Pentode buffer.

[Navyblue]

Why Pentode based? After having looked around at a lot of tube designs, starting off with Triode based designs (one of which I built based on an Aikido CCDS but gave way too much gain for what I was after) I 'think' that a Pentode based design is perhaps better for a buffer?

I am no expert, but, your reason to go pentode doesn't seems to make sense?

I assume you mean the CCDA by John Broskie? If it has too much gain, yes you should give unity gain buffer a shot, but I don't see why you should limit yourself to pentode. And in fact you knew that in your schematic you are using the pentode as triode.

Not sure if you are aware of it, Broskie also has unity gain buffer PCBs, which IHMO is what you should be building instead of the CCDA

Aikido Cathode Follower PCB
ACF-2 Octal Aikido Cathode Follower Kit

 

[underwurlde]

I am no expert, but, your reason to go pentode doesn't seems to make sense?

Perhaps not my friend! Perhaps not. It just seemed to work & do what I wanted (when simulated). The thing against using them (I guess) is akin to using a sledgehammer to crack a nut.

I assume you mean the CCDA by John Broskie?

Yep.

If it has too much gain, yes you should give unity gain buffer a shot, but I don't see why you should limit yourself to pentode.

Not really limiting myself to just using pentodes, just that I could not find a simple Triode design to do what I wanted (as above)...

Not sure if you are aware of it, Broskie also has unity gain buffer PCBs, which IHMO is what you should be building instead of the CCDA

... but A-HA! Now that's more like it. Just ran that circuit up in MultiSim and viola, does what it says on the tin!

Thanks for pointing that out to me! I shall give it a whirl in reality land and build it up.

I admit, I have been going around in circles on this. Mr Broskie's site is chock full-o' ideas and the pure volume of info on there may have caused me to miss this one.

Thanks again,

Andy.

 

[DF96]

I admit, I have been going around in circles on this.

That may be because you didn't start with a clear specification (e.g. gain, drive requirements) and then find designs which would satisfy it. Instead you started with a technology (pentode) and then asked what you could do with it. Like designing a bicycle by first choosing the metal tubing, and then wondering whether to make a unicycle, a mountain bike or a tourer (and should it fold for convenience on public transport?).

 

[underwurlde]

I have been looking at all sorts of circuit ideas outside of this thread. To ask about Pentodes was a dead end I ended up going down, but hence thread - to determine if a good idea & sensible way for me to proceed. Foresight is a wonderful thing, but now I know.

Don't forget that a poster may not have enough knowledge about a particular subject (such as myself when it comes to valves / tubes) to know (what is to you 'simple' and 'obvious') that the use of a Pentode for this may not be the best way to proceed.

Like designing a bicycle by first choosing the metal tubing, and then wondering whether to make a unicycle, a mountain bike or a tourer (and should it fold for convenience on public transport?).

Interesting parable! Can't see where a pentode would be used on a Bicycle. Or is that a Bicyclotron I should be designing next!

Seriously chaps, thanks for the help & apologies for the 'Bi-cyclic' way my brain works.

A