F5 power amplifier

[CBRworm]

Nice Pics MSTR, your first F5 is much nicer than my first F5.

Here's a pic of my first functional channel. It has since evolved into a chassis and grew a brother.

[mstr]

Originally Posted by yildiray

Way to go mstr!!

i m very jealous can i ask to you needless question,where did you buy your eurocard board? from rothelectronic?

Thanks!

I think those boards came from farnell, but I´m not shure because I had them in my drawer for some years, waiting for a project.

We soldered them up-side-down, just to make sure to have access to all nodes after installation of the board. This technique has proven very practical for first measurements.

[yildiray]

actually you right,this's ideal for measurement.i will do this project ıf i can save money but probably i will use peters kits

have a good listen,regards

[Samuel Jayaraj]

Patrick (EUVL) and others, can the Balanced F5 be built with 2SK1058/2SJ162 outputs and can they withstand a bias current of 4Amps; or what about the IRFP 240/9240 devices, without thermistors?

[mstr]

Originally Posted by CBRworm

Nice Pics MSTR, your first F5 is much nicer than my first F5.

Here's a pic of my first functional channel. It has since evolved into a chassis and grew a brother.

Cool, I really like this sort of engineering!

You are far ahead, the brother of my F5 is still under construction, because after the last update I did some mistake and reversed the PSU polarity at one channel... It´s really a pain to let the smoke out of caddock resistors

[CBRworm]

ewww. Good luck getting the smoke back in. . .

[smyslow]

Originally Posted by P. Lambda

I am planning on building a balanced F5. Is your bias 1.6A total for each channel or is that for each pc board ?

As Andrew wrote, it's 1.6A for each pcb I used and therefore 3.2A for each channel.

Uwe

[smyslow]

Originally Posted by Samuel Jayaraj

Patrick (EUVL) and others, can the Balanced F5 be built with 2SK1058/2SJ162 outputs and can they withstand a bias current of 4Amps; or what about the IRFP 240/9240 devices, without thermistors?

Hi Sam,

of course you can use IRFP240/9240. But not with a continuous drain current of 4A! If your rail voltages are let's say +/-24V you get a power dissipation of 24V x 4A = 96W for each device. This is too much! The power dissipation for each device should not be higher then 30W.

Uwe

[Samuel Jayaraj]

Smyslow, thanks for your reply. So I assume that IRFP240/9240 outputs can be used safely without thermistors. However, I was looking at Patrick's (EUVL) schematic which shows rails of 16 volts and he did mention 4Amps bias with Toshiba devices.

I wonder where the 'sweet spot' lies for each of these device pairs when used in a balanced F5: 2SK1058/2SJ162, IRFP 240/9240?

[jackinnj]

What is this thing that DIYr's have w beer?