tnx Grimberg 🙂
first thing - be sane enough to remember to order some, when ordering parts
second thing - order few more, so you can cut them in adequate length, for squeeze work
third thing - be careful when working with them, if you loose them on the floor, chair is having 6 double wheels, each of them being equally ruthless; so order even few more
because of third thing ( done first few more than few times), I'm always in need to do it again
me being even more clumsy, with age
first thing - be sane enough to remember to order some, when ordering parts
second thing - order few more, so you can cut them in adequate length, for squeeze work
third thing - be careful when working with them, if you loose them on the floor, chair is having 6 double wheels, each of them being equally ruthless; so order even few more
because of third thing ( done first few more than few times), I'm always in need to do it again
me being even more clumsy, with age
This implicates that, in your tender age, you weren’t in for the international Office chair races (GPO)chair is having 6 double wheels, each of them being equally ruthless; so order even few more
me being even more clumsy, with age
I was reading a few of Papa's white papers on the FW site, specifically finding the "sweet spot," VFETs and triodes.
It got me wondering (dangerous thing) about the role of temperature and THD with this amp (IRF & THF-51S). Measurements on first page show little to no difference, tho I can hear a difference between cold vs warmed up.
And how does the harmonic distortion spectra shift with bias -- hotter equal more sweet? >🙂
Pa's comments regarding negative vs positive phase were also interesting. I'm guessing the SissySIT is tilted towards negative 2nd/3rd? Guessing so because the sound field and sense of space is greater than what I've heard before, and the presentation isn't very "forward" and in your face. Just a wild guess.
I suppose this is the "art form" for voicing the amp which the Mighty ZM has generously provided.
Also, burn-in seems to be quite real. I've experienced a similar sensation with brand new amps where the first couple hours (t0) are a taste of what's the come, then it takes a turn for the worse, then gradually comes back to t0, eventually blossoming into its full glory. I think I'm experiencing a bit of that right now.
It got me wondering (dangerous thing) about the role of temperature and THD with this amp (IRF & THF-51S). Measurements on first page show little to no difference, tho I can hear a difference between cold vs warmed up.
And how does the harmonic distortion spectra shift with bias -- hotter equal more sweet? >🙂
Pa's comments regarding negative vs positive phase were also interesting. I'm guessing the SissySIT is tilted towards negative 2nd/3rd? Guessing so because the sound field and sense of space is greater than what I've heard before, and the presentation isn't very "forward" and in your face. Just a wild guess.
I suppose this is the "art form" for voicing the amp which the Mighty ZM has generously provided.
Also, burn-in seems to be quite real. I've experienced a similar sensation with brand new amps where the first couple hours (t0) are a taste of what's the come, then it takes a turn for the worse, then gradually comes back to t0, eventually blossoming into its full glory. I think I'm experiencing a bit of that right now.
Really nice build sp33ls 👍
Working with the new slim monoblock chassis must have been tedious at times, Bravo! The Lottery VFet case was slim enough for me, LOL
just wait, you are still not pi$$ing full (destined) amount of Thinner 
all graphs you can see are delivered with amp in temp. equilibrium;
I don't care how they are looking when amp is cold, but as I said oomphteen times - I'm not waiting to enjoy my music until amp is fully warmed, I'm enjoying my music right from the Switch On - try doing the same, life is too short to be wasted on irrelevant rituals ....... besides - music is already there, recorded, take the spirit and just go with the flow
now, SissySIT is, intentionally or not, proper PoorMenSub for SIT-3, meaning - it's brain-obliging THD Factory, 2nd dominant, negative phase
ahem, slight difference in sound of amp being cold vs. full hot - most likely culprit is increased thermal distortion ..... meaning - distortions invoked by minute temperature changes in part itself are, by logic, much greater in system not yet reaching it's temp. equilibrium
I reckon - absolute value of these changes is not changing in two extremes, but its relative value is much smaller when everything is Bloody
all graphs you can see are delivered with amp in temp. equilibrium;
I don't care how they are looking when amp is cold, but as I said oomphteen times - I'm not waiting to enjoy my music until amp is fully warmed, I'm enjoying my music right from the Switch On - try doing the same, life is too short to be wasted on irrelevant rituals ....... besides - music is already there, recorded, take the spirit and just go with the flow
now, SissySIT is, intentionally or not, proper PoorMenSub for SIT-3, meaning - it's brain-obliging THD Factory, 2nd dominant, negative phase
ahem, slight difference in sound of amp being cold vs. full hot - most likely culprit is increased thermal distortion ..... meaning - distortions invoked by minute temperature changes in part itself are, by logic, much greater in system not yet reaching it's temp. equilibrium
I reckon - absolute value of these changes is not changing in two extremes, but its relative value is much smaller when everything is Bloody
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Congrats on your sissysit build. Excellent job getting everything in the chassis!. I think that you will enjoy even more as time goes by. I have put 100+ hours and my build and enjoy it more and more. Find that low volume listening is exceptional as detail is not as compromised as other amps.
I considered using the L aluminum mounted to the sinks as it would be soo much easier adjusting bias and offset. Can understand why Nelson went that route. Particularly in this amp with only 1 mosfet using UMS. Also would have allowed placing of L lower on sinks giving the Sit more room to be centered on the sink. Oh well, Next build. Just ordered some 2sk182's as I suspect Papa or ZM might have another gem for us. Still not sure what to do with my pair of semisouths. I'll keep my eyes open as "buddha is everywhere".
So, I'm trying the SissySIT with headphones (ZMF Atrium) right now and it's laughable how good it sounds.
ZM,
I plan to build, for my SissySIT, a dual mono CRC power supply with 4 capacitors per channel ( 2 caps before the R and 2 caps after).
Which of the following options would you choose?
I plan to build, for my SissySIT, a dual mono CRC power supply with 4 capacitors per channel ( 2 caps before the R and 2 caps after).
Which of the following options would you choose?
- 4 x 47000uf caps per channel
- 4 x 33000uf caps per channel
- (2 x 47000uf) + (2 x 33000uf) caps per channel
In the context of a dual mono PSU (230V), what is the most suitable option to use CL-60 thermistors as a softstart?
- One CL-60 before both transformers
- One CL-60 before each transformer
I ended up doing one CL60 for each primary line (red), so 4 CL60s since I have dual primaries and dual mono.
I saw a website where they offer to improve your First Watt amp via a series of tweaks. One of which was removing the CL60s. Not sure how that would make a difference when you've got 100k+ uF stored in cap banks lol
I opted for one CL-60 in total for my dual-mono SissySIT (230 V; 2 x 400 VA; 528 mF in total). My reasoning is that the amp draws less than 1 A from the wall in steady-state, and I want to have enough current flowing through the CL-60 that it gets hot enough, so that its resistance drops more and I have lower impedance on the primary side. Works absolutely fine, and I have a fuse of 1.6 A or 2.0 A in the IEC inlet, so the CL-60 is still providing enough of a soft start.
Regards, Claas
Regards, Claas