SissySIT

Official Court Jester
Joined 2003
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consider your self lucky to get a pair of any of these, then make anything with them

first - THF51 and 2SK182 - didn't tried latter in Sissy; though , taking in account experience of trying them all in Singing Bush, I'm expecting (in SissySIT) practically no significant difference between THF and 2SK182, while 2SK180 could be slightly different ......... though can't say it's going to be worse

speaking of Sissy - major thing is - acquiring a pair adequate (Ugs) for Sissy, and - I'm having just few more ACS723 in drawer and that's pretty important part ; bummer is - I can't see it available in regular places now and when they'll be available again, who knows

so, from moment when I don't have any, I can't say anything when I can get them again

hm, maybe is time to devise some other loony biasing technique , not involving preputium made of parts :rofl:
 
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Joined 2018
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rhthatcher: It is nice to know that I am on the right track when planning to build a SissySIT/Singing Bush. Question: My subwoofer has a 500W class D plate amp, I don't see how an F5 could replace it.


What sub are you using? My sub is a 100dB Danley DTS-10. I used to run a 2000W pro-sound amp on it. I may switch back to a higher power amp in the future. I will borrow a friend's F5 V3 Turbos I built and try the jump from 25 to 100W. I think 2000W is massive overkill, perhaps there is a happy medium.



https://www.danleysoundlabs.com/wp-content/uploads/2012/04/DTS-10-spec-sheet.pdf
 
Official Court Jester
Joined 2003
Paid Member
as I just wrote to Rewind in PM :

3V5 is - no trouble at all

3V7 is - maybe you'll need to use selected IRFP9140, for greater Ugs ( some are 4V, some 4V5 and you'll need these)

3V86 is - even more trouble for selecting them

however , I believe I'll soon make some efforts to develop another biasing method, especially for these SITs with higher Ugs
 
The link above is about servicing YAMAHA B-1 that came with 2SK77.
"The "2SK180", which will be replaced in short, has a larger drain loss than the genuine "2SK77" by 1.5 times, so it has a larger input capacity. THF-51s, 2SK180ES is even bigger!
Because of this, if you simply replace it, the high frequency characteristics will deteriorate, so you must change the circuit. Circuit changes are not included."
 

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Ofc, Papa already has mentioned something about this (or something similar): Post: #221 Hockey Puck SIT 2SK180 by Tokin source NOS

"I haven't tested the 2SK180 for bandwidth, but it appears comparable to the
2SK182, more likely the THF51S. For the latter, common source operation from
600 ohms gives -3 dB at 10 KHz, so you will want to divide that 600 ohms by
whatever ratio gives you the rolloff frequency you want. 100 ohms might do it.
The output of a 2SK170 buffer would definitely do it." - Papa

It could be something else that also "deteriorates high frequency" or at least rolls off -3dB at 10kHz. I am sure all of this is already considered in the SissySIT and I should just go for THF51S.
 
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speaking of Sissy - major thing is - acquiring a pair adequate (Ugs) for Sissy, and - I'm having just few more ACS723 in drawer and that's pretty important part ; bummer is - I can't see it available in regular places now and when they'll be available again, who knows

so, from moment when I don't have any, I can't say anything when I can get them again

hm, maybe is time to devise some other loony biasing technique , not involving preputium made of parts :rofl:

ZM, are the ACS723 5A the only variant that will work in SissySIT? There are others available from various sources, 10A, 20A, 40A, etc...