New project... Yamaha RX396 Upgrade ( Continuing )

[Adrculda]

Original Thread

Does Anyone have the Schematic for the RX-396 ???

And what do you guys suggest for caps for the power supply cuz the ones i wanted to order are now obsolete.

[ostripper]

http://www.mouser.com/Search/Product...kMgAnHoRxjg%3d
only $5.34US X2

Add some njw0281/0302 outputs ,same beta as the originals ,same case style 20% more SOA - 250v devices , and bias trim (once you find schema).
You might find that this little amp can crank...

If you ever wanted to drive 4R loads ... http://www.onsemi.com/pub_link/Colla...NJW21193-D.PDF , a pair of njw21193/4 with larger drivers would max the amp/PS out , you might ??? get 100+w / 4R (peaks).

And that is about all you could get for 20$ caps/10$ OP's. Any more $$ , and you might want to build a big amp ( my 225/350w 4-8R amps only cost about 35$ apiece using the NJW's).
OS

[rabbitz]

I got the service manual but too large for me to email (ISP restriction). You can buy it here for US$5.
http://www.1servicemanual.com/Yamaha.html

You've got mail.... I have split off the schematic which is small enough for me to email.

[pjp]

http://www.eserviceinfo.com/download...6(396)RDS.html

[Adrculda]

Originally posted by ostripper
http://www.mouser.com/Search/Product...kMgAnHoRxjg%3d
only $5.34US X2

Add some njw0281/0302 outputs ,same beta as the originals ,same case style 20% more SOA - 250v devices , and bias trim (once you find schema).
You might find that this little amp can crank...

If you ever wanted to drive 4R loads ... http://www.onsemi.com/pub_link/Colla...NJW21193-D.PDF , a pair of njw21193/4 with larger drivers would max the amp/PS out , you might ??? get 100+w / 4R (peaks).

And that is about all you could get for 20$ caps/10$ OP's. Any more $$ , and you might want to build a big amp ( my 225/350w 4-8R amps only cost about 35$ apiece using the NJW's).
OS

Your killing me... LOL
i just canceled the other ones and ordered the NJW21193/94'S and the caps. Was a whooping total of $25
They even have Hammond 182S30 Toroid in STOCK !!!
Specs for the 182S30 are as follows...
182S30 625VA Pri. - 60V C.T. @ 10.42A Sec. - 30V @ 20.84A Arrangement - Dual

Now the only thing remaining is if that little rectifier can handle all that current :S
Might have to upgrade that as well :P

PS...
Does anyone have a balance line converter as i want to do away with the phono input and use Balanced inputs on it rather than loose the CD or AUX that i might use where i won't use the PHONO input for sure and will just feed the signal from the XLRs directly where the OPAMP is for the PHONO.

[ostripper]

i just canceled the other ones and ordered the NJW21193/94'S

In that case , your present drivers might be inadequate for the job ,
the 21193/4's have 1/2 the HFE (or less) . With just one pair at 8R ,it just might work.

A better deal would be 2sa1837/sc4793 as drivers , either directly replaced in the (B-C-E) same PCB holes or directly mounted on the main HS.

The other issue with the 21193/4's is their Ft of 4mhz vs 20+ for the originals or njw0281/0302's . On most amps (ones designed for fast Ft's), a slower OP device will improve stability.

when you do 2 pairs and up of the 21193/4's (like on my next amp) , using a triple EF with a pair of 0281/0302's as the DRIVERS is the only way to go with these low gain "beasts".

Sound wise .... the VAS ,drivers and biasing was designed for the higher beta/Ft OP's so any change (besides the caps) to drivers/OP devices will have a unpredictable effect on the amps sonic character..
OS

OS

[Adrculda]

Caps are in...
2 x 14000uF @ 45VDC
The new caps dwarf out the old ones

Sounds completely different, boominess is gone but response is phenomenal, also high and mids are very prominent and clean without any fade as before !!

[Adrculda]

UPDATE:
Pulled the 14,000uF caps out they seemed to mud up the mids and highs badly ( this was noticed after repairing a friends Marantz 2275 ) and replaced them with a pair of 8500uF 80V ones.
Bass is still responsive as before, but mids and highs are back and are crystal clear.
Also my buddy had an older 750VA EI core he had kicking around and replaced that tiny thing.
Night and day difference !!!!
Should mention though I'm seeing 96V at the rectifier
at a 4 Ohm load voltage drop is less than 1.2V at the rectifier

[Adrculda]

A Small update is due as i changed a few things around...

Caps are on a separate board with a "drain" Led.


C1, C2, C5, C6 - 2.2uF 250V MKP
C3, C4 - 470uF 250V
C7, C8 - 5600uF 250V
C9, C10 - 8000uF 250V
C12 4.7uF 250V Film
D1 - 10A05-TDICT-ND
D2 - LED for discharging caps
R1 - 3.3k