F5 power amplifier

[dhole]

is there a definative balanced version as of yet? I am watching the thread but my knowledge is small so Im unable to add anything usefull Nelson has mentioned two versions as possable.

Also out of intertest why are people using Mosfets other than the irfp240/9240 ?

Im also loking for a UK source of AX to no avail as of the moment...

dave

 

[bogdan_borko]

Mr Pass I simulated the amplifier and power dissipation on mosfet source resistors is about 7.5W average for 20V peak output voltage with 4 Ohms load. On the schematic you posted they`re 3W rated. Is that correct?

 

[Babowana]

I simulated the amplifier and power dissipation on mosfet source resistors is about 7.5W average for 20V peak output voltage with 4 Ohms load. On the schematic you posted they`re 3W rated. Is that correct?

As far as I understand,
the amp has max current capacity of abt 5A at peak/MOSFET.
If so, the time average power in 0.47ohms is:

P = 5*5*0.47/4= about 3W

Papa might correct me...

 

[Nelson Pass]

is there a definative balanced version as of yet? I am watching the thread but my knowledge is small so Im unable to add anything usefull Nelson has mentioned two versions as possable.

Also out of intertest why are people using Mosfets other than the irfp240/9240 ?

I have two versions, there are many more possible, none definitive.

The IRFP9240 from IR has a slight flaw which yields higher distortion,
more pronounced in Common Source applications. It's not a deal
breaker, but P channel parts from Fairchild, Harris, and others are
preferred.

 

[dhole]

I have two versions, there are many more possible, none definitive.

The IRFP9240 from IR has a slight flaw which yields higher distortion,
more pronounced in Common Source applications. It's not a deal
breaker, but P channel parts from Fairchild, Harris, and others are
preferred.

I hadnt realised that the part number there is the IR version ( riding a bull in search of a bull) , so the Fairchild version of the same chip is better. I see. Is mixing manufacturers a sin ? ( insert : incompatable )

I guess with the "DIY" ethic here you will be keeping your versions under your hat for the time being....

 

[jackinnj]

FWIW -- Mouser has the Fairchild parts, but the price can't compete with the European GB.

 

[dhole]

yeah but the GB is long gone..... cpc has em at £0.90

 

[EUVL]

There are a couple of easy options :

1. Order from Fairchild direct @ US$3- a pair, and you know for sure they are real parts.
2. Start your own Group Buy, like I did. It didn't take a day to fill the quota.

I have not heard from all who subscribed. Maybe there are some who might not want them anymore. Keep watching at the Group Buy thread.


Patrick

 

[dhole]

so to clarify its the FQA12P20 , and can this be used with the irfp240 without cahnges to the circuit ?

Partik you mentioned a balanced version by Timo I can t find it in the thread , could you point it out ? are you making this one ?

dave

 

[EUVL]

Do a search under FQA12P20, and you will find many threads where people had already published their opinions on the device, including combining them with IRFP240.

Similarly, search under Pass Forum, F5 and user name Zinsula, and you will find his circuit.

Please help yourself.


Nice evening,
Patrick

 

[Nelson Pass]

so to clarify its the FQA12P20 , and can this be used with the irfp240 without cahnges to the circuit ?

It works fine. It was the first channel made, and it works equivalently
to the all-Fairchild version.

 

[dhole]

Cheers

Thanks for the info, I always try and research before I ask questions I guess I didnt dig enough.

dave

 

[metalman]

Re: Homemade PCB's

Laser transfer, muriatic acid+ hydrogen peroxide etch, sprayed soldermask, double sided 140mm x 70mm board.

What product are you using for your soldermask?

Terry

 

[dhole]

Ok so here goes. I am starting a mini gb for FQA12P20 in UK/EU Only. please see here .

http://www.diyaudio.com/forums/showthread.php?s=&threadid=122098

 

[Dennis Hui]

FQA19N20C / FQA12P20 mini GB (non-EU)

I figure I'd see if there's interest for a GB for non-EU countries.

http://www.diyaudio.com/forums/showthread.php?s=&threadid=122103

Cheers,
Dennis

 

[Nicola]

F5 audio spec's

Hello, I've been reading this thread hoping to find some comments on how the F5 compares to F3 (JFET) or F1/F2 for example. Has anybody already comment on it ? What are the tech spec's for the F5, thd, power, freq spectrum, damping, etc ?

 

[Dennis Hui]

Re: F5 audio spec's

Hello, I've been reading this thread hoping to find some comments on how the F5 compares to F3 (JFET) or F1/F2 for example. Has anybody already comment on it ? What are the tech spec's for the F5, thd, power, freq spectrum, damping, etc ?

This quote from the F5 article may interest you:

"This is the lowest distortion yet achieved by either a Zen or
First Watt amplifier, descending to 0.001% below 1W."

 

[Nelson Pass]

This information has been partially presented in previous posts,
however the full article will be going up on www.firstwatt.com
probably this next week.

 

[Nicola]

This information has been partially presented in previous posts,
however the full article will be going up on www.firstwatt.com
probably this next week.

Thanks Mr Pass, look forward to read it, hopefully there will be soon also article like the 6moons or by J Lowther to get a taste of the quality and listener differences between the several models. But may I ask you how would qualify / compare F5 to F1 or F3, if I may.
By the way, do you plan to build & sell some through RenoHifi ? (http://www.diyaudio.com/forums/showthread.php?postid=1493697#post1493697)

Regards

 

[EUVL]

For regular updates of the 1st EU Group Buy of Fairchild MOSFETs now closed, please follow the Group Buy thread :

http://www.diyaudio.com/forums/showthread.php?s=&postid=1495444#post1495444


Thanks,
Patrick