All pentode in pentode mode has too large output impedance to use interstage, for example LL1660.
LL1660 in "Alt Q" wiring has 100H inductance and Lundahl suggest max. 3k source.
LL1660 in "Alt Q" wiring has 100H inductance and Lundahl suggest max. 3k source.
Try it.
Ri "only" 42k in pentode mode
LL1660 (100H) primary impedance at 20Hz about 12.5k, so driving impedance must be it's half, but better if third.
Ri "only" 42k in pentode mode
LL1660 (100H) primary impedance at 20Hz about 12.5k, so driving impedance must be it's half, but better if third.
TBH i don't understand that circuit very well. How do they get anything close to 600ohm driving the LCR? And what are those 2k/220n doing? Compensating for the high driving impedance? And there is some weird nfb too...Almost tempted to simulate it.
can`t say much about the circuit - just found it in my i-net research on lcr circuit and begann to give a pentode a try ...
You can, but you need to load your pentode in order to get acceptable frequency response out of an IT. Then you'll have to check, by looking at a loadline for example, if the loaded pentode delivers the gain you need.
Otherwise you'll need a specific pentode IT which translates to hundreds H of primary inductance, little to none and careful interleaving. Overall capacitance must be kept in the pF range, I'd roughly say 100pF max.
Otherwise you'll need a specific pentode IT which translates to hundreds H of primary inductance, little to none and careful interleaving. Overall capacitance must be kept in the pF range, I'd roughly say 100pF max.
For the price of such an interstage transformer, that actually has hundreds of Henry, and no more than 100pF . . .
You probably can purchase any one of several models of inexpensive tube amplifiers, or inexpensive amplifier kits (yes,
those inexpensive amplifiers may not perform real good.
But for your amplifier, with all that $$$ on the interstage, you still have to purchase all the other parts $$$ too.
And, an interstage with that many turns is going to be super sensitive to any magnetic hum fields, especially if it is a single ended air gapped transformer.
You probably can purchase any one of several models of inexpensive tube amplifiers, or inexpensive amplifier kits (yes,
those inexpensive amplifiers may not perform real good.
But for your amplifier, with all that $$$ on the interstage, you still have to purchase all the other parts $$$ too.
And, an interstage with that many turns is going to be super sensitive to any magnetic hum fields, especially if it is a single ended air gapped transformer.
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