First Watt F7 review

[Zen Mod]

funny round-head

 

[PKI]

I dont know if its ok to post eBay links here, but... Do you think I am sad getting these for the amp: 10P20 10N20 Exicon Audio Lateral MOSFET TO-247AD Plastic TO247 ECX10P20 ECX10N20 | eBay

 

[vdi_nenna]

Not sure why it would be sad...seller has a good rating and they are in the US.

If you are just getting a couple of pairs, it's fine.
If you are buying in bulk, just buy direct from Profusion.
10 pair of same lot number laterals (to PA, USA) came to $130 with expedited shipping.

 

[PKI]

Thank you!

 

[kenev]

Then you understand one my concerns for simplicity.

That reminds me a quote someone once told:

"Τhe hardest thing you can do is to make something simple"

 

[Soundhappy]

That reminds me a quote someone once told

 

[vitalstates]

You can do a circuit with pcf with those devices if you like.

pcf??

did you mean cfp, compound pair?. If not I'm probably being super dense, what's pcf ?

 

[Zen Mod]

positive current feedback , most likely

 

[vitalstates]

Ahh, I was right first time..I was being super dense...merci mon brave.

 

[2 picoDumbs]

Ahh, I was right first time..I was being super dense...merci mon brave.

Positive current feedback.

 

[Nag]

Hi,
As per papa everything is on the table except it is official. Can you please look below images and let us know your thoughts. One is original diagram f7 manual and one from internet and one is actual amp. Look How it is so beautiful with no caps and very less resistors(with pots) components and only 4 transistors.

Thanks.

 

[ColinA123]

Too complicated.

 

[Zen Mod]

I'm happy to declare that F7 is much different

 

[woody]

Yes, Colin way to complicated With these being lateral mosfets are those .47 ohm source resistors realy necesary ?

 

[Nag]

Yeah It is complicated but first stage is correct as per the document "The beast with thousand JFETS". And second stage is correct as per F7 manual, Both are provide by none other than Papa. So if we combine both the circuits we can expect working F7 circuit. Once I got 2SJ74 & 2SK170 I will build and test I verified exicon lateral mosfets they are identical to F7 laterals .

 

[Nelson Pass]

Not actually necessary to use the .47 ohm resistors, as the Lateral outputs
are low temperature drift. You do need something to measure the current
with, maybe .1 ohms. This leaves you with more gain the the .47's and
less degeneration.

 

[Ejam]

No Positive Feedback in Nag's Circuit

Nag

I'm with Zen Mod on this as there is no positive feedback with your circuit, which is inherent in the F7 design (refer to F7 manual).

 

[bra]

I think it is type 2

 

[Nag]

Ejam,
Actually I don't have background in electronics. very Little knowledge. Here we are feeding out put to input stage. As per my understanding it is not negative feedback, so we can assume positive feedback. someone have amplifier/audio circuits experience please explain 1095 post,
Thanks.

 

[2 picoDumbs]

Just do like type 2