<jfie...@austininstruments.com> wrote: >On Thu, 03 Mar 2011 07:15:31 -0800, John Larkin ><jjlar...@highNOTlandTHIStechnologyPART.com> wrote:
>>On Thu, 03 Mar 2011 06:39:42 -0600, John Fields >><jfie...@austininstruments.com> wrote:
>>>--- >>>Actually, what you like to call "clucking and pecking" is nothing more >>>than criticism, but you try to cast it in a light which mitigates its >>>validity by besmirching the veracity of the criticizer.
>>All you ever criticize is my personality.
>--- >Not true.
>I usually criticize some aspect of your work which is flawed and then, >when you refuse to acknowledge the flaw, criticize that part of your >personality which is scared to death to admit to error.
>Remember the relays with infinite gain, for example? >---
>>You said nothing about this circuit.
>--- >Nor will I, since I don't care anything about it. >---
>>On the rare occasion when you do post a circuit, or critize >>one, you're usually wrong the first few times.
>--- >Even if that were true, which it isn't, at least I admit to error and >fix the problem, whereas you try to fix the blame.
>In truth, I post and criticize circuits quite often, and on a rare >occasion I'll be wrong with one or the other or both.
>Of course my record pales next to yours since you never make mistakes, >eh? >---
>>Old hen.
>>John
>--- >Ah, yes, the contribution of the banty rooster is so much greater than >that of the hens since without his crowing the sun couldn't rise.
>--- >JF
That's funny.
It brought up a memory of work today, we saw that weird food guy and some "chef" somewhere was frying up a whole pan full of rooster mop tops (the little frilly things on their heads).
> >> >> >> >>Audio tends to be nonsense, but at least the audio guys have fun > >> >> >> >>playing with circuits, whether they make a lot of sense or not.
> >> >> >> >>John
> >> >> >> >--- > >> >> >> >Even though you scorn and ridicule audio, there's nothing wrong with > >> >> >> >anyone seeking perfection there, just as there's nothing wrong with > >> >> >> >your search for perfection in the genre which pleases _you_ to pursue. > >> >> >> >So, speaking of fun, why don't you do a complete design and assign > >> >> >> >values to the circuit components and identify the semiconductors?
> >> >> >> You're not playing the game. You are sitting in the henhouse, clucking > >> >> >> about the people who do.
> >> >> >He's not playing your game, which involves telling John Larkin how > >> >> >cute his circuits are.
> >> >> He's not designing circuits, which is what this newsgroup is about.
> >> >> You aren't either. Both of you start to cluck and peck when people do > >> >> design circuits. No surprise.
> >> >> >> >Or is that legwork _we're_ supposed to do in order to flesh out your > >> >> >> >divine revelation?
> >> >> >> Chickenleg work!
> >> >> >It's half the story - a few component values make it a lot easier to > >> >> >work out what a circuit is doing.
> >> >> You can't look at a circuit this simple and see what it's doing? OK, > >> >> no surprise.
> >> >Without the component values, it does take a moment's thought, which > >> >is wasted on a bizarre (if simple) circuit with few potential > >> >applications.
> >> Millions of the "GE" circuit have been used for decades. The mosfet > >> hybrid is a very reasonable headphone amp.
> >> Post a circuit, doofus. You've forgotten how to do anything but whine.
> >You are the one who complains all the time. You may have personal > >preferences about the nature of the threads that get started here, and > >the responses that get posted, but they are only of interest to you.
> >You are welcome to demonstrate your preferences by choosing to get > >involved with particular threads and in your particular reactions to > >other responses, but your whining about the nature of those responses > >doesn't make the group a more attractive or rewarding environment.
> >In the meantime, I'll post a circuit when I've got a circuit worth > >posting. Posting a example - without comnponent values - of a circuit > >that has been used in millions, for decades, doesn't strike me as a > >profitable use of bandwidth, but that is a personal preference.
> What I did was spin a signal-level bipolar circuit into a > bipolar-mosfet power amp of similar topology.
> The resulting dynamics is very interesting. Well, not to you.
I haven't got a relevant application at the moment, so of course it isn't interesting to me.
The universe is full of potentially interesting things. Some of them are also interesting to other people. If you weren't quite so self- obsessed, you might not expect everybody else to be interested in what happens to have caught your fancy today.
Along with the hundred other things a boy can do with a 555.
So someone has used a 555 to make a less than impressive radio- receiver. Why would anybody be interested, if they hadn't fixated on the device early in their career and never moved on?
On Mar 3, 6:27 pm, ChrisQ <m...@devnull.com> wrote:
> Bitrex wrote: > > I'm foggy on how such a cascode reduces noise - improved distortion, > > bandwidth, and PSRR I can understand but how does two transistors end up > > less noisy than one? I know with tubes a cascode was considered a low > > noise alternative since two triodes in cascode would have lower noise > > than a single pentode, with similar gain.
> It doesn't. For lowest noise figure at the input, you use a single > silicon pnp transistor, which has a lower base resistance than npn. rb > is effectively in series with the source. Follow that with an op amp > typically. You can also parallel input transistors, but the advantage > soon drops off.
It's the base resistance that's important? Not that I disagree. I've been testing these 'low noise' power supplies with cap multipliers on the output and the negative supply with the pnp always seems to have a bit less noise.
> I'll see if I can find the circuit for a 12 channel mixer input stage > that I designed around 1974. The noise figure related to a 600 ohm > source was around 3 or 4 dB, from what I remember, with thd < 0.05% . > Noise figure is quite important for pa applications, where you also have > a lot of power gain from input to speakers...
> >> >> >> >>Audio tends to be nonsense, but at least the audio guys have fun > >> >> >> >>playing with circuits, whether they make a lot of sense or not.
> >> >> >> >>John
> >> >> >> >--- > >> >> >> >Even though you scorn and ridicule audio, there's nothing wrong with > >> >> >> >anyone seeking perfection there, just as there's nothing wrong with > >> >> >> >your search for perfection in the genre which pleases _you_ to pursue. > >> >> >> >So, speaking of fun, why don't you do a complete design and assign > >> >> >> >values to the circuit components and identify the semiconductors?
> >> >> >> You're not playing the game. You are sitting in the henhouse, clucking > >> >> >> about the people who do.
> >> >> >He's not playing your game, which involves telling John Larkin how > >> >> >cute his circuits are.
> >> >> He's not designing circuits, which is what this newsgroup is about.
> >> >> You aren't either. Both of you start to cluck and peck when people do > >> >> design circuits. No surprise.
> >> >> >> >Or is that legwork _we're_ supposed to do in order to flesh out your > >> >> >> >divine revelation?
> >> >> >> Chickenleg work!
> >> >> >It's half the story - a few component values make it a lot easier to > >> >> >work out what a circuit is doing.
> >> >> You can't look at a circuit this simple and see what it's doing? OK, > >> >> no surprise.
> >> >Without the component values, it does take a moment's thought, which > >> >is wasted on a bizarre (if simple) circuit with few potential > >> >applications.
> >> Millions of the "GE" circuit have been used for decades. The mosfet > >> hybrid is a very reasonable headphone amp.
> >> Post a circuit, doofus. You've forgotten how to do anything but whine.
> >You are the one who complains all the time. You may have personal > >preferences about the nature of the threads that get started here, and > >the responses that get posted, but they are only of interest to you.
> >You are welcome to demonstrate your preferences by choosing to get > >involved with particular threads and in your particular reactions to > >other responses, but your whining about the nature of those responses > >doesn't make the group a more attractive or rewarding environment.
> >In the meantime, I'll post a circuit when I've got a circuit worth > >posting. Posting a example - without comnponent values - of a circuit > >that has been used in millions, for decades, doesn't strike me as a > >profitable use of bandwidth, but that is a personal preference.
> What I did was spin a signal-level bipolar circuit into a > bipolar-mosfet power amp of similar topology.
> The resulting dynamics is very interesting. Well, not to you.
> John- Hide quoted text -
> - Show quoted text -
Yeah, I didn't get the inductor part. Do I have to spice it? Or does it have to do with head phone dynamics.
Say, and what about using the postive rail of an opamp as an output? I never heard of that.
> > >> >> >> >>Audio tends to be nonsense, but at least the audio guys have fun > > >> >> >> >>playing with circuits, whether they make a lot of sense or not.
> > >> >> >> >>John
> > >> >> >> >--- > > >> >> >> >Even though you scorn and ridicule audio, there's nothing wrong with > > >> >> >> >anyone seeking perfection there, just as there's nothing wrong with > > >> >> >> >your search for perfection in the genre which pleases _you_ to pursue. > > >> >> >> >So, speaking of fun, why don't you do a complete design and assign > > >> >> >> >values to the circuit components and identify the semiconductors?
> > >> >> >> You're not playing the game. You are sitting in the henhouse, clucking > > >> >> >> about the people who do.
> > >> >> >He's not playing your game, which involves telling John Larkin how > > >> >> >cute his circuits are.
> > >> >> He's not designing circuits, which is what this newsgroup is about.
> > >> >> You aren't either. Both of you start to cluck and peck when people do > > >> >> design circuits. No surprise.
> > >> >> >> >Or is that legwork _we're_ supposed to do in order to flesh out your > > >> >> >> >divine revelation?
> > >> >> >> Chickenleg work!
> > >> >> >It's half the story - a few component values make it a lot easier to > > >> >> >work out what a circuit is doing.
> > >> >> You can't look at a circuit this simple and see what it's doing? OK, > > >> >> no surprise.
> > >> >Without the component values, it does take a moment's thought, which > > >> >is wasted on a bizarre (if simple) circuit with few potential > > >> >applications.
> > >> Millions of the "GE" circuit have been used for decades. The mosfet > > >> hybrid is a very reasonable headphone amp.
> > >> Post a circuit, doofus. You've forgotten how to do anything but whine.
> > >You are the one who complains all the time. You may have personal > > >preferences about the nature of the threads that get started here, and > > >the responses that get posted, but they are only of interest to you.
> > >You are welcome to demonstrate your preferences by choosing to get > > >involved with particular threads and in your particular reactions to > > >other responses, but your whining about the nature of those responses > > >doesn't make the group a more attractive or rewarding environment.
> > >In the meantime, I'll post a circuit when I've got a circuit worth > > >posting. Posting a example - without comnponent values - of a circuit > > >that has been used in millions, for decades, doesn't strike me as a > > >profitable use of bandwidth, but that is a personal preference.
> > What I did was spin a signal-level bipolar circuit into a > > bipolar-mosfet power amp of similar topology.
> > The resulting dynamics is very interesting. Well, not to you.
> > John- Hide quoted text -
> > - Show quoted text -
> Yeah, I didn't get the inductor part. Do I have to spice it? Or does > it have to do with head phone dynamics.
> Say, and what about using the postive rail of an opamp as an output? > I never heard of that.
> George H.- Hide quoted text -
> - Show quoted text -
have I told you I'm a terrible speller? (positive)
<bill.slo...@ieee.org> wrote: >On Mar 4, 3:31 am, Chieftain of the Carpet Crawlers ><theslipper...@thebarattheendoftheuniverse.org> wrote: >> On Thu, 3 Mar 2011 14:42:40 -0800 (PST), "langw...@fonz.dk"
>> <langw...@fonz.dk> wrote: >> >On 2 Mar., 17:40, John Larkin >> ><jjlar...@highNOTlandTHIStechnologyPART.com> wrote: >> >> I've always sort of liked the classic "GE" tape head/mic preamp >> >> circuit:
>Along with the hundred other things a boy can do with a 555.
>So someone has used a 555 to make a less than impressive radio- >receiver. Why would anybody be interested, if they hadn't fixated on >the device early in their career and never moved on?
Oh, sorry, oh guru.
You are right, that is what 90% of the rest of the world has done. Not moved on.
Or could it be that it is *you* that has the problem?
> >> >> Audio tends to be nonsense, but at least the audio guys have fun > >> >> playing with circuits, whether they make a lot of sense or not.
> >> >> John
> >> >Bizarre??? Just a standard buffered input CE with negative feedback DC > >> >bias to stabilize the operating point against Vbe and reverse leakage > >> >collector current change with temperature- a textbook circuit...
> >> Which textbook?
> >> John- Hide quoted text -
> >> - Show quoted text -
> >Just about any textbook that goes into bias point sensitivity analysis > >of transistor circuits- you remember the S- functions, mainly ICQ > >stability. The big three were HFE, VBE, and ICBO. Then the rest of > >your circuit is just ac-bypass and the shunt-series feedback for > >signals. I've seen it dozens of times.
> I bet you haven't seen the bipolar+mosfet version, with inductive > pullup, used as a power amp.
> John- Hide quoted text -
> - Show quoted text -
I don't see the MOSFET being all that much of a change. And as for the inductor pull-up, this just doesn't make sense for low wattage high impedance headphone loads. Your inductive reactance needs to be a good few integer multiples of the load impedance, making these things prohibitively large if not unobtainable for a headphone app- you would use far less iron/ ferrite by boost switching your supply to accommodate the output swing...guess that's why I've never seen the inductive pullup here.
> On Wed, 02 Mar 2011 22:45:48 -0600, John - KD5YI<soph...@invalid.org> > wrote:
>> On 3/2/2011 10:24 PM, John Larkin wrote: >>> On Wed, 02 Mar 2011 22:06:41 -0600, John - KD5YI<soph...@invalid.org> >>> wrote:
>>>> On 3/2/2011 8:52 PM, John Larkin wrote: >>>>> On Wed, 02 Mar 2011 20:40:27 -0600, John - KD5YI<soph...@invalid.org> >>>>> wrote:
>>>>>> On 3/2/2011 8:32 PM, John Larkin wrote: >>>>>>> On Wed, 2 Mar 2011 17:59:58 -0800 (PST), Bill Sloman >>>>>>> <bill.slo...@ieee.org> wrote:
>>>>>>>> On Mar 3, 2:11 am, John Larkin >>>>>>>> <jjlar...@highNOTlandTHIStechnologyPART.com> wrote: >>>>>>>>> On Wed, 02 Mar 2011 18:36:25 -0600, John Fields
>>>>>>>>> <jfie...@austininstruments.com> wrote: >>>>>>>>>> On Wed, 02 Mar 2011 08:40:42 -0800, John Larkin >>>>>>>>>> <jjlar...@highNOTlandTHIStechnologyPART.com> wrote:
>>>>>>>>>>> I've always sort of liked the classic "GE" tape head/mic preamp >>>>>>>>>>> circuit:
>>>>>>>>>>> Audio tends to be nonsense, but at least the audio guys have fun >>>>>>>>>>> playing with circuits, whether they make a lot of sense or not.
>>>>>>>>>>> John
>>>>>>>>>> --- >>>>>>>>>> Even though you scorn and ridicule audio, there's nothing wrong with >>>>>>>>>> anyone seeking perfection there, just as there's nothing wrong with >>>>>>>>>> your search for perfection in the genre which pleases _you_ to pursue. >>>>>>>>>> So, speaking of fun, why don't you do a complete design and assign >>>>>>>>>> values to the circuit components and identify the semiconductors?
>>>>>>>>> You're not playing the game. You are sitting in the henhouse, clucking >>>>>>>>> about the people who do.
>>>>>>>> He's not playing your game, which involves telling John Larkin how >>>>>>>> cute his circuits are.
>>>>>>> He's not designing circuits, which is what this newsgroup is about.
>>>>>>> You aren't either. Both of you start to cluck and peck when people do >>>>>>> design circuits. No surprise.
>>>>>>>>>> Or is that legwork _we're_ supposed to do in order to flesh out your >>>>>>>>>> divine revelation?
>>>>>>>>> Chickenleg work!
>>>>>>>> It's half the story - a few component values make it a lot easier to >>>>>>>> work out what a circuit is doing.
>>>>>>> You can't look at a circuit this simple and see what it's doing? OK, >>>>>>> no surprise.
>>>>>>> John
>>>>>> Well, I thought designing a circuit included supplying component values. >>>>>> No?
>>>>> I posted topologies. Values can be scaled to the application, but you >>>>> need a topology first. If I were actually going to build this, for >>>>> money, of course I'd have to define specs and then compute values. >>>>> That's just grunt work.
>>>>> John
>>>> Not really. I have a few circuits I could throw out and claim that they >>>> are topologies and you would not be able to use them without values. >>>> Granted, mine are more complex than the one being discussed, but I'm >>>> hoping to make a point.
>>>> John (not Larkin)
>>> I think circuit topologies are fun to play with. Lots of textbooks >>> show, and discuss, circuits without explicit values. Once you have a >>> topology, then you can proceed to specs and component values.
>>> If you think all circuits should be posted with values, post some.
>>> John
>> You are correct, John. Now you have a topology. Please post the >> component values.
>> Thanks, >> John
> Given i/o specs, the DC analysis is simple. But there are two AC > aspects that are sort of interesting: the lf response, and loop > stability. I'm sort of disappointed that nobody has commented on > either.
> As I'm disappointed in how many people want to whine and cluck about > personalities, and avoid actually discussing electronics.
> John
Okay, I put some values to it. It looks like a nice circuit, I admit. Good gain, low distortion, reasonable input impedance. Mind you, I didn't try to optimize it. I did notice that the feedback took higher than expected resistance and I was a bit surprised that the emitter capacitor of the output stage made the response do a camel hump at the beginning if too high.
So, critique away. I might learn something.
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>On 3/3/2011 12:04 AM, John Larkin wrote: >> On Wed, 02 Mar 2011 22:45:48 -0600, John - KD5YI<soph...@invalid.org> >> wrote:
>>> On 3/2/2011 10:24 PM, John Larkin wrote: >>>> On Wed, 02 Mar 2011 22:06:41 -0600, John - KD5YI<soph...@invalid.org> >>>> wrote:
>>>>> On 3/2/2011 8:52 PM, John Larkin wrote: >>>>>> On Wed, 02 Mar 2011 20:40:27 -0600, John - KD5YI<soph...@invalid.org> >>>>>> wrote:
>>>>>>> On 3/2/2011 8:32 PM, John Larkin wrote: >>>>>>>> On Wed, 2 Mar 2011 17:59:58 -0800 (PST), Bill Sloman >>>>>>>> <bill.slo...@ieee.org> wrote:
>>>>>>>>> On Mar 3, 2:11 am, John Larkin >>>>>>>>> <jjlar...@highNOTlandTHIStechnologyPART.com> wrote: >>>>>>>>>> On Wed, 02 Mar 2011 18:36:25 -0600, John Fields
>>>>>>>>>> <jfie...@austininstruments.com> wrote: >>>>>>>>>>> On Wed, 02 Mar 2011 08:40:42 -0800, John Larkin >>>>>>>>>>> <jjlar...@highNOTlandTHIStechnologyPART.com> wrote:
>>>>>>>>>>>> I've always sort of liked the classic "GE" tape head/mic preamp >>>>>>>>>>>> circuit:
>>>>>>>>>>>> Audio tends to be nonsense, but at least the audio guys have fun >>>>>>>>>>>> playing with circuits, whether they make a lot of sense or not.
>>>>>>>>>>>> John
>>>>>>>>>>> --- >>>>>>>>>>> Even though you scorn and ridicule audio, there's nothing wrong with >>>>>>>>>>> anyone seeking perfection there, just as there's nothing wrong with >>>>>>>>>>> your search for perfection in the genre which pleases _you_ to pursue. >>>>>>>>>>> So, speaking of fun, why don't you do a complete design and assign >>>>>>>>>>> values to the circuit components and identify the semiconductors?
>>>>>>>>>> You're not playing the game. You are sitting in the henhouse, clucking >>>>>>>>>> about the people who do.
>>>>>>>>> He's not playing your game, which involves telling John Larkin how >>>>>>>>> cute his circuits are.
>>>>>>>> He's not designing circuits, which is what this newsgroup is about.
>>>>>>>> You aren't either. Both of you start to cluck and peck when people do >>>>>>>> design circuits. No surprise.
>>>>>>>>>>> Or is that legwork _we're_ supposed to do in order to flesh out your >>>>>>>>>>> divine revelation?
>>>>>>>>>> Chickenleg work!
>>>>>>>>> It's half the story - a few component values make it a lot easier to >>>>>>>>> work out what a circuit is doing.
>>>>>>>> You can't look at a circuit this simple and see what it's doing? OK, >>>>>>>> no surprise.
>>>>>>>> John
>>>>>>> Well, I thought designing a circuit included supplying component values. >>>>>>> No?
>>>>>> I posted topologies. Values can be scaled to the application, but you >>>>>> need a topology first. If I were actually going to build this, for >>>>>> money, of course I'd have to define specs and then compute values. >>>>>> That's just grunt work.
>>>>>> John
>>>>> Not really. I have a few circuits I could throw out and claim that they >>>>> are topologies and you would not be able to use them without values. >>>>> Granted, mine are more complex than the one being discussed, but I'm >>>>> hoping to make a point.
>>>>> John (not Larkin)
>>>> I think circuit topologies are fun to play with. Lots of textbooks >>>> show, and discuss, circuits without explicit values. Once you have a >>>> topology, then you can proceed to specs and component values.
>>>> If you think all circuits should be posted with values, post some.
>>>> John
>>> You are correct, John. Now you have a topology. Please post the >>> component values.
>>> Thanks, >>> John
>> Given i/o specs, the DC analysis is simple. But there are two AC >> aspects that are sort of interesting: the lf response, and loop >> stability. I'm sort of disappointed that nobody has commented on >> either.
>> As I'm disappointed in how many people want to whine and cluck about >> personalities, and avoid actually discussing electronics.
>> John
>Okay, I put some values to it. It looks like a nice circuit, I admit. >Good gain, low distortion, reasonable input impedance. Mind you, I >didn't try to optimize it. I did notice that the feedback took higher >than expected resistance and I was a bit surprised that the emitter >capacitor of the output stage made the response do a camel hump at the >beginning if too high.
Yeah, C3 gives the overall amp response a low frequency bump, and C1 and C2 each contribute a low frequency rolloff. They all have to be balanced to make it flat. Probably eliminating C3 is a good idea, if the DC biasing still works. When I used this as a tape head preamp, the LF boost was an asset, part of the tape head response equalization.
R2 could be a lot lower. The open-loop voltage gain of Q1 is just R5/R2, which is only 5, which is pretty low... even lower when it's loaded by Q2. Or, another way to look at it, R2 kills the transconductance of Q1, and adds noise.
If you do my power amp version, with a mosfet for Q2 and an inductor for R4, there's another LF rolloff and the loop stability situation is horrifying.
<gher...@teachspin.com> wrote: >On Mar 3, 6:49 pm, John Larkin ><jjlar...@highNOTlandTHIStechnologyPART.com> wrote: >> On Thu, 3 Mar 2011 15:21:33 -0800 (PST), Bill Sloman
>> <bill.slo...@ieee.org> wrote: >> >On Mar 3, 4:12 pm, John Larkin >> ><jjlar...@highNOTlandTHIStechnologyPART.com> wrote: >> >> On Thu, 3 Mar 2011 00:10:16 -0800 (PST), Bill Sloman
>> >> <bill.slo...@ieee.org> wrote: >> >> >On Mar 3, 3:32 am, John Larkin >> >> ><jjlar...@highNOTlandTHIStechnologyPART.com> wrote: >> >> >> On Wed, 2 Mar 2011 17:59:58 -0800 (PST), Bill Sloman
>> >> >> <bill.slo...@ieee.org> wrote: >> >> >> >On Mar 3, 2:11 am, John Larkin >> >> >> ><jjlar...@highNOTlandTHIStechnologyPART.com> wrote: >> >> >> >> On Wed, 02 Mar 2011 18:36:25 -0600, John Fields
>> >> >> >> >>Audio tends to be nonsense, but at least the audio guys have fun >> >> >> >> >>playing with circuits, whether they make a lot of sense or not.
>> >> >> >> >>John
>> >> >> >> >--- >> >> >> >> >Even though you scorn and ridicule audio, there's nothing wrong with >> >> >> >> >anyone seeking perfection there, just as there's nothing wrong with >> >> >> >> >your search for perfection in the genre which pleases _you_ to pursue. >> >> >> >> >So, speaking of fun, why don't you do a complete design and assign >> >> >> >> >values to the circuit components and identify the semiconductors?
>> >> >> >> You're not playing the game. You are sitting in the henhouse, clucking >> >> >> >> about the people who do.
>> >> >> >He's not playing your game, which involves telling John Larkin how >> >> >> >cute his circuits are.
>> >> >> He's not designing circuits, which is what this newsgroup is about.
>> >> >> You aren't either. Both of you start to cluck and peck when people do >> >> >> design circuits. No surprise.
>> >> >> >> >Or is that legwork _we're_ supposed to do in order to flesh out your >> >> >> >> >divine revelation?
>> >> >> >> Chickenleg work!
>> >> >> >It's half the story - a few component values make it a lot easier to >> >> >> >work out what a circuit is doing.
>> >> >> You can't look at a circuit this simple and see what it's doing? OK, >> >> >> no surprise.
>> >> >Without the component values, it does take a moment's thought, which >> >> >is wasted on a bizarre (if simple) circuit with few potential >> >> >applications.
>> >> Millions of the "GE" circuit have been used for decades. The mosfet >> >> hybrid is a very reasonable headphone amp.
>> >> Post a circuit, doofus. You've forgotten how to do anything but whine.
>> >You are the one who complains all the time. You may have personal >> >preferences about the nature of the threads that get started here, and >> >the responses that get posted, but they are only of interest to you.
>> >You are welcome to demonstrate your preferences by choosing to get >> >involved with particular threads and in your particular reactions to >> >other responses, but your whining about the nature of those responses >> >doesn't make the group a more attractive or rewarding environment.
>> >In the meantime, I'll post a circuit when I've got a circuit worth >> >posting. Posting a example - without comnponent values - of a circuit >> >that has been used in millions, for decades, doesn't strike me as a >> >profitable use of bandwidth, but that is a personal preference.
>> What I did was spin a signal-level bipolar circuit into a >> bipolar-mosfet power amp of similar topology.
>> The resulting dynamics is very interesting. Well, not to you.
>> John- Hide quoted text -
>> - Show quoted text -
>Yeah, I didn't get the inductor part. Do I have to spice it? Or does >it have to do with head phone dynamics.
>Say, and what about using the postive rail of an opamp as an output? >I never heard of that.
>Wild. Sort of a single-slope ADC and a PWM driver. I wonder what the >sensitivity is like.
>I bet you do a similar thing with a single tiny-logic schmitt gate. >Vaguely a superregenerative idea, namely triggering along a slowly >decaying exponential.
I plugged this into LTspice and with a bit of twiddling appears to work well, at least under simulation. I used a supply V of 15V, transistor input resistor (R1) = 100K, input capacitor (C1) = 1uF, transistor emitter resistor (R2) = 3.3K, feedback resistor (R3) = 22K, cap in series with feedback resistor (C3) = 10uF, bypass capacitor (C2) = 2200uF (needs to be big or lose LF gain/damping) output capacitor (C4) = 470uF (let it charge before connecting) inductor size of 10 henries (for sim assuming perfect, 0 ohms) transistor collector resistor (R4) = 3.6K but can vary, mosfet source resistor (R5, parallel with C2) = 47 but can vary. Transistor = whatever (2N5550 in sim), mosfet = IRL530.
These values optimize for medium output power (570mW) into 50 ohms and reasonable power (around 300mW) into 32 ohms and 100 ohms but with off-center clipping. R4 and R5 can be varied to deliver the desired power into the desired load... some of the values I tried...
100 ohm load.. R4=22K R5=22 PDQ=1.5W PDR5=0.3W Pout=730mW into 100, 370mW into 50, 220mW into 32 50 ohm load... R4=9.1K R5=22 PDQ=2.2W PDR5=0.9W Pout=1000mW into 50, 660mW into 32, 530mW into 100 50 ohm load... R4=5.6K R5=33 PDQ=1.6W PDR5=1.1W Pout=788mW into 50, 490mW into 32, 400mW into 100 50 ohm load... R4=3.6K R5=47 PDQ=1.2W PDR5=1.1W Pout=570mW into 50, 330mW into 32, 290mW into 100 32 ohm load... R4=5.1K R5=22 PDQ=2.5W PDR5=1.7W Pout=1180mW into 32, 760mW into 50, 380mW into 100 32 ohm load... R4=3.3K R5=33 PDQ=1.7W PDR5=1.7W Pout=790mW into 32, 560mW into 50, 280mW into 100 32 ohm load... R4=2.2K R5=47 PDQ=1.2W PDR5=1.6W Pout=500mW into 32, 400mW into 50, 200mW into 100
(PDQ is mosfet dissipation, PDR5 is R5 dissipation)
R5 sets the overall power level, then adjust R4 to achieve balanced clipping.
Output impedance is fairly low, not much variance as load changes. Gain is approximately R3/R2 plus a bit. Distortion increases as R4 (and open loop gain) decreases but it appears rather "tuby".
A 10 henry inductor is probably overkill, anything 1H or more will probably be fine, for a HP amp there's plently of overhead and the negative feedback will mostly correct for deficiencies, smaller inductors just have less output at 20hz. Could probably use the secondary of an output transformer with the primary insulated.. but watch out for core saturation. Should have fairly low resistance, preferably less than a few ohms (can tweak values to compensate). Someone in the thread said large inductors are "unobtainium" but that's BS, transformer windings ARE huge inductors, for this level of power a winding of a power transformer will probably work. For class A amps using an inductor or transformer output doubles efficiency and halves the supply voltage needed for a given output. It also presents a high impedance at audio frequencies so that only the load determines the impedance (thus the gain) of the output stage. It's possible to use a resistor load but won't perform as well.
> Audio tends to be nonsense, but at least the audio guys have fun > playing with circuits, whether they make a lot of sense or not.
> John
But this one does make sense. There's a reason this basic circuit has been around about as long as transistors...
> >Along with the hundred other things a boy can do with a 555.
> >So someone has used a 555 to make a less than impressive radio- > >receiver. Why would anybody be interested, if they hadn't fixated on > >the device early in their career and never moved on?
> Oh, sorry, oh guru.
> You are right, that is what 90% of the rest of the world has done. Not > moved on.
> Or could it be that it is *you* that has the problem?
Not really. Most of the people who post here haven't used a 555 for years. Not because they don't know about it or don't like it but because the kind of problem that it was designed to solve started being solved in other wau=ys around 1980.
> You are the one that is not impressive.
I don't impress me. I see no reason why I should impress you.
Bill Sloman <bill.slo...@ieee.org> writes: > On Mar 4, 4:43 am, Chieftain of the Carpet Crawlers > <theslipper...@thebarattheendoftheuniverse.org> wrote:
[...]
>> You are the one that is not impressive.
> I don't impress me. I see no reason why I should impress you.
<jjlar...@highNOTlandTHIStechnologyPART.com> wrote: >On Thu, 03 Mar 2011 14:44:58 -0600, John Fields ><jfie...@austininstruments.com> wrote:
>>On Thu, 03 Mar 2011 10:22:31 -0800, John Larkin >><jjlar...@highNOTlandTHIStechnologyPART.com> wrote:
>>>On Thu, 03 Mar 2011 12:07:36 -0600, John Fields >>><jfie...@austininstruments.com> wrote:
>>>>--- >>>>The truth _is_ you have less of an interest in discussing electronics >>>>in a give-and-take kind of way than you do in exalting yourself, so I >>>>prefer to generally opt out of any threads you infect.
>>>>--- >>>>JF
>>>I didn't "infect" this thread, I started it.
>>--- >>Then it was diseased from the beginning. >>---
>>>So why have you posted so much cluckey blather here?
>>--- >>You call it "cluckey blather" in an attempt to belittle it, I call it >>what it is: criticism.
>Criticism would have some content.
--- It does, and the content accurately enumerates your foibles, which is anathema to you since you've managed to convince yourself and are trying to convince everyone else that you're perfect in every way. ---
>You know, something having to do with the circuit.
--- There are no rules here, as you've proved by your gross abuse of the newsgroup with your legion off-topic posts, and if I choose to not comment on your circuit, that's my right. ---
>All you've done is whine.
--- Not so.
What I've done is simply point out technical errors which you've made, over the years, and then been forced to respond to the calumny you invariably invoke in order to try to make your stance seem unsullied. ---
>>>You refuse to discuss this circuit, then you attack me personally for >>>not doing give-and-take discussion of this circuit!
>>--- >>It's not an attack, it's an observation, and it's not about this >>circuit in particular, it's about your fanatical need to be in >>control.
>Electronic design is all about control. Of signals.
>But you probably meant some sort of personal control. How does posting >a circuit, and opening it for discussion, suggest control? I thought >discussing circuits is what s.e.d. is for.
--- Then why do you defy the group's charter by posting off-topic, irrelevant nonsense? ---
>You're just a crabby old git who won't discuss electronics.
--- With you, since all you're interested in is fostering your agenda, the inflation of your ego.
However, with others I have little reticence to join in a discussion, and often do.
For instance, I'll refer you to the
"Driving Triac Directly with 555 Output?", the
"Looking for cheap, simple PIR detector module" and the
<jfie...@austininstruments.com> wrote: >On Thu, 03 Mar 2011 15:55:19 -0800, John Larkin ><jjlar...@highNOTlandTHIStechnologyPART.com> wrote:
>>On Thu, 03 Mar 2011 14:44:58 -0600, John Fields >><jfie...@austininstruments.com> wrote:
>>>On Thu, 03 Mar 2011 10:22:31 -0800, John Larkin >>><jjlar...@highNOTlandTHIStechnologyPART.com> wrote:
>>>>On Thu, 03 Mar 2011 12:07:36 -0600, John Fields >>>><jfie...@austininstruments.com> wrote:
>>>>>--- >>>>>The truth _is_ you have less of an interest in discussing electronics >>>>>in a give-and-take kind of way than you do in exalting yourself, so I >>>>>prefer to generally opt out of any threads you infect.
>>>>>--- >>>>>JF
>>>>I didn't "infect" this thread, I started it.
>>>--- >>>Then it was diseased from the beginning. >>>---
>>>>So why have you posted so much cluckey blather here?
>>>--- >>>You call it "cluckey blather" in an attempt to belittle it, I call it >>>what it is: criticism.
>>Criticism would have some content.
>--- >It does, and the content accurately enumerates your foibles, which is >anathema to you since you've managed to convince yourself and are >trying to convince everyone else that you're perfect in every way. >---
>>You know, something having to do with the circuit.
>--- >There are no rules here, as you've proved by your gross abuse of the >newsgroup with your legion off-topic posts, and if I choose to not >comment on your circuit, that's my right. >---
>>All you've done is whine.
>--- >Not so.
>What I've done is simply point out technical errors which you've made, >over the years, and then been forced to respond to the calumny you >invariably invoke in order to try to make your stance seem unsullied. >---
>>>>You refuse to discuss this circuit, then you attack me personally for >>>>not doing give-and-take discussion of this circuit!
>>>--- >>>It's not an attack, it's an observation, and it's not about this >>>circuit in particular, it's about your fanatical need to be in >>>control.
>>Electronic design is all about control. Of signals.
>>But you probably meant some sort of personal control. How does posting >>a circuit, and opening it for discussion, suggest control? I thought >>discussing circuits is what s.e.d. is for.
>--- >Then why do you defy the group's charter by posting off-topic, >irrelevant nonsense? >---
>>You're just a crabby old git who won't discuss electronics.
>--- >With you, since all you're interested in is fostering your agenda, the >inflation of your ego.
My agenda is, and always has been, to design electronics. My ego has been tuned to further that end. Electronics design requires a combination of arrogance (to believe you can do things other people can't) and humility (to avoid the thousands of possible mistakes) and compulsiveness (to get it all done, all right.) And, more than anything else, brutal honesty. Not many people an manage all that, and lots of other people don't like the people who can.
There's not many things more fun than doing this with other people who know how. Especially since the whiteboard was invented.
<jjlar...@highNOTlandTHIStechnologyPART.com> wrote: >On Fri, 04 Mar 2011 06:31:40 -0600, John Fields ><jfie...@austininstruments.com> wrote:
>>On Thu, 03 Mar 2011 15:55:19 -0800, John Larkin >><jjlar...@highNOTlandTHIStechnologyPART.com> wrote:
>>>On Thu, 03 Mar 2011 14:44:58 -0600, John Fields >>><jfie...@austininstruments.com> wrote:
>>>>On Thu, 03 Mar 2011 10:22:31 -0800, John Larkin >>>><jjlar...@highNOTlandTHIStechnologyPART.com> wrote:
>>>>>On Thu, 03 Mar 2011 12:07:36 -0600, John Fields >>>>><jfie...@austininstruments.com> wrote:
>>>>>>--- >>>>>>The truth _is_ you have less of an interest in discussing electronics >>>>>>in a give-and-take kind of way than you do in exalting yourself, so I >>>>>>prefer to generally opt out of any threads you infect.
>>>>>>--- >>>>>>JF
>>>>>I didn't "infect" this thread, I started it.
>>>>--- >>>>Then it was diseased from the beginning. >>>>---
>>>>>So why have you posted so much cluckey blather here?
>>>>--- >>>>You call it "cluckey blather" in an attempt to belittle it, I call it >>>>what it is: criticism.
>>>Criticism would have some content.
>>--- >>It does, and the content accurately enumerates your foibles, which is >>anathema to you since you've managed to convince yourself and are >>trying to convince everyone else that you're perfect in every way. >>---
>>>You know, something having to do with the circuit.
>>--- >>There are no rules here, as you've proved by your gross abuse of the >>newsgroup with your legion off-topic posts, and if I choose to not >>comment on your circuit, that's my right. >>---
>>>All you've done is whine.
>>--- >>Not so.
>>What I've done is simply point out technical errors which you've made, >>over the years, and then been forced to respond to the calumny you >>invariably invoke in order to try to make your stance seem unsullied. >>---
>>>>>You refuse to discuss this circuit, then you attack me personally for >>>>>not doing give-and-take discussion of this circuit!
>>>>--- >>>>It's not an attack, it's an observation, and it's not about this >>>>circuit in particular, it's about your fanatical need to be in >>>>control.
>>>Electronic design is all about control. Of signals.
>>>But you probably meant some sort of personal control. How does posting >>>a circuit, and opening it for discussion, suggest control? I thought >>>discussing circuits is what s.e.d. is for.
>>--- >>Then why do you defy the group's charter by posting off-topic, >>irrelevant nonsense? >>---
>>>You're just a crabby old git who won't discuss electronics.
>>--- >>With you, since all you're interested in is fostering your agenda, the >>inflation of your ego.
>My agenda is, and always has been, to design electronics. My ego has >been tuned to further that end. Electronics design requires a >combination of arrogance (to believe you can do things other people >can't) and humility (to avoid the thousands of possible mistakes) and >compulsiveness (to get it all done, all right.) And, more than >anything else, brutal honesty. Not many people an manage all that, and >lots of other people don't like the people who can.
>There's not many things more fun than doing this with other people who >know how. Especially since the whiteboard was invented.
>John
--- On the above, I'm not at odds with you except for the "brutal honesty" part which, when you're found to be in error, all of a sudden doesn't apply to you.
> >> >> >> >> >>Audio tends to be nonsense, but at least the audio guys have fun > >> >> >> >> >>playing with circuits, whether they make a lot of sense or not.
> >> >> >> >> >>John
> >> >> >> >> >--- > >> >> >> >> >Even though you scorn and ridicule audio, there's nothing wrong with > >> >> >> >> >anyone seeking perfection there, just as there's nothing wrong with > >> >> >> >> >your search for perfection in the genre which pleases _you_ to pursue. > >> >> >> >> >So, speaking of fun, why don't you do a complete design and assign > >> >> >> >> >values to the circuit components and identify the semiconductors?
> >> >> >> >> You're not playing the game. You are sitting in the henhouse, clucking > >> >> >> >> about the people who do.
> >> >> >> >He's not playing your game, which involves telling John Larkin how > >> >> >> >cute his circuits are.
> >> >> >> He's not designing circuits, which is what this newsgroup is about.
> >> >> >> You aren't either. Both of you start to cluck and peck when people do > >> >> >> design circuits. No surprise.
> >> >> >> >> >Or is that legwork _we're_ supposed to do in order to flesh out your > >> >> >> >> >divine revelation?
> >> >> >> >> Chickenleg work!
> >> >> >> >It's half the story - a few component values make it a lot easier to > >> >> >> >work out what a circuit is doing.
> >> >> >> You can't look at a circuit this simple and see what it's doing? OK, > >> >> >> no surprise.
> >> >> >Without the component values, it does take a moment's thought, which > >> >> >is wasted on a bizarre (if simple) circuit with few potential > >> >> >applications.
> >> >> Millions of the "GE" circuit have been used for decades. The mosfet > >> >> hybrid is a very reasonable headphone amp.
> >> >> Post a circuit, doofus. You've forgotten how to do anything but whine.
> >> >You are the one who complains all the time. You may have personal > >> >preferences about the nature of the threads that get started here, and > >> >the responses that get posted, but they are only of interest to you.
> >> >You are welcome to demonstrate your preferences by choosing to get > >> >involved with particular threads and in your particular reactions to > >> >other responses, but your whining about the nature of those responses > >> >doesn't make the group a more attractive or rewarding environment.
> >> >In the meantime, I'll post a circuit when I've got a circuit worth > >> >posting. Posting a example - without comnponent values - of a circuit > >> >that has been used in millions, for decades, doesn't strike me as a > >> >profitable use of bandwidth, but that is a personal preference.
> >> What I did was spin a signal-level bipolar circuit into a > >> bipolar-mosfet power amp of similar topology.
> >> The resulting dynamics is very interesting. Well, not to you.
> >> John- Hide quoted text -
> >> - Show quoted text -
> >Yeah, I didn't get the inductor part. Do I have to spice it? Or does > >it have to do with head phone dynamics.
> >Say, and what about using the postive rail of an opamp as an output? > >I never heard of that.
