F4 meditation

myleftear

Member
Paid Member
2017-09-10 6:33 pm
Luzern
Hi friends

I hit the button (ordered parts), I'll have no excuses :)

I've still doubts if F4 won't be way too roaring a beast for me and my listening habits... I'll build and hear.

But while reading along, I visited BA-3. This is more or less a F4 with a gain stage, isn't it? And it can be expanded (mo' Mosfets), correct?

Uhm... can it be shrunk, too? Would this shrink the performance, or the quality (the latter of course not being an option)?


Another grand question (of faith) is about the gain-stage.

I "know" that BA-3 is great.
I also "know" that great ZM's vegetable (pumpkin + shunty) is just as great.

where should I head to, this, or that?

(I know that this question is not appropriate, but it often helps to have other opinions.)
 

mordikai

Member
2005-11-07 3:34 pm
I don't think you can go wrong with any of the mentioned options, but how would a 25- 50 watt amp be too much of a roaring beast? I have a lot of these different amps and use most of them interchangeably. I pay some attention to speaker resistance and sensitivity but I've tried most of my amps with most of my speakers just out of curiosity and haven't blowed up nothin yet. ;)
 

myleftear

Member
Paid Member
2017-09-10 6:33 pm
Luzern
I don't think you can go wrong with any of the mentioned options, but how would a 25- 50 watt amp be too much of a roaring beast?


...and haven't blowed up nothin yet. ;)


Well, I have a ACA running. Input is a ADL GT40a USB DAC. At 40% I have to stop. Never measured the output, but I‘m sure it‘s not much...

And there‘s neighbors...
 
"I've still doubts if F4 won't be way too roaring a beast for me and my listening habits... I'll build and hear."

You may know this, but the F4 has no voltage gain; it is a current buffer. So, subjectively, it may be less of a roaring beast than the ACA. What I mean by that is that you'll need to turn the knob on the GT40a further (past 40%) to get the same volume from your speakers compared to the ACA. Are you planning to use the GT40a as your pre-amp / DAC for the F4? It looks like it's rated at 5Vrms. So, ~7Vpk.

You'll still be able to play it plenty loud, but just don't be surprised when you have to crank the knob on your GT40a further. Assume you have 8ohm speakers...

If my math is wrong, someone will hop in and correct.

7V0 => 0A875 into an 8ohm load
0A875 x 7V0 = Roughly 6.125W max power from that setup.

It's the voltage from your GT40a that will limit the output.

Still - that is more than likely plenty of power based on what you were saying re: how you use your ACA.

Enjoy the build! :D:D:cool::cool:
 

myleftear

Member
Paid Member
2017-09-10 6:33 pm
Luzern
"I've still doubts if F4 won't be way too roaring a beast for me and my listening habits... I'll build and hear."



You may know this, but the F4 has no voltage gain; it is a current buffer. So, subjectively, it may be less of a roaring beast than the ACA. What I mean by that is that you'll need to turn the knob on the GT40a further (past 40%) to get the same volume from your speakers compared to the ACA. Are you planning to use the GT40a as your pre-amp / DAC for the F4? It looks like it's rated at 5Vrms. So, ~7Vpk.



You'll still be able to play it plenty loud, but just don't be surprised when you have to crank the knob on your GT40a further. Assume you have 8ohm speakers...



If my math is wrong, someone will hop in and correct.



7V0 => 0A875 into an 8ohm load

0A875 x 7V0 = Roughly 6.125W max power from that setup.



It's the voltage from your GT40a that will limit the output.



Still - that is more than likely plenty of power based on what you were saying re: how you use your ACA.



Enjoy the build! :D:D:cool::cool:


I can‘t wait to hear it!
Now, after choice paralysis comes the pre-solder panic [emoji849][emoji41][emoji4]

Thanks for encouraging!
 

myleftear

Member
Paid Member
2017-09-10 6:33 pm
Luzern
gain stage


Are you planning to use the GT40a as your pre-amp / DAC for the F4? It looks like it's rated at 5Vrms. So, ~7Vpk.


Thanks, itsallinmyhead!

I'm pretty convinced I'll build a gain-stage (BA-3 or that ZM-thingy). If not for audio-bliss, then at least to have a reason to stay onboard @ diyaudio. This forum is one of the reasons I got and keep being hooked on this stuff :)

I really enjoy to get here and get "treatment" :sing:

It doesn't matter, in this context, wether F4 will be too roary a beast or just perfect :cool: