Whats next F4, J2, or F5?

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JamieMcC

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Joined 2014
#1
Hi all

I expect I'm not alone in agonizing over choosing between the Aleph J or F5 However recently a friend of mine has graciously made the offer of a gratis set of matched mosfets for a F4 so am very curious to where the F4 might sit with regards to Nelsons comments below?

A little insight would be very much appreciated.

Cheers
Jamie


Nelson Pass said:
F5: Dynamic, accurate, a little unforgiving. On speakers with peaks in the
top end, it will reveal as too bright and annoying. On speakers with a slightly
diminished top end, it adds a little sparkle, this in spite of being flat out at
high as 500 KHz. Good control - if your speaker is a little boomy, it will tend
to tighten it up. Overall, probably the most neutral of the FW amps. It will
drive 4 ohm loads without particular issues. Oh, and it does sound very good.

J2: A more relaxed version of the F5. Decent bottom end control, a warm
midrange, excellent depth. Overall, one of the most popular pieces. Still
in production, it best hits the mainstream taste of the FW audience, probably
because it delivers a consistently pleasant sound. Not intended for 4 ohms
unless the speaker is particularly efficient, which is rare.

😎
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#3
What Zenmod said about F4, and your pre better be able to drive F4, as it has no gain. While much is personal preference, between F5 and Aleph J, no contest, Aleph J for me. Lots here depends on your speakers, room, ancillaries and volume requirements.

Russellc
 
#8
6L6 said:
If you have a preamp capable of swinging lots of volts the output, yes, build an F4.

Or use those transistors for a BA-3, which is a slightly scaled-down F5 gain stage driving an F4 output stage. It is the best of both. And can be driven by normal sources. 🙂


BA-3 Amplifier illustrated build guide


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My BA3 with 30 volt rails (As in 6L6's build guide) is one of my favorite amps, period. All the good First Watt Class A benefits, with more umpff than the regular 25 watt jobs.

Still want to build 2 more, as balanced mono block at around 100 watts per channel or so.🙂

Of the 25 watt First Watt amps, M2 and Aleph J are current faves. Sissy Sit in works, (just got delivery notice on the output SITs), F7 clone in works, J2 clone box of parts full, and M25 are waiting.....Oh, forgot my Vfet kit too!

Russellc
 
#11
6L6 said:
If you have a preamp capable of swinging lots of volts the output, yes, build an F4.

Or use those transistors for a BA-3, which is a slightly scaled-down F5 gain stage driving an F4 output stage. It is the best of both. And can be driven by normal sources. 🙂


BA-3 Amplifier illustrated build guide


.
Click to expand...


If I already have a BA-3 gainstage preamp and an F5, could I swap the F5 boards for F4 and have a BA-3 amp?
 
#12
Yes.

It would work better if you used the BA-3 complimentary output stage, but yes. You could even take the BA-3 gain stage, put it in the amplifier chassis, and use the BA-3 pre for housing a new project.
 
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