L'Amp: A simple SIT Amp

[juanitox]

it looks like a CRC filter board and a bias supply input board with the 10uf input cap..

 

[Aleksi M]

Aleksi M, what are we looking at here? Are these boards for a SIT amp or just power supplies?

juanitox pretty much nailed it. "Universal" PSU board, biasing board (including 10uF input cap) and the third one is for the output caps (Electrolytic + 10uF PP).

 

[Michael Rothacher]

Cool.

 

[vdi_nenna]

Gyrator Circuit?

Anyone look into using a gyrator circuit to take the place of an inductor or is a CCS still a better option? Can a gyrator circuit increase power effeciency like an standard inductor?

 

[Zen Mod]

..... Can a gyrator circuit increase power effeciency like an standard inductor?

nope

there is no inductive storage

 

[vdi_nenna]

Ok, thanks.

 

[PSz.]

Here is my SIT amp loaded with 193V inductors. Big thanks to NP and Michael also to Wayne, Wrenchone and everyone that helped troubleshoot it at BAF.

Just in case anyone is wondering, the mounting lugs on big Rifa caps are internally connected to the negative terminal. So beware if you plan to use them for output coupling.

The description of the sound from the Firstwatt articles/manuals is spot on.

 

[generg]

incredible nice.......!

 

[PSz.]

Thanks!

Here is an upskirt shot for those into that sort of thing taken by AMB at BAF. I still need to clean up the wiring because I was in a hurry to get it ready for BAF.

Thanks also to my friend David who took care of the machining on the heatsinks.

 

[juanitox]

trés mignon le petit dernier!

mine have a little problem, as i change to a passive preamp ( ldr) i have changed the input caps to go with my choke gate leak from 1uf to 3,9uf
now i have full bass again but i pick some hum

do you think it"s my unshielded input cap that is making antenna , or a ringing between choke and caps? or it"s just an horrible halloween buzz

 

[nicoch58]

turn the caps as the outer foil work as shield

 

[wrenchone]

PSZ and everyone else - hindsight is always keen... The case on any comupter electrolytic cap is always at the potential of the (-) terminal of the cap, which is one reason why you see them often with plastic sleeving around the case. In the instance of the Rifa long-life computer ekectrolytics with the stud on the bottom of the case, well, that stud is at the same potential as the case/(-) terminal of the cap.This is not a biggie if the cap is used for the usual filtering purposes ( but not for negative supplies, obviously). When used as coupling caps, the mounting stud on the bottom of the cap must be isolated, otherwise you are shorting the amp output to chassis. Obvious in retrospect, but not on Sunday - sheesh...

 

[juanitox]

hum gone, i think it was the grid choke having to big ac impedance and turning my non shielded cable to antenna , i just put a 27K resistor to charge the gate and still have strong bass with a 3.9uF input capacitor , it seems 10uf is a little overkill in this place

 

[juanitox]

somtehing tells me christmas time is coming sooner this year

 

[Michael Rothacher]

Here's something else:

Fun with PASS-SIT-1

 

[stefanobilliani]

Here's something else:

Fun with PASS-SIT-1

But wow ! Will we be able to purchase some of the PASS SIT-1 this year ?
Can't wait!

s

PS

I did read the news ( and all the article ) . But I keep crossing my fingers .

 

[Michael Rothacher]

I wouldn't hold your breath, though.

 

[juanitox]

michael , i was thinking of our christmas not only yours

Mr pass , what do you want for a pair of these ? (except 5000$ for a SIT2)
drugs, girls,french wine?

 

[Zen Mod]

Maybe Nelson bumped his head or something; I don’t know why he’d make me this offer, but believe me, I don’t question it. For me, this was like George Lucas inviting a random fan to Skywalker Ranch to preview one of the Star Wars films. And I don’t mean Phantom Menace.

yeah , wakoo Pa

 

[Antoinel]

More fun with PASS-SIT-1

Here's something else:

Fun with PASS-SIT-1

The weight of a TO-247 package is 0.2 oz for a bjt selling for $2; or 10 USD/oz. Do a similar calculation for a PASS SIT-1 transistor [TO 247] and then position it in this following field of precious metals:

• Au at 1,689 USD/oz
• Pt at 1,540 USD/oz
• Rh at 1,150 USD/oz
• Ir at 1,050 USD/oz
• Pd at 600 USD/oz
• Ru at 110 USD/oz
• Ag at 31 USD/oz
• SemiSouth R100A at 250 USD/oz
• bjt at 10 USD/oz

PASS-SIT -1 may be poised to trade in the market of precious metals. It'll easily surpass Silver and may gracefully sit between Ruthenium and Iridium.
The TO-3 metal package [2SB.. and 2SD..bjts] made in Japan weighed ~0.4 oz. The weightliest was ~0.5 oz. Those DIYers who used KD82 are in a position to place this SIT in the above list.