L'Amp: A simple SIT Amp

[gadut]

Can the L'amp chock loaded and CCS version survive a 4 ohm load?

4 ohm midrange with choke loaded and 4 ohm tweeter with CCS version.

Why not? dont need to worry about 4 Ohm. especially it's not a woofer, midrange and tweeter wil have lower load.

it's sunday morning, the sky is clear. every house in my cluster is making noise, vacum cleaner, boys playing around. It' s my time to make noise too 😀

Playing modern records : black eyed peas - i got a feeling & coldplay - ink

I crank up full volume, with one speaker only in my 4x3m bedroom, it's really loud. It's not the level of my normal stereo listening. Low is solid, but high is not too impressive. if my memory correct, AlephJ even more dull on first running on single channel.

Now AJ has more sparkle, but after AJ been running for several days. Maybe this what ppl say as break-in period.

another notes: SIT is not recomended for new age bad recording. AJ is still tolerable for them. Play only good recording and it will shine with SIT 😀

 

[vdi_nenna]

To test new xovers, I ran tweeters and mids with the SIT amps at full range. They did fine. Better than I expected. On one acoustic track, I could hear it clip on one part. It was strong low frequencies.
In the three way setup, the mids/SIT amp won't see these low frequencies.
Will also take pico's advice and bring up the low/mid crossover point.

 

[2 picoDumbs]

To test new xovers, I ran tweeters and mids with the SIT amps at full range. They did fine. Better than I expected. On one acoustic track, I could hear it clip on one part. It was strong low frequencies.
In the three way setup, the mids/SIT amp won't see these low frequencies.
Will also take pico's advice and bring up the low/mid crossover point.

There is never an absolute answer to these sought of questions (without experimentation) when close to the razors edge.
You might find 80Hz is achievable, if not just keep raising the cross over point till you get the best result.

 

[Soundhappy]

Low is solid, but high is not too impressive....
if my memory correct, AlephJ even more dull on first running on single channel.....
Maybe this what ppl say as break-in period.

@ Gadut
Yes is break-in period
SIT amplifier are perfect for simple experiments with components
and influence on sound for example :
bypass 10K uF electrochemical with MKC or MKP 1837 polypropylene
and try other kind of 10 uF capacitor. You can bypass psu cans as well.
Signal path resistors change for more watts derating ones or
other technology and have fun with audiophile myth and legends.
Greetings 🙂

 

[davidinnewzealand]

Hello Fellow SIT amp builders.
I have finished up my Inductor L'amp
But i need more bias voltage to reduce some current.
I have used the attached power supply except I have a 0.33 Resistor at R1
My PT is 0-18 so have about 7V at C2 and it passes 2.5AC at S3
Do I try a larger cap to get more voltage at this point?
Thank you guys very much

 

[Zen Mod]

increase C2 , decrease R5

 

[davidinnewzealand]

Ok Ive got only juuust enough with a 20Uf C2 and 180R R5 , would like a bit more
Ive only 1 20uf C2 plastic cap on hand, Tried a crossover bipolar and big buzzz.
So If i put larger electro in there on the secondary leg, do i put + towards it? bit of a dumb question im sorry
ohh by the way I have a + bias network and a - HT for PNP sit

 

[Zen Mod]

S2 is negative to gnd , at enclosed schematic

go figure

 

[davidinnewzealand]

is that why, I got firecracker effect from an elctro i tried with + to secondary.
I put - to secondary and hide for a while?

 

[Zen Mod]

draw exact schematic you're using and then I'll tell you

 

[davidinnewzealand]

OK

 

[davidinnewzealand]

Well I had this scheme going for a few hours, but Now the 1000uf/35V and the 470uf/35V Bias filter caps have expanded and are about to pop? I seem to get quite a drift in bias over that length of time too.?

 

[flg]

Theses symptoms are usually caused by reverse polarity on a polarized cap, or excessive ripple current through the cap?
My guess is there is an error in connection or a wrong polarity diode connection? After a coffee, I might be able to follow that schemo but it's to early now...

 

[audioexplorations]

Are the "not-quite-unobtainable" 2SK28/2SJ28 available anywhere? Would love to take on this project.

 

[wdecho]

The 2SJ28 is still available and can be used by reversing the polarity.

Vfet Sony's RARE 2SJ28 KF 33 P CH 1 Piece | eBay

You can order them here or on his website. Papa is coming out with design for this transistor without using the OPT not that it is anything wrong with this design. Maybe at the Burning amp festival.

 

[Soundhappy]

Would love to take on this project.

Hi Audioexplorations & Diyers

Days of Burning Amplifier Festival 17th octobre can
bring us the last news about SIT amplifiers from Uncle MR.
Greetings 😀

 

[davidinnewzealand]

I found my error, I had the bias filter caps at wrong polarity. Have new one in correct with plenty of volts to put the brakes on. thank you ZM and flg for tips and lessons. find and updated back of the envelope schemo

 

[gadut]

When i walked on Legian Bali last night, I saw an amazing store with this light bulb. I am totally amazed that this kind of bulb exist, and it's cheap only $6 - $12 each. But this is 220V and maximum is 100W, not ideal as CCS.

I'm thinking to put this lamp on top of SIT chassis just like tube amp, but it is connected to mains 😀 camouflage only for appearance

Google says they are called Edison Bulb

 

[2 picoDumbs]

I'm thinking of using these 1000W linear tungsten halogen lamps for our 240V mains.
Philips 1000w Clear R7 Double Ended Linear Halogen Globe | Bunnings Warehouse

 

[sensphoto]

input impedance and value of coupling capacitor

hi there..
I'm on progress building this amp with choke load and a bit confuse about resistor between bias trimpot wiper to gate stopper resistor. which the exact value? 10K or 47K?
with 10k or 47k I think coupling capacitor (10uF) is too much overkill
10k with 10uF 1.5Hz
47k with 10uF 0.3Hz
please enlighten me....😛