In several of the amplifiers there are preamp sections that do not use emitter degeneration but are configured as CC. V3B is one example. I'm a bit unsure why a capacitor was not added across the emitter resistor.
I've seen similar circuitry used for the input tube where no emitter resistor was used at all such as the supro Amp or the silvertones with no emitter degeneration at all.
From what I understand the "emitter degeneration" is actually used to create a stable bias for the tubes essentially lifting the emitter up a few volts which effectively lowers the gate a few volts. This allows input singles with no DC have full swing instead of being clipped.
Even more confusing is the input stage into the power amplifiers. This looks to be class B, i.e., push pull, with the input stage being a cathode coupled paraphase amplifier. What I don't understand is how the gate's are creating the 180 out of phase signals that are driving the power stage.
> In several of the amplifiers there are preamp sections that do not use > emitter degeneration but are configured as CC. V3B is one example. I'm > a bit unsure why a capacitor was not added across the emitter > resistor.
The resistor is used in this case as a negative feedback. It has the effect of reducing the gain while keeping the frequency response flat over a wider range.
> I've seen similar circuitry used for the input tube where no emitter > resistor was used at all such as the supro Amp or the silvertones with > no emitter degeneration at all.
> From what I understand the "emitter degeneration" is actually used to > create a stable bias for the tubes essentially lifting the emitter up > a few volts which effectively lowers the gate a few volts. This allows > input singles with no DC have full swing instead of being clipped.
> Even more confusing is the input stage into the power amplifiers. This > looks to be class B, i.e., push pull, with the input stage being a > cathode coupled paraphase amplifier. What I don't understand is how > the gate's are creating the 180 out of phase signals that are driving > the power stage.
Note that there are two inputs to these stages. One is feedback from the output and the other is the audio input It is a little confusing from the way it is drawn but this is a differential amplifier. Any signal fed into one side will appear at both plates with a 180 deg phase shift. The feedback input compensates for the transformer frequency response and makes sure the gain is the same for both phases going to the power stage.
> In several of the amplifiers there are preamp sections that do not use > emitter degeneration but are configured as CC. V3B is one example. I'm > a bit unsure why a capacitor was not added across the emitter > resistor.
> I've seen similar circuitry used for the input tube where no emitter > resistor was used at all such as the supro Amp or the silvertones with > no emitter degeneration at all.
> From what I understand the "emitter degeneration" is actually used to > create a stable bias for the tubes essentially lifting the emitter up > a few volts which effectively lowers the gate a few volts. This allows > input singles with no DC have full swing instead of being clipped.
Shunting the cathode/emitter resistor of a common cathode/emitter stage with a capacitor doesn't change the static (i.e.. 'DC') working point but it reduces the dynamic (i.e. 'AC') negative feedback within the stage, and this is often done to increase the stage gain. V3B in the given example follows the effects return input and its purpose is to bring the output of an effect device up to the same level (i.e. AC voltage) as what was fed into V3A, so the same overall gain is achieved with the effect in or out of circuit. The signal output by the cathode-follower V3A can be attenuated by up to about 19 dB by the 'send level' pot (to avoid clipping in the outboard effect device, which may have been designed to take a guitar-level signal). V3B then needs to provide 'make up' gain of up to 19 dB. With its non-bypassed cathode resistor, the stage will provide a voltage gain of about 12x or 21 dB which is then reduced somewhat by the resistors in series with the 'output' pot.
> Even more confusing is the input stage into the power amplifiers. This > looks to be class B, i.e., push pull, with the input stage being a > cathode coupled paraphase amplifier. What I don't understand is how > the gate's are creating the 180 out of phase signals that are driving > the power stage.
> Any thoughts on whats going on?
The cathode-coupled 'paraphase' phase splitter operates in the same way as a long-tailed pair. The pair of triodes share a common cathode resistor so when one triode is biased further into conduction, its increased cathode current raises the voltage of both cathodes so the second triode is biased further out of conduction (assuming its grid voltage doesn't change). The given example is a bit more complicated because the 330 k grid-leak resistors are connected to the 15 k + 100 R part of the common tail resistor (probably to raise the static operating voltage of the whole stage), whilst the 470 R part between the cathodes and the junction with the grid-leak resistors is the part that will cause the long-tailed pair behaviour. The signal to be phase-split is fed to the grid of one triode, two antiphase signals appear at the pair of anodes to be passed to the push-pull output valves, and the grid of the other triode can be connected to earth or used to add another signal (with reversed phase relative to the grid of the triode first mentioned). In the given example, a signal from the loudspeaker output is fed to this other grid to provide output-stage negative feedback.
On Thu, 09 Jul 2009 11:38:08 -0700, Bob.Jones5...@gmail.com wrote: > cathode coupled paraphase amplifier. What I don't understand is how > the gate's are creating the 180 out of phase signals that are driving > the power stage.
> Any thoughts on whats going on?
THERE IS NO PHASE SHIFT!!!!!!!!!!!!!
There is merely a polarity inversion.
Admittedly, an inverted sine wave LOOKS EXACLTY THE SAME AS one that's phase-delayed by 180 degrees, but THEY ARE NOT THE SAME. To shift the phase, you need some reactance in the signal path. There is none here, merely a POLARITY INVERSION.
I wish people could get this abstract thought through their concrete heads.
>> cathode coupled paraphase amplifier. What I don't understand is how >> the gate's are creating the 180 out of phase signals that are driving >> the power stage.
>> Any thoughts on whats going on?
>THERE IS NO PHASE SHIFT!!!!!!!!!!!!!
>There is merely a polarity inversion.
>Admittedly, an inverted sine wave LOOKS EXACLTY THE SAME AS one that's >phase-delayed by 180 degrees, but THEY ARE NOT THE SAME. To shift the >phase, you need some reactance in the signal path. There is none here, >merely a POLARITY INVERSION.
>I wish people could get this abstract thought through their concrete >heads.
Nothing abstract at all: polarity inversion is 180 degree phase shift.
> On Thu, 09 Jul 2009 11:38:08 -0700, Bob.Jones5...@gmail.com wrote: > > cathode coupled paraphase amplifier. What I don't understand is how > > the gate's are creating the 180 out of phase signals that are driving > > the power stage.
> > Any thoughts on whats going on?
> THERE IS NO PHASE SHIFT!!!!!!!!!!!!!
> There is merely a polarity inversion.
> Admittedly, an inverted sine wave LOOKS EXACLTY THE SAME AS one that's > phase-delayed by 180 degrees, but THEY ARE NOT THE SAME. To shift the > phase, you need some reactance in the signal path. There is none here, > merely a POLARITY INVERSION.
> I wish people could get this abstract thought through their concrete > heads.
> Thanks, > Rich
I WISH YOU OMNIFICENTS WOULD LEAVE US IGNORANT MORTALS ALONE!!!!!!!!!!!!
> On Thu, 09 Jul 2009 11:38:08 -0700, Bob.Jones5...@gmail.com wrote:
>> cathode coupled paraphase amplifier. What I don't understand is how >> the gate's are creating the 180 out of phase signals that are driving >> the power stage.
>> Any thoughts on whats going on?
> THERE IS NO PHASE SHIFT!!!!!!!!!!!!!
> There is merely a polarity inversion.
> Admittedly, an inverted sine wave LOOKS EXACLTY THE SAME AS one that's
Set your oscilloscope for external triggering, and you might find that they are not exactly the same. Or, take advantage of your dual-trace scope to establish a phase reference. A 180 degree phase shifted waveform does not look EXACTLY the same, when one knows what to look for and has a decent scope and knows how to use it.
> In several of the amplifiers there are preamp sections that do not use > emitter degeneration but are configured as CC. V3B is one example. I'm > a bit unsure why a capacitor was not added across the emitter > resistor.
> I've seen similar circuitry used for the input tube where no emitter > resistor was used at all such as the supro Amp or the silvertones with > no emitter degeneration at all.
> From what I understand the "emitter degeneration" is actually used to > create a stable bias for the tubes essentially lifting the emitter up > a few volts which effectively lowers the gate a few volts. This allows > input singles with no DC have full swing instead of being clipped.
> Even more confusing is the input stage into the power amplifiers. This > looks to be class B, i.e., push pull, with the input stage being a > cathode coupled paraphase amplifier. What I don't understand is how > the gate's are creating the 180 out of phase signals that are driving > the power stage.
> Any thoughts on whats going on?
Tubes DO NOT have emitters or collectors or gates. You have your terminology of tubes, bipolars and FETs all mixed up. And what is this with the meaningless "with no DC have full swing" junk? No voltage across a device means no *possibility* of any "swing". Oh yea; that "Lonestar" reference is not a schematic so "cathode coupled" is an ASS-u-ME-ption along with others...
Rich Grise wrote: > Admittedly, an inverted sine wave LOOKS EXACLTY THE SAME AS one that's > phase-delayed by 180 degrees, but THEY ARE NOT THE SAME.
Yes, they are. They're two different ways of talking about the same thing -- one in the the time domain, the other in the frequency domain.
You seem to have a misconception about what the term "phase shift" means. It doesn't imply any kind of time delay, nor any particular physical process.
It's purely a description of how the output waveform is related to the input waveform. It says nothing about how the relationship comes about.
> In several of the amplifiers there are preamp sections that do not use > emitter degeneration but are configured as CC. V3B is one example. I'm > a bit unsure why a capacitor was not added across the emitter > resistor.
> I've seen similar circuitry used for the input tube where no emitter > resistor was used at all such as the supro Amp or the silvertones with > no emitter degeneration at all.
> From what I understand the "emitter degeneration" is actually used to > create a stable bias for the tubes essentially lifting the emitter up > a few volts which effectively lowers the gate a few volts. This allows > input singles with no DC have full swing instead of being clipped.
> Even more confusing is the input stage into the power amplifiers. This > looks to be class B, i.e., push pull, with the input stage being a > cathode coupled paraphase amplifier. What I don't understand is how > the gate's are creating the 180 out of phase signals that are driving > the power stage.
> Any thoughts on whats going on?
OOPS! Sorry about that..having dial-up makes one impatient.
See V5A & V5B; they are configured as what is called as a "long-tailed pair". The unequal plate resistors compensate for the lower gain of the "B" side WRT the "A" side. Signal going into the grid of "A" drives it making a same-phase signal on the cathode and an opposite (and larger) signal on its plate. Assume that the GRID of "B" is constant; the voltage variations from "A" drives "B" giving a same phase signal on its plate. Those semi-equal (remember those plate resistors) signals then drive the power output stage. Too bad the transformer does not have screen taps...
John Larkin wrote: > On Thu, 09 Jul 2009 22:15:35 GMT, Rich Grise <richgr...@example.net> > wrote:
>> On Thu, 09 Jul 2009 11:38:08 -0700, Bob.Jones5...@gmail.com wrote:
>>> cathode coupled paraphase amplifier. What I don't understand is how >>> the gate's are creating the 180 out of phase signals that are driving >>> the power stage.
>>> Any thoughts on whats going on? >> THERE IS NO PHASE SHIFT!!!!!!!!!!!!!
>> There is merely a polarity inversion.
>> Admittedly, an inverted sine wave LOOKS EXACLTY THE SAME AS one that's >> phase-delayed by 180 degrees, but THEY ARE NOT THE SAME. To shift the >> phase, you need some reactance in the signal path. There is none here, >> merely a POLARITY INVERSION.
>> I wish people could get this abstract thought through their concrete >> heads.
> Nothing abstract at all: polarity inversion is 180 degree phase shift.
> John
...then build us a (say) 135 degree phase shifter good from (say) 10Hz to 100KHz...
Charles wrote: > Set your oscilloscope for external triggering, and you might find that they > are not exactly the same. Or, take advantage of your dual-trace scope to > establish a phase reference. A 180 degree phase shifted waveform does not > look EXACTLY the same, when one knows what to look for and has a decent > scope and knows how to use it.
Reading between the lines, I'm guessing that what you have in mind is comparing the output of an inverting stage with that of some kind of reactive phase shifting network, when you feed them both with a pure sine wave.
If they differ, all you've shown is that at least one of them is not doing a perfect job of implementing a 180 degree phase shift at that frequency without altering the signal in any other way. Given the imperfections of real-world circuitry, that's not very surprising.
This has no bearing on the issue at hand, which is a matter of the definition terms. Inverting the signal and shifting its phase by 180 degrees are the same thing *by definition*.
>>> On Thu, 09 Jul 2009 11:38:08 -0700, Bob.Jones5...@gmail.com wrote:
>>>> cathode coupled paraphase amplifier. What I don't understand is how >>>> the gate's are creating the 180 out of phase signals that are driving >>>> the power stage.
>>>> Any thoughts on whats going on? >>> THERE IS NO PHASE SHIFT!!!!!!!!!!!!!
>>> There is merely a polarity inversion.
>>> Admittedly, an inverted sine wave LOOKS EXACLTY THE SAME AS one that's >>> phase-delayed by 180 degrees, but THEY ARE NOT THE SAME. To shift the >>> phase, you need some reactance in the signal path. There is none here, >>> merely a POLARITY INVERSION.
>>> I wish people could get this abstract thought through their concrete >>> heads.
>> Nothing abstract at all: polarity inversion is 180 degree phase shift.
>> John
>...then build us a (say) 135 degree phase shifter good from (say) 10Hz >to 100KHz...
I'm not sure what you are suggesting. I didn't say anything about 135 degrees.
The thing you suggest isn't impossible, or even seriously difficult, but it's not a polarity inverter.
>>>> On Thu, 09 Jul 2009 11:38:08 -0700, Bob.Jones5...@gmail.com wrote:
>>>>> cathode coupled paraphase amplifier. What I don't understand is how >>>>> the gate's are creating the 180 out of phase signals that are driving >>>>> the power stage.
>>>>> Any thoughts on whats going on? >>>> THERE IS NO PHASE SHIFT!!!!!!!!!!!!!
>>>> There is merely a polarity inversion.
>>>> Admittedly, an inverted sine wave LOOKS EXACLTY THE SAME AS one that's >>>> phase-delayed by 180 degrees, but THEY ARE NOT THE SAME. To shift the >>>> phase, you need some reactance in the signal path. There is none here, >>>> merely a POLARITY INVERSION.
>>>> I wish people could get this abstract thought through their concrete >>>> heads.
>>> Nothing abstract at all: polarity inversion is 180 degree phase shift.
>>> John
>>...then build us a (say) 135 degree phase shifter good from (say) 10Hz >>to 100KHz...
>I'm not sure what you are suggesting. I didn't say anything about 135 >degrees.
>The thing you suggest isn't impossible, or even seriously difficult, >but it's not a polarity inverter.
>John
It's almost trivial to make phase shifters that are quite good over an octave. I do it all the time for use in image-reject mixers.
Over a wide range, it's been done, though not as easily... IIRC, see papers by Darlington... yep the same guy (at Bell Labs, of course ;-)
...Jim Thompson -- | James E.Thompson, P.E. | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 |
I love to cook with wine Sometimes I even put it in the food
On Thu, 09 Jul 2009 16:07:00 -0700, John Larkin wrote: > On Thu, 09 Jul 2009 22:15:35 GMT, Rich Grise <richgr...@example.net> >>On Thu, 09 Jul 2009 11:38:08 -0700, Bob.Jones5...@gmail.com wrote:
>>> cathode coupled paraphase amplifier. What I don't understand is how >>> the gate's are creating the 180 out of phase signals that are driving >>> the power stage.
>>> Any thoughts on whats going on?
>>THERE IS NO PHASE SHIFT!!!!!!!!!!!!!
>>There is merely a polarity inversion.
>>Admittedly, an inverted sine wave LOOKS EXACLTY THE SAME AS one that's >>phase-delayed by 180 degrees, but THEY ARE NOT THE SAME. To shift the >>phase, you need some reactance in the signal path. There is none here, >>merely a POLARITY INVERSION.
>>I wish people could get this abstract thought through their concrete >>heads.
> Nothing abstract at all: polarity inversion is 180 degree phase shift.
NO IT IS NOT! The two waveforms LOOK identical, but one has been phase shifted, the other merely iverted.
On Thu, 09 Jul 2009 16:36:18 -0700, Bob.Jones5...@gmail.com wrote: > On Jul 9, 5:15 pm, Rich Grise <richgr...@example.net> wrote: >> On Thu, 09 Jul 2009 11:38:08 -0700, Bob.Jones5...@gmail.com wrote: >> > cathode coupled paraphase amplifier. What I don't understand is how >> > the gate's are creating the 180 out of phase signals that are driving >> > the power stage.
>> > Any thoughts on whats going on?
>> THERE IS NO PHASE SHIFT!!!!!!!!!!!!!
>> There is merely a polarity inversion.
>> Admittedly, an inverted sine wave LOOKS EXACLTY THE SAME AS one that's >> phase-delayed by 180 degrees, but THEY ARE NOT THE SAME. To shift the >> phase, you need some reactance in the signal path. There is none here, >> merely a POLARITY INVERSION.
>> I wish people could get this abstract thought through their concrete >> heads.
> I WISH YOU OMNIFICENTS WOULD LEAVE US IGNORANT MORTALS > ALONE!!!!!!!!!!!!
>> Admittedly, an inverted sine wave LOOKS EXACLTY THE SAME AS one that's >> phase-delayed by 180 degrees, but THEY ARE NOT THE SAME.
> Yes, they are. They're two different ways of talking > about the same thing -- one in the the time domain, > the other in the frequency domain.
> You seem to have a misconception about what the > term "phase shift" means. It doesn't imply any kind > of time delay, nor any particular physical process.
> It's purely a description of how the output waveform > is related to the input waveform. It says nothing about > how the relationship comes about.
Let's try this little demonstration with a non-sinusoidal wave, say a pulse train:
>>>> cathode coupled paraphase amplifier. What I don't understand is how >>>> the gate's are creating the 180 out of phase signals that are driving >>>> the power stage.
>>>> Any thoughts on whats going on?
>>>THERE IS NO PHASE SHIFT!!!!!!!!!!!!!
>>>There is merely a polarity inversion.
>>>Admittedly, an inverted sine wave LOOKS EXACLTY THE SAME AS one that's >>>phase-delayed by 180 degrees, but THEY ARE NOT THE SAME. To shift the >>>phase, you need some reactance in the signal path. There is none here, >>>merely a POLARITY INVERSION.
>>>I wish people could get this abstract thought through their concrete >>>heads.
>> Nothing abstract at all: polarity inversion is 180 degree phase shift.
>NO IT IS NOT! The two waveforms LOOK identical, but one has been phase >shifted, the other merely iverted.
In article <pan.2009.07.10.21.15.22.393...@example.net>, Rich Grise <richgr...@example.net> wrote:
>> Nothing abstract at all: polarity inversion is 180 degree phase shift.
>NO IT IS NOT! The two waveforms LOOK identical, but one has been phase >shifted, the other merely iverted.
>Inversion does not shift phase.
In the case of a pure sine wave, inversion and a 180-degree phase shift are precisely identical, mathematically and in practice. You cannot distinguish them based solely on the signals themselves (although you can look inside the "black box" and figure out whether the *mechanism* was one of inversion or time delay / phase shift).
Mathematically, sin(x + pi) = -sin(x) - the former is a phase shift and the latter an inversion.
For any repeating signal (i.e. composed of the sum of sines of different frequencies), you can exactly invert the signal by phase-shifting each frequency component by exactly 180 degrees at that frequency.
You cannot exactly invert such a signal (in general) by shifting the *whole* signal by a time equivalent to 180 degrees at its primary component frequency. It will (in general) look different.
The same is true for non-repeating or irregular signals.
-- Dave Platt <dpl...@radagast.org> AE6EO Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior I do _not_ wish to receive unsolicited commercial email, and I will boycott any company which has the gall to send me such ads!
>>> Admittedly, an inverted sine wave LOOKS EXACLTY THE SAME AS one that's >>> phase-delayed by 180 degrees, but THEY ARE NOT THE SAME.
>> Yes, they are. They're two different ways of talking >> about the same thing -- one in the the time domain, >> the other in the frequency domain.
>> You seem to have a misconception about what the >> term "phase shift" means. It doesn't imply any kind >> of time delay, nor any particular physical process.
>> It's purely a description of how the output waveform >> is related to the input waveform. It says nothing about >> how the relationship comes about.
>Let's try this little demonstration with a non-sinusoidal wave, say >a pulse train:
And, as you pointed out, that's not a sine wave. It's a sum of different (harmonically-related) sines (assuming that it's a precisely regular pulse train, as your drawing suggests).
In this case, inverting the signal shifts *each* of these component sines by 180 degrees at its individual frequency.
What you describe as "phase-shifted 180 degrees" is only a 180-degree phase shift at *one* frequency - that of the fundamental. It's quite a bit more than 180 degrees at each of the other component frequencies. As a result, the component sines don't sum up to an inverted version of the original pulse train.
-- Dave Platt <dpl...@radagast.org> AE6EO Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior I do _not_ wish to receive unsolicited commercial email, and I will boycott any company which has the gall to send me such ads!
>>>>> cathode coupled paraphase amplifier. What I don't understand is how >>>>> the gate's are creating the 180 out of phase signals that are driving >>>>> the power stage.
>>>>> Any thoughts on whats going on?
>>>>THERE IS NO PHASE SHIFT!!!!!!!!!!!!!
>>>>There is merely a polarity inversion.
>>>>Admittedly, an inverted sine wave LOOKS EXACLTY THE SAME AS one that's >>>>phase-delayed by 180 degrees, but THEY ARE NOT THE SAME. To shift the >>>>phase, you need some reactance in the signal path. There is none here, >>>>merely a POLARITY INVERSION.
>>>>I wish people could get this abstract thought through their concrete >>>>heads.
>>> Nothing abstract at all: polarity inversion is 180 degree phase shift.
>>NO IT IS NOT! The two waveforms LOOK identical, but one has been phase >>shifted, the other merely iverted.
>>Inversion does not shift phase.
>>Thanks, >>Rich
>How bizarre.
>John
Sorry John, Rich is actually right on this one. Just consider a moderately asymmetrical waveform.
>On Thu, 09 Jul 2009 16:36:18 -0700, Bob.Jones5...@gmail.com wrote: >> On Jul 9, 5:15 pm, Rich Grise <richgr...@example.net> wrote: >>> On Thu, 09 Jul 2009 11:38:08 -0700, Bob.Jones5...@gmail.com wrote: >>> > cathode coupled paraphase amplifier. What I don't understand is how >>> > the gate's are creating the 180 out of phase signals that are driving >>> > the power stage.
>>> > Any thoughts on whats going on?
>>> THERE IS NO PHASE SHIFT!!!!!!!!!!!!!
>>> There is merely a polarity inversion.
>>> Admittedly, an inverted sine wave LOOKS EXACLTY THE SAME AS one that's >>> phase-delayed by 180 degrees, but THEY ARE NOT THE SAME. To shift the >>> phase, you need some reactance in the signal path. There is none here, >>> merely a POLARITY INVERSION.
>>> I wish people could get this abstract thought through their concrete >>> heads.
>> I WISH YOU OMNIFICENTS WOULD LEAVE US IGNORANT MORTALS >> ALONE!!!!!!!!!!!!
>> Set your oscilloscope for external triggering, and you might find that they >> are not exactly the same. Or, take advantage of your dual-trace scope to >> establish a phase reference. A 180 degree phase shifted waveform does not >> look EXACTLY the same, when one knows what to look for and has a decent >> scope and knows how to use it.
>Reading between the lines, I'm guessing that what you have >in mind is comparing the output of an inverting stage with >that of some kind of reactive phase shifting network, when >you feed them both with a pure sine wave.
>If they differ, all you've shown is that at least one of >them is not doing a perfect job of implementing a 180 degree >phase shift at that frequency without altering the signal >in any other way. Given the imperfections of real-world >circuitry, that's not very surprising.
>This has no bearing on the issue at hand, which is a matter >of the definition terms. Inverting the signal and shifting >its phase by 180 degrees are the same thing *by definition*.
>sin(x + 180deg) = -sin(x), for all x.
Only for single frequencies. Just try that comparison for complex waveforms. BTW shifting the phase of each frequency and re-normalizing all the respective amplitudes is doable. It makes interesting differences in the sound though.
John Larkin wrote: > On Fri, 10 Jul 2009 02:56:20 -0700, Robert Baer > <robertb...@localnet.com> wrote:
>> John Larkin wrote: >>> On Thu, 09 Jul 2009 22:15:35 GMT, Rich Grise <richgr...@example.net> >>> wrote:
>>>> On Thu, 09 Jul 2009 11:38:08 -0700, Bob.Jones5...@gmail.com wrote:
>>>>> cathode coupled paraphase amplifier. What I don't understand is how >>>>> the gate's are creating the 180 out of phase signals that are driving >>>>> the power stage.
>>>>> Any thoughts on whats going on? >>>> THERE IS NO PHASE SHIFT!!!!!!!!!!!!!
>>>> There is merely a polarity inversion.
>>>> Admittedly, an inverted sine wave LOOKS EXACLTY THE SAME AS one that's >>>> phase-delayed by 180 degrees, but THEY ARE NOT THE SAME. To shift the >>>> phase, you need some reactance in the signal path. There is none here, >>>> merely a POLARITY INVERSION.
>>>> I wish people could get this abstract thought through their concrete >>>> heads.
>>> Nothing abstract at all: polarity inversion is 180 degree phase shift.
>>> John
>> ...then build us a (say) 135 degree phase shifter good from (say) 10Hz >> to 100KHz...
> I'm not sure what you are suggesting. I didn't say anything about 135 > degrees.
> The thing you suggest isn't impossible, or even seriously difficult, > but it's not a polarity inverter.
> John
Well...put the design up in SED or confess that it ain't so easy..
