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25W Single Ended Hammond 193V Choke Loaded 2SK180 L'Amp
25W Single Ended Hammond 193V Choke Loaded 2SK180 L'Amp
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Old 11th June 2021, 09:08 AM   #371
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25W Single Ended Hammond 193V Choke Loaded 2SK180 L'Amp
yeah

flipping nature of ZM is exact thing which allowed making of SissySIT


step aside, flip everything, see what's happening

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Old 11th June 2021, 09:13 AM   #372
nautibuoy is offline nautibuoy  United Kingdom
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The world through ZM's eyes:

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Old 11th June 2021, 09:49 AM   #373
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25W Single Ended Hammond 193V Choke Loaded 2SK180 L'Amp
it would be nice that is so simple flipped

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Old 11th June 2021, 04:00 PM   #374
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25W Single Ended Hammond 193V Choke Loaded 2SK180 L'Amp
Quote:
Originally Posted by nautibuoy View Post
OK, got it thanks.

So, with the Lundahll LL1694 inductors I'm planning to use, the static resistance of each winding of 0.9 ohms, I'll be using them in parallel so that's 0.45ohms. Assuming a current through the choke of 2.5A that gives a potential difference, or bias, of 1.125V.

Mapping that onto the simulation Ben Mah ran in post #325

25W Single Ended Hammond 193V Choke Loaded 2SK180 L'Amp

which shows a bias of -2.5V, I'll likely still need to provide a negative bias supply.
The Tokins in real life have Vgs that vary from sample to sample, so you cannot rely on the Vgs from simulations.
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Old 11th June 2021, 05:34 PM   #375
nautibuoy is offline nautibuoy  United Kingdom
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Thanks Ben. I appreciate there is some variability, 'tis why I said '...likely to still need... ...a negative bias supply'.
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Old Yesterday, 07:03 AM   #376
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Quote:
Originally Posted by analog_sa View Post
Dunno how audible that regulator is. The final cap in the biasing circuit is certainly audible but it is not an earth shattering difference.
The noise is shunted through the inputcap of 10 uF to a source at the buffer of typically 5-10 ohms. And the noise is "resisted" through a 20 K gate resistor. So 10/20.000 is more than 60 dB attenuation, while the LM7912 already will be better than -60 dB typically.
So . . . why bother with an extra resistor?

You don't even need an extra RC - that would only slow down the ramp-up of the bias voltage.
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Old Yesterday, 08:33 AM   #377
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25W Single Ended Hammond 193V Choke Loaded 2SK180 L'Amp
proper biasing circuit, in this context, is inaudible ...... if we are talking about biasing circuit as variable voltage reference

there is always big elco as total shunt for all audio freq
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Old Yesterday, 01:08 PM   #378
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25W Single Ended Hammond 193V Choke Loaded 2SK180 L'Amp
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Originally Posted by triode_al View Post
You don't even need an extra RC - that would only slow down the ramp-up of the bias voltage.
No RC after the regulator, just a capacitor.
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