F5 power amplifier

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Nelson Pass

Nelson Pass

The one and only
Joined 2001
Paid Member
Nicola said:
Thanks Mr Pass, look forward to read it, hopefully there will be soon also article like the 6moons or by J Lowther to get a taste of the quality and listener differences between the several models. But may I ask you how would qualify / compare F5 to F1 or F3, if I may.

By the way, do you plan to build & sell some through RenoHifi?
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I am not planning a write of up the subjective differences between the
models, but Srajan at 6moons will undoubtedly offer his own opinion.

They will be available from Mark@renohifi shortly, although I probably
should tell him about it.

:cool:

There will be a short piece on tweaking F5's, and then the next major
article is about buffers.
 
T

TimS

Member
Joined 2004
High Power Balanced F5

To run the amp at a higher supply voltage, as some one suggested, I tried cascoding the input JFET's but I really couldn't find much advantage. I find just adding resistors fixes the problem and the performance is almost identical.

I think this is my last iteration of this design, I have tried many other variations with not much improvement in the performance. Though I may scale the design down for a preamp.

I think my next step will be to build it. I have the heatsinks, the transformers and most of the metal work for the case. I just need to design a board and find some JFETs.

Cheers

Tim
 

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Nicola

Member
Joined 2006
Subjectivty on F5

Nelson Pass said:

I am not planning a write of up the subjective differences between the models, but Srajan at 6moons will undoubtedly offer his own opinion.

There will be a short piece on tweaking F5's, and then the next major article is about buffers.
Click to expand...


Some "subjective differences" are more subjectives that others :)
& i'm pretty sure your comment are factuals. But so far is there some spec that provide an indication on power, damping factor, distortion, as you have been writing on F2, F1, none of them where that subjective.

"and then the next major article is about buffers" avaialable under FistWatt.com ?

Regards
 
T

TimS

Member
Joined 2004
jameshillj said:
Tim,
While you're at your computer, could you possibly scale this cct down to drive a pair of headphones from 32R (grado ) up to 600R (Senn), with matched pairs of k170+j74 and 610+9610? And still have Zin of >100kR?
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I could probably do that, I could make it a preamp that is able to drive headphones, but do you realize, you would have to cut the plugs off your headphones and replace them with a 4 pin plug.
 

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Nelson Pass

Nelson Pass

The one and only
Joined 2001
Paid Member
Re: Subjectivty on F5

Nicola said:
But so far is there some spec that provide an indication on power, damping factor, distortion, as you have been writing on F2, F1, none of them where that subjective.

"and then the next major article is about buffers" avaialable under FistWatt.com ?
Click to expand...

FistWatt. I like that. :cool:

Suffice it to say that the F5 has more power, more damping,
more current, more bandwidth, lower distortion, and higher
input impedance than the other F's. Many will think it sounds
better.
 
J

jameshillj

Member
Joined 2005
Yeah Tim,
Have rewired the 701s (Z=63R) and using an "unbal - bal" adapter that also includes the adjustable series resistors (varies with different amps unfortunately).
[Amazing sound connected directly to o/p of F3 (as unbal)]

Estimate about 350mA thru the 610/9610 fets, and about 5mA thru the Jfets.

Expecting some pcbs for a mini Babblefish J (from ZM) as an upgrade to Marchello Originals [also approx +/- 15v rails].

... Thanks.

Anybody, looking for a 15H (not mH!)/ 350mA+/ <15R choke for the L-C supply - any ideas?
 
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