A new amp....for me at least..Rawson F-5
NotaSuv
Posts: 3,851
A very nice sounding Rawson built F-5 this one makes me rethink the whole more is better thing 
took quite a while to warm up but damn it sounded great..
Here's what Nelson himself has to say about the F5 :
"So far, First Watt has made a few different amplifiers: Very different amplifiers.
Quite a few people have asked me for a regular sort of amplifier, you know the kind you plug like any other, with some voltage gain and a real damping factor. Amplifiers that have low distortion and noise, and will drive a 4 ohm load.
The last time people asked for that they got the Aleph J, which satisfied most of those requirements. Single-ended Class A, the Aleph J is an easy-going design which is happy driving 8 ohm loads with a warm, relaxed presentation.
By way of contrast, I present the F5 (taa-daa!), a push-pull Class A amplifier, utilizing JFETs and MOSFETs in a very simple two stage complementary circuit a little bit like a complementary version of the Aleph J. But like all the other First Watt amps so far this one is different.
In many ways, its an ordinary topology - the basic circuit is found in numerous preamp circuits and the odd power amplifier (Check out the Profet amp from Selectronics). But the F5 is the product of numerous decisions that set it apart.
It has very wide bandwidth, DC to > 500 KHz.
No capacitors anywhere in the circuit. (except in the power supply, of course!)
It has a high input impedance 100 Kohms, and a high damping factor (~60)
The distortion is very low, between .001% and .005% at 1 watt.
Its very quiet, about 60 microvolts or so.
It will drive a 2 ohm load without burping, and 1 ohm without misbehaving.
Did I mention that it sounds terrific?"
25 watts per channel of Class A goodness.
__________________
took quite a while to warm up but damn it sounded great..Here's what Nelson himself has to say about the F5 :
"So far, First Watt has made a few different amplifiers: Very different amplifiers.
Quite a few people have asked me for a regular sort of amplifier, you know the kind you plug like any other, with some voltage gain and a real damping factor. Amplifiers that have low distortion and noise, and will drive a 4 ohm load.
The last time people asked for that they got the Aleph J, which satisfied most of those requirements. Single-ended Class A, the Aleph J is an easy-going design which is happy driving 8 ohm loads with a warm, relaxed presentation.
By way of contrast, I present the F5 (taa-daa!), a push-pull Class A amplifier, utilizing JFETs and MOSFETs in a very simple two stage complementary circuit a little bit like a complementary version of the Aleph J. But like all the other First Watt amps so far this one is different.
In many ways, its an ordinary topology - the basic circuit is found in numerous preamp circuits and the odd power amplifier (Check out the Profet amp from Selectronics). But the F5 is the product of numerous decisions that set it apart.
It has very wide bandwidth, DC to > 500 KHz.
No capacitors anywhere in the circuit. (except in the power supply, of course!)
It has a high input impedance 100 Kohms, and a high damping factor (~60)
The distortion is very low, between .001% and .005% at 1 watt.
Its very quiet, about 60 microvolts or so.
It will drive a 2 ohm load without burping, and 1 ohm without misbehaving.
Did I mention that it sounds terrific?"
25 watts per channel of Class A goodness.
__________________
Post edited by NotaSuv on
Comments
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Now you're getting a taste of what my Aleph sounds like. Simple is better --2 gain stages, single ended class A. Tim Rawson is well known cloner, but I can imagine a real F5 would even be better.
Glad you are enjoying it."Appreciation of audio is a completely subjective human experience. Measurements can provide a measure of insight, but are no substitute for human judgment. Why are we looking to reduce a subjective experience to objective criteria anyway? The subtleties of music and audio reproduction are for those who appreciate it. Differentiation by numbers is for those who do not".--Nelson Pass Pass Labs XA25 | EE Avant Pre | EE Mini Max Supreme DAC | MIT Shotgun S1 | Pangea AC14SE MKII | Legend L600 | BlueSound Node 3 - Tubes add soul! -
Now you're getting a taste of what my Aleph sounds like. Simple is better --2 gain stages, single ended class A. Tim Rawson is well known cloner, but I can imagine a real F5 would even be better.
Glad you are enjoying it.
sounds very nice and warms the room at the same time....thanks -
I just sold one of these.
Nice sounding amp, works best with a medium/high gain pre and efficient speakers."He who fights with monsters should look to it that he himself does not become a monster. And when you gaze long into an abyss the abyss also gazes into you." Friedrich Nietzsche -
I just sold one of these.
Nice sounding amp, works best with a medium/high gain pre and efficient speakers.
Thanks looking for a pre now................ -
