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Old 17th November 2016, 04:35 AM   #11
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Originally Posted by needtubes View Post
Perhaps a variation on the Aleph CCS?
Single ended may even mean that the circuit is just not a balanced circuit like the rest of the XA series.
I'm not willing to bet the house on it either way.
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Old 17th November 2016, 05:21 AM   #12
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I did a quick mock-up in SPICE based on the description linked in the first post. While just a basic mu-follower, it simulates very well and matches the stated specs fairly well.
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Old 17th November 2016, 05:57 AM   #13
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Originally Posted by 2 picoDumbs View Post
Single ended may even mean that the circuit is just not a balanced circuit like the rest of the XA series.
I'm not willing to bet the house on it either way.
clever cheapskate can always joggle with approach to and difference between balanced , symmetrical and differential .......
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Old 17th November 2016, 08:41 AM   #14
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Originally Posted by needtubes View Post
I did a quick mock-up in SPICE based on the description linked in the first post. While just a basic mu-follower, it simulates very well and matches the stated specs fairly well.
The only problem is, this seems to suggest a different front end,

"The simple front end circuit uses uses two pairs of NOS complementary Fets in common-source mode"
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Old 17th November 2016, 08:49 AM   #15
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If you look at the F1 it's described as a Ballenced Single ended so I assume the same term could be applied to the X series of amps. FIRST WATT F1
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Old 17th November 2016, 08:58 AM   #16
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The latest XA .8 series amps have complementary push pull output stages, although they do have a small amount of single ended bias.
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Old 17th November 2016, 09:08 AM   #17
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I wonder whether a Taylor Current Source (source follower output) might be used.
Would that be considered single ended? Or is that cheating.
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Old 17th November 2016, 02:09 PM   #18
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The artwork linked above doesn't show the two large power resistors mounted to the center heatsink on each side.
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Old 17th November 2016, 02:38 PM   #19
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Quote:
Originally Posted by 2 picoDumbs View Post
The only problem is, this seems to suggest a different front end,

"The simple front end circuit uses uses two pairs of NOS complementary in common-source mode"
Yep, I accounted for that. Used complementary JFETs in front end with IXYS mu-follower on output. Got results which were pretty close to the published specs. Power output matched into 2, 4, 8-ohms, distortion at 25W into 8-ohm was similar, but max power distortion into 2, 4-ohms was higher in my simulation.
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Old 17th November 2016, 02:55 PM   #20
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Quote:
Originally Posted by needtubes View Post
Yep, I accounted for that. Used complementary JFETs in front end with IXYS mu-follower on output. Got results which were pretty close to the published specs. Power output matched into 2, 4, 8-ohms, distortion at 25W into 8-ohm was similar, but max power distortion into 2, 4-ohms was higher in my simulation.
Interesting!
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