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Old 1st November 2007, 06:27 PM   #21
Magura is offline Magura  Denmark
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Default Re: Re: Re: "Circumcising" the F3

Quote:
Originally posted by apassgear


I run something very similar to this with input buffer and a CLC PSU and results are just as good, though different lineamp, in this case toobs.

Oh yes, I forgot to mention the PSU, but it's important that it's a CLC filter, as the PSU noise rejection of this topology is not very high. If only using a C filter, you can hear the 100Hz when using sensitive speakers.

I found that 5mH and 2*68.000uF keeps the noise down.


Magura
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Old 1st November 2007, 06:28 PM   #22
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Default Re: Re: Re: Re: Re: "Circumcising" the F3

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Originally posted by Vix


.....
Btw, I don't like politics nor politicians. We'd be much better off if they listened to music instead of doing what they do: :bs:

.......

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Old 1st November 2007, 06:59 PM   #23
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Default Re: Re: Re: Re: "Circumcising" the F3

Quote:
Originally posted by Magura



Oh yes, I forgot to mention the PSU, but it's important that it's a CLC filter, as the PSU noise rejection of this topology is not very high. If only using a C filter, you can hear the 100Hz when using sensitive speakers.

I found that 5mH and 2*68.000uF keeps the noise down.

Magura
In my case I use two secondaries, one each channel, with 15mf + 10mH + 20mf with no apreciable noise on a FE164
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Old 4th November 2007, 06:59 AM   #24
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Default Re: Re: Re: Re: Re: "Circumcising" the F3

Quote:
Originally posted by Vix


Btw, I don't like politics nor politicians. We'd be much better off if they listened to music instead of doing what they do: :bs:

I'm lucky: I'm an engineer . . .


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Old 4th November 2007, 04:40 PM   #25
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Default Re: Re: "Circumcising" the F3

Quote:
Originally posted by Magura
I agree that the aleph CCS is to be omitted for the Z 9, I took a step back and simply modified a Z 1 to fit the bill. The upper spectre improves, and not so long ago somebody posted measurements that backed this up. The reason it sounds better without the aleph CCS seems to be that the aleph CCS is not adding the same amount current at all frequencies.
The current source has a flat response with regard to frequency.

Disabling the AC current gain in the current source does result
in a different spectrum because the circuit cancels some second
harmonic. At the same time though, it dramatically reduces the
total distortion by effectively doubling the load impedance.

So you have a choice - Lots of second harmonic with lower power,
or much lower distortion. Me, I was pleased to see THD figures
as low as .003% at 1W, 1KHZ. You would not see anything like
that with the constant current source.

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Old 4th November 2007, 04:49 PM   #26
Magura is offline Magura  Denmark
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Default Re: Re: Re: "Circumcising" the F3

Quote:
Originally posted by Nelson Pass


The current source has a flat response with regard to frequency.

Disabling the AC current gain in the current source does result
in a different spectrum because the circuit cancels some second
harmonic. At the same time though, it dramatically reduces the
total distortion by effectively doubling the load impedance.

So you have a choice - Lots of second harmonic with lower power,
or much lower distortion. Me, I was pleased to see THD figures
as low as .003% at 1W, 1KHZ. You would not see anything like
that with the constant current source.

Hmm, we have made a few blind tests of this, and the conclusion was that people preferred the CCS ov the active curret source. Yes distortion is sure higher with the CCS, this is also the result I have come to, so what could the reason for the preferrence of the CCS be then?

I wonder if this is one of those cases where it's the distortion people like?

Magura

EDIT:

Untill I have found the graphs that showed the non liniarity of the active current source....let's just say that it's my memory playing tricks on me
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Old 5th November 2007, 12:44 AM   #27
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I have no argument with those that say they like the sound of
a CCS over an Aleph, or those who like the sound of a resistor
or a CCS, but curves is curves...

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Old 5th November 2007, 10:16 AM   #28
Fuling is offline Fuling  Sweden
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I guess that the speaker load should be taken into consideration too. A 3-way bass reflex speaker would probably sound better with the active CCS while Lowther or Fostex drivers might sound better without it.
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Old 6th November 2007, 02:08 AM   #29
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Quote:
Originally posted by Fuling
I guess that the speaker load should be taken into consideration too. A 3-way bass reflex speaker would probably sound better with the active CCS while Lowther or Fostex drivers might sound better without it.
I agree. The Aleph CCS is there to provide additional current on low impedances. That's why an Aleph 3 sounds bigger than its rating. Turbo...when you need it.
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Old 6th November 2007, 02:17 AM   #30
Magura is offline Magura  Denmark
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Quote:
Originally posted by Fuling
I guess that the speaker load should be taken into consideration too. A 3-way bass reflex speaker would probably sound better with the active CCS while Lowther or Fostex drivers might sound better without it.

Quote:
Originally posted by Blues


I agree. The Aleph CCS is there to provide additional current on low impedances. That's why an Aleph 3 sounds bigger than its rating. Turbo...when you need it.

The test was performed with a FE166E based Abbey clone, so we agree this far. What I don't understand is why, now that Nelson tells us that the Aleph current source is 100% liniar all the way?
He is right that the regular CCS does result in higher distortion.



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