Electronics Today International ETI 4000 speaker article?

Hi there,

Wondering if anyone has the ETI magazine article for these speakers?

I think they were ETI 4000 or ETI 4001. Each speaker box has 4 speakers,

12" bass, 7" low-mid, 2" dome hi-mid and 1" dome tweeter. Box stands a metre high and the Rod Irving ones are 19mm chipboard.

I built them way back around 1980 or so, from kits by Rod Irving Electronics in Thornbury, the passive crossovers were by Selectronics (? I think) Very expensive at the time and improved a great deal a few years ago when I replaced the bipolar caps in the thing. Bass was always a bit low response but nicely defined since they're sealed enclosures.

An extra sealed inner enclosure for the 7" low-mid speaker.

I'm interested in seeing the original design specs, like crossover frequencies. Reverse working from the circuit is a bit difficult.

I'm considering ripping the passive crossover out, at least for the bass, maybe go three-way active? Dunno, all fluffy ideas at the moment. Was quite amazed how new higher voltage rated bipolar caps helped the bass along, been thinking quite some time about going to active crossovers, get rid of the E core laminated low frequency inductors and bipolar caps. I imagine the hi-mid and tweeter are okay with passive xover, or I could drop something active up there too, not so much power required?

Ideas welcome :)

So, does anyone have a copy of the articles they could scan? Last time I checked there were no library copies available, even our local uni had dumped their magazines from that era. Or is there an online magazine repository?

Thanks, Grant.

Reply to
Grant
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s,

Any idea of the month/year ? I would be 90% sure of still having mags from that era but would be quite a search without this

Reply to
kreed

"kreed" Grant

Any idea of the month/year ? I would be 90% sure of still having mags from that era but would be quite a search without this

** The ETI 4000 4 way speaker was published in February 1980.

The PCB is coded et496.

A 3 way version was published in June 1980.

Source is the RCS Radio PCB listing.

..... Phil

Reply to
Phil Allison

**It'll be in one of a couple of dozen boxes, somewhere. I could not lay my hands on my copy for quite some time, due to time constraints, though I've promised myself that I'll sort through my back issues next year. Maybe.
**Not a bad idea, given the low cost of electronic crossovers and cheap amplification nowadays. The Behringer crossovers are reasonably well resolved and extremely flexible.

Was quite amazed how new higher voltage rated bipolar caps

**More important would be to replace the HF driver with something more modern, as big advances have been made in recent years. Now I think on it, replacing the bass driver with a Peerless XLS would be a smart move too.
**Like I said: Next year. Maybe. Perhaps someone else can locate it for you. You could try calling RCS Radio. They may be able to supply a copy.
--
Trevor Wilson
www.rageaudio.com.au
Reply to
Trevor Wilson

"Grant is a Jerk "

** That is a very fluffy idea.

** Pure self delusion.

** Out of the frying pan and into to fire.

** So is the damn woofer.

** Forget going active - the advantages are grossly overstated.

Having speakers that are not compatible with a normal hi-fi amplifier is a real PITA.

.... Phil

Reply to
Phil Allison

Smooch :)

Nah, I reckon new 100V bipolars let the bass come through heaps better than near 30 year old tiny 50V bipolar caps -- besides, after all that work I put in, they *must* sound better :)

I tend to agree, if the amp dies, it's another story though. But yeah, lots of work for maybe no real benefit. Certainly being in my fifties I'm not hearing much from the tweeters ;)

Once I was close to ripping out the bass xover and run 4 x 50W amps from PC sound card doing the electronic crossover. But after I replaced the bipolar caps the improved bass was enough, lost motivation to complete the amplifiers, so they're partially built in a cardboard box, for when the stereo gives up the ghost.

Grant.

Reply to
Grant

Grant is a total Jerk "

** What flawless logic.

( Shite deleted )

... Phil

Reply to
Phil Allison

I don't hear that much HF. Though I have another pair of boxes need new drivers, made of plywood, but the bass is so bad I think the magnets lost it or something. Different project that one, just fill the holes with cheap speakers for a second pair.

Don't think I'd replace the woofers, I had trouble with one of the lo-mids and a bad solder joint, but it survived my repair from some years back, that wire up from the voice coil is so fine, compared to the flexiwire from cone to solder lugs.

Thanks, Phil pointed at them too.

Cheers, Grant.

Reply to
Grant

Thanks Phil, you turned hours of work into 5 minutes :)

I do have both these issues, unfortunately my 1980 set are in a binder, the front and back (glossy) covers of each mag have somehow glued themselves together and also to the vinyl of the binder so they can't be removed and cant be laid flat on a scanner. The pages are also fragile.

The June 1980 article is probably what you want as that has the details as well as a plotted graph showing the frequency ranges of each speaker etc.

Will try and photograph the pages and see how well that works, can you provide an email address please.

Reply to
kreed

If you continue to delete "s**te"best lop off your meat smoking head

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Reply to
atec77

Hey Grant,

Just sent scans of the original article to your email address.

Thes came from ETI Top Projects Vol 6

Regards, Mark.

Reply to
Art Vanderlay

...

Thanks Mark:)

Cheers, Grant.

Reply to
Grant

The state library of nsw keeps copies of a lot of stuff.I was looking for an old power supply circuit and had a huge slanging match with phill during which he mentioned the article and magazine date which was a huge help.Went to state library (had to join library) got article and copied it at library

Reply to
F Murtz

Be nice, yes. There was that earlier technical discussion of the project.

At the time I built the 100W/channel MOSFET amps and that preamp with the LED level meters.

OP's addr is snipped-for-privacy@grrr.id.au The stuff Mark sent is the speaker project itself. It's got the crossover frequency info I was after, so knowing why they loaded / adjusted the crossover network is icing on the cake :)

Thanks! Grant.

Reply to
Grant

Possibly the old ones had lost capacitance, obviously it wasn't the higher voltage rating by itself that made any difference, if there was one.

MrT.

Reply to
Mr.T

Wrong attrib

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Reply to
atec77

r

Agree, lost capacitance or developed a resistance across them that was pulling down the power to the woofer. With 30 year old caps, this is definitely on the cards.

I fail to see how the voltage rating can change anything.

Reply to
kreed

"kreed"

Agree, lost capacitance or developed a resistance across them that was pulling down the power to the woofer.

** Absolute bunkum.

With 30 year old caps, this is definitely on the cards.

** Insane to assume any such thing in this case.

I fail to see how the voltage rating can change anything.

** You fail to see a lot of things.

Like the inherent worthlessness of the OP's subjective opinion.

.... Phil

Reply to
Phil Allison

rote:

ct.

t

It has been sent.

If it doesn't come today, check your spam folder for "ETI 1980 article"

Hope it is what you need.

Reply to
kreed

They're bigger, lower impedance, I had to drill out some PCB holes for the larger wire. Besides I added more of lower value in parallel (for example 3 x 33uF instead of original 2 x 47uF), so it's not just upping the cap voltage rating, it's about lowering ESR.

Upping the cap V rating is simply because the local Jaycar agent sold

100V bipolars at a decent price at the time. Quite an obvious thing to do. Especially since rereading the articles I received -- Thanks Guys!

Grant.

Reply to
Grant

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