The secret is the plates of the lower tubes are tied to ground thru 510 Ohm resistors. Must be a plate follower.
Craig
Craig
Hi Stee;
What do you smoke this time?
They seem to be coming in droves this weekend.
Stee, what are you trying to accomplish here? The design looks fundamentally flawed.
He's just ripping off other people's schematics and mangling them. At least he left out the 4.7K resistor in series with the speaker this time ...
Me too. Like why have all the cost & bother of SRPP stages if you take the signal off the lower cathode?
If you want just x1 gain CF outputs, it can be done 1/ far better and 2/ far simplier.
Regards, Allen
Hey Stee,
Great, you´re capable of using both rubber- and pencil- as well as the text-tool in MSPaint.
So now you´ve got a digital drawing of an overcomplicated, easy distorting CF capable of a some hundred volts positive swing and about three volt negative swing.
Personally I like to drink lots of Tuscan wine to my pasta. Do you?
Great, you´re capable of using both rubber- and pencil- as well as the text-tool in MSPaint.
So now you´ve got a digital drawing of an overcomplicated, easy distorting CF capable of a some hundred volts positive swing and about three volt negative swing.
Personally I like to drink lots of Tuscan wine to my pasta. Do you?
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Sure, it may be better for you than what you drink now: what swing on cathodes are you talking about, if anodes are loaded on high resistance? 😀
Perhaps it would be better to explain exactly what is wrong with this implementation and why and how it could be done so much more simply. This fellow has posted several other very technically questionable designs in the past, and my take on it is that his English is seriously limited, and that he is not necessarily a troll.
Clearly this proposal is the product of someone with less than a basic understanding of electronic circuit design theory. This strikes me as nothing more than an experiment based on a complete lack of understanding of how an SRPP stage actually works, and is applied along with an observation that taking the signal off of the cathode seems to work in some fashion. (As it will with any cathode biased common cathode design.) The fact that what he has effectively ended up with is a lousy CF with a high impedance plate load seems to have escaped the OP's understanding.
Incidentally I suspect this circuit might swing a volt or two rms with rather mediocre linearity so if you really like 2nd harmonic distortion this might even be your cup of tea.
Obviously if you deliberately were aiming for a 6SN7 CF you might load the cathode with a CCS which could even be half of the 6SN7 and this would obviously provide much better linearity, swing, and a lower output Z, if you felt terribly clever you might even use bi-polar or floating supplies.
Clearly this proposal is the product of someone with less than a basic understanding of electronic circuit design theory. This strikes me as nothing more than an experiment based on a complete lack of understanding of how an SRPP stage actually works, and is applied along with an observation that taking the signal off of the cathode seems to work in some fashion. (As it will with any cathode biased common cathode design.) The fact that what he has effectively ended up with is a lousy CF with a high impedance plate load seems to have escaped the OP's understanding.
Incidentally I suspect this circuit might swing a volt or two rms with rather mediocre linearity so if you really like 2nd harmonic distortion this might even be your cup of tea.
Obviously if you deliberately were aiming for a 6SN7 CF you might load the cathode with a CCS which could even be half of the 6SN7 and this would obviously provide much better linearity, swing, and a lower output Z, if you felt terribly clever you might even use bi-polar or floating supplies.
No I don't think Stee is a troll, but I was already chuckling about all the cathode follower circuits being flung about (apparently seriously) with 3 volts below the cathode and then this one comes along. And the title of the post: "secret of the best preamp" ... well...
What I see is a cathode follower with a very high impedance CCS plate supply. BTW, the upper triode is not a "load" at least in the circuit sense.
If the components were ideal, i.e. an ideal CCS. it wouldn't be able to produce any output at all because the current would be held constant by the CCS plate supply. To drive any output load requires some current. I guess with enough drive voltage the grid current would break on through...
If you were to fix the supply and use either a just small resistor in the plate circuit or better yet cap couple the top triode's grid to the output 😉 then the only problem would be lack of swing in the negative direction.
Cheers,
Michael
What I see is a cathode follower with a very high impedance CCS plate supply. BTW, the upper triode is not a "load" at least in the circuit sense.
If the components were ideal, i.e. an ideal CCS. it wouldn't be able to produce any output at all because the current would be held constant by the CCS plate supply. To drive any output load requires some current. I guess with enough drive voltage the grid current would break on through...
If you were to fix the supply and use either a just small resistor in the plate circuit or better yet cap couple the top triode's grid to the output 😉 then the only problem would be lack of swing in the negative direction.
Cheers,
Michael
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Anatoly, I am glad I don´t drink the same stuff that you drank late last night😉.
Why not look at it as kinda CF? Even if it is worthless. Your concerns are valid with a CCS on top but the upper 6SN7 is loading with somewhat like 15kohm.
Bring out that old slide-ruler and doublecheck.
What did you win😕?
No more tube-talk tonight, instead going out in garden to eat(not pasta) and drink Rioja(not Tuscan) and watch the sun go down😎.
Well, that's why i asked what he's trying to accomplish. A target is always a good preliminary before aiming and shooting.
Sorry, it's a colloquial way of expressing exuberant agreement. I was agreeing with Anatoliy's assesment of one of the circuit's main flaws, which is way too high impedance in the plate circuit.
The sun has been up 4 hours here and it's hot
What is wrong in black tea except the color? 😀
PS: it's 11:09 here, I'm printing resumes and driving to San Francisco: a Job Fair started, ends at 2pm. I have to hurry!
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I guess you've been missing the comments about the numerous posts he's been putting up over the last while. I doubt he's actually building these, unless he solders every waking minute. 😀
Stee's art reminds me one great book I read long time ago, about what happened after WW-III that destroyed the civilization. Monks were collecting remains of schematic diagrams, restoring and redrawing them. Some black and white diagrams that did not contain flowers, ivory, and similar symbolic, were considered as Apocrypha, and banned. 😛
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