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Old 20th October 2009, 08:30 AM   #251
DQ is offline DQ  Romania
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Originally Posted by Jon Ver Halen View Post
It has actually been awhile since I plugged the F2 into the system, so detailed comparisons are not to be made. In general, my recollection is that the F2 is not as clean as the F1, and not as sweet as the J2. It seems to me that a single ended version using the J-Fet of the J2 should have merit, which is why I asked Nelson to upgrade mine. After hearing his simple power J-fet SE amp at Burning Amp, I feel even stronger that this deserves to be explored.

Hopefully, my F2 will receive a transplant, and I will report back later.
Thank you very much Mr. Ver Halen and I'm eagerly waiting for your future impressions on the improved F2. For reasons I will not go into right now, my mind is pretty much set on building an F2 and all this talk about the new potions The Mighty Wizard Mr. Pass is preparing for making this design even better is making me very excited.
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Old 20th October 2009, 08:31 AM   #252
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Originally Posted by R-K Rønningstad View Post

... that discussion/guesswork almost was (is?) whether resistors should be 332 or 330 ohm, almost that level. And that is missing the point, I believe.

-rk
Forgive my naive curiosity.
I hadn't noticed this forum was for E.E. only.

Last edited by bobodioulasso; 20th October 2009 at 08:36 AM.
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Old 20th October 2009, 09:08 AM   #253
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I think what he was trying to say was, we don't need to try and copy Nelsons design to the nth degree nor should we worry too much about every detail of the design.
The basic topology that Nelson has provided is more than enough.
I think we should be using that topology to make the design as simple as possible (Zen like) we needn't concern ourself with trying to match Nelson's design at this point in time.
Let us be free to use our own zen creativity on this one.

Well I think that was what he was trying to say.

Last edited by Melon Head; 20th October 2009 at 09:11 AM.
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Old 20th October 2009, 03:05 PM   #254
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Originally Posted by bobodioulasso View Post
Forgive my naive curiosity.
I hadn't noticed this forum was for E.E. only.
Sorry, bobodioulasso, I did not mean to be rude. The forum should be open for all kinds of questions. It is not always so easy to see what is important, and what is not so important. And in the end, maybe what seems not so important, after all IS important!
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Old 20th October 2009, 03:37 PM   #255
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The full review from 6moons is out.



6moons audio reviews: FirstWatt J2
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Old 20th October 2009, 04:29 PM   #256
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Originally Posted by Nelson Pass View Post
The full review from 6moons is out.



6moons audio reviews: FirstWatt J2
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Old 20th October 2009, 09:01 PM   #257
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Originally Posted by Jon Ver Halen View Post
The biggest potential weakness of the current source amp (F1 or F2) is its bass. With no real damping factor, you had to rely on the speaker and cabinet to provide and damping. The J2, with its lower output impedance, does a much better job of controlling the bass for most speakers. (Yes, the J2 is a voltage source amp, not a current source amp).

Perhaps the ideal speaker for a current source amp is a back loaded horn. It has plenty of internal damping, and the increased impedance at resonance created a situation where the current source could better drive it. Under these conditions, the current source is the better amp for bass.

So, as always in this sport, you have to balance your system.

So Jon are you saying that the F1 and J2 are both equally resolving of inner detail and texture of music but what makes the difference is the damping factor; F1 in BLH = J2 in non-BLH. Or does the F2 have an edge in detail, speed and musicality?
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Old 21st October 2009, 01:54 AM   #258
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Originally Posted by Samuel Jayaraj View Post
So Jon are you saying that the F1 and J2 are both equally resolving of inner detail and texture of music but what makes the difference is the damping factor; F1 in BLH = J2 in non-BLH. Or does the F2 have an edge in detail, speed and musicality?
I think it is more than just the damping factor, but I have not done a close side by side comparison. The J2 sounds just a touch sweeter, and a little "softer" in comparison to the F1. F1, as I recall, is a tad more dynamic. They sound extremely similar, with just minor shades of coloring. Not sure which one is closer to the mythical "straight wire with gain", and you get to decide which one sounds better to you.
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Old 21st October 2009, 08:42 AM   #259
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Originally Posted by Tea-Bag View Post
Time for me to read the review of the real J2...
I have read it and it is interesting. Adds SE listening impressions and a bit more.
Nelson's pdf article (linked there) about the sweet spot is a must read instead.
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Old 21st October 2009, 08:47 AM   #260
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Originally Posted by Jon Ver Halen View Post
I think it is more than just the damping factor, but I have not done a close side by side comparison. The J2 sounds just a touch sweeter, and a little "softer" in comparison to the F1. F1, as I recall, is a tad more dynamic. They sound extremely similar, with just minor shades of coloring. Not sure which one is closer to the mythical "straight wire with gain", and you get to decide which one sounds better to you.
Thanks Jon. More than enough details.

When diyers made their own F5, many said that it was the best amp they had ever heard. No doubt that the F5 is what people say it is.

But from what you say, it seems that if the F1 is implemented with a good FR driver is a BLH or VTL type of enclosure, one could almost touch what the J2 can deliver with a wider array of speaker configurations.

This is as good as it gets, before Nelson supersedes these comparable performances with newer parts (perhaps, custom made) and intuitive designs.

Nelson, hats off to you. You are a wizard. Thanks a ton.
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