curse that falls on the the few all-knowing transistor gurus of the electrical world. Who the heck knows! Anyway, I appreciate the info, but you can shove the attitude (I assume you know where, or are you not as adept with biology as you are with transistors?)
Steve G.
Just kidding- just my sense of humor, get it?
Well, anyway... You jumped all over my use of one of these antiquated transistors in my post on a current sourced zen balanced line stage. If you had taken the time to even read through the previous posts, you would have seen that it was only used in the schem. because it was one of the models in my freeware software. The circuit was put together just to learn and see what could be done, and to stimulate conversation.
So, what's my point here? Just that this forum has been a place where people with less experience (such a myself) can go to learn and talk about circuit theory. Why the burden of policing the DIY community for part correctness has been placed on you, I don't know. Maybe it's some kind of curse that falls on the the few all-knowing transistor gurus of the electrical world. Who the heck knows! Anyway, I appreciate the info, but you can shove the attitude (I assume you know where, or are you not as adept with biology as you are with transistors?)
Steve G.
Signoro Dice:
There is nothing for me to disagree with, and much to recommend. Just because some of it came from tube design does not matter. The principles are the same. Only the topologies have been changed to protect the innocent [joke]. (You didn't really think I could go far without at least one, did you?) You and your friend are definitely on the right track.
I use a real-time analyzer to look at the modualtion on the rails. Gives me more insight as to what is going on. But sometimes I do take the output and listen to it. Yes, I measure stuff to death, but only to understand what is happening and why. Measuring for the sake of "well, this number better be such-and-such or this thing will never sound right" is fruitless. Measurements are a tool, not the goal.
I have to say that I am constantly amazed by how well some many non-Americans can converse in our bastardized English. Makes it too easy to forget that they are not all of us are. My Italian is terrible, and what little I know is......well........something we can't use here!
Back to linearity:
I was only refering to the device itself. I don't see the sense in using a lousy part, that can not be helped by all the feedback in the world when there are better parts available. Parts that do not cost much more than generic ones. Yes, I started out picking parts out of someone elses scrapheap. If that is all you can afford, well..........fine. But buying heat sinks and filter caps for your next amp project will be a tall mountain to climb.
So for all of you in the USA:
Digi-Key
MCM
They sell all manner of parts, relatively cheap. Since you can afford to buy a computer, be online, figure out how to participate in this forum, then it would seem logical that you can order a 2SC2240 online from MCM instead of some ancient part. Try it sometime.
Signoro Giacouomo
There is nothing for me to disagree with, and much to recommend. Just because some of it came from tube design does not matter. The principles are the same. Only the topologies have been changed to protect the innocent [joke]. (You didn't really think I could go far without at least one, did you?) You and your friend are definitely on the right track.
I use a real-time analyzer to look at the modualtion on the rails. Gives me more insight as to what is going on. But sometimes I do take the output and listen to it. Yes, I measure stuff to death, but only to understand what is happening and why. Measuring for the sake of "well, this number better be such-and-such or this thing will never sound right" is fruitless. Measurements are a tool, not the goal.
I have to say that I am constantly amazed by how well some many non-Americans can converse in our bastardized English. Makes it too easy to forget that they are not all of us are. My Italian is terrible, and what little I know is......well........something we can't use here!
Back to linearity:
I was only refering to the device itself. I don't see the sense in using a lousy part, that can not be helped by all the feedback in the world when there are better parts available. Parts that do not cost much more than generic ones. Yes, I started out picking parts out of someone elses scrapheap. If that is all you can afford, well..........fine. But buying heat sinks and filter caps for your next amp project will be a tall mountain to climb.
So for all of you in the USA:
Digi-Key
MCM
They sell all manner of parts, relatively cheap. Since you can afford to buy a computer, be online, figure out how to participate in this forum, then it would seem logical that you can order a 2SC2240 online from MCM instead of some ancient part. Try it sometime.
Signoro Giacouomo
Jocko,
irreverent, with a passion for DIY audio, funny username (maybe one day I will disclose what mine means), solid-state tendencies, love for Japanese transistor...
if I didn't know better I'd say you sound like one of my alter ego s...
MY GOD HERR DOKTOR, I do have multiple personalities disorder!
Though I think I can account for most of my day today, I can't racall posting anything.
You are on the fast track of being ostracized by the some of the 'founding fathers' of this site.
Let the good times tRoll!
irreverent, with a passion for DIY audio, funny username (maybe one day I will disclose what mine means), solid-state tendencies, love for Japanese transistor...
if I didn't know better I'd say you sound like one of my alter ego s...
MY GOD HERR DOKTOR, I do have multiple personalities disorder!
Though I think I can account for most of my day today, I can't racall posting anything.
You are on the fast track of being ostracized by the some of the 'founding fathers' of this site.
Let the good times tRoll!
Irreverent? Who? Me?
Not at all [joke].
traderbam:
I used to work in the advanced technology lab of a major telecom company in the US. Then one day they decided that they really didn't need one anymore. (Some say it was a thinly veiled excuse to get rid of the company's biggest trouble maker. Guess who! [no joke.....especially to all of the other engineers thrown out too.] Careful.......there are more than one us here. Some of them like tubes, though.)
Anyway.....irreverent, probably, but always willing to help.
I answer all my email and help whomever asks. Except for the guy who asked what brand of tape should he use to record CDs with.
I have had people that I know nothing about, in places like the backwoods of South Africa, about ask me "Hey, I hear you may a have a copy of such-and-such book. Can you copy Chapter ## and send it to me?" The answer was yes on all counts. Did so at my expense, and was pleased to receive a postcard from some place in South Africa I still couldn't find on a map.
I once received a nice homemade gift from a guy in the Netherlands who needed some Sanken data sheets.
But I will settle for a simple "thanks", and the knowledge that someone out there actually was able to benefit from my expertise. And that they could proudly point to their system and proclaim "Hey, just try that with your Bose!"
Does that help answer your question?
subwo1:
I recently shoved a 24-bit Burr-Brown digital filter/DAC into an old Philips CD player. Parts were so small I needed a magnifier to build it. And we won't even duscuss how many times I burned my fingers.
Next one will be on a PCB. Won't be fun, but I hope to have less burns.
Roll Tide! [College football cheer]
Not at all [joke].
traderbam:
I used to work in the advanced technology lab of a major telecom company in the US. Then one day they decided that they really didn't need one anymore. (Some say it was a thinly veiled excuse to get rid of the company's biggest trouble maker. Guess who! [no joke.....especially to all of the other engineers thrown out too.] Careful.......there are more than one us here. Some of them like tubes, though.)
Anyway.....irreverent, probably, but always willing to help.
I answer all my email and help whomever asks. Except for the guy who asked what brand of tape should he use to record CDs with.
I have had people that I know nothing about, in places like the backwoods of South Africa, about ask me "Hey, I hear you may a have a copy of such-and-such book. Can you copy Chapter ## and send it to me?" The answer was yes on all counts. Did so at my expense, and was pleased to receive a postcard from some place in South Africa I still couldn't find on a map.
I once received a nice homemade gift from a guy in the Netherlands who needed some Sanken data sheets.
But I will settle for a simple "thanks", and the knowledge that someone out there actually was able to benefit from my expertise. And that they could proudly point to their system and proclaim "Hey, just try that with your Bose!"
Does that help answer your question?
subwo1:
I recently shoved a 24-bit Burr-Brown digital filter/DAC into an old Philips CD player. Parts were so small I needed a magnifier to build it. And we won't even duscuss how many times I burned my fingers.
Next one will be on a PCB. Won't be fun, but I hope to have less burns.
Roll Tide! [College football cheer]
hello Jocko,
i am living in Monaco di Bavaria, not the state Monaco on the Italian peninsula not that it matters much regarding distance, only pedants complain about that
Noone having gotten that far like us is innocent . Iron man Thomas Mayer feels quite comfortable with the voltages in his 211-driven 211 amp, 1200V= at the plate is still handlable, he thinks. Just not wise to be careless with 1200V. Real thin the air gets with this 4kV= SET amp a guy named Orin Block built (did i remember the name correctly?)
RRRight. Told you Manfred is a tube guru. Although i'afraid he will not like to read himself adressed as such. Suggestion: you build yourself a headphone amp as descibed and then marry what you see on your spectrum analyzer with what you hear with the headphone amp.
And come back with results
Any audible distortion spots a complex load behaviour where maybe a resistive should be.
Thank you for the implicite compliment.
My Italian too is terrible, close to being nonexistent. Having had Latin at school, this helps me a lot if i have to read Italian, but listening to an Italian, just forgetaboutit, they talk *speed-of-light* fast
But my German is fair to good, i guess.
Latin is a wonderful language to learn how a language works (or should i say "should work"). It is completly consistent and logical and has VERY few exceptions (exceptions are the PITA of every beginner). It is what Italian has developed from but today i guess it is closer to English as far as grammar is concerned.
Italians, please correct me if necessary .
English grammar is utterly powerful and effective when it comes to describing causal relations. English texts describing technology are atleast 35% shorter than a German text describing the same. Yet the English text is usually clearer and easier to understand.
English also is powered if not boosted by having a mighty vocabulary with mighty concepts. I have collected about 12 German words non-translatable to English because no concept exists there. Collecting English words non-translatable to German i have given up to collect, too many.
The human brain has to learn early (during childhood) how to learn languages and how a language works. Otherwise learning a foreign language as an adult person will be a very hard job. IMO, most English speaking countries which do not force their children to learn foreign languages do them no favour by this.
I wish this would be the case with vacuum tubes. Although there still are some nice unknown beauties out there not yet hunted by the crowd of tube collecting maniacs. The #46 tetrode e.g, it still is dirt cheap, one gets 2.5Watts out of a pair triode-wired, 2.5 Watts of sonic heaven.
It took me a hard and expensive learning curve to find out that from 2A3 single plate an ordinary guy like me will never get some decent matched pairs for a decent PP amp. Now i decided to sell the 7 perfect but unmatchable samples i got and forgetabout the 16 tubes i had to buy to get 7. Sooo pissed off! Learning fees.
But living in AD1-land, i was able to collect some AD1 (better equivalent of the mentioned 2A3) of a less sought-after hence cheaper brand and later to -- surprise, surprise -- find out that this brand has the nicest sonics of all AD1 avaialble. This is the crux with a zeroFB tube amp as with any simple topology: any component has its clearly audible sonic footprint. For an exotic beast like the AD1 with its exotic side contact base, even the pot sockets cost $$. And then there are input transformers, IS transformers, output transformers, plate chokes, grid chokes, huge foil caps having not much capacitance but lethal voltage ratings ....
be happy with your heatsinks, not a tall mountain to climb , a gentle hill maybe
Question: how would you substitute a power tube by one or more semiconductors (for testing and measuring purposes)? I want to have a "tube dummy" for checking that the amp is healthy and not killing tubes before i plug the $$$ AD1 in. I already tucked 4 unknown pentodes aside having the same 8 pin side contact base to slaugther the bases of.
In a Ratheon engineering data book i found a circuit of two N-channel J-Fets in series with the lower device's drain connected to the upper device's source and the lower device's source connected to the upper device's grid and serving as the "cathode", the lower device's gate serving as a "grid" and and upper device's drain serving as "plate". The data book claims this SSVTR circuit to be a pentode substitute but gives no hint how to dimension it to substitute a given tube. Those circuits must have been available as integrated or hybrid devices.
Do you know of triode substitutions or how to realize them? If not, a pentode substitution will do for testing.
i am living in Monaco di Bavaria, not the state Monaco on the Italian peninsula
not that it matters much regarding distance, only pedants complain about that Noone having gotten that far like us is innocent
. Iron man Thomas Mayer feels quite comfortable with the voltages in his 211-driven 211 amp, 1200V= at the plate is still handlable, he thinks. Just not wise to be careless with 1200V. Real thin the air gets with this 4kV= SET amp a guy named Orin Block built (did i remember the name correctly?)RRRight. Told you Manfred is a tube guru. Although i'afraid he will not like to read himself adressed as such. Suggestion: you build yourself a headphone amp as descibed and then marry what you see on your spectrum analyzer with what you hear with the headphone amp.
And come back with results
Any audible distortion spots a complex load behaviour where maybe a resistive should be.
Thank you for the implicite compliment.
My Italian too is terrible, close to being nonexistent. Having had Latin at school, this helps me a lot if i have to read Italian, but listening to an Italian, just forgetaboutit, they talk *speed-of-light* fast
But my German is fair to good, i guess.
Latin is a wonderful language to learn how a language works (or should i say "should work"). It is completly consistent and logical and has VERY few exceptions (exceptions are the PITA of every beginner). It is what Italian has developed from but today i guess it is closer to English as far as grammar is concerned.
Italians, please correct me if necessary
.English grammar is utterly powerful and effective when it comes to describing causal relations. English texts describing technology are atleast 35% shorter than a German text describing the same. Yet the English text is usually clearer and easier to understand.
English also is powered if not boosted by having a mighty vocabulary with mighty concepts. I have collected about 12 German words non-translatable to English because no concept exists there. Collecting English words non-translatable to German i have given up to collect, too many.
The human brain has to learn early (during childhood) how to learn languages and how a language works. Otherwise learning a foreign language as an adult person will be a very hard job. IMO, most English speaking countries which do not force their children to learn foreign languages do them no favour by this.
I wish this would be the case with vacuum tubes. Although there still are some nice unknown beauties out there not yet hunted by the crowd of tube collecting maniacs. The #46 tetrode e.g, it still is dirt cheap, one gets 2.5Watts out of a pair triode-wired, 2.5 Watts of sonic heaven.
It took me a hard and expensive learning curve to find out that from 2A3 single plate an ordinary guy like me will never get some decent matched pairs for a decent PP amp. Now i decided to sell the 7 perfect but unmatchable samples i got and forgetabout the 16 tubes i had to buy to get 7. Sooo pissed off! Learning fees.
But living in AD1-land, i was able to collect some AD1 (better equivalent of the mentioned 2A3) of a less sought-after hence cheaper brand and later to -- surprise, surprise -- find out that this brand has the nicest sonics of all AD1 avaialble. This is the crux with a zeroFB tube amp as with any simple topology: any component has its clearly audible sonic footprint. For an exotic beast like the AD1 with its exotic side contact base, even the pot sockets cost $$. And then there are input transformers, IS transformers, output transformers, plate chokes, grid chokes, huge foil caps having not much capacitance but lethal voltage ratings ....
be happy with your heatsinks, not a tall mountain to climb , a gentle hill maybe
Question: how would you substitute a power tube by one or more semiconductors (for testing and measuring purposes)? I want to have a "tube dummy" for checking that the amp is healthy and not killing tubes before i plug the $$$ AD1 in. I already tucked 4 unknown pentodes aside having the same 8 pin side contact base to slaugther the bases of.
In a Ratheon engineering data book i found a circuit of two N-channel J-Fets in series with the lower device's drain connected to the upper device's source and the lower device's source connected to the upper device's grid and serving as the "cathode", the lower device's gate serving as a "grid" and and upper device's drain serving as "plate". The data book claims this SSVTR circuit to be a pentode substitute but gives no hint how to dimension it to substitute a given tube. Those circuits must have been available as integrated or hybrid devices.
Do you know of triode substitutions or how to realize them? If not, a pentode substitution will do for testing.
SteveG:
Might be easier, and faster, for all of us if I emptied out my parts bin, and listed what was there. Acceptable ?
I notice in my MCM catalog that Motorola/ON 2N2222s are more expensive than what I use! The 2N3904s are cheap though, but big deal. Pennies difference.
I know more than one high-end manufacturer that buys ALL their parts from MCM and Digi-Key. Availablity is the name of the game, and they have mnost every thing you should need. Except big heat sinks. (I used to buy extrusions direct from Thermalloy, and machine them at work. No idea what I will do now.)
dice45:
I would hope your Italian is worse than mine [joke]. My grandparents came from there about a century ago. But I don't speak it. Rather hard to learn, but I occasionally give it a go. Keeps me form going nuts after working with those SMT digital filters.
I suspect that one reason us "ugly Americans" have little skill in foreign languages, and anything else foreign, might have something to do with my parents' generation (the WWII crowd) being embarrassed that their parents were [dirty, smelly] emigrants that weren't welcomed with open arms in the flood of immigrants in the late 19th and early 20th centuries.
Enough of Sociology 101.
What you are describing is the concept behind dual-gate MOSFETs, something RCA did a lot of in the late 60s/ early 70s. I have books on that, but they are packed away right now. The transfer curves roughly followed a pentode, but they were pretty much useless, except as a front-end transistor in receiver circuitry. The used the second gate for AGC control.
Back in the "good old days", designers were struggling with ways to make SS circuits act just like tube circuits. Tubes were all they knew, and our wonderful education system wasn't much help in moving students foward. The texts of the time droned on and on about "hole" and electron movement, the valence bond, and garbage like that. Things that did nothing to enable you to build a single-transistor amp. So they constantly came up with circuits like you found. It was all very empirical, and largely due to their heads being stuck in the wrong place. (Another reason why early SS amps had interstage coupling and output transformers.)
I imagine some SPICE devotee can model it, but trial and error might be your best bet. At least you have access to some good, rugged MOSFETs where you are. Biggest problem I suspect will be the bias voltages needed will not be compatible. You are definitely on you own here!
Might be easier, and faster, for all of us if I emptied out my parts bin, and listed what was there. Acceptable ?
I notice in my MCM catalog that Motorola/ON 2N2222s are more expensive than what I use! The 2N3904s are cheap though, but big deal. Pennies difference.
I know more than one high-end manufacturer that buys ALL their parts from MCM and Digi-Key. Availablity is the name of the game, and they have mnost every thing you should need. Except big heat sinks. (I used to buy extrusions direct from Thermalloy, and machine them at work. No idea what I will do now.)
dice45:
I would hope your Italian is worse than mine [joke]. My grandparents came from there about a century ago. But I don't speak it. Rather hard to learn, but I occasionally give it a go. Keeps me form going nuts after working with those SMT digital filters.
I suspect that one reason us "ugly Americans" have little skill in foreign languages, and anything else foreign, might have something to do with my parents' generation (the WWII crowd) being embarrassed that their parents were [dirty, smelly] emigrants that weren't welcomed with open arms in the flood of immigrants in the late 19th and early 20th centuries.
Enough of Sociology 101.
What you are describing is the concept behind dual-gate MOSFETs, something RCA did a lot of in the late 60s/ early 70s. I have books on that, but they are packed away right now. The transfer curves roughly followed a pentode, but they were pretty much useless, except as a front-end transistor in receiver circuitry. The used the second gate for AGC control.
Back in the "good old days", designers were struggling with ways to make SS circuits act just like tube circuits. Tubes were all they knew, and our wonderful education system wasn't much help in moving students foward. The texts of the time droned on and on about "hole" and electron movement, the valence bond, and garbage like that. Things that did nothing to enable you to build a single-transistor amp. So they constantly came up with circuits like you found. It was all very empirical, and largely due to their heads being stuck in the wrong place. (Another reason why early SS amps had interstage coupling and output transformers.)
I imagine some SPICE devotee can model it, but trial and error might be your best bet. At least you have access to some good, rugged MOSFETs where you are. Biggest problem I suspect will be the bias voltages needed will not be compatible. You are definitely on you own here!
Favorite Transistors
My favorites:
Fet
2SK389
2SJ109
2SK170
2SJ74
2SK147
2SJ72
IR610
IRF9610
IRF150
ZVN3310
ZVP3310
bipolar
2SA970
2SC2240
2SA872
2SC17775
ZTX450
DEVO song
http://www.alsongs.com/browse/sourcesong51.htm
H.H.
My favorites:
Fet
2SK389
2SJ109
2SK170
2SJ74
2SK147
2SJ72
IR610
IRF9610
IRF150
ZVN3310
ZVP3310
bipolar
2SA970
2SC2240
2SA872
2SC17775
ZTX450
DEVO song
http://www.alsongs.com/browse/sourcesong51.htm
H.H.
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