Well, i have to say, i am really curious about how it sounds??
How it Sounds!
So? Anyone yet? Some about the amps actual musicality focused reviewer - is of course of utmost importance, and always prefeered.
🎷🙂🎸
How it Sounds!
So? Anyone yet? Some about the amps actual musicality focused reviewer - is of course of utmost importance, and always prefeered.
🎷🙂🎸
it depends who is gonna first publicly
FR lovers - it sounds splendid!
FR haters - meeh........

FR lovers - it sounds splendid!
FR haters - meeh........

Yeah well, thats your personal Zen Master take on it all. But. Still, for sure very interesting info 🤘🙂🎸
always nice to hear about new Papamp, but this time even more nice seeing smile and calm demeanor of Mr. Fullranger himself


So how do you make a mono amplifier with the FW chassis and the THF51?
Seems it would be beyond awkward to have some kind of bridge between the two heat sink halves without a tremendous loss of, would you call that heat sinking efficiency?
Seems it would be beyond awkward to have some kind of bridge between the two heat sink halves without a tremendous loss of, would you call that heat sinking efficiency?
SIT on one sink, “other FET” on the other sink (for up/down power transistors in schematic per channel)? I of course have no idea what the circuit has in it.
The heat sink on each side of the chassis appears to be one piece. A SIT on one side of the chassis and a MOSFET on the other side of the chassis.
thermal conundrum ........ say two active devices - SIT + Mosfet
with decent capability (criteria - caps not melting) - 60-ishW of heat per side of FW case
means, stereo - SIT + Mosfet per heatsink/side
monoblock, increased dissipation - SIT on one side, whatever mosfet on other side (pair od TO247 or one puck)
thermal tracking and inertia are good enough as case is one volume - no need for thermal bridges between left and right heatsink
with decent capability (criteria - caps not melting) - 60-ishW of heat per side of FW case
means, stereo - SIT + Mosfet per heatsink/side
monoblock, increased dissipation - SIT on one side, whatever mosfet on other side (pair od TO247 or one puck)
thermal tracking and inertia are good enough as case is one volume - no need for thermal bridges between left and right heatsink
This is probably the only Common Source example. Additional product is expected as Common Drain at much higher power.


I got to hear the SIT-4 with a pair of Cube Audio full rangers. Had a nice listening session with Nelson where we listened to several amplifiers. My most memorable of the lot was the SIT-4. Absolutely glorious sound. Like you were being coddled in your mother's bosom... just want to keep enjoying the warmth and never want to stop. If I didn't already have VFET amps, I'd be putting in an order for one right now.
as I wrote somewhere - for my logic (and with info available; see pic down) - SIT 4 is sorta Mini BAF 2015 SIT amp, derivation of it being Singing Bush
with few twists of course, not just decreased Iq and what not
one thing is sure - Pa made it differently than I would

now, ZM's conundrum;
whatever popular approach is, and I'm not questioning no-one's approach, for me - using scarce parts in follower configuration is somewhat "inappropriate"
reasons are - say that one can explore full measure of part's intrinsic characteristics in common source arrangement ( so with gain), counting there my Fetish DEF arrangement too, while if we use triodish part in form of pure follower - it's sorta sacrilege - there are many not so scarce parts which we can use and get pretty much same results
examples are all around - some dumb simple some little less simple ....... but many of them being different to SIT follower amp only in fact that in the end you know you have SIT inside, or you don't have
just from top of my head - Mr. MR's MoFo - you can tailor it's sound to your liking till end of time ......... OS of M2, OS of NEM AI-50 ........
illustration being - you all probably had/still have small stash of some unobtaniums/made of preputium parts, which you save/d for years "for some special construction" ...... I mean - just savoring parts and dreaming how to use them is almost of same importance/enjoyment as actually making damn gadget
with few twists of course, not just decreased Iq and what not
one thing is sure - Pa made it differently than I would

now, ZM's conundrum;
whatever popular approach is, and I'm not questioning no-one's approach, for me - using scarce parts in follower configuration is somewhat "inappropriate"
reasons are - say that one can explore full measure of part's intrinsic characteristics in common source arrangement ( so with gain), counting there my Fetish DEF arrangement too, while if we use triodish part in form of pure follower - it's sorta sacrilege - there are many not so scarce parts which we can use and get pretty much same results
examples are all around - some dumb simple some little less simple ....... but many of them being different to SIT follower amp only in fact that in the end you know you have SIT inside, or you don't have
just from top of my head - Mr. MR's MoFo - you can tailor it's sound to your liking till end of time ......... OS of M2, OS of NEM AI-50 ........
illustration being - you all probably had/still have small stash of some unobtaniums/made of preputium parts, which you save/d for years "for some special construction" ...... I mean - just savoring parts and dreaming how to use them is almost of same importance/enjoyment as actually making damn gadget
Last edited:
I don't know, Ben. There is more art and experience to it than what meets the eye. While the parts themselves are very fine, there can be a difference between sounding good and sublime. That's what you get from Papa.
In any case, I am going to try it out for myself and see what happens. I got more than a few hints from Pa 🙂
In any case, I am going to try it out for myself and see what happens. I got more than a few hints from Pa 🙂
- Home
- Amplifiers
- Pass Labs
- New First Watt product at Axpona 2023