L'Amp: A simple SIT Amp

🙂 and that 's why i was going crazy with my toroids hum and buzz :no:

few hours later , i confirm what michael say , the source degeneration with no bypass cap sounds less magical, clean but constricted 🙂 tomorrow i will put some 47000uf on it 🙂
 
oh I feel honored "mon ami....."

take a 10k pot and go with the outer pins to the 9V battery, the middle goes to the 47k or 10k of the gate

and of course you have to connect the + of the battery with the ground of the amp to go nine volt lower

you have to measure the output at the middle of the pot and start with 9V to be sure no "PUFF" will happen, later you choose the 2,x Volt...but you know this all...🙂

look at Mikes picture.....nearly the same....
252656d1322857693-lamp-simple-sit-amp-completeschempartone.png
 
:wave2: this morning , i have finished V.3 of my sit with Fig 11 ,swapp the 10uF input cap and bypass the 1ohm source resistor with 47000uf epcos and 470uf MKP bypass ... the amp is now simple at max and sounds much better than my version with negative bias. the magic is here again even more relaxed and refined , simply fantastic pure sound...

i don't understand why , perhaps i'm more in the sweet spot for my speaker noww than before or it is the input cap ? or my negative bias who was making problem.
so for the ones who wants to go with fig11 directly i can confirm it works very well but you must bypass the source Res with good stuff to have the magic sound :spin:
 
I'd like to see someone build L'amp with 1500w 220v halogen sticks, like I did on my F2, some years ago...beside sounding magical, it will look magical as well... 😉
 

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Always something new...

Hi Nicoch58!!

Here is something I just spotted on Farnell - PRO-LITE - K1/110V-PROPLUS - LAMP, D-ENDED, 110V, 118MM, 500W!!!

Two of these in paralell will give app... 12,5 ohm and then you are close.

And the price = ultra cheap!

Wanna try - someone?



Olav
 
Hi Stefano!

As far as I remember, halogen sticks were some no-name ones, (the cheapest chinese ones I guess).
Stick sockets? Hehehe...I was scratching my head back then how to solve that one. In the end, I just bought a pair of cheapest reflector lamps (like the at the pic) scraped them and used the sockets 🙂
Also, there are some air-cooled power resistors of 75 ohms each, otherwise of no use, but I just used them in paralell with the sticks to provide a bit more current...

By the way, I was also considering using some infrared quartz heater elements instead of halogen sticks, but turned out I didn't need them... (not sure if they would work, maybe someone could try 🙂
 

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Hi Stefano!

As far as I remember, halogen sticks were some no-name ones, (the cheapest chinese ones I guess).
Stick sockets? Hehehe...I was scratching my head back then how to solve that one. In the end, I just bought a pair of cheapest reflector lamps (like the at the pic) scraped them and used the sockets 🙂
Also, there are some air-cooled power resistors of 75 ohms each, otherwise of no use, but I just used them in paralell with the sticks to provide a bit more current...

By the way, I was also considering using some infrared quartz heater elements instead of halogen sticks, but turned out I didn't need them... (not sure if they would work, maybe someone could try 🙂

Hi Vix !
Wonderful stuff ! infrared quartz heater ? oh are they cheap ?
By the way below there is a picture with the photo lamp that I did find here in Italy . I will build into 2 of them ( 500 watt times 2 ) plus one of 200w par channel . Building the "case " right now .🙂
 

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