Plus, most of the drivers liking a current source are happy with low wattage.
I like bushes, especially making them sing.
Yes, it is a challenging situation. It paves the way for Papa’s revised positive energy coefficient massless speaker, connected directly to ozon cooled AC so as to spare the bodies of the listeners, powered perhaps by a fusion core 5kW ampSE CCs, very attractive in winter. Not so much if the power utility is down and sky is grey
and house is running on batteries.
Describes my situation yesterday and today, probably for another few days.
Tempted to listen to (or even design/build) one 5 w class AB amp?SE CCs, very attractive in winter. Not so much if the power utility is down and sky is grey
and house is running on batteries.
Describes my situation yesterday and today, probably for another few days.
But, the one that sounds (quite) a bit better than a TDA 2003?
Of course, on top lid of that amp should be written: "Use only in case of emergency"... 😉
Tonight I used a Chinese class D / tube hybrid. We watched a couple episodes of "Six Feet Under".
The hangman is being hanged. 😉Tonight I used a Chinese class D / tube hybrid. We watched a couple episodes of "Six Feet Under".
https://www.diyaudio.com/community/...20r100-pair-of-sic-jfets.394447/#post-7238792
For anyone who’d like to try a F2J…I’ve already hoarded my share
For anyone who’d like to try a F2J…I’ve already hoarded my share
I’m starting to source the components for my F2J monoblocks. Without wishing to start a debate about whether expensive caps make a difference, I’ve decided to spend a bit on the input and output coupling caps. I’ve got Twitchie’s PCBs with the optional holes for those caps. At 45mm long I think I can just squeeze on the 1 uF Pur caps from Clarity Caps.
I just got done with my F2. I wanted to make sure I got everything right before going to F2J, so I don't put the SemiSouth parts at risk.
It's mess to look at; but, man, does it sound good!
I'm driving a pair of Abbys with it. They've moved from a McIntosh MC275. Of course this sounds better because I built it 🙂 But, the bass is noticeably more articulate. Surprisingly, the midrange has more depth. It's much of what I expected after reading Papa's descriptions.
I'll listen for a week or two before converting it. I'm already very happy with the results.
I've read quite a few times that the F1/F1j/F2/F2j only shine with single driver sensitive speakers. I now believe the inverse is also true. The Abbys have never sounded so good 🙂
It's mess to look at; but, man, does it sound good!
I'm driving a pair of Abbys with it. They've moved from a McIntosh MC275. Of course this sounds better because I built it 🙂 But, the bass is noticeably more articulate. Surprisingly, the midrange has more depth. It's much of what I expected after reading Papa's descriptions.
I'll listen for a week or two before converting it. I'm already very happy with the results.
I've read quite a few times that the F1/F1j/F2/F2j only shine with single driver sensitive speakers. I now believe the inverse is also true. The Abbys have never sounded so good 🙂
Hi all, I was lucky enough to come in to possession of a pair of Semisouths, and am thinking I’ll build an F2J with them. Does anyone know of a good source for the F2 boards? Also, if anyone has a BOM on hand that they wouldn’t mind sharing, I’d be most grateful. Thanks!
Scott
Scott
Send me you e-mail address on PM. Drop the @ and replace with (at). No bom but my mouser receipt for the J.
Ask Twitchie for boards, perhaps some are left. Next on list is Peppennino.
Ask Twitchie for boards, perhaps some are left. Next on list is Peppennino.
I’ve been enjoying my F2J with the SJEP120R100 and love what it does, especially with my sensitive full-range field coil speakers.
However, I’ve been thinking about the original CCS used in the F2. It’s elegant and minimal, which is great and simple to build for DIYers, but when I tried using this CCS in another circuit, a fellow engineer pointed out that it might be prone to high-frequency instability due to phase shift and lack of frequency compensation 😳
Now, I know that in some of his later designs, Mr. Pass used optocoupler-based CCS for biasing and current regulation. From what I understand, these offer better thermal tracking and potentially smoother high-frequency behaviour, thanks to the isolation and slower response. Right?
So I’m wondering:
I’ve already done some LTSpice simulations of a modified optocoupler-based CCS, and the results look clean - but I’d love to hear from people with real-world experience or similar experiments.
However, I’ve been thinking about the original CCS used in the F2. It’s elegant and minimal, which is great and simple to build for DIYers, but when I tried using this CCS in another circuit, a fellow engineer pointed out that it might be prone to high-frequency instability due to phase shift and lack of frequency compensation 😳
Now, I know that in some of his later designs, Mr. Pass used optocoupler-based CCS for biasing and current regulation. From what I understand, these offer better thermal tracking and potentially smoother high-frequency behaviour, thanks to the isolation and slower response. Right?
So I’m wondering:
- Has anyone tried replacing the F2’s original CCS with an optocoupler-based one, similar (or identical) to those later designs
- Could this improve high-frequency stability or sonics with complex speaker loads? (In my case, the field coil itself is also powered by a CCS - so I may have two CCS circuits “fighting” each other)
I’ve already done some LTSpice simulations of a modified optocoupler-based CCS, and the results look clean - but I’d love to hear from people with real-world experience or similar experiments.
Also, the optocoupler CCS seems to solve the soft start issue as well, so there’s no need for the 15mF large cap.
If you want to play/run it in LTSpice, I’ve attached the ASC file.
PS. I intentionally added a reactive load, as that’s the real challenge. Ignore the Vout, it’s ugly. Check the current through R5 (L2) instead 😍
If you want to play/run it in LTSpice, I’ve attached the ASC file.
PS. I intentionally added a reactive load, as that’s the real challenge. Ignore the Vout, it’s ugly. Check the current through R5 (L2) instead 😍
I have NO circuit design ability to understand or analyze what you propose.
I’m just a fan of the F2J and it has been my favorite amp since I built it.
I have used my F2J monoblocks with Sonido field coil widebands (driven by a CCS power supply)and it has been the best sounding combination I have tried in probably a decade. They are the most balanced and resolving combination of a fullrange/wideband system I have personally experienced.
So I have to ask. What is it that you hear that makes you feel it needs fixing or improvement?
Perhaps it is just the challenge/exercise of “what if it could be better?” that you enjoy?
I’m just a fan of the F2J and it has been my favorite amp since I built it.
I have used my F2J monoblocks with Sonido field coil widebands (driven by a CCS power supply)and it has been the best sounding combination I have tried in probably a decade. They are the most balanced and resolving combination of a fullrange/wideband system I have personally experienced.
So I have to ask. What is it that you hear that makes you feel it needs fixing or improvement?
Perhaps it is just the challenge/exercise of “what if it could be better?” that you enjoy?