POLL: Which is your fave Pass design ? F3, F4, F5, AJ

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J

Jay

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AudioSan said:
whitch amp sound better?
thats the most impossible question there is.
whats your definition of good. and what do the rest of your system sound like? every piece counts. one amp can sound good with X system and the other amp sounds best with the Y system.
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This thread is not about the best amp. This is about favorite amp.

Nelson Pass said:
On the less forgiving side, the F5.
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About 2 amps where one (Amp#1, e.g F5) has low overall distortion and the other (Amp#2) has higher overall distortion but with pleasant distortion, there are common 2 ways of seeing it:

1) Amp#1 is accurate and "true to the source", so sometimes it can sound harsh and boring. (--> POSITIVE)

2) Amp#1 can play complex music better but for most music it is often less musical, harsh and boring (--> NEGATIVE)

About "true to the source", I don't see it that way. To me:

3) Simple circuits tend to have problems. Do you want to mask the problem or not?

By seeing it that way I don't accept that accurate system must be boring or harsh, and there is always hope for better system.

Mosfet drive is very important if you can hear subtle difference in sonic. And this determines if the amp is musical or boring (Nothing to do with distortion or THD spectrum). In fact, you can make "things" cosmetically better but sound more boring (there is always trade-off, rite?).

I'm sorry, but I think experienced builders (technically capable) and listeners (love music and have good ears) will not want to live with boring non musical amp in his main system. I have seen so many high end audio builders who do not really like music.

In the F5, the JFET cannot drive IRF hexfet up to my standard. BJT input do it better. But JFET input can drive the Toshiba hexfet. Latfet is not suitable in F5 topology (it requires one more stage for proper drive).

I can see JFET-Toshiba F5 good performance only from simulation. I can see that people have built it but there is no good report yet. May be I was wrong? :confused: (or I simply do not follow those threads :D). I hope someone will report it here.
 
J

Jay

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Oh, as you can see, the master and the more experienced builders do not choose F5. I hope this doesn't dismotivate others to choose F5 :D

Don't be ashamed if you like F5. It is probably the best "overall" design for 25W amp. You just need more knowledge and skill and others to benefit from F3 or F4 :D
 
J

Jay

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Joined 2003
Melon Head said:
The PLH is due for a revisit Nelson.
I started reworking it but my design ideas were more ambitious than my ability, so I lost interest. It is always in the back of my mind though.
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There is nothing wrong with PLH simulated result, so I think the problem with sound quality might be caused by:

1) Application of feedback to the gate of input mosfet.

2) Effect of N-N configuration to supply noise rejection.

3) Bootstrap not good enough for hexfet.

If the 3 above are addressed, then it wont be a PLH anymore. So case closed for me.
 
Tea-Bag

Tea-Bag

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I've build or heard them all.

F5 you cannot go wrong, so I will vote on that. It will run in almost any system.

But Generg's ear's and taste are really close to mine. So I trust his words almost 100%.

Also, if you have full range, I think the F2J is the best sound I've ever got out of my system, within it's power limitations.
 
Botte

Botte

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OK I'm in for the BA-3, just to add another option to the list.

Very relaxed and ambient compared to F5 with more punch than the F3. The F3 is very seductive with small ensemble music and the BA-3 can handle full orchestra without strain. :)
 
R

ra7

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My vote goes to the M2. It sits right in that sweet spot - an ideal balance of truthfulness and musicality. It is so close to the 2A3 I had heard, which I thought was above everything else. But the M2 adds more power and control on the bass. Very well done!
 
N

Nelson Bass

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My favourite Firstwatt is my own variant of the J2 based on what we know about the original. I built a crippled F5 before the J2.

My preferred amp is sadly not a Firstwatt amp nor a solid state amp. I badly want a SS amp to be my last amp but that will properly only happen if NP will sell those SITs to DIY... ;-)
 
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