First Watt website update

[codyt]

Hmmm. Did I get lucky ? I ordered 4 instead of 2 SS devices. 2 for babelfish 2j .....

Just what I was thinking

 

[MEPER]

What about a "Long skinny" F8 PCB?
I have not yet built the "Long skinny" J2 amp.....

 

[Nelson Pass]

THD 0.016% 1W into 8R.

You got the distortion figure right.....

 

[EUVL]

Needed to use some tricks.

Just wanted to see if DC couple is possible.
Looks like it is.


Cheers,
Patrick

 

[claudio52]

Hi Patrick,I tried to simulate your scheme with two IRFP240. Without changing anything it, works very well.

 

[plasnu]

EUVL, thank you so much for sharing this.

 

[kasey197]

Lovely articles - thank youuuu !!

 

[Zen Mod]

If (there's) not Boeing, I'm not Goeing

If (there's) not Babelfish, I'm not Speaking

 

[EUVL]

Different Idss

The spice file posted yesterday has a P-JFET with Idss of 6.5mA.
I checked also Idss 8mA, which is also possible with some adjustments of resistor values.
The updated files here also has an adjusted bias of 1.3A.
Distortion sink further to < 0.014% for the lower Idss version.
So there are enough knobs that you can use to tailor distortion level, DC offset, and bandwidth, to the difference in devices.

It is important to realise that these are just simulations and not reality.
But I shall stop here in any case.


Cheers,
Patrick

.

 

[Ejam]

F8 and JLH69 Amplifiers

Nelson

One is struck by the similarities of your new F8 and the JLH69 amplifier, less of course the JLH driver stage and bootstrap loading.

 

[2 picoDumbs]

F8 has no phase splitter. (JLH Q2)
That is a very significant difference

 

[Zen Mod]

if we go step further, we can compare it with Loftin-White



and just a little toe more, with anything having 3 resistors and 1,5 actives in it

nature of things when you are in stripping business

 

[Zen Mod]

Today my spreadsheet told me that I have to update the First Watt
website, and so I did.......


......

Oh no, he did it again

 

[2 picoDumbs]

Just got finished reading the latest article.
Only dumb people are able to find it.

 

[EUVL]

> F8 has no phase splitter. (JLH Q2)
> That is a very significant difference

The phase splitter is not necessary a disadvantage.
Can even be an advantage.


Patrick

 

[2 picoDumbs]

Not saying which is better just that it's a significant difference
JLH has something like 2.5 or 3 gain stages depending on your definition.
F8 has 2 gain stages.

It's Different not really similar.

 

[EUVL]

Phase splitter has no gain.
But whatever pleases you.




Cheers,
Patrick

 

[2 picoDumbs]

That would be like saying there is no voltage gain out of the input transistor of a folded cascode front end.

Pretty sure you have voltage gain out of the collector of Q2 which then goes to the base of the upper transistor Q4 which provides some current gain.
Out of the emiiter of Q2 you have current gain and then voltage gain on the lower output device Q3.
Pretty sure that's what you have.

 

[EUVL]

If you consider a gain of -1 is gain, then yes.
Phase Splitter - Electronics-Lab.

I shall also stop.


Cheers,
Patrick

 

[2 picoDumbs]

My point was it's bloody different.

I'm not wrong.


You chose to argue over something totally unrelated.