JC Morrison circuits

jan.didden · 2nd December 2010, 06:14 AM

Last weekend was the European Triode Festival. There's some reports from the (all tube) events here:
European Triode Festival 2010
JC Morisson, currently a designer for Silbatone in Korea, had a presentation with several unusual but creative tube circuits. Another ETF attendant put these on-line here:
(new adventures in) ultra‐fi: new stuff from jc morrison

Enjoy!

jan didden

planet10 · 2nd December 2010, 06:26 AM

Thanx for that Jan...

dave

Wavebourn · 2nd December 2010, 06:51 AM

Hi Jan;
Do you mean CCS loaded pentode? How well it drives grid currents and Miller capacitances?

jan.didden · 2nd December 2010, 08:57 AM

Quote:

Originally Posted by Wavebourn

Hi Jan;
Do you mean CCS loaded pentode? How well it drives grid currents and Miller capacitances?

Hi Anatolyi,

I have no expreience with these circuits, but they look different and innovative so that's why I posted the link here.
Apparently they are used in the no-holds-barred Silbatone equipment.
JC specifically said he wanted them out in the open to avoid some 'smart' guys to patent them.

jan didden

Wavebourn · 2nd December 2010, 09:57 AM

Quote:

Originally Posted by janneman

Hi Anatolyi,

I have no expreience with these circuits, but they look different and innovative so that's why I posted the link here.
Apparently they are used in the no-holds-barred Silbatone equipment.
JC specifically said he wanted them out in the open to avoid some 'smart' guys to patent them.

Smart decision; I often do the same!

I am going to publish Vostok solid state assisted tube amp soon...

I'm still breadboarding it, to explore all possibilities.

It is kind of new replacement for SRPP, with some better qualities.

SY · 2nd December 2010, 11:06 AM

Nice to see someone out there being creative for a change. Now, if you combined that pentode circuit with Frank Bloehbaum's hybrid screen setup...

revintage · 11:28 AM

Even if the the circuit is DC-connected from input to output, it still must be AC-connected signal-wise as C1 shorts the CCS.

About innovative circuits at ETF, Frank (Blohbaums?) Gm-circuit really should be mentioned. Used in his presented phono-amp.

jan.didden · 2nd December 2010, 11:31 AM

Quote:

Originally Posted by SY

Nice to see someone out there being creative for a change. Now, if you combined that pentode circuit with Frank Bloehbaum's hybrid screen setup...

I understand the two are talking a lot.... (to each other).

jan didden

DF96 · 2nd December 2010, 01:26 PM

I'm not quite sure what the point of these inverted circuits is. Have I missed something?

If your first stage has a very high output impedance you had better be sure that your second stage has a very linear input impedance and very low Miller capacitance. Also very low heater-cathode leakage in the first valve, even with a DC heater, as this appears in parallel with the output unless you bootstrap the heater supply reference voltage. There is a reason why, until recently, most people used the classic simple circuits - and it was not ignorance!

ErikdeBest · 2nd December 2010, 02:22 PM

Gary Pimm shows some work on CCS loaded pentodes, and I have recently seen a power amp schematic somewhere showing exactly the same concept. So Mr Morisson himself, or anybody else willing to burn up some money, could probably still apply for a USPTO patent, maybe even get it, but it would never survive a trial process if someone was willing to challenge it (I don't know the exact terms in English).

2nd December 2010, 06:14 AM	#1
jan.didden diyAudio Member Join Date: May 2002 Location: Great City of Turnhout, Belgium Blog Entries: 6	JC Morrison circuits Last weekend was the European Triode Festival. There's some reports from the (all tube) events here: European Triode Festival 2010 JC Morisson, currently a designer for Silbatone in Korea, had a presentation with several unusual but creative tube circuits. Another ETF attendant put these on-line here: (new adventures in) ultra‐fi: new stuff from jc morrison Enjoy! jan didden __________________ /Yes! Its out: Linear Audio Vol 5! I'm not an "accademic", just a plodder who loves a challenge - Ian Hegglun

2nd December 2010, 06:26 AM	#2
planet10 frugal-phile(tm) diyAudio Moderator Join Date: Oct 2001 Location: Victoria, BC, NA, Sol III Blog Entries: 5	Thanx for that Jan... dave __________________ community sites t-linespeakers.org, frugal-horn.com, frugal-phile.com ........ commercial site planet10-HiFi p10-hifi forum here at diyA

2nd December 2010, 06:51 AM	#3
Wavebourn diyAudio Member Join Date: Sep 2006 Location: Pleasant Hill, CA	Hi Jan; Do you mean CCS loaded pentode? How well it drives grid currents and Miller capacitances? __________________ If I disappear suddenly, that means I finally created a time machine and pushed wrong button that brought me to Stalin's Russia. In any experiment any result is the result. Even if it is negative.

2nd December 2010, 11:06 AM	#6
SY diyAudio Moderator Join Date: Oct 2002 Location: Chicagoland Blog Entries: 1	Nice to see someone out there being creative for a change. Now, if you combined that pentode circuit with Frank Bloehbaum's hybrid screen setup... __________________ If there's a sucker born every minute, where do the rest of them come from?

2nd December 2010, 11:17 AM	#7
revintage diyAudio Member Join Date: May 2007	Even if the the circuit is DC-connected from input to output, it still must be AC-connected signal-wise as C1 shorts the CCS. About innovative circuits at ETF, Frank (Blohbaums?) Gm-circuit really should be mentioned. Used in his presented phono-amp. Last edited by revintage; 2nd December 2010 at 11:28 AM.


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2nd December 2010, 01:26 PM	#9
DF96 diyAudio Member Join Date: May 2007	I'm not quite sure what the point of these inverted circuits is. Have I missed something? If your first stage has a very high output impedance you had better be sure that your second stage has a very linear input impedance and very low Miller capacitance. Also very low heater-cathode leakage in the first valve, even with a DC heater, as this appears in parallel with the output unless you bootstrap the heater supply reference voltage. There is a reason why, until recently, most people used the classic simple circuits - and it was not ignorance!

2nd December 2010, 02:22 PM	#10
ErikdeBest mostly thinkerer diyAudio Member Join Date: Mar 2003 Location: Maputo - Mozambique	Gary Pimm shows some work on CCS loaded pentodes, and I have recently seen a power amp schematic somewhere showing exactly the same concept. So Mr Morisson himself, or anybody else willing to burn up some money, could probably still apply for a USPTO patent, maybe even get it, but it would never survive a trial process if someone was willing to challenge it (I don't know the exact terms in English). __________________ my surname is indeed 'de Best': neither misspelling nor snobbism! Ask SY!

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