Wanted - First Watt F5 good DIY build

[montesquieu]

Is there no penalty for driving these chips hard? Otherwise why run them gently at all, as in the original?

[Bksabath]

There is a common opinion that 1.3 A bias is the ideal for sound quality whit the stock mosfets or about 25 W dissipation on each so the stock / Vanilla version runs at 18 V 1.3 A

Whitout cascading the maximum voltage for the inputs Jfet is at around 30 Volts and as the mosfets are voltage driven it is quite easy to drive several of them in parallel the limiting factors became the size of the heath sink and the quality of the coupling and as one push the output voltage the propensity of the amplifier to go in to current clipping, that is much worst than voltage clipping.
Then one must consider that if the Mosfets break down they became closed circuit, so one end up whit the full rail voltage at the output, broken speakers and GF telling you I told you so
I have the NTE7100 speaker protection on mine whit amplimo relays it all ads up to the cost
I would certainly like to ear mine's whit a pair of Tannoy instead of the Polk IMO if you have Tannoy the vanilla version should be plenty

[montesquieu]

if you have Tannoy the vanilla version should be plenty

Was pleasant enough but not enough to really get the bottom octave sounding properly compared to my 100w Radford STA100 or even the 35w STA25 I'm running while this gets restored.

Tannoy HPDs have a fairly complex crossover and also braced cones that need a lot more control than the earlier Gold series. It wasn't a good match.

[montesquieu]

For those interested I've just posted a mini review of the incoming power amp http://theartofsound.net/forum/showt...654#post935654

[disarmamant]

I’d like to try a well built F5 power amp in my system as an alternative to valves. Does anyone have one that they’d like to sell please?

Thanks, jake

Jake - If you are still looking this one looks good over on PFM

http://www.pinkfishmedia.net/forum/t...hannel.211059/

[lordmortlock]

Thanks Martin, thanks for looking out for me. It’s looks very well built but a fair bit more than I was expecting to pay for a diy unit.

[Brumjam]

Thanks Martin, thanks for looking out for me. It’s looks very well built but a fair bit more than I was expecting to pay for a diy unit.

Indeed. The parts cost (including the case) should be approx £500 - £700, maybe a bit more if boutique components have been used, but these amps sound great using the std BoM.

[anubisgrau]

1750 may be just about the right price, if not too expensive, for a used stock version.

there used to be a US builder who was selling FW amps at diyaudio.com forum. long time ago, i would say 10 years since he was massively loathed there. he was able to cut down costs on irrelevant parts (chasis) so was affordable, say $500. i used to have his F3 and it sounded as good as it gets. can't remember the name though, they appear from time to time.

i would certainly extend the search to aleph series of sufficient power. F5 is hyped but in reality, sound-wise, not any better than alephs so a synergy with speakers may be more important.

[hifinutt]

Indeed. The parts cost (including the case) should be approx £500 - £700, maybe a bit more if boutique components have been used, but these amps sound great using the std BoM.

yes i was thinking that about that amp
winters audio have a f1 if you get stuck

[lordmortlock]

1750 may be just about the right price, if not too expensive, for a used stock version.

there used to be a US builder who was selling FW amps at diyaudio.com forum. long time ago, i would say 10 years since he was massively loathed there. he was able to cut down costs on irrelevant parts (chasis) so was affordable, say $500. i used to have his F3 and it sounded as good as it gets. can't remember the name though, they appear from time to time.

i would certainly extend the search to aleph series of sufficient power. F5 is hyped but in reality, sound-wise, not any better than alephs so a synergy with speakers may be more important.

Tim Rawson iirc Gordan ... I remember reading about his amps. The thrust seemed to be that the diy community had an issue with him profiteering from the pass schematic that had been released for the benefit of self builders