Amp killers

[@BigWill63]

I drive my Kappa 9 speakers with a Crown XLS1002 amplifier. Sounds great, really lets them sing with not one complaint.

[@marcusalvblad1752]

In driving my Kappa 8 with a new BHK 250, BHK preamp and really good Audioquest cables. It sounds amazing!!

[@gerryk3114]

Love my Infinity QLS-1’s, purchased New 1978 and are Still impressing me Every Day !!!

[@roberthurley1685]

I inherited a pair of Kappa 6's about 3-4 years ago, replaced the mids and the woofers' surrounds and they still work with a 4 ohm (2 channel) receiver

[@efertheredfish2]

I once tried a McIntosh MC75 full-range (2-ohm tap) and a Spark 810 (4-ohm tap). The seamless transition between the mids and highs and the crystalline glint on my skin brought tears to my eyes. It had room-shaking bass. At the lowest frequencies, you feel the spacious air floating around you as they are softening and loosing up a bit, but the sound is out of this world.

[@shipsahoy1793]

Good answer Paul. Exactly right. Tube amps don’t tolerate open circuited output transformer secondaries, and transistor amps don’t tolerated short circuited outputs unless protections are in place.👍

[@dhpbear2]

3:32 - That 'lost sound' is a HUGE dip in the frequency response! I would guess the Kappas would sound horrible at ANY volume when driven by a tube amp! Come to think of it, ANY speaker driven by a tube amp will have *vastly* different frequency response that 'follows' a given speaker's impedance curve!

[@brandonburr4900]

Paul. If I remember right you mentioned arnie would power his speakers with aonic frontiers tube monoblocks? Forgot the model. But a lot of tubes! Thanks!

[@77Phatkid]

When I first received my Kappa 9’s, I tried them on my av surround receiver with the impedance switch on extended. It clipped immediately! I also tried my vintage receivers, a Marantz 2330B and a Kenwood KR9400. They ran with no problems, and I pushed them hard. I’ve also ran them on mono block tubes, Laboratory West (Will Vincent) tube amps and Audio Research. They responded very well to those.

[@johndii2194]

I am glad I can't afford those speakers because I couldn't afford the amplifiers. An interesting piece of history.

[@swinde]

My first solid state amplifier was a Marantz Model 15. (actually a dual mono-block). It had red lamps on each channel to indicated an overload. I had the amp connected to a pair of Acoustic Research AR-3a speakers. At moderate volume, it worked fine, but at higher volumes these lamps would start to come on. The sound was fine, but I knew the amp was being overloaded. The AR-3a has an impedance of 4 ohms and can dip as low as 2.5 ohms depending on the settings of the midrange and high frequency controls on the speaker. I replaced the power amp with a Marantz Model 250 to solve the problem.

[@terryreese663]

I have had a pair of these from new. Beautiful sounding. Terrible reputation. Like Paul mentioned, there is a switch on the rear of the speakers. But, this switch was only avalable on the last year of production. From memory, I believe these were made in 87,88 and 89. Only the last year (89 models, to the best of my memory) had the switch and were known as the 9a . Admittedly, the speakers sound better without the crutch of an extra resistor in the circuit to ameliorate the issues present with these speakers. If yours were from an earlier vintage, protection circuit amplifiers are a must. Another approach is to look for those amps that are said to be stable at 2 ohm or less. They exist. I have some Parasound JC1 amps which are just one of this kind of amp. I think Anthem had/has an amplifier (P2 and P5) that would supposedly run to a short circuit (essentially a welder). Anyway, you will enjoy these speakers only if you find an amp to handle these excursions. I have kept switch enabled and only at times tried with switch disabled. Thankfully I have great protection circuitry to save the amp from these torture devices. These are dipole speakers before dipole was a thing so they would perform best pulled from the wall some distance (up to a third into room). The good news is that I doubt the speakers you own have ever been run hard, because they cannot be run without this occurrence. The better news is that there are several amps that can now carry the load of this tortuous speaker. Once run with proper power, you have an incredible speaker set.

[@Hiluxtaco]

Hey, wait. Are those Elac Debut 2.0's sitting back there behind Paul?

[@ziqfriq]

Back when Gordon Holt reviewed the Infinity Servo Static, he recommended you try a Dyna Stereo 70 to drive the top end (you needed two stereo amps for these speakers). Arnie replied in the manufacturer's comments--back when the manufacturer's comments were more than just "Thank you for having the good taste to give our product a favorable review"--he didn't feel a tube amp could reproduce "hard transients" like a solid state model. I guess he had second thoughts. But IMO he was right. I briefly tried a pair of Latino M125 monoblocks with my Martin Logan CLS II's, which have a similarly abusive impedance curve, but with with no secret switch to make them more amp friendly. The problem is that when the impedance of the speaker dips and the impedance of the amp is high, so does the output. There are many happy Latino M125 users, but they're a poor match for Martin Logan's full range ESL's. Presumably, a "vintage" tube amp would produce similar results with the Kappa. BTW, a speaker with an erratic impedance curve isn't "poorly designed". Any engineering design involves trade-offs. To me personally, the trade-off's of the CLS are well worth it.

[@andydelle4509]

Paul, I am sure you have heard this old saying when it comes to audio amplifiers: The real purpose of the output transistors is to protect the fuses!

[@charleswade1673]

I have 2 pair Infinity Kappa 9 speakers, I use ADCOM limited edition gold amps they work great if you do pop a fuse easy to replace in the back.

[@whydonotme]

I've had Infinity Kappa 9.2 speakers for 25 years, which I've been feeding for 15 years with two hot Vincent SP-991 Plus Class A monoblocks, to which the SMSL M400 DAC is directly connected. I don't use a preamp. The amplifiers never turned off under heavy load, even when jokingly, they sometimes acted as a bass fan and trouser legs flew around with loud 24-bit clean sound. I use AudioQuest Dragon Zero Speaker Cables. This set is gorgeous. In the future I want to connect to McIntosh MC1.25KW, although I do not expect a difference.

[@mmmbbq]

None of the .1 or .2 are amp killers.

[@dell177]

We made some 150 watt switch mode power supplies that had one tough requirement. They had to withstand a one minute 700w overload without collapsing the output. The supplies also had very tight cost restraints so we could not use very robust output devices, we had to stick with TO220 case style device My solution was to accumulate output device peak currents in a capacitor and use that to trigger a 2n7000 FET which would clamp the 3544 control chip if a set-point was exceeded. That would clamp the output and then let it come back slowly over a couple of seconds. We actually exceeded the FET peak current when in this overload mode but Motorola enginnes assured me they should be fine as long as the FET die stayed at a safe temperature (

[@tacofortgens3471]

Mostly if well deaigned the fuse blows in the amp

[@BoudewijnvanHouten]

My Threshold Stasis 3 with output fuses (and okay updated PSU caps) drives them with problems as did my Krell KRS-100's ;-)

[@Bassotronics]

The car audio guys have an obsession for going under 1 ohm just for bragging rights. Then they need to cram a bunch of batteries just to keep the electrical stable from going so low. Ridiculous.

[@nikolaygeorgiev147]

Hey Paul, I noticed the Elac Debut 2.0 behind. With your perception of sound and quality could you please drop 2-3 words regarding those? I assume that as long as you put them in your sales area it should be good enough for background listening or even more?

[@01sapphireGTS]

Thanks for the post.

[@sawyerramos3113]

I see ppl putting speakers high up on the wall, on the right and left front channels, does go plugged into the same channels of front right and left? an addition to the floor standing right and left?

[@machintelligence]

I'm not too sure about which brands qualify as "modern" but my 50 year old Pioneer receiver has effective output protection circuitry.

[@leekumiega9268]

Buy used and get a Cob Carver designed Sunfire amplifier as they are load invariant ,will double down to 2 ohms and according to Bob can drive speakers where the impedance drops below 1 ohm at some frequencies. I can't believe your early amps were not protected from low impedances as back in 1971 Bob's Phase linear amplifiers had something he called an Energy Limiter. With this early form of protection as safeguard, you could literally short the amplifier-even overdrive it-and the output transistors typically would not fail. Harry Pearson in the very first issue of The Absolute Sound tested this by shorting the outputs and the amp survived.

[@machone539]

What is weird is better mid to high end car amps can handle half to 1 ohm loads without sweating.

[@briancampbell7712]

so i couldn't use Infinity Kappa 9 Die with my vintage Yamaha M2❓

[@jeanious2009]

What about protection circuits? Overcurrent? Current sensing? Clip sensing and mute circuit? I bet your new amps have all that.

[@TonyHarper-j7f]

I know nothing about this subject, but just bought a Marantz Cinema 30 and the idea of any speaker damaging any equipment scares the @#$% out of me. Can a Kappa 9 damage my new receiver. I don’t yet have the $ to buy speakers worthy for this receiver and trying to find something worthy until then…

[@ryanschipp8513]

Paul, why are you only only mentioning a couple amplifiers that you carry that are class d?

[@Mikexception]

Interestins for which harmonics with thi speakers this dip occures and impedance falls below say 3 Ohm

[@scottwolf8633]

I'm driving 4.5 Ohm planar magnetics crossed over at 200 Hz to two Morel, 8 Ohm, 164's wired in parallel for about a system 4 Ohm impedance. The OTLs output only 25 Watts at such a, "Low", impedance and any lower and something is going to blow.

[@TheDoctor46]

Hi Paul. I’m buying used Trio C - 100 it’s it a good integrated amplifier? Matching whit my bookshelf Monitor audio speakers

[@Roof_Pizza]

Sounds ;like buying an old German car, have fun with the issues. Shoulda bought a Lexus instead. Emotiva will make you a custom amp I'm sure. I'm running an Emotiva high current amp at 2x2 ohms for subwoofers that's said to be one ohm stable, doesn't even get warm.

[@Jack96993]

I'll take my 1973 BMW 2002tii over a Lexus any day 😅

[@Roof_Pizza]

@@Jack96993 I drove a '74 (? ) for a while. Not bad at all but my '98 CIVIC would kill it.

[@robinr5787]

Old Volkswagen cars would be older than any Lexus could be 😊.

[@tcngr]

1/2 an Ohm....?!

[@beans4gas]

I go to the thrift shop for my audio equipment. I gota busted keyboard, cause it was 99 cents! I'm going pop some tags.

[@paulstubbs7678]

Sounds like a poorly designed speaker to me, using sneaky low impedance antics to grab extra power from an amp to make up for very bad dips in efficiency.

[@f430ferrari5]

It is poorly designed but it was sold back in the day when “more” was better. 2 12 in sub woofers 1 5 in mid woofer 1 3 in midrange 1 EMIT tweeter 1 Super EMIT tweeter. The above is for the Infinity Kappa 9’s. Once separate powered subwoofer cabinets came along the old school style speakers went away. Most audiophiles go with the tall skinny max 6 or 7 in driver type and have a separate subwoofer. Or they even go bookshelf style on stands.

[@finscreenname]

@@f430ferrari5 There is no replacement like displacement. I've always said, if you like a set of speakers, buy another set and set them right next the first set. Even dividing up the power you used with the original set will still sound better and fuller.

[@f430ferrari5]

@@finscreenname your analogy isn’t good. So you’re saying you would try to put a 454 engine in a 2,200 lb car with low gear ratios and just spin the tires all day long? Seems like you’re full of smoke? You would put the Kappa 9’s in a small room with the both tweeters above your ears? You risk frying your amp? Back to full of smoke?

[@jpatrickmoore5158]

There's one alternative that a lot of people don't think of doing: put in a fuse that's rated lower. Start with a lot lower and figure out when they blow, and then adjust. In college, I had a receiver that took 3 amp fuses. I was going on Spring Break and told a roommate to enjoy my stereo while I was gone... but I put 1/4 amp fuses in before leaving. Either he never turned it up, or the fuses were still rated high enough that it wasn't a problem.

[@finscreenname]

All (bigger) Infinity's are amp killers. I've seen a lot of black electrical smoke come from amps over the years from my RS IIIa's. I ended up with a QSC CX 254. Never looked back.

[@36karpatoruski]

I’ve got RSIIIb’s. My Carver M1.5t would constantly kick in it’s protection circuitry and shut down. My Aragon 4004 MK II handles them easily at the same or greater volume. Both are about the same power rating for the nominal 6 ohm load, but will dip to 1.8 ohms below 100hz, same as the IIIA. The Aragon is a monster. The Carver was a wimp.

[@vegaslimoguy2376]

Been running a pair of Kappa 9s for over 20 years with an Adcom GFA 5802 and I have never ever had a shutdown or anything, not even a clipping indicator light come on and i play my music very loud! Still as of today, never have had any problems whatsoever.

[@36karpatoruski]

@@vegaslimoguy2376 the Adcom is a great high current amp as is the Aragon. I never had a problem with the Aragon. The Carver did not cut it, and if not for the protection circuitry would have f tried. The stories of Infinity amp killers are legendary. Many people learned the hard way.

[@jeanious2009]

Just throw 2k watts to each driver, I bet they won’t kill that amp.

[@hhvictor2462]

I need shelves like that, wall to wall.

[@shangrilaladeda]

Get rich

[@franciscorompana2985]

😢

[@franciscorompana2985]

I double the shelves (back to back) from IKEA so they don't bend in the middle. They are made of paper. Another option is buying the kitchen shelves (stronger) or the office series. Edit: the problem with shelves is that they don't last long, unless say your books or vinyl🍷 In this case I would buy industrial storage shelves.

[@davidfromamerica1871]

@@franciscorompana2985 Build your own shelves 👍 from real wood, 👍 not from store bought pressed wood. If you don’t have the tools you need, you can rent them. You can design the selves any way you want to fit your needs. Paint or stain them.

[@RoderikvanReekum]

Get a good PA amplifier or a vintage Crown D-150A

[@shangrilaladeda]

I use modern crown amplifiers

[@RoderikvanReekum]

@@shangrilaladeda Yes, I do not have experience with the vintage Crown but I have read that it is good with difficult loudspeakers and is stable to 2Ohms. I have experience with the LabGruppen PA amplifiers and they were great for Hifi. I think Crown does have the LabGruppen brand. You get a lot more for your money with Pro audio, it does not have all this audiophile markup.

[@shangrilaladeda]

@@RoderikvanReekum yes I know I’m using some xls 1502 to 2502 and also one xti 6002

[@spacemissing]

People fault designers for impedance dips that cannot be avoided if a speaker is to work right. I just laugh...

[@f430ferrari5]

Infinity Kappa 9 or these series types of speakers are old school and not worth the concept and headache that comes along with it. 6 drivers in one cabinet - bi-ampable. 2 12 in woofers 1 5 in mid woofer 1 3 in mid range 1 EMIT tweeter 1 super EMIT tweeter If crossover and speakers re-wired in series vs parallel concept then it would take a massive amp back in the day to power. Good Class D didn’t exist back then. The speaker is nearly 60 inches tall which is 5 feet and the tweeters would be above anybody’s ears sitting down. Can work in some large listening room. The days when separate subwoofer cabinet designs arrived then these large Infinity type speakers disappeared it seems. This Infinity type speaker can be bi-amped and seems to be the way to go.

[@ianmontalegre9616]

😅

[@mikepxg6406]

Why purchase stupid speakers.......

[@richardwestmoreland4796]

If you have never listened to Infinity speakers I can understand why you might think they are stupid. However,if you know what the speakers are capable of you simply use an amp that has the specs to go with those speakers. Some older amps may not give the consumer all the specs that you need to make the right call but newer equipment that is of even mid-fi quality should provide those specs. True hi-fi should give the specs 100% of the time or it should not even be considered to be high fidelity aka hi-fi.

[@kx8960]

Oh man, those are the first speakers I actually lusted after. It was the early/mid '90's in Cleveland, and the audio dealer just wanted to get rid of them. I think he only wanted $1,500 for the pair! But, in demo-ing them, I put a Carver amp into thermal shutdown trying to drive them. Luckily, after turning down the volume and a few seconds to cool off, the Carver came back online (thank God!), and it was then that I knew my current Sansui amp (2x100watts) would not be able to drive them. So, I knew spending thousands of dollars on audio gear (on a $40k/yr salary) wasn't gonna cut it with my new wife, so... I DO regret NOT buying them now though, I should have made it work. Ah well. I will sau I'm VERY happy with my newly-acquired, 7 (1 for each channel), Focal 826 Chora's I got from Crutchfield (for an insanely good price) for my home theater. Now that I can finally afford Infinity speakers, unfortunately they sold out years ago and are no longer the company they were when I bought my car audio speakers from them in the late '80's with the EMIT tweeters I loved. And who can afford the Genesis brand they've become? Sad.

[@richardwestmoreland4796]

It is sad that Infinity has become something only for the deep pocketed because they were a company/brand that were world renowned with those who knew good hi-fi for the sound that they could reproduce. There comes a point of diminishing returns once you reach a certain price point and I am someone that won't be held hostage for incremental improvements that cost a small fortune.

[@kx8960]

@@richardwestmoreland4796 You mean "Genesis", right? That's what happened to the REAL Infinity, and now the Genesis speakers aren't able to be purchased by normal people. The existing Infinity speakers totally lack the EMIT and SEMIT drivers and technology the older ones had. I regret losing the Infinity speakers I had in my car. Ah well, I'm REALLY liking my Focals, so...

[@cjmmjc2131]

that would have been when Audio Warehouse was shutting down... i got my Infinity Q4s in 1979