Any point in running Kappa 9s with a Purifi 400 stereo amp?

[Deleted member 48726]

I have had really weird issues when attempting to repair gear. I would get to the point where I would whip out the isopropyl alcohol or methyl hydrate, thoroughly/lightly scrub the PCB with a toothbrush and voila they worked after. Whiskers could have been be the issue.

Ah, because the strands are so small they can't be seen?

 

[Doodski]

Ah, because the strands are so small they can't be seen?

Yes. There is huge massive pressure in the metal and it forces out these little whiskers.

 

[restorer-john]

Yes. There is huge massive pressure in the metal and it forces out these little whiskers.

I’ve had heaps of trouble in the distant past with old germanium transistor rebuilds caused by tin whiskers inside the metal transistor cases themselves. Same issue as NASA in satellites built in the 60s/70s.

I know a lot of old speakers were plated with anti corrosion metal which also is seriously toxic when it turns into ‘spider webs’ on the magnet structure etc. You must wear a mask and wipe it off outside and throw out the cloth sponges. It’s not dust or actual webs- it’s a strange reaction of whiskers.

 

[Doodski]

I’ve had heaps of trouble in the distant past with old germanium transistor rebuilds caused by tin whiskers inside the metal transistor cases themselves. Same issue as NASA in satellites built in the 60s/70s.

I know a lot of old speakers were plated with anti corrosion metal which also is seriously toxic when it turns into ‘spider webs’ on the magnet structure etc. You must wear a mask and wipe it off outside and throw out the cloth sponges. It’s not dust or actual webs- it’s a strange reaction of whiskers.

Yes, those whiskers and fuzz are trippy stuff for sure. First time I saw that stuff I was at a loss to what the stuff was. My reaction was clean the stuff off no matter what it was...lol. It's only after I got internet and surfed the topic that I found the NASA webpage detailing the whiskers and fuzz. NASA has great resources on the topic.

 

[Sokel]

I have listen to them more than once,owner uses a modest power Accuphase amp (I don't think it's more than 2x100 in 8 Ohms) in a 30m³ room and they are fantastic!
Open "big" sound,beautiful highs that don't get tiresome,they have slam (no small speaker comes close) and low seems well controlled.
Nothing missing and they could go pretty loud without screaming.

I would get them and if small Purifi would not be enough I would go for the bigger ones.

 

[Deleted member 48726]

@tmtomh
So, did you get them?

 

[damage]

So, I run original Kappa 9s with a GFA-5500. It plays them loud enough.

I removed the 4x500uf input caps and turned off the "extended" switch. With this configuration, the clip lights never come on until well past 230wpc.

I listen to Rock, 70s/80s/90s Pop, and Jazz mostly.

I find the 3" mid dome to be shouty. Other than that, they are OK speakers. I have multiple of better vintage speakers. So don't break the bank trying to make them work.

The Fosi BT amplifier will run them to listening casual levels. As do multiples of my vintage 80s receivers.

 

[damage]

I didn't mention that with the caps and extended switch on, the clips lights came on more often and bass output suffered.

 

[damage]

Pic for attention.

 

[tmtomh]

So, I run original Kappa 9s with a GFA-5500. It plays them loud enough.

I removed the 4x500uf input caps and turned off the "extended" switch. With this configuration, the clip lights never come on until well past 230wpc.

I listen to Rock, 70s/80s/90s Pop, and Jazz mostly.

I find the 3" mid dome to be shouty. Other than that, they are OK speakers. I have multiple of better vintage speakers. So don't break the bank trying to make them work.

The Fosi BT amplifier will run them to listening casual levels. As do multiples of my vintage 80s receivers.

Thanks! These were my father’s speakers, so I heard them periodically over the course of years. I too found the midrange domes shouty and unpleasant. Then one day a few years ago he told me he’d read online that they tend to disintegrate gradually over the years, and when he took off the grill cloth covers of his speakers to inspect them, his domes were in terrible shape. He installed replacements (maybe 3rd party?) and it made a very noticeable difference.

Thanks for the tip about extended vs non-extended mode. I’m content to run them in non-extended mode if need be. I plan to move them up to my place next month and try them out, with my current amp. If that setup doesn’t work or satisfy, I’ll just sell the Kappas - my understanding is that they’ll get snapped up pretty quickly. Then I’ll put the proceeds towards something else (probably a pair of 8351s, which had been my plan before these Kappas became an option).

Honestly I’m still only 90% sure I’m going to try the Kappas. Part of me still wonders if I shouldn’t just sell them, sell my amp, and put all that money (plus the savings of not having to pay to move the Kappas) into the Genelecs. That would be the simpler (albeit more expensive) route.

What’s tempting me about the Kappas is the height of the soundstage they put out, plus those 4x 12” bass drivers - I’m not a basshead, but they’re just so effortless and don’t have to rely on high excursion the way smaller drivers do - it’s a cool listening experience.

I’m confident the Genelecs would give me satisfying (albeit different) bass. It’s the soundstage height I’m wondering about - I’ve never been able to get that kind of height with stand-mounts.

 

[Deleted member 48726]

Thanks! These were my father’s speakers, so I heard them periodically over the course of years. I too found the midrange domes shouty and unpleasant. Then one day a few years ago he told me he’d read online that they tend to disintegrate gradually over the years, and when he took off the grill cloth covers of his speakers to inspect them, his domes were in terrible shape. He installed replacements (maybe 3rd party?) and it made a very noticeable difference.

Thanks for the tip about extended vs non-extended mode. I’m content to run them in non-extended mode if need be. I plan to move them up to my place next month and try them out, with my current amp. If that setup doesn’t work or satisfy, I’ll just sell the Kappas - my understanding is that they’ll get snapped up pretty quickly. Then I’ll put the proceeds towards something else (probably a pair of 8351s, which had been my plan before these Kappas became an option).

Honestly I’m still only 90% sure I’m going to try the Kappas. Part of me still wonders if I shouldn’t just sell them, sell my amp, and put all that money (plus the savings of not having to pay to move the Kappas) into the Genelecs. That would be the simpler (albeit more expensive) route.

What’s tempting me about the Kappas is the height of the soundstage they put out, plus those 4x 12” bass drivers - I’m not a basshead, but they’re just so effortless and don’t have to rely on high excursion the way smaller drivers do - it’s a cool listening experience.

I’m confident the Genelecs would give me satisfying (albeit different) bass. It’s the soundstage height I’m wondering about - I’ve never been able to get that kind of height with stand-mounts.

Midrange and treble are adjustable on the back though. But it seems some people think better of some of the polydome replacements than the original. I've got a pair with the Scanspeak Discovery replacement and a pair with the Dynaudio D-52 replacement. I have the original broken domes but I dig the Dynaudio D-52's though. They are superb measuring and have some crazy power handling capabilities as well. 200 W nom. 1000 W peak.

The Scanspeak Discovery shouts a bit stock and are clearly not the same quality as the Dynaudios.

Scanspeak Discovery

Dynaudio D-52

 

[damage]

I've got a pair with the Scanspeak Discovery replacement and a pair with the Dynaudio D-52 replacement. I have the original broken domes but I dig the Dynaudio D-52's though.

I have a pair of D-52s. Is there a crossover mod that goes with that replacement?

I bought the replacement domes off ebay. The repair wasn't hard for me. I did put rockwool behind one dome, but haven't measured. It seem to help a bit. I do feel that break-in time has helped also. I'll sweep them in REW soon.

Turning down the output helps, but there is no disguising the ~1400Hz honk. At least not with Rock music.

One super tweeter has a slight buzz. Most people wouldn't notice but I can. But I have a musician's ear so YMMV.

The stereo separation is really good. Certainly plenty of height. Surprisingly you don't get much lobing between sitting and standing. You aren't fatigued by being locked into a sweet spot during extended listening. And that is certainly a plus which is why 6 months later I haven't swapped them out yet.

 

[Deleted member 48726]

I have a pair of D-52s. Is there a crossover mod that goes with that replacement?

I bought the replacement domes off ebay. The repair wasn't hard for me. I did put rockwool behind one dome, but haven't measured. It seem to help a bit. I do feel that break-in time has helped also. I'll sweep them in REW soon.View attachment 281603

Turning down the output helps, but there is no disguising the ~1400Hz honk. At least not with Rock music.

One super tweeter has a slight buzz. Most people wouldn't notice but I can. But I have a musician's ear so YMMV.

The stereo separation is really good. Certainly plenty of height. Surprisingly you don't get much lobing between sitting and standing. You aren't fatigued by being locked into a sweet spot during extended listening. And that is certainly a plus which is why 6 months later I haven't swapped them out yet.

The 7.2i's with the Scanspeak Discovery units have had a mod with an extra resistor it seems. As far as I remember when I got them and compared the crossovers. They are 8 ohm nominal units as opposed to the 4 ohm Polydome and they should also have way higher sensitivity hence the resistor. Should perhaps have been a higher value resistor because it does have an elevated mid-range frequency range in my measurements.

The 8.2i's are the ones with the Dynaudio D52's. And they measure flat with the knobs in center pos. No mod to the crossover. A drop-in replacement for the poly's and lauded by many to be better than the Polydomes.

 

[tmtomh]

Midrange and treble are adjustable on the back though. But it seems some people think better of some of the polydome replacements than the original. I've got a pair with the Scanspeak Discovery replacement and a pair with the Dynaudio D-52 replacement. I have the original broken domes but I dig the Dynaudio D-52's though. They are superb measuring and have some crazy power handling capabilities as well. 200 W nom. 1000 W peak.

The Scanspeak Discovery shouts a bit stock and are clearly not the same quality as the Dynaudios.

Scanspeak Discovery
View attachment 281582

Dynaudio D-52
View attachment 281583

Thanks for the info - very interesting. I’ll have to take another look to see what he used for replacements.

 

[tmtomh]

Well, I finally got the Kappas moved in to my space and set up, and so far I'm really enjoying them!

After breaking them down, packing them up, having them transported, unpacking, and setting up again (all with help of course - these things are ridiculously heavy and unwieldy), I'd say the best news is that they survived! If I hadn't inherited these for free (my father passed away recently), I'd never even have considered buying a pair.

At any rate, I ran low-level 20Hz-20kHz frequency sweeps on each channel separately and heard nothing weird - no obvious volume changes, no rubbing drivers, distortion, or extra frequencies that weren't supposed to be there.

When I first started playing music, I got totally spooked - the sound kept muting every few minutes and I thought my Purifi 400-based amp wasn't up to the task of driving these things after all. After 20 minutes of this, and being part way through typing a version of this comment where I was asking about amp recommendations, I remembered that my Mac mini-based streaming setup has always had a weird little bug that only crops up when it's been running uninterrupted for weeks or months: the Music app just stops outputting sound after about 2 minutes' worth of playback. Fortunately that was the issue, fixed by a restart.

So far I haven't pushed them really hard, but they seem to be doing fine at SPLs in the low 80s from my 3-meter listening position - which if I have my math right means they're putting out about 92dB SPL at 1 meter. That's plenty for my everyday listening volume, and it's 3-5dB from my personal preferred max volume so I'm feeling pretty optimistic.

And I'm hearing something with the Kappas in my setup that I've never heard before in the 30+ years I heard these speakers in my parents' house: silence! No hum from the power amp, no hiss from the speakers. Just total silence. It's very cool.

I do have some questions for @Doodski and all the other knowledgeable folks here:

1. I took my graphic EQ out of the circuit, which allowed me to go to fully balanced interconnects: it's just my Oppo UDP-205 to the Audiophonics amp. This has radically changed the gain-staging: where I used to have the Oppo's volume in the high 70s to low 90s, it's how in the high 30s to mid 40s. I have the amp in its high-gain setting (26.5dB). If I were to reset it to its default (20dB), would that have any beneficial effect on the amp's ability to drive the Kappas? I know lowering the amp's gain will slightly increase its measured performance, but I don't care about that since it's already a stellar performer at its highest gain.

2. I've been pleasantly surprised at how nice these speakers sound with no EQ in the chain - but I am thinking of getting a MiniDSP SHD to put between the Oppo and the power amp so I can really get the in-room response as good as it can be. Is the MiniDSP designed to operate at unity gain, or is it inevitably going to increase the level of the signal going into the power amp? Is there any particular gain-stating configuration that would make the speakers as easy as possible for the power amp to drive - or is the final SPL in the room the only thing that matters?

3. Finally, the Kappas have 4 dials that can be used to alter how the crossover network works - the relative volume of the various drivers. I was shocked to discover that my father had all the dials set to minimum. I reset them all to the factory default of flat/nominal, and they're like whole different speakers. I can tell that this all-flat setting will need to be adjusted a bit, but if @Doodksi or anyone else has any advice or recommendations on which of those 4 dials to start with, or where to start fiddling, I'd be grateful - because it seems like a lot of dependent variables there.

Oh - and I have the Extended/Normal switches to Normal, and the speakers seem to have plenty of bass for my taste. Once I get more confidence in the amp's ability to drive the speakers fully, though, I'll experiment with the Extended setting.

 

[Doodski]

@tmtomh Sorry to hear about the recent passing of your father. The Kappa 9 are a full sized speaker for sure. They grow on a person and become part of the environment. They can go fairly loud from what I remember and I was not afraid to push them at the time due to having full warranty for any testing errors. I had no issues with them and I was not babying them. Very fun speaker to see how different tunes sound on them! I would run at the highest gain setting for max peak output with the Kappa 9s. As for the dials I am a madman with the PEQ so I would expect something pretty bright sounding if I adjusted the Kappa 9s.

 

[tmtomh]

Thanks very much!

As for the amp, I finally got up the nerve to play some Massive Attack and turn it up a bit. I'm playing Mezzanine, and according the NIOSH SPL app on my phone, I'm hitting 3-meter SPLs in the 87-92dB range, and the amp hasn't gone into protection or blown up, so I think I'm in good shape in that regard - in fact, the only reason I'm even playing this album this loud is that I'm the only one home right now.

As for gain, I'd love to hear others' input - I have no problem getting the needed volume, but right now I'm getting that volume with the Oppo's volume in the 40s (on a 0-100 scale). So I'm just wondering about reducing the amp's gain and then feeding it a correspondingly higher signal from the Oppo, since the Oppo has plenty of extra headroom to spare as my source component.

This question of gain staging will become more important (I think) if I get a MiniDSP SHD, which based on initial listening I will probably eventually decide I need. The sound from the Kappas is fantastic with some material, but with other material I can tell that some dialing-in is going to be needed.

The biggest surprise sonically, I think, is that I expected these beasts to activate the heck out of whatever bass modes are in my room. But while I'm sure there are peaks and nulls that room-correction software would easily detect, the subjective sound so far is quite pleasant in the bass region, with no glaring resonances or suck-outs that jump out at me. The region where I'm feeling some dialing-in will be needed is somewhere in the upper-mid or lower treble. I'll have to listen more and play with the L-pads on the back a bit more, as I'm sure I can get it closer to optimal just by experimenting with those.

 

[Doodski]

Thanks very much!

As for the amp, I finally got up the nerve to play some Massive Attack and turn it up a bit. I'm playing Mezzanine, and according the NIOSH SPL app on my phone, I'm hitting 3-meter SPLs in the 87-92dB range, and the amp hasn't gone into protection or blown up, so I think I'm in good shape in that regard - in fact, the only reason I'm even playing this album this loud is that I'm the only one home right now.

As for gain, I'd love to hear others' input - I have no problem getting the needed volume, but right now I'm getting that volume with the Oppo's volume in the 40s (on a 0-100 scale). So I'm just wondering about reducing the amp's gain and then feeding it a correspondingly higher signal from the Oppo, since the Oppo has plenty of extra headroom to spare as my source component.

This question of gain staging will become more important (I think) if I get a MiniDSP SHD, which based on initial listening I will probably eventually decide I need. The sound from the Kappas is fantastic with some material, but with other material I can tell that some dialing-in is going to be needed.

The biggest surprise sonically, I think, is that I expected these beasts to active the heck out of whatever bass modes are in my room. But while I'm sure there are peaks and nulls that room-correction software would easily detect, the subjective sound so far is quite pleasant in the bass region, with no glaring resonances or suck-outs that jump out at me. The region where I'm feeling some dialing-in will be needed is in somewhere in the upper-mid or lower treble. I'll have to listen more and play with the L-pads on the back a bit more, as I'm sure I can get it closer to optimal just by experimenting with those.

Leave enough gain for lower level dynamic recordings.

 

[Deleted member 48726]

Well, I finally got the Kappas moved in to my space and set up, and so far I'm really enjoying them!

After breaking them down, packing them up, having them transported, unpacking, and setting up again (all with help of course - these things are ridiculously heavy and unwieldy), I'd say the best news is that they survived! My goodness they are heavy and unwieldy. If I hadn't inherited these for free (my father passed away recently), I'd never even have considered buying a pair.

At any rate, I ran low-level 20Hz-20kHz frequency sweeps on each channel separately and heard nothing weird - no obvious volume changes, no rubbing drivers, distortion, or extra frequencies that weren't supposed to be there.

When I first started playing music, I got totally spooked - the sound kept muting every few minutes and I thought my Purifi 400-based amp wasn't up to the task of driving these things after all. After 20 minutes of this, and being part way through typing a version of this comment where I was asking about amp recommendations, I remembered that my Mac mini-based streaming setup has always had a weird little bug that only crops up when it's been running uninterrupted for weeks or months: the Music app just stops outputting sound after about 2 minutes' worth of playback. Fortunately that was the issue, fixed by a restart.

So far I haven't pushed them really hard, but they seem to be doing fine at SPLs in the low 80s from my 3-meter listening position - which if I have my math right means they're putting out about 92dB SPL at 1 meter. That's plenty for my everyday listening volume, and it's 3-5dB from my personal preferred max volume so I'm feeling pretty optimistic.

And I'm hearing something with the Kappas in my setup that I've never heard before in the 30+ years I heard these speakers in my parents' house: silence! No hum from the power amp, no hiss from the speakers. Just total silence. It's very cool.

I do have some questions for @Doodski and all the other knowledgeable folks here:

1. I took my graphic EQ out of the circuit, which allowed me to go to fully balanced interconnects: it's just my Oppo UDP-205 to the Audiophonics amp. This has radically changed the gain-staging: where I used to have the Oppo's volume in the high 70s to low 90s, it's how in the high 30s to mid 40s. I have the amp in its high-gain setting (26.5dB). If I were to reset it to its default (20dB), would that have any beneficial effect on the amp's ability to drive the Kappas? I know lowering the amp's gain will slightly increase its measured performance, but I don't care about that since it's already a stellar performer at its highest gain.

2. I've been pleasantly surprised at how nice these speakers sound with no EQ in the chain - but I am thinking of getting a MiniDSP SHD to put between the Oppo and the power amp so I can really get the in-room response as good as it can be. Is the MiniDSP designed to operate at unity gain, or is it inevitably going to increase the level of the signal going into the power amp? Is there any particular gain-stating configuration that would make the speakers as easy as possible for the power amp to drive - or is the final SPL in the room the only thing that matters?

3. Finally, the Kappas have 4 dials that can be used to alter how the crossover network works - the relative volume of the various drivers. I was shocked to discover that my father had all the dials set to minimum. I reset them all to the factory default of flat/nominal, and they're like whole different speakers. I can tell that this all-flat setting will need to be adjusted a bit, but if @Doodksi or anyone else has any advice or recommendations on which of those 4 dials to start with, or where to start fiddling, I'd be grateful - because it seems like a lot of dependent variables there.

Oh - and I have the Extended/Normal switches to Normal, and the speakers seem to have plenty of bass for my taste. Once I get more confidence in the amp's ability to drive the speakers fully, though, I'll experiment with the Extended setting.

Thanks for the follow-up. I always enjoy these shared experiences on topics I find interesting.

IR to sequence of dialing in the tone controls on the crossover, Infinity have it described in their manual. You should be able to source it from hifiengine.

Oh, and pictures of the old ladies would be appreciated (but voluntary)

 

[tmtomh]

Thanks for the follow-up. I always enjoy these shared experiences on topics I find interesting.

IR to sequence of dialing in the tone controls on the crossover, Infinity have it described in their manual. You should be able to source it from hifiengine.

Oh, and pictures of the old ladies would be appreciated (but voluntary)

Thanks! I do have the manual, but unless there's another, more detailed manual I'm unaware of, it basically just says to start with the treble/emit tweeter pad, get that right, and then work on the others. That makes sense of course - but I've also found that small changes in mid-bass can have a dramatic impact on the perception of the higher frequencies. In fact, in my experience when doing my own home-made remasters of certain recordings/masterings I think could use some help, I've found that playing with the mid-bass has often given me more fine-grained control of how the treble sounds to me than directly boosting or cutting the treble. But I'll experiment for a bit and see what happens.

I'm not one of those folks who loves the process of experimenting or "the journey," though, so at some point soon I'm going to take some SPL meter readings at different frequencies to get a rough sense of where the tonal balance is at, and if things are too uneven then I'm going to try to set the L-pads to get the most even response I can and then supplement with a MiniDSP to get it right.

Here's a quick shot of them in place. I have a decent-sized room, but even with that I'm at the limits of what Infinity recommends for spacing from the side walls and from each other. Each one is 27" from the side wall, and they're about 6-1/2 feet apart from each other.