First Watt F1 with 30W output power

[Adams_Leo]

I have buit SOZ with 10w output power,the sounds very nice and nature.I plan to build the F1 power amplifier with 30W output. Anybody can help me modify the schematic with 30W power outpu?thanks in advice

Per Nelson's request not to publish schematics but rather link to his site I removed the picture and added the link to the manual

/Netlist

[Netlist]

As the F1 is intended to use with very high efficiency loudspeakers in the range of +90dB/watt, cranking up the volume to as high as 8 watts will result in 99dB of headroom. Perhaps there’s a way to make the amp deliver more power but I presume we will deviate from the original idea of simplicity and thus will be penalized soundwise. The F1 was designed to work only well with a limited amount of speakers, being high efficiency and full range as their most important parameters.
Not wanting to temper your enthusiasm, could you tell us what speakers you have in mind?

/Hugo

[Tweeker]

I think ~20watts would be possible without resorting to more devices with oodles of cooling and flogging it hard. Reliability would suffer, burning FETs is one thing, just dont burn any fancy drivers.

F1 in qualifying trim?

[altor]

Originally posted by Adams_Leo
I have buit SOZ with 10w output power,the sounds very nice and nature.I plan to build the F1 power amplifier with 30W output. Anybody can help me modify the schematic with 30W power outpu?thanks in advice

Per Nelson's request not to publish schematics but rather link to his site I removed the picture and added the link to the manual

/Netlist

Adams_Leo, the input power of the 1st_w is 100W/one ch. - i.e efficiency=10% (@ 8 Ohm load).
If you built 30W you need 300W per channel, you are ready ?

If yes, you should increase the voltage from 24v up to 45-50v, and increase the current (decreasing R27 & R28)

[Tweeker]

I think 30 watts would mean ~75w/device using the stock overall layout and efficiency. You might be able to drop it some by tailoring it to a specific load, either sacrificing voltage for low impedance or current for high.

[jh6you]

Adams

High power F1 . . . ?

If we have a wild horse, who has a good potential character but is too sensitive, nervous in a way and afraid of tough control, we might need a horseman to lightly stroke and calm her down. Then, we could manage to get her shining character. If we have a speaker behaving like the wild horse, we might need F1 as the horseman—i.e. the current source amp of the first watt.

As far as I understand, Nelson likes F1 just for such first watt . . .

Good luck and Regards
jH

[Adams_Leo]

Originally posted by Tweeker
I think ~20watts would be possible without resorting to more devices with oodles of cooling and flogging it hard. Reliability would suffer, burning FETs is one thing, just dont burn any fancy drivers.

F1 in qualifying trim?

yeah,I think 20W power output would be better.

Originally posted by altor


Adams_Leo, the input power of the 1st_w is 100W/one ch. - i.e efficiency=10% (@ 8 Ohm load).
If you built 30W you need 300W per channel, you are ready ?

If yes, you should increase the voltage from 24v up to 45-50v, and increase the current (decreasing R27 & R28)

altor,thanks,I will try it.I have purchased the heatsink for this.

[Adams_Leo]

Originally posted by jh6you
Adams

High power F1 . . . ?

If we have a wild horse, who has a good potential character but is too sensitive, nervous in a way and afraid of tough control, we might need a horseman to lightly stroke and calm her down. Then, we could manage to get her shining character. If we have a speaker behaving like the wild horse, we might need F1 as the horseman—i.e. the current source amp of the first watt.

As far as I understand, Nelson likes F1 just for such first watt . . .

Good luck and Regards
jH

I use SOZ with 10w power output driver Harbeth P3,the sounds very good.now I plan to use F1 with 20~30w output to driver Dynaudio counter 1.3 SE.

[altor]

altor,thanks,I will try it.I have purchased the heatsink for this.

Try

And don't forget to tell us the results


P.S. I send you a private message.

[Adams_Leo]

Originally posted by altor


Try

And don't forget to tell us the results


P.S. I send you a private message.

Ok,I will.

I don't know how to get the private message.pls send it to my mail box.lxiaojun@cn.ibm.com