Old ETI453 amp info

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I'm looking for the circuit and ETI article for the mini-amp ETI453 from
ETI April 1980 (also published (I think) as the HE105.)
I've got a couple of PCBs but have long ago thrown out the ETI mag.
It seems to use an op-amp, three small-signal transistors and two power
transistors, from the pcb pattern.
Any old-timers out there who can help shed any light?







Re: Old ETI453 amp info
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What I did after some helpful info from Phil (and some abuse) about
which issue, was to join the big library in sydney (they keep copies )
and copy article.

Re: Old ETI453 amp info

"yaputya"
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** Is the PCB designed to accept PSU components and two TO3 devices on
heatsinks like this:

http://media.digikey.com/photos/Aavid%20Thermalloy%20Photos/50150&501603B00000.jpg



...  Phil



Re: Old ETI453 amp info

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heatsinks like this:
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http://media.digikey.com/photos/Aavid%20Thermalloy%20Photos/50150&501603B00000.jpg
Quoted text here. Click to load it

No, it doesn't seem to have rectifiers etc. and has 6 pads near the edge
of the pcb that would take 2 TO220 transistors, not TO3s.
PCB is 83mm x 50mm, coded ETI453.





Re: Old ETI453 amp info
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I would still have it around here somewhere

Re: Old ETI453 amp info
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I got old "Audio Projects from ETI" mag with this amp, it uses LM301, BC557,
BC639/BC640 and TIP31/32 for output stage. If you provide working email I can
scan and send you the article.

Tom

Re: Old ETI453 amp info

"Tom"
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** That is the same PCB I used a few times back in the early 80s - but
modified it so TO3s (ie  2N3055 and MJ2955 ) would fit in place of the
TO220s.

Configured it as a Wien bridge, self oscillating, sine wave power amplifier
using a 6.3 volt bulb for amplitude stability. The output drove a 15 watt
valve output transformer ( A&R ) in reverse to produce a 240V, 50 Hz  sine
wave with adjustable frequency over a narrow range.

The purpose was fine pitch tuning for a synchronous turntable.

Was published in the design ideas pages of  ETI in the early 80s.


....   Phil





Re: Old ETI453 amp info

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BC639/BC640 and TIP31/32 for output stage.
Quoted text here. Click to load it
modified it so TO3s (ie  2N3055 and MJ2955 ) would fit in
Quoted text here. Click to load it
using a 6.3 volt bulb for amplitude stability. The
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a 240V, 50 Hz  sine wave with adjustable frequency
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That is interesting, could you scan your circuit and post it somewhere
(or just email it to me).




Re: Old ETI453 amp info

"yaputya"
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 ** After 30 years, I no longer have a copy.

    Silicon Chip magazine have back issues of most EA and ETI mags and will
copy articles for a small fee.


...  Phil



Re: Old ETI453 amp info

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BC639/BC640 and TIP31/32 for output stage. If you
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Thanks, I use a working email for ngs so just reply to sender.



Re: Old ETI453 amp info
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Hi yaputya
I built the ERI453 way back when and found it again half an hour ago when
cleaning out my workshop. (I found your request when Googling it myself)
If you're still looking for the article I'm sure I have it.

If so, email me at snipped-for-privacy@yahoo.com    (Please put the word 'orchid' in
the subject to avoid the spam filter.)

Barry

Re: Old ETI453 amp info

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cleaning out my workshop. (I found your request when
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the subject to avoid the spam filter.)
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Thanks very much for the offer, but I've already got the ETI article from
someone else on aus.electronics!





Re: Old ETI453 amp info
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cleaning out my workshop. (I found your request when
Quoted text here. Click to load it
in the subject to avoid the spam filter.)
Quoted text here. Click to load it
someone else on aus.electronics!

Have you built the amp yet ?

Re: Old ETI453 amp info

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from
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cleaning out my workshop. (I found your request when
Quoted text here. Click to load it
in the subject to avoid the spam filter.)
Quoted text here. Click to load it
someone else on aus.electronics!
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I actually built two of them about 30 years ago to replace the power amps in a
stereo gramophone unit.
Last year I removed them before the old unit was chucked out, they are now used
to boost the speaker audio from my workshop PC.
They work well enough for the job, but probably would sound even better if the
op-amps were replaced with NE5534s.





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