Why plate degeneration in a cathode follower?

Are you perhaps seeing a "phase splitter" and not knowing it?

What is your application for a cathode follower? Hand warmer ?>:-} ...Jim Thompson

-- | James E.Thompson, CTO | 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

| 1962 | I love to cook with wine. Sometimes I even put it in the food.

At least for a triode... should be almost zero effect for a pentode (if the screen doesn't also connect below the resistor).

Same thing a collector resistor does on a BJT follower -- dampens the common-collector oscillation mode. Base/grid/gate stopper is more traditional though, better efficiency.

Tim

-- Deep Friar: a very philosophical monk. Website:

? Common collector? The device i am fixing has triodes (a number of 6SN7s to be more specific) and every cathode follower has a 10K resistor in the plate, NO pickoff for phase splitter-type use.

The plate resistor reduces the cathode follower gain, and i do not think that it could possibly reduce distortion...it might even increase the distortion (K-A voltage varies more).

..Now if usage was as inverter and resistor was added in the cathode, again the gain would be reduced but the distortion also would be reduced (less G-K resultant drive).

[...]

1) Equalising load currents between several valves in parallel without a significant increase in output impedance?

2) Peak current protection in the event of an inter-electrode short or other abnormal operating conditions?

3) Reducing the difference in the output impedance between positive and negative half-cycles so as to avoid high frequency rectification effects due to charging and discharging the cathode-heater capacitance?

--
~ Adrian Tuddenham ~ 
(Remove the ".invalid"s and add ".co.uk" to reply) 
www.poppyrecords.co.uk

The plate resistor increases the Miller Effect which causes HF roll off.

What's the cathode load? Maybe post a schematic? ...Jim Thompson

--
| James E.Thompson, CTO                            |    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.

..Please wait; my access to my site is down temporarily.

What? What? Is the Joerg "flu" spreading ?>:-} ...Jim Thompson

--
| James E.Thompson, CTO                            |    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.

For the PDF, find it at

I do believe... I see phase-splitting >:-}

Can't you _simulate_ that ?:-) ...Jim Thompson

--
| James E.Thompson, CTO                            |    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.

"Jim Thompson" wrote in message news: snipped-for-privacy@4ax.com...

Come on Jim, ain't your rusty ol' brain remember this stuff?

If Robert's referring to V2, they aren't doing anything helpful.

Very old circuit. Mine has "Eico" painted on it, but uses 6K6s for the higher power bits. 6X4? Gah, a submini in an octal set... what an abomination :)

Tim

--
Deep Friar: a very philosophical monk. 
Website: http://seventransistorlabs.com

The octal 6X5 it replaced like to take out power transformers.

I remember EICO... I built a VOM from one their kits. Then I graduated to Dynaco >:-} ...Jim Thompson

--
| James E.Thompson, CTO                            |    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.

EICO is still around, but in the real estate business.

I have an Eico 536 VOM that someone built from a kit, but it's a nasty piece of work. Most of the solder joints were cold, and some wires fell off the terminals. Here is one on Ebay:

...but...it is an AN-TEEK!

I knew a guy who soldered by wiggling the wires until the solder froze. I told him to stop doing that.

--

John Larkin                  Highland Technology Inc 
www.highlandtechnology.com   jlarkin at highlandtechnology dot com    

Precision electronic instrumentation 
Picosecond-resolution Digital Delay and Pulse generators 
Custom timing and laser controllers 
Photonics and fiberoptic TTL data links 
VME  analog, thermocouple, LVDT, synchro, tachometer 
Multichannel arbitrary waveform generators

I found the PDF, I was just musing about who couldn't access it.

Your "was/now" and arrows are confusing. Who's on first ?:-) ...Jim Thompson

--
| James E.Thompson, CTO                            |    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.

Of course. I was just being facetious. Did you forget that I grew up in a radio and TV repair shop? I built my tube superhet about age 10 (?, I'm in Cub Scout uniform in the photo :-) ...Jim Thompson

--
| James E.Thompson, CTO                            |    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.

He's preparing to grill the final tube pair, the cathode bias is destroyed by moving the grid resistor low ends, and the plate current protection resistors are shorted.

The oscillator quality is compromised by moving the output tap from the buffer to the feedback line, and the buffer isolation is compromised by adding the cathode bypass.

Hope he has spare tubes ...

--

Tauno Voipio ( ham since the tube age, OH2UG )