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Old 2nd October 2012, 04:14 PM   #2201
lhquam is offline lhquam  United States
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Here is a simulation of my latest circuit tweaks shown in the attached schematic. The purpose of these tweaks is to see how low I can get the 2nd harmonics and THD.

The primary changes are to allow one on the primary windings to freely float, the careful choice of the Rswip values to balance the AC currents through the source resistors, and the careful choice of C3 to null the 2nd harmonic at high frequencies.
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Old 2nd October 2012, 04:26 PM   #2202
Zen Mod is offline Zen Mod  Serbia
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why trying all the time to have K2 below K3 and K>3 ?

your ears will start bleeding

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Old 2nd October 2012, 04:30 PM   #2203
lhquam is offline lhquam  United States
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The objective is to understand the role of the circuit parameters in determining the 2nd harmonic, not the configuration for best listening.

BTW: In the sweep, the sum of the harmonics greater than H3 is lower than H2.

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why trying all the time to have K2 below K3 and K>3 ?

your ears will start bleeding


Last edited by lhquam; 2nd October 2012 at 04:33 PM.
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Old 2nd October 2012, 04:35 PM   #2204
Zen Mod is offline Zen Mod  Serbia
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Quote:
Originally Posted by lhquam View Post
The objective is to understand the role of the circuit parameters in determining the 2nd harmonic, not the configuration for best listening.

BTW: In the sweep, the sum of the harmonics greater than H3 is lower than H2.
agree for understanding

anyway - try to adjust to have K2 above K3 , then listen

btw - in sim , maybe is better to have one secondary flippin' in the breeze , but I think that better inter-coil coupling with both prim. connected , will give better results in vivo
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Last edited by Zen Mod; 2nd October 2012 at 04:37 PM.
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Old 2nd October 2012, 05:34 PM   #2205
lhquam is offline lhquam  United States
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With the winding floating, its AC voltage will be Vin*(Gain+1)/3 (ignoring all other circuit capacitances). If Gain=2, then the winding will float at the same AC voltage as the other primary winding.

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Originally Posted by Zen Mod View Post
agree for understanding

anyway - try to adjust to have K2 above K3 , then listen

btw - in sim , maybe is better to have one secondary flippin' in the breeze , but I think that better inter-coil coupling with both prim. connected , will give better results in vivo
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Old 2nd October 2012, 05:44 PM   #2206
Zen Mod is offline Zen Mod  Serbia
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I was thinking of better/tighter magnetic coupling between P and S

it is always better when you have P:S:P:S , than S:P:S

for my logic , better signal transfer will result in greater verity , even taking in account increased capacitive losses

I spent some time playing with MM and MC heads feeding various xformers , amongst others even repeaters (my lucida intervala ) , so those are my conclusions

anyway - check those sims with ears , and use whatever suits you more
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Last edited by Zen Mod; 2nd October 2012 at 05:48 PM.
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Old 2nd October 2012, 07:09 PM   #2207
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Old 3rd October 2012, 03:36 AM   #2208
lhquam is offline lhquam  United States
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Regarding sims (and nuclear arms treaties): Trust But Verify!

My objective is to understand how to get the best measured performance, and then add back harmonics in a controlled fashion. If I can null the H2 effects of the transformer interwinding capacitances, then I can controllably add H2 back with the Zen Pot.

Quote:
Originally Posted by Zen Mod View Post
I was thinking of better/tighter magnetic coupling between P and S

it is always better when you have P:S:P:S , than S:P:S

for my logic , better signal transfer will result in greater verity , even taking in account increased capacitive losses

I spent some time playing with MM and MC heads feeding various xformers , amongst others even repeaters (my lucida intervala ) , so those are my conclusions

anyway - check those sims with ears , and use whatever suits you more
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Old 3rd October 2012, 05:21 AM   #2209
BudP is offline BudP  United States
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A P,S/S, P winding format, with an increase in wire size by one AWG diameter in the outer P, to help balance DCR and with the secondaries wound bifillar should eliminate all of these considerations. The two secondaries will be tightly coupled to each other, but this should be an improvement in distortion characteristics.

Bud
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Old 3rd October 2012, 05:28 AM   #2210
lhquam is offline lhquam  United States
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I am working with the Jensen JT-123-FTPCH transformer which is quadfillar. I am assuming (possibly incorrectly) that the windings are identical and have equal couplings to each other.

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A P,S/S, P winding format, with an increase in wire size by one AWG diameter in the outer P, to help balance DCR and with the secondaries wound bifillar should eliminate all of these considerations. The two secondaries will be tightly coupled to each other, but this should be an improvement in distortion characteristics.

Bud
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