F5 power amplifier

[gaborbela]

OK you right !
I read still on your previous attachment Renesans/Toshibas
But I don't care , I check the data .
You wrong about the Renesans , they only produce the ex Hitachi devices .
Please look up the data .
Any way I do not want to argue over these .Not my cup of tea .
I'd rather make friends and learn from them ! That is more important .
The second attachment is OK , I just mentioned because some people does not read well English . Probably they see RENESANS /TOSHIBA and can make a mistake .
Please do not take it as I want to criticize you , not at all!!! Seriously.
Please take a look at cvillier board with the Toshiba mosfet.
Greets

[tinitus]

Originally Posted by gaborbela

OK you right !
I read still on your previous attachment Renesans/Toshibas

Probably they see RENESANS /TOSHIBA and can make a mistake .

Ok, I really messed it up
But I clearly write 2SJ162/2SK1058

But you are right
I dont know why I thought Renesas was made on a Toshiba patent, which clearly is a Hitachi patent, and stands in BIG letters
How I could be so confused I dont know, sorry about that
Which means I should proably not be doing stuff like this
Thanks for the correction

[tinitus]

The big confusion
It has been mentioned that Toshiba devices should be easier to drive
Its also been mentioned that it really mostly concerns the laterals
Its been stated that Toshibas are just another vertical
I dont know if there are any lateral Toshiba

I bought the Renesas/Hitachi laterals based on that information
Completely my own doing, as info has been rather thin and random
Facts are
Curve tracer matched quads, and Vgs with 3digit accuracy
2x quad 2SJ162 are all within 0.50 Vgs, and 2x quad 2SK1058 all within 0.83 Vgs
Seems pretty good to me
But now Im whispered in my ear that Renesas are harder to drive
Im confused more than ever

I have to deal with this somehow
But if any attempt to clarify this issue only starts another big confusion, please dont, just ignore

[Ryssen]

Hi,
Can someone tell me what parasitic oscillations sound like? Is it something obvious or more subtle that needs to be measured on an oscilloscope?

The sound I heard when unplugging the DAC sounded like an oschillating sond that got higher and higher until it dissapeared.If it involved any uhearable sound that had to be messaured to see I dont know,maybe sommeone ellse can expaine better,just hoping that none of the transistors was blown..

[generg]

This thread got so interesting for me the last days. Danke schön, to all who are fighting to X Nelsons F5. I learn so much! Even by some errors.

[gaborbela]

Tinitus
No problem at , we all make mistakes . You know who does not make any mistake .Those people they are doing nothing at all .
We are not perfect , at least I'm far from that .So possibility for mistake is always there .

Greets

[tinitus]

Yeah, I suppose the best we can do learn from our own mistakes, and others
Unfortunately mostly we dont, and just repeat the mistakes, because thats what we do

Anyway, I have learned to trust my intuition
But man, it feels much like windsurfing in stormy weather, never knowing when you end in the water fighting fore your life
And yeah, I have been there too
Pure adrenaline rush

Somehow I think I have managed to find the balance
Quad Renesas laterals
Only 7A, thus keeping the original rail voltage
Raised bias
Cascoded Jfet
Mono with double HUGE heatsinks
It have to work, but maybe only that way
Thanks

[tinitus]

btw, where did this schematic come from
Is it just a theoretical marriage of F5 and GrandProfet
Or is it a tested proven one, or simulated, or
The difference on gate resistor, 680R on J162 and 470R on K1058, indicates something have been considered
Hmm, yeah, my J162 do have lower Vgs than K1058, is that it
And higher value of gate ressitor relates to its low Vgs, and ease of drive
But IR device seems to have lower on-resistance, I dont get it with these Vgs/Vds figures
Man, I have learned to say "gate-resistor"

[tinitus]

But Grandprofet is a 3-stage curcuit with a driver
Does this mean that gate resistors really shouldnt be THAT big in F5

[CBRworm]

The source resistor values are 220mOhm? Shouldn't it be <1 ohm?

Nevermind - I guess that's 220 Milliohm, not Megaohm.