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Where is it detached? Does the surround between the port hole and case itself come out of the case when you pull the cable out? The photos don’t really show the fault.

Can you explain what you mean by the optical output cover has detached? Do you have a photo of this?

PM sent.

Yep, that was me, $3,601. Ask him what his max bid was so I know how much I missed on it by. - it might make me feel better! Gutted, again.

Alright who won the eBay auction on these RS4.5’s!?! That the second time I have lost an auction for RS4.5’s!

I will buy it. How much if I pick it up today and pay cash? I live nearby.

Will you accept payment via PayPal and ship to Brisbane?

PM Sent

I would like to buy it but I would need it shipped to Brisbane. Would you be willing to arrange shipping at my cost?

PM sent

Nice work. I have a pair of 2.5’s and missed out on an eBay auction In the last 3 seconds for some 4.5’s. There were only 400 os so of that model ever made, so kudos for incurring the cost to save them.

See my post above about a fix for the Polydomes. Not cheap, the remains true to original spec.

I drive my Kappa 9’s in extended mode with a 4 channel Nord Acoustics amp that uses 500w (into 4 ohm) Hypex Ncore amp modules which handLes the 0.8ohm dip.

There is a guy in Germany - Bernd Reinhold from hifinity.de - he has the original tooling for original polydomes. I bought a refurbished pair delivered to AUs for about $800. Cheaper if you send yours over to be refurbished.

I. Would love to hear the 4.5’s with the Graz EMIM’s. Do you have he Servo controller? How bad are the other cabs?

I have Kappa 9’s, RS2.5’s, RSM’s and non-vintage Kappa Centre and Kappa Sub.

Contact Bill Watkins. I have spoken to him before and he is willing to repair and refoam woofers if you deal with al the postage/courier arrangements.,

Thanks Andy. It’s been a good learning experience and it’s why I have bothered to wrap back around to his old discussion to pass on my feedback in case it helps others in the same boat. Thankfully I took the advice of a trusted source that gave me the confidence to have a crack and ignore those that were suggesting I was suicidal not not following their personal advice. I suspect that there have been real developments in recent years with Class D amplification that make some old views redundant.

Can anyone recommend a good speaker tech in Melbourne that is known for having good experience with vintage Infinity models?

Just wanted to wrap back to this old discussion to offer some feedback on my final solution. I went with a Nord Acoustics Class D amp powered by two 500w Hypex NCore Amp Modules - so that’s 4 channels of 500w each. I have put the Kappa 9’s through their paces and have experiened no issues. They cope with the low impedances of the Kappa 9’s no problem. I have tested this set up for a few months now before providing this feedback. Temps of the amp are staying under 40c even after running them under load for hours on end. Perhaps people need to be more open in their prior thinking on these newer Class D power amps, as I couldn’t be happier with the result and the cost I paid. You don’t need to spend $40k on a pair of Krell Monoblocks to enjoy these speakers. Very much appreciate all the feedback and advice from this forum. Thanks again.

Item: Vintage Infinity Speakers - RSM, RSB, RS1.5, Qa, Qb, Q5, Quantum Junior etc Location: Brisbane Price: Budget of around $400 to $500 Item Condition: reasonable Reason for selling: wanting to buy Payment Method: Pickup - Cash, Paypal, COD Only Extra Info: I am looking to to buy my brother a pair of vintage Infinity speakers at the lower end of the spectrum. I have had a pair of Reference Studio Monitors (RSM’s) for 25+ years and I’d would like to find something similar to buy my brother as he has always lusted over these speakers. These are for a gift, so I can’t afford speakers at the upper end of the Infinity range, like the Kappa 9’s or the RS4.5’s, but something like the RSM’s such as RSB, RS1.5, Qa, Qb, Quantum Junior would work. Let me know if you have something like this that you might be willing to offlload for the right price. Example pic of the RSM’s for attention. Pictures:

Thanks or all the great feedback and advice - it’s been a really interesting discussion. I raised the concerns outlined above around the ability for the 250w Hypex Ncore modules to handle the dip below 1 ohm. The audio engineer I have been talking to wrote to Hypex with a copy of the impedance graph (very much appreciate that being supplied - a big help) and asked the question. This was their response: ‘I think these drops of impedance to 0.8 ohm should not be an issue at all. Yes of course it can happen that a not so powerful module can go into protection but then I would suggest using a slightly higher power module. One modules I can suggest is the NC502MP. This is a 2 times 500W into 4 ohm module including power supply. If you look at the datasheet each channel can even doe 450W into 2 ohms. https://www.hypex.nl/img/upload/doc/ncore_mp/nc502mp/Documentation/NC502MP_02xx_03xx.pdf” So now I am looking at a 4 channel amp that will use two NC502MP modules, each of which is 2 x 500w. One module for each speaker with separate channels for mid/highs and lows. I will never be pushing a full 500w, but it means if I am only pushing say 200w then the amp will have enough head room to drop down to 1ohm loads for periods of time. Nord Acoustics in the UK make an amp set up exactly like this and it’s way cheaper than some of the other options that have been suggested to me. https://www.nordacoustics.co.uk/product-page/nord-one-mp-nc500-4-6-channel-amplifier-black

I know this is years old, but did you ever sell the RS4.5's?

Thanks so much for all the great responses. I realise I have a lot to learn and totally underestimated what sort of power (and cost) is required to make these speakers sing. I also now realise that I have never really heard the true potential of my old Reference Studio Monitors as I have never listened to them being driven by a high quality amp. I looked into the aftermarket crossovers being sold on ebay, but the feedback from the vintage Infinity crowd wasn’t good. Off the back of this feedback I threw out a lifeline and called my uncle who is a veteran audio engineer (live concerts, studio recording etc). He put me in touch with his mate who is an engineer in pro audio electronics. I discussed my situation and he has offered to build me a couple of amps using 250w Hypex Ncore NC252MP amplifier modules that will be within my budget.

How much?