Patent or not, it's a trivial circuit, but one which can be
made to work fairly well. I've made the equivalent with
the Zen circuit, and the results were fine, but there is
difficulty applying feedback unless the supply is very
well regulated, and without the feedback, the output
impedance of the amplifier will be very high - essentially
the impedance of the coil.
made to work fairly well. I've made the equivalent with
the Zen circuit, and the results were fine, but there is
difficulty applying feedback unless the supply is very
well regulated, and without the feedback, the output
impedance of the amplifier will be very high - essentially
the impedance of the coil.
Thank you Scott Nixon!
The patent does seem to make claims for the circuit that do not
appear supportable. At least it gets high marks for its sound
quality! For some, that will be all that matters.
P.S. I would welcome rebuttal from anyone who understands
what's going on here better than I do.
The patent does seem to make claims for the circuit that do not
appear supportable. At least it gets high marks for its sound
quality! For some, that will be all that matters.
P.S. I would welcome rebuttal from anyone who understands
what's going on here better than I do.
Joe,
Yes, possibly 1% H2 is acceptable. Indeed, from all reports, it sounds lovely. I believe the appropriate term is 'go figure.....'.
There are ways of achieving low Zout with this circuit.
Arguably the best way is to increase the transconductance of the output device. I have found the best option is to go CFP, with a bipolar driver. Hell, this is Class A, so the perennial issues of switching the damn thing on and off are not relevant.........
And if you can run the driver at constant current, all the better. Then the output becomes a simple step function of the input. Furthermore, the very high feedback factor using a CFP (with an IRF Hexfet) will greatly lessen the Zout, though as Nelson remarks, it will be to some degree limited by the DCR of the coil, which can still be made pretty low. Nonetheless, the coil is a good idea as it doubles the efficiency over a straight CCS. (Which I use on my Glass Harmony).
Cheers,
Hugh
Yes, possibly 1% H2 is acceptable. Indeed, from all reports, it sounds lovely. I believe the appropriate term is 'go figure.....'.
There are ways of achieving low Zout with this circuit.
Arguably the best way is to increase the transconductance of the output device. I have found the best option is to go CFP, with a bipolar driver. Hell, this is Class A, so the perennial issues of switching the damn thing on and off are not relevant.........
And if you can run the driver at constant current, all the better. Then the output becomes a simple step function of the input. Furthermore, the very high feedback factor using a CFP (with an IRF Hexfet) will greatly lessen the Zout, though as Nelson remarks, it will be to some degree limited by the DCR of the coil, which can still be made pretty low. Nonetheless, the coil is a good idea as it doubles the efficiency over a straight CCS. (Which I use on my Glass Harmony).
Cheers,
Hugh
scottnixon, thanks ^2
The link you provided (PS*), fed my curiosity for the INPOL topology. At the same time it made me realize that patenting something can be silly (but profitable). Like the "gen" patents. It is enough to study something, describe it on paper, and apply for a patent for that. What would you say if i would describe (i have studied it enough) the function of a voltage divider consisting of two resistors, and then apply for the patent? And i will arrange a special discount price for all the members of this site, when they will have to pay royalties for the incorporation of MY patent on their designs.
Well, on the INPOL patent claims, there was nothing about calculated impedances of coil-capacitor-speaker combination. (The only think that they didn't claim as original. Pitty though, because if they had claimed it, it -too- would have been accepted. I think that Einstein was lucky enough to leave his position as patent examiner, on time!)
Now a question. Having no intention to infringe the said patent, but having still the desire to build a normal (as all of us, except the patent examiner knows) class A, inductance loaded output stage, to be used not in audio, but as a driver of a vibrator (do not comment on this please, or i will be insulted), which has to operate from 20Hz to 20kHz +/- 1 db with a total of 2% second order THD (tests have proved that this sort of distortion, is interacting well with the sensory organs of the medium that the said vibrator is destined to vibrate). The vibrator has to be supplied with 20W of electrical power in order to vibrate adequately, and being an electrodynamic device, it will presents a nominal load of 8 Ohms to the amp, presumably resisto-capasito-inductive in nature. The question is what are the specifications that the coil has to fulfill in order to be eligible as a load that will be placed between the source of an "N" power MOSFET source follower and the ground of the above mentioned vibrator driver. Note please that the coil should have as small a size as possible, but it should present a low DC resistance, as the vibrator might be DC coupled to it, and any DC voltage in excess of 500mV might mechanically bias the vibrator in an extended (prefered) or retracted (less prefered) position. rolleyes:
Should the above driver be ever implemented, i intend (for obvious reasons), to give it the name "Lust".
Regards
George
(PS*) Scottnixon,Is it possible to post the adress of the US Patent Office site as well? Thanks in advance .
The link you provided (PS*), fed my curiosity for the INPOL topology. At the same time it made me realize that patenting something can be silly (but profitable). Like the "gen" patents. It is enough to study something, describe it on paper, and apply for a patent for that. What would you say if i would describe (i have studied it enough) the function of a voltage divider consisting of two resistors, and then apply for the patent? And i will arrange a special discount price for all the members of this site, when they will have to pay royalties for the incorporation of MY patent on their designs.
Well, on the INPOL patent claims, there was nothing about calculated impedances of coil-capacitor-speaker combination. (The only think that they didn't claim as original. Pitty though, because if they had claimed it, it -too- would have been accepted. I think that Einstein was lucky enough to leave his position as patent examiner, on time!)
Now a question. Having no intention to infringe the said patent, but having still the desire to build a normal (as all of us, except the patent examiner knows) class A, inductance loaded output stage, to be used not in audio, but as a driver of a vibrator (do not comment on this please, or i will be insulted), which has to operate from 20Hz to 20kHz +/- 1 db with a total of 2% second order THD (tests have proved that this sort of distortion, is interacting well with the sensory organs of the medium that the said vibrator is destined to vibrate). The vibrator has to be supplied with 20W of electrical power in order to vibrate adequately, and being an electrodynamic device, it will presents a nominal load of 8 Ohms to the amp, presumably resisto-capasito-inductive in nature. The question is what are the specifications that the coil has to fulfill in order to be eligible as a load that will be placed between the source of an "N" power MOSFET source follower and the ground of the above mentioned vibrator driver. Note please that the coil should have as small a size as possible, but it should present a low DC resistance, as the vibrator might be DC coupled to it, and any DC voltage in excess of 500mV might mechanically bias the vibrator in an extended (prefered) or retracted (less prefered) position. rolleyes:
Should the above driver be ever implemented, i intend (for obvious reasons), to give it the name "Lust".
Regards
George
(PS*) Scottnixon,Is it possible to post the adress of the US Patent Office site as well? Thanks in advance .
Hands on with a Pathos
I know the thread is dead, but thought I'd add to the archive. Repaired a Pathos InPower this week. Basically a differental tube front driving a bridged version of the TwinTower amp. The output inductor for each side of the amp is 120mh 1 ohm DCR. There is 3.25 volts on top of it and the sources ( 4 IRFP240 per channel w/.22r between each source and topside of the inductor)
Hey that's 3.25 amps per side (it is a bridge).
It's also direct coupled ! Each side has the 3.25v to ground but nulls across a load, kinda funky. Runs hot as blazes. They also have a choke input supply for the output stage, 30mh 0.4 ohm between bridge and supply caps. Much prettier outside than inside
I know the thread is dead, but thought I'd add to the archive. Repaired a Pathos InPower this week. Basically a differental tube front driving a bridged version of the TwinTower amp. The output inductor for each side of the amp is 120mh 1 ohm DCR. There is 3.25 volts on top of it and the sources ( 4 IRFP240 per channel w/.22r between each source and topside of the inductor)
Hey that's 3.25 amps per side (it is a bridge).
It's also direct coupled ! Each side has the 3.25v to ground but nulls across a load, kinda funky. Runs hot as blazes. They also have a choke input supply for the output stage, 30mh 0.4 ohm between bridge and supply caps. Much prettier outside than inside
One side of one amp died. Gate diodes shorted
and 2 fets were 'open'. Really odd. I suspect since the owner had Quad 63 monitors, the crowbar protection did a number on the amp. There is that potential 3v dc on each side, if you have one speaker lead connected and the other sees the chassis, accidentially, the triac may sense impending doom and shut the dooe Just a guess, as we know all audiophiles power down their amps before changing connections, right? 
and 2 fets were 'open'. Really odd. I suspect since the owner had Quad 63 monitors, the crowbar protection did a number on the amp. There is that potential 3v dc on each side, if you have one speaker lead connected and the other sees the chassis, accidentially, the triac may sense impending doom and shut the dooe
Just a guess, as we know all audiophiles power down their amps before changing connections, right? 
inpol schematic
Hi!
Could somebody post here a clearer schematic of the earlier posted by Scott? Maybe Scott self could you help me??
I can't see clear some resistores, the inductor and voltage values.
I don't understand why are the -330V on the anods and the +24V on the gates??
Greets:
Tyimo
Hi!
Could somebody post here a clearer schematic of the earlier posted by Scott? Maybe Scott self could you help me??
I can't see clear some resistores, the inductor and voltage values.
I don't understand why are the -330V on the anods and the +24V on the gates??
Greets:
Tyimo
Re: inpol schematic
Hi Tyimo
In the anodes of the valves there are +300 volts, as you can see by the polarity of the 100uF capacitor at upper left (anyway is the only way that tubes operate. with the anode positive ).
As the gates of the mos-fets are isolated from the tube stage by the 10uF interconnect capacitor , they have is own polarization voltage, 24 volts via a pot that regulate the bias ....
Cheers
Tyimo said:
Hi Tyimo
In the anodes of the valves there are +300 volts, as you can see by the polarity of the 100uF capacitor at upper left (anyway is the only way that tubes operate. with the anode positive ).
As the gates of the mos-fets are isolated from the tube stage by the 10uF interconnect capacitor , they have is own polarization voltage, 24 volts via a pot that regulate the bias ....
Cheers
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