F5 power amplifier

[generg]

Originally Posted by gaborbela

Hello
I would like to ask some (help) opinion about a high power F5X with out cascode using multiple power mosfet.
It is possible to use 3pair power mosfet / channel powered from 24V rail power supp. based on the the attached schematic ?
I like these simple schematic (unfortunately it is hard to read any value of the components) any way probably with 24V rail would need adjust most of the resistor values .
In case someone interested for a high power F5X please let me know .
We could make some plan together ,I do not have the skill to modify the schematic to a high power verizon .
I have 14PC 2SK1528 & 18PC 2SJ200 matched Toshiba mosfet , JETs , a 20-0-20VAC 1.5KVA Plitron toroid & monster heat sink (enclosure) over 25lb.
I would like to use these to build a F5X instead a high power F5 .
The (enclosure) heat sink was design for a Aleph2 but I like the X topology better. I have a Aleph X , I like the sound of the X so much , it would be great a high power F5X .
Thank for any advise or help .
Greets

Hi Gaborbela,

The x-schematic I suppose, is from euvel, he wrote many pages before how to manage it. Open Word, import this wmf (windows meta file) like a picture by insert -picture- from datei. Now you can enlarge the view in Windows and all details are visible!

[gaborbela]

Thank Thanh
You are always very helpful , greatly appreciated !
The reason I would like to use 3 pair mosfet everything I have at hand . Heat sink , transformer , mosfets etc . Just need the resistors of course I have redesign my PC boards for the X . Because I want it with out cascode.
Also the 2SK1529 & 2SJ200 (I have it) it has less power than the bigger brother 2SK1530 & 2SJ201 used by Smyslow .
My AlephX is based on the Kristijan design also I ordered the PC board from him about 4 years a go .
It running close to 7A /channel .Total 8 IRFP240/channel . About the sound in one word incredible .
I would like to build something similar or at least over 50W in Class A using the F5X topology .
Even if it would be 50W the heat sink and the transformer it would be over sized wich is not a problem .
If you or someone can help further with the schematic that would be great . That is not my strength .
Thank you very much
Greets

[gaborbela]

Generg
I did tried to enlarge the schematic I attached (without the current lim.) I get a mess only .
In one word I can't read it .
But because I would like to run my F5X 24V rail probably those resistors used by Smyslow may be it need some adjustment in to the correct value to feet a higher power verizon.
Greets

[generg]

Originally Posted by gaborbela

Generg
I did tried to enlarge the schematic I attached (without the current lim.) I get a mess only .
In one word I can't read it .
But because I would like to run my F5X 24V rail probably those resistors used by Smyslow may be it need some adjustment in to the correct value to feet a higher power verizon.
Greets

It seems you did not succeed to open it in windows, I attache the windows doc and the schematic is inside.

[Melon Head]

Hopefully you can read this one

[jacco vermeulen]

Jeno,

if EUVL's FX5 has 16V rails, 0.22 Ohm drain resistors and 2SJ200/2SK1529 requires about 2V to open up, how many watts can one expect from a balanced act like that ?

[gaborbela]

Thank Thanh
Yes I can read that but I would like to go with these simplified verizon used by smyslow ,only using 3 pair mosfet instead one pair due to the higher power supp .
Do I have to change any resistor value since I plane to use 24V rail power supp?
For me these is a very important to be clear before I start to go on design PC board or purchase any resistors .
Greets

[bobodioulasso]

Why not simply to x the normal F5 with doubled outputs?

[gaborbela]

Jacco thank you
I need help even to understand your question .Please forgive me I'm not a technician or a engineer .
If I have a ready schematic I can go on design the PC board and build it .
My question to U it is possible to go on with 3par mosfet with 24V rail idea of course with the necessary mods if it need any .
Greets

[jacco vermeulen]

Jeno,

a balanced F5 is not the equivalent of a balanced single ended Aleph amplifier.
If 50W is all you want, just raise the rails a few points and drop the bias to 1.75 Amp.
Patrick picked 16Vdc rails because that's 12Vac rectified.