A guide to building the Pass F4 amplifier

Okay, well the low gain version from the last two years so it’s probably not that. Just wondering if low gain could have accounted for the lack of drive you’re reporting at loud volumes.

Looking at your system, I’m seeing a lot parallels with my own path so your posts are always appreciated.
 
Thanks to @6L6, it begins again...
 

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PKI

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Colleagues, would you be willing to help me with one thing: build F4 with one pair of outputs and no buffer jfets (crippled?) on a F5 board? I have on of those tiny layout board for the F5 circuit thinking if I can make that no-an-actual F4 with that. I know many people are really good in building all sorts of Frankenstein monsters on different boards, but I am pretty slow with that, so you assistance will be huge appreciated.
 

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If'n I have the right formulas still in my head:

10V input will give a 16.7W output assuming a nominal 6 ohm load. (P = V*I = V^2/R = 10^2/6 = 16.7W)

16.7W will give a 12.23dB boost (10*log_10(16.7)).

So 98dB max output @ 1m from your speakers (86 + 12.23).

Not sure how loud and close you listen but 98dB @ 1m is pretty loud.
 
Greetings,

Please let me know if this is in the wrong location. I'd really like to build this amp based on reviews I've read but would (like others) need to know if it is appropriate for my setup. Please let me know if any information is lacking and thank you for any information:

Preamp:
Jolida JD3000B
Max Output Voltage: 20 V
Voltage Gain: 20 dB
Frequency Response: 5Hz to 110KHz, 10 V
Distortion THD: Less than 1%; 1 KHz, 10 V
Input Impedance: 100K ohms
Output Impedance: 600 ohms
Tube Complement: 2 pcs. 12AX7; 2 pcs. 12AT7
Dimensions: 17 1/2 in. W X 12 in. D X 4 1/4 in. H

Speakers:
Solstice MLTL (Jeff Bagby)
Specifications:
  • Tweeter: Morel CAT 308 1-1/8" soft dome tweeter
  • Woofers: Two x Morel TiCW 638Nd Titanium Series Hybrid Cu 6" woofer 8 ohm
  • Power handling: 200 watts RMS/350 watts max
  • Frequency response: 30 - 20,000 (-3 dB)
  • Sensitivity: 87 dB 2.83V/1m
  • Nominal Impedance: 4 Ohms
  • Dimensions: 38" H x 8.75" W x 11" D
Room:
Medium size room 17 x 17