Macca's Lash Up 2: Lash Harder

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Originally Posted by Marco

The other thing to consider, which may be responsible for the current lack of 'excitement' in Martin's system, is that big powerful solid-state amps, such as Krells, primarily designed for difficult loads, and providing speakers with grip [which he doesn't own or need], usually have a high damping factor, and in the wrong system that can have the effect of sucking the life out of the music - especially if needing serviced.

One thing you could try in the interim to us visiting, Martin, is plumb in the XTZ again. Or if you don't want to disturb the TV system, and still have a power amp from 'he who cannot be named', which I think you said that you had somewhere, use that, and then see if despite it resulting in some sonic compromises, the 'excitement' (and possibly "crunch") comes back...

Please do this when you can and report back :)

Marco.

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Interestingly, amp damping factor is considered to be irrelevant driving planar magnetic speakers. And planar magnetic headphones. Just thought I'd say. I have an amp with variable DF, and I can't really hear a difference on the Apogees.

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Originally Posted by tubehunter

your problem is:

P90SA passive pre

into


Krell KSA-50S power amplifier Specifications

Input sensitivity: 1.34V RMS. Gain: 26dB. Input impedance: 47k ohms.


Try an active pre


Happy Days

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What you need is the Jez Arkless buffer between passive pre and power amp. ;)
He made me one, if you recall, and it works fab, but not needed in my current setup.
Jez reckoned the buffer would be in its element in this situation.

Happy to loan it to you to try out, Martin.

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Originally Posted by User211

Interestingly, amp damping factor is considered to be irrelevant driving planar magnetic speakers. And planar magnetic headphones. Just thought I'd say. I have an amp with variable DF, and I can't really hear a difference on the Apogees.

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You won't - the mass of the diaphragms of planar speakers such as Apogees, Magnaplanars or electrostatics is very low; far lower than the mass of the cone of a conventional driver.

Quote:

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Originally Posted by tubehunter

your problem is:

P90SA passive pre

into


Krell KSA-50S power amplifier Specifications

Input sensitivity: 1.34V RMS. Gain: 26dB. Input impedance: 47k ohms.


Try an active pre


Happy Days

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Good suggestion, Dunc! Martin could try the buffer thing, if he wants Jerry to loan him it, and/or I could take the Croft with me to perform active preamp duties :)

Marco.

Quote:

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Originally Posted by User211

Interestingly, amp damping factor is considered to be irrelevant driving planar magnetic speakers. And planar magnetic headphones. Just thought I'd say. I have an amp with variable DF, and I can't really hear a difference on the Apogees.

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Yup... Like I said "in the wrong system", which yours isn't, so it doesn't apply ;)

Marco.

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Originally Posted by Barry

You won't - the mass of the diaphragms of planar speakers such as Apogees, Magnaplanars or electrostatics is very low; far lower than the mass of the cone of a conventional driver.

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I'm not so sure. I have an Apogee bass panel foil hanging around. I'll go weigh it now.

The buffer won’t add any gain though, and that Krell has low gain / low input sensitivity. As a comparison my amp has 0.8v input sensitivity and 33db gain, which on paper is a better match for passive or unity gain active (buffer) preamps.

46 grams.https://uploads.tapatalk-cdn.com/201...a63e1eba97.jpg

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Originally Posted by Yomanze

The buffer won’t add any gain though, and that Krell has low gain / low input sensitivity. As a comparison my amp has 0.8v input sensitivity and 33db gain, which on paper is a better match for passive or unity gain active (buffer) preamps.

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Ah, I had no idea how the buffer thingy Jerry was recommending works, so that's out then. But Dunc's observation is right, so Martin needs to hear the Krell with an active preamp, to hear what he might be missing, and also his existing passive pre with a different power amp.

Marco.

https://www.ebay.com/p/12-Tall-Roll-...d=132227131178

If the mass of that cone in a cheap sub is typical at 140g, and the Apogee bass panel is equivalent to 3 of them, which it is supposed to be, we have 420g versus 46g i.e. a factor of ten lighter.

More of a difference than I appreciated as the foil/kapton/glue mix doesn't feel light. The bass panel's mass will be beyond that of a mylar only panel, but they just can't do substantial dynamic deep bass in ESL designs.