Best Firstwatt amp for backloaded horns?

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To Mr Pass or Who else has experience to answer.

In a 6 Moons page it made this statement about F4:
"If you've got a low-power SET and want to hear bass, definition and linearity you never knew you could, go humbucker and tie an F4 to its outputs"

As I'm feeling that the F3 is more for my taste.

@ 15 watts into 8r could I not at a later date, add as above states, a F4 or 2 to a F3 if I wanted more volume to drive a wider range of speakers. ?
 
I just finished the F5 and I'm giving it my first listen (Bruce Cockburn's Dancing in the Dragon's Jaws). Already it's evident this amp is more detailed and faster than the tubelab by a large margin. The bass is tighter and the treble isn't rolled off. It has a teensy little bit less "lushness" in the midrange and the vocals are a little nasal sounding. As much as I love my tubelab there's really no contest between these two, although I've only listened to one record.

To be fair to the tubelab, I'm using the cheapest 45 tubes I could find on ebay. More expensive tubes might even the contest out a little.
 
I've hooked up a Grounded Grid preamp, and now the nasal sound is gone. I was using a 100k passive pre before, I don't that's a good match for the F5. I also think the heightened resolution of the F5 is revealing the chintzy sound of the opamp-based Bugle phono stage I'm using. Next project will be a jfet phono, maybe the Pearl 2...
 
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Wow, I'm already on my second firstwatt amplifier, the F2. I bought PD's boards and stuffed both channels before I realised Cviller's F5 psu board can't be rejiggered to output dual +24 supplies that the F2 needs.

Luckily I bought PD's PSU boards, and my plan is to use these boards for both the F2 and F5 with jumpers to switch between dual +24 and +/-24. However, I noticed the F2 PSU schematic uses 1 ohm resistors whereas the F5 uses .47 ohm. Are these values critical, or are either fine for both amplifiers?
 
Thanks, Tea-Bag. I'll repurpose the cviller f5 psu for the Pearl 2 I intend to build. I'm looking forward to your semisouth GB so I can turn this f2 into an F2J!
Cooking right along, aren't you?

:cool:

Yeah... Building a firswatt amp was supposed to just be an experiment, a different flavor to plug into my system from time to time. But it's just so damn good that I can't go back to the Tubelab SE!But even though it's considerably better in virtually every way, I do miss that touch of tube sweetness. I hope either the F2 or F3 will get me a little closer to that tube sound without losing the supreme clarity and immediacy of the F5. But if I have to chose between the crystal clarity of the F5 and the mellow sweetness of a SET, I'll take the F5 any day of the week.

And of course the F5 has illuminated other weak spots in my audio chain. So I'm also building a DCB1 (almost done, just waiting on a transformer) and next I'm going to P2P a Pearl 2. I've also cast doubt on my beloved backloaded horns, so I'm planning to build an open baffle. it turns out Ron Clark, who designed the backloaded horns I'm using, is now running an OB in his own system. And an OB opens the door to biamping and active crossovers... It never ends!

Also, I've come to realise about 80% of the music I own is just terribly recorded. Nothing I can do about that, though.
 
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you can always use F5 for a bass amp. It's what I am doing. Driving a 3 ohm load just fine.
I would choose any SemiSouth enhanced product over an F3 personally. The F3 maybe to SET sound for me or something. I did not like it. The F2J has punch, and a 'cleaner sound' than default F2. I've been listening to the F2J in OB into a lowther, and it's closer than you think to the F5, good sense of atmosphere. It doesn't have the dynamic punch of F5, but you may not need that in OB. If you didn't have F5 to compare it to you may not know. You can get the F2j to sound differently by changing the source resistance a bit, gate resistors etc. Of course a current type compensation across the terminals helps a bit, and can change the sound of F2.
 
I guess I should spend time tweaking the F2j before I move on to an F3. I already have the matched jfets for an F3 so I might as well build it someday.

I managed to buy a pair of Coral "Holey basket" fullrangers on ebay for a decent price, which are apparently a variant of FE103a, and a pair of Eminence alpha 15a's. Assuming the drivers are in good condition, I'll start work on the OB this spring.
 
blue lander,

can you please provide an update on your listening impressions between your F2J and F5 builds? Also, does the F2J have enough juice with the B1?

Curious to know as I am about to begin an F2J BOM collection, but the F5 is nawing at me also... :)
 
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