Which amp should I built for my 16 ohm speakers?

[ajohn]

My speakers' impedance is 16 ohm. Which Pass Labs amp should I build? I have some experience building DIY tube pre-amps but in fact I possess very basic electronics knowledge.

 

[Zen Mod]

you didn't said what's efficiency of your speakers , but I presume that they're easy to drive ;

anyway - one of solutions is on first few pages of F4 thread - F4 with just one pair of output mosfets ;

F4 is "just" current buffer , so tube pre is welcome , with usual tube voltage swing

so - find latest F4 schematic ( probably is on First Watt site as pdf file ) , leave just one output pair of mosfets in place , and enjoy

if you have some more questions - just ask

 

[flg]

Probably not a bad idea But, in that case I would pump up the bias a little more Maybe 1A or so... Just my 2 cents.

 

[Zen Mod]

Probably not a bad idea But, in that case I would pump up the bias a little more Maybe 1A or so... Just my 2 cents.

it really depends of nature of his speakers

in any case - valid and good note

 

[ajohn]

I don't know the sensitivity for sure but it should be about 95 db.
Is the F4 easy to build?

 

[flg]

Well, 95 is a good eff # for most people😀 I acctually made a little mistake in my post 🙄 "I" would actually try to run the output FETs in their most reliable/linear range. And to me that would be about 30-35W dissapation. 65C Heatsink temp max. Considering maybe 22-23Vds. 1.4 or 1.5A Iq. A 70W heatsink is not that difficult😉
There are other factors but... For instance, you can gain a bunch by insolated H.S. and Arctic Ice with no pads, mica etc. ect.

 

[ajohn]

Please tell me why a F4 is more suitable for my 16 ohm speakers rather than, say, the F5.

 

[Bill Fuss]

It isn't necessarily, mathematically speaking. A 16ohm driver pulls less current than an 8ohm and would like a proportionally higher rail voltage. You would be optimising the amp for that particular load and could do it by lowering the bias current simply by eliminating some output transistors. IMHO the F4 would be a better choice if your tube pre has enough voltage swing.

But that's just my opinion.