Thanks Sir Rothacher@soundhappy
Certainly, yes. The 2SK180 likes a little more voltage across it and it has a good bit more capacitance.
I recommend trying both if you have the luxury of experimenting.
Always art of compromises in some aspect non ideal SIT around.
Classic Inductor L'Amp circuit for now is great fun !
Work in progress on bias regulators i get ready two 15 V little toroids.
Kindest regards
ps : Surprise in Japanese Diyers MJ Magasine Nr 909 | 4 | 2016
i find Mr Pass article speak at California Audio Show haha cool
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@soundhappy
dont you also have VFET2 and M2 that need to be completed
focus focus focus
Yes absolutly and i soldered fine components last days to completed them.
We need to be efficient in every day life some time is tired me and stress.
Hobby & electronic i do to feel good and relax with peaceful mind
Yes absolutly and i soldered fine components last days to completed them.
We need to be efficient in every day life some time is tired me and stress.
Hobby & electronic i do to feel good and relax with peaceful mind
Well said. and BTW thanks for your kind words.
I am the happy father of a new single ended SIT amp with 2SK180. Thank to Mr Pass, Mr. Rothacher for all his input and encouragement and last but not least, to Nishizawa San.
I didn't have a decent L bracket so I created a sandwich heat transfer device (the 180's top being flat) to double heat transfer area, for my ugly DIY box
It works so far, for around 1A bias...
BTW, Vbias and B+ get their own regulated supply and I used 40mF pre-regulator capacitance, an excess for me, of regular quality caps, reserving the best quality electrolytics for the output, this time. I use a combination of PETP and polyestyrene (Russian War surplus) for in/out DC blocking. Works very well.
A couple of pics from the power regulator and sandwich heat transfer system, pre-finish.
Instantly recognizable V-FET sound: coherency and roundness of sonic images. Stringed instruments excel, especially plucked. Arab oud seemed to throw emotional arrows directly to my heart with each note...
And it sounds powerful man.
Cheers,
M.
PS: as Mr. Rothacher said, the Load element protects the SIT in case of lack of V-bias
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I see a Amphenol-like thermistor in the 6-moon's SIT-1 picture. (top right)
http://www.6moons.com/audioreviews/firstwatt14/proto_big.png
Can I use a thermistor to avoid power on thump?
And if it's so, CL-150 is the best for L'amp?
http://www.mouser.com/ds/2/18/AAS-920-325D-Thermometrics-NTC-Inrush-031814-web-850596.pdf
http://www.6moons.com/audioreviews/firstwatt14/proto_big.png
Can I use a thermistor to avoid power on thump?
And if it's so, CL-150 is the best for L'amp?
http://www.mouser.com/ds/2/18/AAS-920-325D-Thermometrics-NTC-Inrush-031814-web-850596.pdf
Dual PSU L'amp
I prototyped L'amp with regular First Watt supply. A few members here are probably still wondering if it's doable, so I post the result of my experiment.
1 Choke version - My choke is a surplus 0.1H 2.5 ohm 2.25A from Ebay. Works fine, but it gets warm as expected.
2 Transformer input - My DAC has 600:600 output transformer, so I just directly connected it to the input of the L'amp.
3. Resistor bank -This is a self biased version. The bank enables to adjust the voltage and bias with croc cables for matching left and right. Popular 0.47 Panasonic, and they get hot. An additional pot enables further bias adjustment as well.
4 ZM recommended motor caps are really good. I also recommend motor caps for this amp.
5 Additional LC filter was needed to eliminate the hum. I used 8mH and 10000u, and it works great.
6 My prototype is with 2SJ28 but 2SK82 should work well.
Conclusion - Amp works very well, and sounds really nice with no hum.
I prototyped L'amp with regular First Watt supply. A few members here are probably still wondering if it's doable, so I post the result of my experiment.
1 Choke version - My choke is a surplus 0.1H 2.5 ohm 2.25A from Ebay. Works fine, but it gets warm as expected.
2 Transformer input - My DAC has 600:600 output transformer, so I just directly connected it to the input of the L'amp.
3. Resistor bank -This is a self biased version. The bank enables to adjust the voltage and bias with croc cables for matching left and right. Popular 0.47 Panasonic, and they get hot. An additional pot enables further bias adjustment as well.
4 ZM recommended motor caps are really good. I also recommend motor caps for this amp.
5 Additional LC filter was needed to eliminate the hum. I used 8mH and 10000u, and it works great.
6 My prototype is with 2SJ28 but 2SK82 should work well.
Conclusion - Amp works very well, and sounds really nice with no hum.
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Glad Plasnu your L'Amp work fantastic. Congratulations !
My is not finshed yet because i spend last week's all my hobby €$ budget on new drivers
and the next vintage 12'' full range alnico's pairs too.Full ranges are 98 dB.
Drivers have 102dB efficiency so i can enjoy flea watt's amplifiers use practicaly 1 watt and that plenty.
My Inductor 193V L'Amp project is for play music with this new efficient stuff
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@ Michael Rothacher and Diyers
No 18 V secondaires toroids for the moment to power on my prototype but i get 2 bench power supply's 30V/5 A.
My point-to point wiring is practicaly ready, bias circuit too.
I am affraid to start power on because vfet is depletion type.
My question : how i make them safe power on with 2 lab psu's ?
No 18 V secondaires toroids for the moment to power on my prototype but i get 2 bench power supply's 30V/5 A.
My point-to point wiring is practicaly ready, bias circuit too.
I am affraid to start power on because vfet is depletion type.
My question : how i make them safe power on with 2 lab psu's ?
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If you mean to use one bench supply for B+ and the other for bias then you just want to make sure the bias supply is switched on first. I do this sort of thing all the time. I usually set the bias supply for -12V or more then slowly bring it up to where I want it after I switch on the B+.
Remember to have fun
Remember to have fun
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If you mean to use one bench supply for B+ and the other for bias then you just want to make sure the bias supply is switched on first. I do this sort of thing all the time. I usually set the bias supply for -12V or more then slowly bring it up to where I want it after I switch on the B+.
Remember to have fun
Thanks Michael and PSz for helpful answers.
Ok psu for the bias first.
On the side of 2K resistor i need 0V right ?
Green ground of the lab psu connected together with red (+) i guess.
Best regards
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Soundhappy, MR, thank you for your words.
My attempt is probably not really practical, but I was really curious if my LTSpice simulation would work the same in real world. I'm happy to see it works, and I find LTSpice is more accurate than I expected.
Now I have more confidence to realize LTSpice emulation.
A perfectly inefficient amp for an efficient speaker.
My attempt is probably not really practical, but I was really curious if my LTSpice simulation would work the same in real world. I'm happy to see it works, and I find LTSpice is more accurate than I expected.
Now I have more confidence to realize LTSpice emulation.
A perfectly inefficient amp for an efficient speaker.
Thanks Michael and PSz for helpful answers.
Ok psu for the bias first.
On the side of 2K resistor i need 0V right ?
Green ground of the lab psu connected together with red (+) i guess.
Best regards
Nice Altecs! What is the other one? Phillips? Now my L'mp is connected to old Jensens.
Yes silver colour is the alnico 1255 Phillips 8 ohm's bi-cones.
What i like they are large 12''~30 cm not 8 ''
can play music without crossover contrary to coaxials.
You can find them at affordable price on the flea market.
What your Jensens reference ?
Me like that high quality old school audio model's.
Must go sleep now but tomorrow i do try how Phillips sound
with Inductor L'Amp prototype if all work correctly
Better than 300B ?
https://www.youtube.com/watch?v=JtibVx4_8Ms