JC Morrison circuits

[janneman]

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]

Thanx for that Jan...

dave

[Wavebourn]

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

[janneman]

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]

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]

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]

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.

[janneman]

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]

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]

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).