F4 power amplifier

[carpenter]

That's how it works, having your personal nanny 😀


Magura 🙂

You mean I get to have Mrs. Magura work for me?😀

 

[Magura]

You mean I get to have Mrs. Magura work for me?😀

I hate to tell you this....but that's just not happening! She's off the market for good😀

So as for a nanny, you'll have to put up with my services😉

Magura🙂

 

[carpenter]

I hate to tell you this....but that's just not happening! She's off the market for good😀

So as for a nanny, you'll have to put up with my services😉

Magura🙂

I always thought of nanny as being female; that would make your a nanner....a nanoo-nanoo....ah hell, numb-nuts....😀

 

[SCD]

New F4 is created

Hello folks:
I would like to thank Nelson Pass for his design, Peter Daniels for his boards and Jason for his help.
Here are a series of pictures of the F4 I built.

 

[carpenter]

Now, isn't that cute! Very nice job, and a slick looking faceplate to boot.😀

 

[SCD]

pic 2

 

[SCD]

pic3

 

[Cal Weldon]

Great Scott.

Sorry, just had too. 😉

 

[SCD]

I would like to thank the folks that made useful contributions to this thread. It was a long slog to filter the value from this thread but it was worth the effort.

Thanks for the help

 

[SCD]

Hello CaL:
I guess I suffer from proud parenthood just like everyone else. I am really happy with this amp. It sounds very good on my bipole fe127 fonkens.

Hope to see you soon

 

[doorman]

Well done, Scott!
Perhaps a listening session is in order?
Don

BTW, has it replaced the "toaster-oven"!?

 

[SCD]

Hello Don:
Yes the toaster oven has been moved back to the shop for a face lift.
Listening session yes I am keen to hear your Grounded grid through this amp.

 

[wirewiggler]

New born

My f4 is born with its twin soon to be delivered, I will be adding a pumpkin to be their Nanny. Will have to wait - leaving for Vancouver in 30 minutes, drat have to ski all week.

Bill

 

[RKH]

Re: New born

My f4 is born with its twin soon to be delivered, I will be adding a pumpkin to be their Nanny. Will have to wait - leaving for Vancouver in 30 minutes, drat have to ski all week.

Bill

Very nice build! What? No snow in Bakersfield? 😉

 

[carpenter]

How about a close-up? Looks very intriguing.

 

[Andrzej Sochon]

Re: New born

My f4 is born...Bill

Congratulations, Bill.

Good news from me too: yesterday my balanced f4 was born, the twin should be ready next weekend, I hope.
I would like to express my admiration for Mr. Nelson Pass project. Absolutely no problems with startup. I reach thermal stability during 25-30 minutes (50-55 C), with 250 mV bias and final excellent 0 V offset. No cracks, no bumps during power ON/OFF, cold or warm. Bias and offset adjustments are stable, every amp is like self-regulating system.
I listened it for a while, the sound is clear and nice, but at the moment this is one channel only and to quiet, driven directly from DAC by typical balanced line-level signal. As I suspected I must think about pre-amplifier, I decide to use ZenMod hand-made schematic (Post #1641), I will appreciate very much any suggestions regarding Power Supply (+60/-20V, DC).
I would like to share one of my adventures especially with novices. I start all four amps one by one separately, carefully checking voltages, bias, offset, heatsink temperature. Then I put together two amps as one balanced (goodbye my SOZ). When I switch power ON I discovered +23V at all metal parts of housing. That was a short-circuit through insulation pad caused by a piece of metal filing. In other words one of IRFP240 was connected directly to the heatsink by a very small piece of metal. Fortunately nothing wrong happened, I replaced the pad and everything is okay now. Here is the proposal dedicated to all novices (and old-hands smart guys like me): before switching power ON check if drains of all power MosFets are electrically well isolated from heatsink.
Best Regards,
Andrzej

 

[Zen Mod]

Re: Re: New born

.......................... Here is the proposal dedicated to all novices (and old-hands smart guys like me): before switching power ON check if drains of all power MosFets are electrically well isolated from heatsink.
Best Regards,
Andrzej

just one observation - that's regular praxis for non- novices 😉

I'm glad that you are pleased with new toys ........... entering new dimension in favorite tunes is always overwhelming experience ........ and I'm sure that you have that now 😉

 

[hershann]

I am building the Pumpkin preamp with balanced output as mentioned in the other thread. I also intend to use a balanced DAC as the source.

I do have 2 pairs of F4 PCB but am intending to only build a stereo pair for the time being. The reason being I listen to music at relatively low volume and my speakers are 93db sensitive. I hardly use the 8W from my old tripath amps for these speakers and I'm sure the 25W from the F4 is more than enough.

Also have 2 huge heatsink chassis of Class A amplification is probably not sit well with my wife.

So how big a improvement will a dual mono-block setup be if I don't need the power?

her shann

 

[Babowana]

So how big a improvement will a dual mono-block setup be if I don't need the power?

Dual mono blocks? What is the reason you heard about?

 

[hershann]

Dual mono blocks? What is the reason you heard about?

Sorry I meant a balanced F4 setup with 2 F4 boards per channel instead of a simple stereo setup with 2 boards total.

her shann