Given the choice of speakers for use w/an F5 and preamp with healthy gain which would you use/have used?
A) 2-way, 85db sensitivity, 8 ohm w/6 ohm min.
B) 2.5 way, 90-ish db, 8 ohm w/4 ohm min.
C) 3 way, 90 db-ish, 4 ohm w/3 ohm min.
I am starting to think the f5 plays nice w/a flat impedence speaker...it's not really a matter of sensitivity if you listen at sane levels (say 90db-ish). Your thoughts/experiences?
A) 2-way, 85db sensitivity, 8 ohm w/6 ohm min.
B) 2.5 way, 90-ish db, 8 ohm w/4 ohm min.
C) 3 way, 90 db-ish, 4 ohm w/3 ohm min.
I am starting to think the f5 plays nice w/a flat impedence speaker...it's not really a matter of sensitivity if you listen at sane levels (say 90db-ish). Your thoughts/experiences?
Right now, I cant say enough good about my combo in the bedroom, where my turntable is located. The speakers fall in the 8 ohms, 6ohms minimum @ 85 dB category. I believe we are using the same pre, BA-3. With B-1 I could get sane levels, but at or near full throttle which led me to a tube pre amp which also has a requisite phono section. With the BA-3 and Pearl, it is a very nice set.
I also have a set to try that are about 91dB, 4 ohms. Also Not tried yet are some Econowaves, with wave guides and compression drivers, but they are too big to haul upstairs. I have tried the F-5 on them, as well as BA-3 with digital source and that was also nice. These are pretty much 8 ohm speakers and very efficient, at least mid 90s dB.
Last, tried with F-5 and a tube pre amp were my basement set of Altec A-7, way efficient and they also sound nice, but there is no need for the extra gain...they are over 100 dB!
A large factor is also room size. When I took the smaller 85 dB speakers down stairs, they could clip a 150 watt A/B power amp at louder than normal but not insane loud levels. In the bedroom system, the room is smaller and easier to reach satisfactory levels.
Sounds like we are on similar paths... I am finishing a BA-3 Power Amp as we speak. This should end any gain needs! Let me know what you find!
Russellc
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Got Polk LSi15 very happy whit it
4 ohms nominal are not a problem whit twins on 2.6A bias and plenty loud
If one can get 7.999999 ohms and 110 dB speakers he would be Lucky Bastard
This is D I Y so get speakers U like and then make them sound better whit F5.
Plenty of scope to build as U need and can afford
F5 is plenty fast dog whit load off fight in it
4 ohms nominal are not a problem whit twins on 2.6A bias and plenty loud
If one can get 7.999999 ohms and 110 dB speakers he would be Lucky Bastard
This is D I Y so get speakers U like and then make them sound better whit F5.
Plenty of scope to build as U need and can afford
F5 is plenty fast dog whit load off fight in it
Well, I just picked up a pair of KEF R700s...3 way, 89db, 8 ohm/3.2R min. I didn't think the f5 would drive them well but surprise, surprise. No problem getting loud about 3/4 way up the dial. Good bass too. My F5 is biased high (1.7A) and seems to have no problem loud.
This speaker, although rated at 8 ohms, is really probably a 4 ohm speaker. I am going to look at adding more mossiest to get more juice for the 4 ohm load.
This speaker, although rated at 8 ohms, is really probably a 4 ohm speaker. I am going to look at adding more mossiest to get more juice for the 4 ohm load.
After a weekend more of listening I might need a little more power. The f5 is pretty comfortable up to about 85db(not peak) but after that the soundstage collapses a bit. This is with a ba3 front end, Iam using about 75 percent of the volume knob. I havent heard any clipping yet but I dont want to.
I might go to 35v rails, dual mono. This will get me a little more power. Probably wont cascode the fets unless zen mod makes a fuss. 35V is pushing it but my jfets are 8ma and i might use little sinks on them.
Another idea is to put 2 more f5 boards in the same chassis for a total of 4 channels on one psu and then biamp the speakers.
I might go to 35v rails, dual mono. This will get me a little more power. Probably wont cascode the fets unless zen mod makes a fuss. 35V is pushing it but my jfets are 8ma and i might use little sinks on them.
Another idea is to put 2 more f5 boards in the same chassis for a total of 4 channels on one psu and then biamp the speakers.
The change in sound as you increase the volume is almost certainly due to clipping of the transients.
Either increase the sensitivity of the speakers, +6dB may be affordable.
Or increase the power of the amplifiers fourfold for the same +6db of extra transient handling capability. If your speakers can handle 4 times the power !
You might be right. But I can't listen much over 85/90db these days anyways. Too loud is not relaxing.
I might look into raising the rail voltage of my F5 to 35ish volts. Any disadvantages assuming same bias on a single pair of mosfets?
Increasing the voltage gets you how much more headroom?
Work it out...
The other way to get a collapsed sound stage is to cause the PS to dip and increase substantially in ripple. The F5 is not known for excellent PSRR, so you would do well to use a power xfmr rated over current, and perhaps more filtering following the rectifier than is otherwise normal... soft recovery rectifiers might sound good too...
A single pair of Mosfets is a bit slim at 35volts. There's not really enough current capability there, imo, not to mention reasonably high output Z, certainly more Z than two pair.
Bridged is one way to get more omph, but you need "more amplifier".
Regardless, unless ur nearfield, very close and in a small room ANY ~15watt or so amplifier, Class A or not, is going to be hard pressed to reproduce any SPL, except with ~100dB class speakers.
Otoh, properly constructed (not all that simple) the F5 can sound quite wonderful.
Work it out...
The other way to get a collapsed sound stage is to cause the PS to dip and increase substantially in ripple. The F5 is not known for excellent PSRR, so you would do well to use a power xfmr rated over current, and perhaps more filtering following the rectifier than is otherwise normal... soft recovery rectifiers might sound good too...
A single pair of Mosfets is a bit slim at 35volts. There's not really enough current capability there, imo, not to mention reasonably high output Z, certainly more Z than two pair.
Bridged is one way to get more omph, but you need "more amplifier".
Regardless, unless ur nearfield, very close and in a small room ANY ~15watt or so amplifier, Class A or not, is going to be hard pressed to reproduce any SPL, except with ~100dB class speakers.
Otoh, properly constructed (not all that simple) the F5 can sound quite wonderful.
Dude next 2 doors up got plenty of SPL whit my 24 volts AC trafos
to double up on mosfets is easy. To get 2 TO 220 running at 2.6 A for 3or 4 years not so much
Build vanilla version and then up it up just get 1000VA traffo to start with
Before U waste dosh stick a meter on speakers and measure voltage or search for Pano tread How much power U really need IMO 2 or 3 volts may be enough for 50 MPH and F5 still sound pretty good
Bear can U post picture of 100dB speakers so can I ask GF blessing
to double up on mosfets is easy. To get 2 TO 220 running at 2.6 A for 3or 4 years not so much
Build vanilla version and then up it up just get 1000VA traffo to start with
Before U waste dosh stick a meter on speakers and measure voltage or search for Pano tread How much power U really need IMO 2 or 3 volts may be enough for 50 MPH and F5 still sound pretty good
Bear can U post picture of 100dB speakers so can I ask GF blessing
Well, 35V rails would get me 50W into 8 ohms...maybe enough.
I am hesitant to go from single pairs to a F5 turbo, multiple pair configuration. Everything I've read says it sounds more "relaxed". I don't want more relaxed. I am running 1.7A bias now with a 600va transformer and 6 x 33,000uf capacitance. I might have enough power but I always wonder. 99% percent of the time I don't feel the need for more...but when the wife and kids are out I like to crank it up. Everybody wants more I guess. My speakers are rated 89db with a 3.2 ohm low but looks like most of the audioband is 4-6 ohms. Would multiple pairs of outputs be wise? I know it would provide more current into 4 ohms. I don't want to lose the charm of the F5 as I know it, however.
As for the fast recovery diodes do you have a rcommendation? That's a cheap and easy thing to try. Preferably something in a "block" type case (not discrete)?
Dude next 2 doors up got plenty of SPL whit my 24 volts AC trafos
to double up on mosfets is easy. To get 2 TO 220 running at 2.6 A for 3or 4 years not so much
Build vanilla version and then up it up just get 1000VA traffo to start with
Before U waste dosh stick a meter on speakers and measure voltage or search for Pano tread How much power U really need IMO 2 or 3 volts may be enough for 50 MPH and F5 still sound pretty good
Bear can U post picture of 100dB speakers so can I ask GF blessing
Meter on the speakers is a damn good idea. Now if I can only find my pink noise cd...
That's open to misinterpretation
I know the thread is about the F5...but my 93db CT-1000's get more than they need from the F4, and in 900sq ft of space. 1/2 on the BA-3FE ( stock ) is as far as I can take it.
That's open to misinterpretation
Disregard please. I seem to have confused the etymology of Pink Floyd with that of Steely Dan
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