Hi guys. Do you think the pentode section of a 8BU11 tube could drive a transformer with a 10k primary in pentode parafeed resistor loaded configuration? Or should I just forget about it and try to wire it as a triode?
It is essential for my project to drive the output with the pentode section... it's is 2.5w maximum plate dissipation, so I think that should be enought???
What do you guys think? Plate resistance in pentode parafeed would be an issue for directly driving the transformer primary? What do this section would behave like if I connect it as a triode?
I designed it at 270v B+ with 12k Plate R = 12mA at 125v Eb (1.2w) and 150v G2 (0.51w). Cathode R = 150R and G2 R = 33k + 1.2k + 1uF, but I am not so sure, as I never designed with pentodes before. How do I calculate effective output impedance?
I don't really need lots of power. Un fact 0.3 to 0.5w would be enought.
Here is the datasheet:
http://www.google.com.br/url?sa=t&r...tFxjHTWx29mo0cw&bvm=bv.80642063,d.eXY&cad=rja
It is essential for my project to drive the output with the pentode section... it's is 2.5w maximum plate dissipation, so I think that should be enought???
What do you guys think? Plate resistance in pentode parafeed would be an issue for directly driving the transformer primary? What do this section would behave like if I connect it as a triode?
I designed it at 270v B+ with 12k Plate R = 12mA at 125v Eb (1.2w) and 150v G2 (0.51w). Cathode R = 150R and G2 R = 33k + 1.2k + 1uF, but I am not so sure, as I never designed with pentodes before. How do I calculate effective output impedance?
I don't really need lots of power. Un fact 0.3 to 0.5w would be enought.
Here is the datasheet:
http://www.google.com.br/url?sa=t&r...tFxjHTWx29mo0cw&bvm=bv.80642063,d.eXY&cad=rja
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Thank you, but I am afraid this is really not what I am looking for. I know it would make a pretty cool input stage. But in my project I need to use the pentodes at the output stage.
I will look into making B+ lower, and consequently also the plate resistor, so I get a lower output impedance. I guess that will do it. Also, I may try and find a 15k primary transformer.
I will look into making B+ lower, and consequently also the plate resistor, so I get a lower output impedance. I guess that will do it. Also, I may try and find a 15k primary transformer.
I have been looking into curves of more common tubes like 6au6, EF86, EF80, 6aK5, etc... trying to find what is this pentode on that compactron 8BU11 modeled after, but none of these curves looks similar. If I find the info, I could use spice model of a common tube to make some simulations with it.
Does anyone knows what this pentode behaves alike? I found one reference that said 6EW6, but this tube is equally rare, so no spice model for this.
Does anyone knows what this pentode behaves alike? I found one reference that said 6EW6, but this tube is equally rare, so no spice model for this.
OK! I am done designing by now. I will wire it and actually test the effective output impedance, and the capability of this tube driving the output transformer. Lowered the B+ and the resistors somewhat, and made the primary of the transformer 15k. That should do it!
I thought that there would be people involved in small tube amps to add something. I remember seeing a plethora of mini amps affictionados some other day. But that was some other day... who knows???
That's it:
I thought that there would be people involved in small tube amps to add something. I remember seeing a plethora of mini amps affictionados some other day. But that was some other day... who knows???
That's it:
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No, my goal is 300mW minimum. And also my goal is to use this pentode section of this specific tube. I am not really interested in alternatives. If I would, I know there are plenty out there.
My goal is to use just one tube for this project, and the two triodes on this particular model is perfect for the job. So, If I can drive the output with enough power, say 300mW, I am game on this one!
I have found these spice models for pentode and triode connected 6CB6, but they do not work at all with LTspice (from Linear Technologies). Anyone knows how could I use them on LTC. I am very used to LTC, and if these could be converted for using with this, that would be great. Here are the models:
and
I use models downloaded from all over the internet, and I generally do not have issues. I don't know why these doesn't work. I am not into the core of spice workings at all...
Here is the thread I've got the models form:
http://www.diyaudio.com/forums/tubes-valves/202210-6cb6-spice-model-wanted.html
and
I use models downloaded from all over the internet, and I generally do not have issues. I don't know why these doesn't work. I am not into the core of spice workings at all...
Here is the thread I've got the models form:
http://www.diyaudio.com/forums/tubes-valves/202210-6cb6-spice-model-wanted.html
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