sc350w

[fity]

I am a madman of the audio,
Can somebody help me or to say me if this design has good guys proven to be?
Has somebody constructed it?
I need slight knowledge to construct also the power supply, he has a consumption of 5A
Can somebody help me?

(copyrighted attachment deleted by moderators)

[lineup]

Studio 350 - High Power Amplifier Kit

Ref: Silicon Chip Jan/Feb 2004.
This fantastic new amplifier kit will deliver 200WRMS into a 8Ω load, or 350WRMS into a 4Ω load. It is super quiet, with a signal to noise ratio of -125dB(A) at full 8Ω power. Harmonic distortion is a fantastic 0.002%, and frequency response is almost flat between 15Hz and 60kHz. Kit supplied with PCB and all electronic components.

SC = Silicon Chip
If you can get the PCB it would be easy to build.
Notice Q7, Q8 and Q9 is on heatsink.
If you can not find BF469/470 you can replace with MJE340/350.

I think is a good amplifier, and should be safe to build.
This Kit is being sold at several websites.

Silicon Chip homepage in Australia has info and instructions for building:
http://www.siliconchip.com.au/cms/A_100503/article.html

http://www.siliconchip.com.au/cms/A_100618/article.html

[lineup]

for the power supply
which is +-70 Volt DC

You need 2 transformers: 50V+50V 500VA

Parts list:
Power supply - for one channel
------------------------------------
50V+50V 500VA toroidal mains transformer (Altronics Cat. M-5750)
35A 400V chassis-mount bridge rectifier
6 8000uF 75V chassis-mount electrolytic capacitors (Altronics Cat. R-6722)
2 470nF 100V MKT polyester capacitors
4 15kOhm 1W resistors

[quasi]

This design is based on a well proven topology that has been around for 20 years or so. Improvements over time have been the availability of better semiconductors and a better PCB layout (which impacts the sound).

Overall it is an excellent design and should provide great satisfaction. Be aware though of the total project price, if you had to buy everything new I doubt there would be much change out of $1,000 US. It might even cost more depending on your choice of components & case.

Cheers

[mastertech]

These guys (sc) design for low distortion, yes the design is typical
of theirs over the years they have stuck with pury much std topologies of low dist., yet this design doesnt go as far into their
philosophy quasi prety much has said it all, i am sceptical about
its sonic impact however

thank you guys for sharing

Regards

[PM650]

This is a bit off topic, but I would be curious to know anyones comments on this amp schem compared to the Studio 350:
http://www.mustangmods.com/data/2197/amp_schematic.jpg
The reason I'm asking is the amp can be purchased in kit form very cheap ($30) with heatsink, and it seems to be similar to the 350 at a glance.

[lineup]

Originally posted by PM650
This is a bit off topic, but I would be curious to know anyones comments on this amp schem compared to the Studio 350:
http://www.mustangmods.com/data/2197/amp_schematic.jpg
The reason I'm asking is the amp can be purchased in kit form very cheap ($30) with heatsink, and it seems to be similar to the 350 at a glance.

... it seems to be similiar ...

Yes, really.
So many components are identical, that the one making this
has used the Studio 350 schematic and changed a few things.
Or the other way around.

Main difference is this has only 1 output pair and 60V supply = lower power.
This one has a current/power limiter for protection.
A few other small details also are different.
But this is 'same' amplifier.

[PM650]

Well, I'm glad to hear this lineup. I constructed my first amplifier using a pair of these so I guess my cheapness didnt get the best of me, for once.

[quasi]

This schematic is a direct copy from one published by Electronics Australia Magazine in 1989 (or maybe they copied it) with only a couple of minor changes. One change that I would reverse is feedback resistor R12, this was originally 1K. This will set the gain to 27. As it stands the amplifier has too much gain (48) and will perform better with a gain of 27.

The output stage (2SC5200 / 2SA1943) is not strong enough for 50 volt rails, and at high volumes a 4 ohm load would surely blow them. It does have over-current protection, but this seems to be configured for stronger transistors.

But if the kit includes a heatsink, a pcb and all the components, it's a steal. Even if you upgraded the output transistors it is still great value.

Cheers

[lineup]

Some pictures of Studio 350

Close up of built amplifier
http://us1.webpublications.com.au/st...100503_4mg.jpg

Horisontally mounted, drawing of amplifier with parts.
http://us1.webpublications.com.au/st...00618_14mg.jpg

Vertically mounted to heatsink.
http://us1.webpublications.com.au/st...100618_3mg.jpg

Scope1: this waveform shows the excellent square wave response of the amplifier,
taken at 1kHz and 102V p-p into 8Ω.
This equates to a power output of about 300W RMS.
http://us1.webpublications.com.au/st...100503_6mg.jpg

Altronics sells Studio 350 as a Kit
with heatsink included.
http://www.altronics.com.au/index.as...=item&id=K5185

Altronics also sells recommended toroid transformer 2x50V 500VA
http://www.altronics.com.au/index.as...=item&id=M5750

What prices would be in € Euro or in $ USDollar I do not know.