First Watt F3 - what are the thoughts a year after?

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anubisgrau

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Hello aa

By the end of February I will take on a delivery of my new speakers which are 114db multihorns - 2x15" active bass in an isobarik chamber with BMS DC driver for 300-25k hz duties in a tractrix horn.

So it's time to think about a proper amplification for these. The manufacturer recommends a highly tweaked gainclone: I've heard it and despite overall excellent impressions I thought it lacks a final touch of "life" that only a great SET can give.

The caveat is that my system is used by my lady too and we also have 3 cats so my attention was caught by the reviews of F3 that it may be a good solution for these who wants SET sound but can't have valves for different reasons.

I am aware that it is often that a product is welcomed as a killer of this and of that, however only time will tell the truth. So my post is addressed to those who have an extensive experience with F3: how does it really behave in a room on a long run. Is it a keeper or its SS nature is still something it can't runaway from.

My listening priorities are an overall sense of "live"-ness, good drive and dynamic capabilities, but also a natural and sweet timbre and tone.

Another option for me would be to mod my current Altmann BYOB which is I'm afraid unsufficient for really outstanding results in its stock form. It took me quite some time to listen to it in a highly revealing system to realize that there is much more to an amp duty than what it delivers.

jrebman

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Re: First Watt F3 - what are the thoughts a year after?
« Reply #1 on: 6 Jan 2008, 08:51 pm »
I don't know about the F3, but the F1 and F4 run quite hot -- 50 degrees C or more, so don't know if that's a consideration or not.  I believe you can build a lower power version of the F4 that may run a bit cooler, but I may be confusing this with something else.  BTW, the F4 is basically a unity gain (actually very slightly less) current buffer amp, or impedance converting amp, that depends on the linestage for voltage gain.

I'm intrigued enough that I've bought a set of boards and PSU boards for the future -- which you can do through Peter Daniel on the diyaudio forum.  See the classifieds section and the wtb: pc boards for F4 thread.  This amp supposedly combines the best attributes of the previous F series amps.

Or... how abvout a tube cage :D.

-- Jim


anubisgrau

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Re: First Watt F3 - what are the thoughts a year after?
« Reply #2 on: 6 Jan 2008, 09:01 pm »
I don't know about the F3, but the F1 and F4 run quite hot -- 50 degrees C or more, so don't know if that's a consideration or not.  I believe you can build a lower power version of the F4 that may run a bit cooler, but I may be confusing this with something else.  BTW, the F4 is basically a unity gain (actually very slightly less) current buffer amp, or impedance converting amp, that depends on the linestage for voltage gain.

I'm intrigued enough that I've bought a set of boards and PSU boards for the future -- which you can do through Peter Daniel on the diyaudio forum.  See the classifieds section and the wtb: pc boards for F4 thread.  This amp supposedly combines the best attributes of the previous F series amps.

Or... how abvout a tube cage :D.

-- Jim



That's another thought I've had, however I was warned that it's not certain how would F4 behave with a rather complicated filter my horns utilize. For sure a current amp won't work, it needs a standard gain feed to work. The another caveat is that IMHO F4 shifts the responsibility for speakers' drive from a power amp to a pre so it would open another Pandora's box: to find a really outstanding, dead quiet preamp with enough gain. Currently I have EAR 864 which is excellent but I don't know how it would behave in such a scenario, as well as a TVC that would be out of question.

sts9fan

Re: First Watt F3 - what are the thoughts a year after?
« Reply #3 on: 6 Jan 2008, 09:32 pm »
The F1-3 are current source amps.  They are generally considered inappropriate for use with passive crossovers.

anubisgrau

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Re: First Watt F3 - what are the thoughts a year after?
« Reply #4 on: 6 Jan 2008, 10:02 pm »
The F1-3 are current source amps.  They are generally considered inappropriate for use with passive crossovers.

F3 is not a current amp, it's a gain amp (15db gain I think).

sts9fan

Re: First Watt F3 - what are the thoughts a year after?
« Reply #5 on: 7 Jan 2008, 01:15 pm »
I was wrong.  The F3 is a voltage source. 

JoshK

Re: First Watt F3 - what are the thoughts a year after?
« Reply #6 on: 7 Jan 2008, 02:31 pm »
That's another thought I've had, however I was warned that it's not certain how would F4 behave with a rather complicated filter my horns utilize. For sure a current amp won't work, it needs a standard gain feed to work. The another caveat is that IMHO F4 shifts the responsibility for speakers' drive from a power amp to a pre so it would open another Pandora's box: to find a really outstanding, dead quiet preamp with enough gain. Currently I have EAR 864 which is excellent but I don't know how it would behave in such a scenario, as well as a TVC that would be out of question.

I, personally, think the Aikido amp is just about the perfect gain stage for the F4.  Apparently I am not alone, since many others have already done this.  I ordered some F4 boards to play around with at some point.  6SL7 into 6SN7 yields around 29dbs of gain with low noise (due to noise canceling), low distortion and low output Z. 

Do you have a impedance curve for your drivers with network?  How about phase angle w/ freq?  Those two together should tell you what you need to know about how hard it is to drive for any amp. 

jrebman

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Re: First Watt F3 - what are the thoughts a year after?
« Reply #7 on: 7 Jan 2008, 04:27 pm »
I too think the Aikido would be a great choice to drive the F4 with.  You could even build as a dual mono and take it another step up.  I believe many folks are using their F4s with multi-way speakers with passive crossovers.  As to how friendly those crossovers are, you'd probably have to weed thrugh the giant thread on diyaudio to find out specific speakers.  I'm quite confident that the ACI Sapphires will be fine with this amp.

-- Jim

Les Lammers

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Re: First Watt F3 - what are the thoughts a year after?
« Reply #8 on: 26 Jan 2008, 08:14 pm »
Hello aa

By the end of February I will take on a delivery of my new speakers which are 114db multihorns - 2x15" active bass in an isobarik chamber with BMS DC driver for 300-25k hz duties in a tractrix horn.

So it's time to think about a proper amplification for these. The manufacturer recommends a highly tweaked gainclone: I've heard it and despite overall excellent impressions I thought it lacks a final touch of "life" that only a great SET can give.

The caveat is that my system is used by my lady too and we also have 3 cats so my attention was caught by the reviews of F3 that it may be a good solution for these who wants SET sound but can't have valves for different reasons.

I am aware that it is often that a product is welcomed as a killer of this and of that, however only time will tell the truth. So my post is addressed to those who have an extensive experience with F3: how does it really behave in a room on a long run. Is it a keeper or its SS nature is still something it can't runaway from.

My listening priorities are an overall sense of "live"-ness, good drive and dynamic capabilities, but also a natural and sweet timbre and tone.

Another option for me would be to mod my current Altmann BYOB which is I'm afraid unsufficient for really outstanding results in its stock form. It took me quite some time to listen to it in a highly revealing system to realize that there is much more to an amp duty than what it delivers.

I had the F-3 for a while and sold it. *I* never had/found the right preamp for it. *I* did not think it sounded like tubes. Depending on the complexity of your crossover, 10 watts may not be enough even with 114db speakers. I know someone who has $$$ GOTO compression drivers that are 106db and ten watts was not enough. Are these speakers you designed yourself?

Paul_Bui

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Re: First Watt F3 - what are the thoughts a year after?
« Reply #9 on: 26 Jan 2008, 08:59 pm »
I've been quite happy with a GC amp (AS Patek SE) and a tube pre (SP MPX3) driving a single driver speaker via the BYOB DAC.  I'd check out Decware ZEN 26w Torii mk II (no preamp needed).

Oh, I had an FW F2 for a while and sold it.

Telstar

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Re: First Watt F3 - what are the thoughts a year after?
« Reply #10 on: 19 Jul 2009, 10:20 am »
I have a F3 for a few months already, and it's a keeper.

However, it DOES NOT LIKE passive crossovers. 15W are enough to drive directly a fullrange or midrange of 95db+ efficiency.
Preamp match is also difficult with a tube-like impedance.

PaulFolbrecht

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Re: First Watt F3 - what are the thoughts a year after?
« Reply #11 on: 9 Sep 2009, 07:30 pm »
I have a F3 for a few months already, and it's a keeper.

However, it DOES NOT LIKE passive crossovers. 15W are enough to drive directly a fullrange or midrange of 95db+ efficiency.
Preamp match is also difficult with a tube-like impedance.

I really have to disagree about your crossover comment.  I drive my Audio Note AN/Es with the F3 and it is very dynamic and snappy and sounds extremely good.  In fact it goes toe to toe with my favorite 45 SET amp in terms of tonality (and is more dynamic and extended).

My transformer-couple Audio Note Kits L3 seems to be a perfect match as well.

sts9fan

Re: First Watt F3 - what are the thoughts a year after?
« Reply #12 on: 9 Sep 2009, 07:40 pm »
I would also disagree on the crossover comment.  I have used mine ( Zv9)  with a few crossovers, no crossover and 1st order high pass filters.  All with great success.  Also I think Nelson would disagree that it is difficult to match a pre to.

Quote
The input impedance is the IHF standard of 10 Kohms, and the input capacitance
is very low, so you should find it easy to drive with tube equipment if you like. It
would be a pitiful source that would not be able to deliver 240 micro-amps
required to clip this amplifier. The amplifier is largely indifferent to the source
impedance of your preamp, so a high source impedance is not a problem.


Low gain is the only issue so you would want the pre to be 12-20db.   

PaulFolbrecht

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Re: First Watt F3 - what are the thoughts a year after?
« Reply #13 on: 9 Sep 2009, 08:54 pm »
I would also disagree on the crossover comment.  I have used mine ( Zv9)  with a few crossovers, no crossover and 1st order high pass filters.  All with great success.  Also I think Nelson would disagree that it is difficult to match a pre to.

Quote
The input impedance is the IHF standard of 10 Kohms, and the input capacitance
is very low, so you should find it easy to drive with tube equipment if you like. It
would be a pitiful source that would not be able to deliver 240 micro-amps
required to clip this amplifier. The amplifier is largely indifferent to the source
impedance of your preamp, so a high source impedance is not a problem.


Low gain is the only issue so you would want the pre to be 12-20db.

Yeah, I'm aware Nelson says source Zout doesn't matter and I bet he's right.  Anyway, a low Zout is always good!

My AN/Es are realistically about 95 dB/W and the AN pre's gain 18 dB.  The vol control is normally open a quarter to a third, with about 12:00 being the max and very loud on most material.  So, with reasonably sensitive speakers a moderate-gain pre would be just fine.

dspringham

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Re: First Watt F3 - what are the thoughts a year after?
« Reply #14 on: 10 Sep 2009, 02:15 am »
Paul,

Any comments on the F-3 pushing your Tonian TL-D1's?

Dave

PaulFolbrecht

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Re: First Watt F3 - what are the thoughts a year after?
« Reply #15 on: 10 Sep 2009, 02:19 am »
Paul,

Any comments on the F-3 pushing your Tonian TL-D1's?

Dave

Also an excellent match.  Since the Tonians are just a bit hot in the midrange the slightly more mellow mids of the F3 compared to the Korneff 45 is nice. The Tonian speaker seems to be a bit more efficient than the AN/E and so the extra power of the F3 isn't as noticeable.

Basically every permutation of these two speakers and amps is heavenly. :)