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Topic: Pentode

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	Pentode
		Pentode was developed from tetrode by inserting the fifth electrode called as supressor grid or grid No 3.
		The purpose of inserting suppressor grid is avoiding secondary emission occurs in tetrode that reduce plate current, as seen on b-c curve from tetrode characteristic.
		Test circuit to achieve pentode plate characteristic seen on Figure 17, except the tube is pentode not tetrode
	www.geocities.com /tube_theory/Pentode.htm (0 words)

	SoundStage! The Y-Files - Turning KT-88s into Gutsy Triodes? (8/2001)
		The conventional triode-connected pentode scheme hooks the screen grid to the plate.
		Enhanced triode mode uses the grids of a pentode in a different manner.
		He wanted to coax a pentode into behaving like a low-mu 300B triode in the areas of gain, output impedance and overall distortion characteristics.
	www.soundstage.com /yfiles/yfiles200108.htm (1607 words)

	Alternative Pentode Connections. (Page 1) (Site not responding. Last check: )
		Standard Pentode connection (g1 as stepped parameter, g2 at a constant voltage, and plate voltage and current plotted for the stepped input), triode connection (g2, g3 connected to the plate) and suppressor input triode mode (g1=0V, g2 at a constant voltage, g3 as the stepped (input) parameter) are presented.
		In a true pentode (as opposed to a beam power tube), depending on the construction, it is sometimes practical to use the suppressor grid as the signal input.
		This is due to the use of the screen stopper in the pentode and g3 driven case and the fact that the screen in those two modes does not contribute to the overall "plate" current as it does in triode mode.
	members.aol.com /sbench102/pentmode.html (675 words)

	Tube FAQ
		The pentode is thus capable of large output voltages with minimal distortion.
		Whereas a quality pentode design requires a stiffly regulated screen grid supply, all that is needed to implement an ultralinear output stage is a pair of transformer primary taps.
		Whether this is due to an inherent quality of triode-strapped pentodes, or is a consequence of modifying a topology that was not designed with triode output in mind, is open for debate.
	www.ken-gilbert.com /techstuff/vtf.html (3841 words)

	The Valve Wizard (Site not responding. Last check: )
		The cathode, control-grid and anode in a pentode serve the same purpose as in a triode, and the connections to these are the same as for a triode.
		Part of the difficulty in designing a pentode stage is that the grid curves change depending on the screen voltage, and the quiescent screen voltage must not be greater then the quiescent anode voltage.
		In this example the pentode is to be at the input of the amp where HT is low, at 240V.
	www.freewebs.com /valvewizard/pentode.html (2184 words)

	7199:RCA Application Notes
		Assume that the pentode unit of the 7199 is to be used in the input stage of an amplifier having a sensitivity of 100 millivolts RMS.
		Normal variations among pentodes of the same type are such that a quiescent point which is just above the "knee" for one tube may be on or under the "knee" for another, and thus result in low gain and very high distortion.
		In this circuit, the average grid-No.2 voltage of the pentode is 35 volts.
	www.triodeel.com /7199.htm (1914 words)

	mu stage
		This is highly desirable for a CF and contributes to the excellent sonic accuracy of the pentode CF.
		Although pentodes make the best CFs, the bottom tube, V1, should be a triode because operating a triode at constant current allows it to reach maximum linearity.
		With a pentode CF (or MOSFET SF) on top, the Mu Stage is capable of producing the most constant-current operation as well as very low output impedance.
	www7.taosnet.com /f10/mustage.html (5171 words)

	DECWARE - Article about fake Triodes vs. the real thing.
		Pentodes are far more efficient than triodes and with the same bottom line can usually produce 5 times more power.
		In a pentode such as the EL34 where the screens are not tied together internally, it is possible to wire it as a "true triode".
		It is the only pentode I know of that is. The other ones have internal connections on the screens that can't be changed so you end up with a "Pseudo triode" as I've heard it called.
	www.decware.com /paper16.htm (1820 words)

	AudiogoN Forums: Triode vs. Pentode
		To my ear, pentode gives me the impact on the head of the ba...
		"pentode" means that an extra grid in the output t...
		Tetrode or pentode by contrast creates a double-whammy applied in push-pull: higher- and more odd-order harmonics are generated than with triode, and then on top of that the output stage configuration tends to cancel-out what lower- and more even-order harmonic content does exist - content which would otherwise help to mask this less-pleasing timbral quality.
	forum.audiogon.com /cgi-bin/fr.pl?aamps&1099871837&openflup&16&4 (1527 words)

	EL34 Integrated (Site not responding. Last check: )
		A regulated power supply is used, having a hexfet as the series pass element and an EF86 pentode as the error amplifier.
		This amplifier topology has been auditioned against a superbly-executed 45 SE design (by Walter Clay of Newburyport, MA) using Altec-Lansing horns and gave away little to the 45 SE in transparency although it is perhaps slightly less dynamic and "slower" than the 45 due to the rather limited drive current available from the 6SL7.
		Furthermore, the transparency suggests that the pentode is indeed, not degrading the sonic performance of the 6SL7, merely ensuring perfect balance (within the limits of plate and succeeding grid leak resistor matching).
	members.tripod.com /richard984/el34_integrated.htm (358 words)

	el34
		It has a rated anode dissipation of 25 Watts and the high mutual conductance of 11 mA/V. This valve covers all applications requiring powers between 11 W (single valve) and 100 W (push pull), and is equally suitable for high quality domestic amplifiers and public address equipment.
		Connecting the output pentodes as triodes is equivalent to moving the screen grid taps to the anode ends of the windings.
		On the other hand, for the normal pentode connection the screen grids would effectively be connected to the centre tap.
	www.r-type.org /static/el34.htm (0 words)

	Carvin BBS :: View topic - Vintage 16 Pentode/Triode Question
		I realize that the triode is only using 3 of something and the pentode is using 5 of something, therefore the triode is without a doubt the 5w setting and the pentode is the 16w setting.
		In both cases the grid is given a negative voltage (varying with the input signal) which impedes flow of charge within the tube depending on the size of the grid voltage, which in turn regulates (changes) the high voltage across the tube (between cathode and anode).
		So the "pentode is 5 and triode is 3" observation isn't a direct mapping to higher versus lower amplification stage.
	www.carvin.com /carvinbbs/viewtopic.php?t=1598&start=0&postdays=0&postorder=asc&highlight= (874 words)

	Tube-based Buffer amplifier
		For example, if the pentode sees a peak output into the loudspeakers of 16V and a -30V bias voltage, then the input signal to the pentode’s grid must be at least 46V to get to a zero cathode-to-grid voltage.
		So when the inverse is taken, a pentode with a transconductance of 10mA/V would equal 100-ohms; and the 100 ohms dived by 25 would equal the output impedance—namely, 4 ohms, for a damping factor of 2.
		For example, a pentode with twice the transconductance (or two of the same pentodes in parallel) would yield half the output impedance.
	www.tubecad.com /2006/06/blog0068.htm (1633 words)

	Ultra-linear Aikido Amplifers
		In any case, the idea is an interesting one: a twin-ganged potentiometer allows us to vary the pentode’s mode of operation from 100% triode to 100% pentode, with any ultra-linear ratio in between also selectable; at the same time, it allows us to maintain the optimal power-supply noise injection into the noise nulling output stage.
		But it will change the amount of pentode plate signal that is fed back to its screen and the amount of power-supply noise that is fed back to the output stage’s bottom triode’s grid.
		The pentode remains a pentode, as its screen is effectively grounded through the 1µF capacitor.
	www.tubecad.com /2006/06/blog0069.htm (1013 words)

	Beam power and power pentode tues
		Because of high-plate resistance and internal construction, tubes such as the triode, tetrode, and pentode are used only as voltage amplifiers.
		Because of this loss of electrons from the stream, conventional tetrodes and pentodes are not suitable for power amplifiers.
		For this reason, both beam-forming and power pentodes are suitable for use as power amplifiers.
	www.tpub.com /neets/book6/21a.htm (1733 words)

	SEX, MUSIC AND PENTODES (Site not responding. Last check: )
		Because pentode tubes have more elements than DHTs, there are OPT design choices to be made that do not exist with SETs…and we have now entered one of the most interesting areas of the tube audio arts….the art of designing pentode OPTs…an activity whose goal it is to create maximum pentode beauty.
		Pentode amplifiers changed my life by permitting me to join a tribe of music aliens who demand the most passionate erotic relationship to music.
		As part of this "Save America, Love a Pentode" policy, demonstrations will be given in high schools so students can hear the big difference in sand based and tube amplifiers…so they don't grow up with an ache in their soul that drives them to substance abuse.
	www.meta-gizmo.com /Tri/june/SEX.html (4216 words)

	Audio Amplifiers From TV Compactrons
		There are many types of Duodecar TV tubes which have a pentode and a beam power tube, or a triode and a power pentode in the same envelope.
		All of these are pentode / beam power tubes and in my circuit can be switched with one another and the only change that needs to be made is the heater voltage.
		Since a lot of gain is not required, and the idea of a pentode front end doesn't appeal to me, I decided to connect the pentode unit in a triode fashion.
	www.angelfire.com /vt/audio/compactron.html (1381 words)

	Pipsqueak pentode DIY guitar amp
		Arc Moonlight projects, I learned that a single pentode stage provides plenty of gain with a tone quality that reduces the need for a a gain-sucking tone stack behind it.
		AX84, Mark mentioned that 6AU6's (and other RF pentodes) tended to be microphonic.
		I was all excited about lashing up a 6AK5 preamp to a 6AK6 power pentode, but unfortunately I didn't have any 6AK6's in my massive trove of random tubes acquired in bulk from a hamfest in summer 2003.
	www.frontiernet.net /~jff/pipsqueak_pentode/Pentode_DIY_guitar_amp.html (1599 words)

	www.myspace.com/pentode (Site not responding. Last check: )
		Just as a song or a slogan does not the foundation of identity make, one's life cannot be summarized within the confines of experiences, accomplishments, failures.
		pentode is the terminal stage of introspection, the great self reflected in the form of void, expressed in countless groups of sixteen ones and zeros that represent sound.
		pentode is the woeful conclusion that existence is a heap of misery, shored against the broken dreams of meat foolish enough to think itself alive.
	www.myspace.com /pentode (175 words)

	Multi Grid Tubes.
		This gave rise to the Tetrode, 4 element tube, and the Pentode, 5 element tube.
		In a pentode the screen grid is sitting there at a positive potential and because the plate voltage is going up and down with signal the screen grid may be, at that instant, more positive than the plate.
		Pentodes do tend to produce more distortion than triodes which accounts for the popularity of the 12AX7.
	www.angelfire.com /electronic/funwithtubes/Basics_05_Multigrid.html (1938 words)

	diyAudio Forums - Pentode vs Ultralinear
		Pentode mode is usually considered more expensive (or at least, more trouble) to implement than UL.
		The purist pentode practitioner will have you believe that you must provide a totally separate PS for g2, with its own power tranny, rectifiers and choke-input filter.
		My experience with Triode - UL - Pentode experiments in an amp similar to yours were not in favor of Pentode operation.
	www.diyaudio.com /forums/showthread.php?goto=newpost&threadid=90165 (1568 words)

	Tube numbering
		Note that signal pentodes and tetrodes which end in even numbers are sharp cutoff tubes.
		An E446 is a H.F. pentode with a heater current between 0.4 and
		Voltage amplifier tetrode or pentode with voltage amplifier triode.
	www.duncanamps.com /technical/tubenumber.html (603 words)

	diyAudio Forums Archive - Pentode models
		Yesterday night I implemented the pentode equations into the same program, but the parameter fit is less straight forward that for the triode case.
		Whereas with a typical beam pentode there is one line coming out of the zero point, and then each grid curve branches off that line more or less horizontally.
		But if it is more than the diode line current, then the plate current is given as equal to that diodel line current, and the "excess" current is given to the screen grid.
	www.diyaudio.com /forums/showthread/t-57935.html (1555 words)

	PSW Recording Forums: Oliver Archut => Triode vs. pentode preamps
		You raised a curiosity of mine concerning the triode vs. pentode as an ideal amplifier.
		Was the choice of using pentodes throughout based on the fact that the pentodes of the time were better built than triodes, or is a pentode wired as triode superior to a standard triode under all respects?
		In my personal opinion a pentode has a fuller and warmer sound, triodes are good as a buffer amp with nearly no gain, unless you go into the world of non linear amplifiers like Fender an alike....
	recforums.prosoundweb.com /index.php/m/40587/0 (1244 words)

	Pentode Press Legal Notice
		"Pentode Press" is a sole proprietorship registered in the State of Washington, USA.
		Pentode Press and its owners also make no representations or warranties as to whether the information accessible via this web site, or any web site with which it is linked is accurate, complete, or current.
		The information on this web site is posted with the understanding that Pentode press, its owners, and writers are not engaged in rendering any professional services.
	www.pentodepress.com /disclaimer.html (0 words)

	Ham University
		Pentode allows you to test your skill at any level, Novice through Extra.
		Pentode was also part of the #1 Edutainment package of 1995 (and 1966) as judged by Consumers Reports.
		Pentode® is the game that is included and helps you increase your speed and have fun at the same time.
	hamuniversity.com /features.html (0 words)

	Pentode
		The pentode was developed and patented by Philips.
		The pentode was developed originally for the high anode swing involved in the output stage of radio receivers.
		The first appeared in 1927 and by 1928 the UK Mullard company was selling two pentode types.
	www.r-type.org /static/grid03.htm (0 words)

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