A guide to building the Pass F4 amplifier

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#1,761
5U/500 Modushop case would likely cope with that


I know that I'll be more than happy with regular F4, having 25W/8R in A Class and 50W/4R in AB Class, driving ESL63

there are few more candidates, probably even better to drive it, but they aren't current buffers without voltage gain

point is - you don't need that voltage headroom, nor you need more current than F4 is capable to give easily

anyway, as any project is, beside many other things, complex set of compromises - you need to choose your own set
 
#1,763
Zen Mod said:
5U/500 Modushop case would likely cope with that


I know that I'll be more than happy with regular F4, having 25W/8R in A Class and 50W/4R in AB Class, driving ESL63

there are few more candidates, probably even better to drive it, but they aren't current buffers without voltage gain

point is - you don't need that voltage headroom, nor you need more current than F4 is capable to give easily

anyway, as any project is, beside many other things, complex set of compromises - you need to choose your own set
Click to expand...

5U/500 😱, I was thinking of the 4U/300 as suggested in DIYShop, or the 3U/400 witch has approximately the same heatsink area as 4U/300.
 
#1,765
Hi DIY team.

I hope all well and safe. I am a new member building a F4 amp. I am looking at ordering the parts. F4 boards are sold out so I hope they come in soon.

When I buy the parts shall I follow the BOM in the Nelson Pass F4 manual dated 2007 OR shall I follow the diyaudio store BOM dated 2011?

R3-4 and R8 and R10-15 are different Nelson vs store.

I have not ordered any parts yet so I just like to make sure I do it right.

Some help is appreciated.
 
#1,766
Norrlands Guld said:
Hi DIY team.

I hope all well and safe. I am a new member building a F4 amp. I am looking at ordering the parts. F4 boards are sold out so I hope they come in soon.

When I buy the parts shall I follow the BOM in the Nelson Pass F4 manual dated 2007 OR shall I follow the diyaudio store BOM dated 2011?

R3-4 and R8 and R10-15 are different Nelson vs store.

I have not ordered any parts yet so I just like to make sure I do it right.

Some help is appreciated.
Click to expand...

..................NELSON PASS MANUAL....VS..... DIY STORE
R3+R4 ...................10R..............................22.1R.......................??
R8..........................27.4K ...........................22.1K......................??
R10-15....................150R.............................100R.......................??
 
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#1,768
Dennis Hui said:
It looks like the store was referencing a slightly older schematics. I suggest
using the values in the current manual.
Click to expand...

Thanks a lot Dennis!

The DIY Store schematics is dated 2011 and the store BOM by JojoD818 is dated 2013.

The NP Manual schematics is dated 2007.

So I shall follow the NP 2007 schematics as attached. Correct?
 

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#1,773
6L6 said:
Use the inexpensive one that has the most in stock. The circuit has 2 pots in it to let you adjust it perfectly.
Click to expand...

Thanks 6L6!!

The cheapest one with big stock is TL431CZT. 2% tolerance and 100 ppm. EUR 0,315.

The TL431BVLPRAG is EUR 0,405 and 0,4% and 50 ppm.

If I can find the EUR 0,1 extra in my pocket is it a good idea and will it work to buy TL431BVLPRAG??

TL431BVLPRAG ON Semiconductor | Mouser Sverige

Thanks for your support.
 
#1,774
#1,778
Dennis Hui said:
Get the part that will make you sleep better at night.
The only suggestion I have is to buy at least 10 to get quantity discount,
since you can use them in other designs.... 🙂
Click to expand...

I find that it is invariably the best quality part not the cheapest that ‘sits well with me’ long term. Even if it’s under the hood, I know it’s there!
 
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