ETI 470 + ETI471 Schematic

[stainless]

Hi, everyone.

I am looking for the ETI 470 amp, ETI 471 pre amp Schematic and PCB layout.

it used the philips BDV64/64 output transitors.

published in May 1979

Can any one help.

Many Thanks

[Filby]

Here you go...
http://www.4shared.com/file/63555882...2/ETI_470.html

[stainless]

Many thanks for posting it Filby

[Symon]

Just a quick note as I build this power amp many years ago.
The amp sounded great but was unreliable. This proved to be because the specified power supply voltage was just too high.

In the original 1979/80 version the power transformer was 30-0-30, and could cause break down of the input devices.
I note in this version it's 28-0-28, I ended up using 25-0-25,
as a safe option.

I also added some over current protection set to 3 amps, which saved the output devices from thermal runaway when I didn't get them perfectly flat on the heat sink.

[sakis]

i would built a think like that is for fun ....

in any case you decide to do so keep in mind that your outputs have to be made my the same mom like you cannot have a bdv 66 from philips and a bdv 67 from ST ...

the reason is that they may say that they are bdv 66 or 67 but due to the construction inside might have diference ( not matching ) inside depending on the part number ......

any way i would go for ON SEMI MJ 11015-16 FAR MORE BETTER AND ROW BUST .....

to symon

the above reason is NO 1 reason for thermal runaway cause in this case you adjust idle to specs but that apply only when amp is on idle if you power it up then things are pretty much messed up

measuring voltage drop on every emmiter resistor might be some help cause you may find some diference there but still that cannot tell you much since even if you do find a diference there is nothing you can do about it ......its just an indication .....

regards sakis

[dangus]

I built one of these too, but I used TIP transistors for the outputs. Transformer was 56VCT, with 26,000 uF per rail for a stereo amp.

ETI (though not the Canadian edition) later published an input buffer board for this amp since in the stock form it has a pretty low input impedance. I've got a photocopy someplace, which I ought to scan.

I blew a channel once by shorting the speaker cable, and more recently blew both channels when I used it as a DJ monitor amp. I'm leaning towards filling the box with LM3886's instead...

[sakis]

SHELF A DX AMPLIFIER FROM CARLOS DESTROYER X

you are simply going to love it .....3886 is fine but not so nice as dx

[crt]

oh no, DX Standart VS 3886 ?

i have build a DX Amp, sound to superb if compare to lm3886.
JUST GO FOR DX AMP! by Carlos MERGULHAO.