F5 power amplifier

[Nelson Pass]

The lateral parts have lower transconductance but also lower temperature coefficients.

I do have a diy version using the Alfet laterals, scheduled for release this year.

 

[DIYHarry]

Sry, dont know all threads

but is there amp project with 2 or 3 Lateral MOSFET OPS

 

[DIYHarry]

There's a modification required in the feedback circuit discussed earlier thread, and is conceptually similar to the F7, at least the first drawings presented by Nelson in that thread. I've successfully used 3 pair output with the original feedback network and values (50/10R ~15dB gain) with no issues, three pairs LATFET at ~1.7A cumulative bias are required to yield similar CLG to a single pair of vertical MOSFETs @1.3A

It still has less feedback, which is something you might like, or not.

Or a link pls— thanks

 

[Sangram]

There isn't a readymade circuit for what you're asking. Have patience:

https://www.diyaudio.com/community/threads/f5-power-amplifier.121228/post-7574683

 

[von Ah]

All the recent F5m talk got me to put my 2SK1530 / 2SJ201 F5 back in the main system.

 

[tamra]

@von Ah
Did you modified like F5m?
Or changed something for 2sk530/j201?

 

[von Ah]

The change to 2SK1530 / 2SJ201 from stock F5 v3 was very simple. I merely swapped out the outputs, changed the output resistors to 0.2R, and set bias/offset per the normal procedure. Easy change!

 

[cucu70]

Hi guys. J162 & k1058 its ok? Thank you.

 

[von Ah]

Not without additional schematic changes. Those are lateral mosfets. See the F5m and F5m kit threads for relevant lateral fet discussion.

 

[Rush]

All the recent F5m talk got me to put my 2SK1530 / 2SJ201 F5 back in the main system.

So, do you like the 2SK1530/2SJ201 F5 better?

Rush

 

[cucu70]

Von Ah, do you can send me a link please? Thank you.

 

[von Ah]

@Rush , I like it more than stock, yes. But I really liked the stock build, too. I don’t have FFT measurements to compare, so it’s all subjective, regardless. “Entertainment, not dialysis.”

 

[von Ah]

I am no expert. Just relating my experiences and enjoyment of building these machines.
@cucu70 , the threads are currently popular ones right here in the Pass forum. They are not terribly long. Search in them for “lateral”
Edit: Old man grumbling
F5m
F5m kit

 

[cucu70]

Ok, thank you a lot!!

 

[dake13]

I'm assembling an F5 using the parts kit/chassis/boards etc. from the store and realized that I'm missing the X1/Y1 capacitor for the wiring at the terminal block. Not sure if I forgot to order it or simply can't find it in my mess of a work area (I ordered parts a while ago). What are my options? I have lots of caps on hand of various types and I hate to put in an order for one item from Digikey...

 

[TungstenAudio]

That capacitor isn't necessary for proper operation, it simply may filter a little line noise before it gets inside the transformer.
Go ahead build and enjoy the amp without, maybe order one some other time. (The X1/Y1 rating is safety precaution for direct line connection.)

 

[Dennis Hui]

I agreed with TA.

Leave it out instead of using a non-safely rated one. It's not needed for operation and you can retrofit it later if desired.

 

[dake13]

Thanks TA and Dennis. This is what I suspected from searching the thread, but I wasn't sure that I could go without it (for now). One other question, I saw from searching that the value of the X1/Y1 capacitor isn't as important as the X1/Y1 rating itself... Is this capacitor something I might find locally, at an electronic supply store etc., or should I just plan on ordering it from Mouser or Digikey?

 

[DCE1198]

The rating is the important bit for caps used across the AC line. The ratings have to do with the mode of failure depending on where they are placed across the AC line.

Dan

 

[dake13]

OK, thanks. Thought I'd seen posts saying the value wasn't critical, but maybe I'm not remembering right.