long interconnects vs long speaker cables...

bob mccluckie said:
Err.....
I'm running active with 4X15 metres of speaker cable from amps in one room to speakers in another.

Bob
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i guess this an audiophile's drema to have not only a separate listening room but also to have a separate equipment room :p

from another hand - isn;t it nice to see all this tubes glowing :D
 
I think I'm using 7m speaker cables.

The relevance of output impedance is that amp makers quote 'damping factor' which is the ratio of output impedance to 8 Ohms. By adding 0.01 or 0.02 Ohms of speaker cable you've substantially downgraded the damping factor. This only matters if you care about the numbers.

Paul
 
Not necessarily just caring about the numbers.

During some recent testing with prototypes, we tested several different variations with different measured damping factors, and there was a noticeable difference. Some people preferred the lower damping factor case, I preferred the higher damping factor case as it had greater slam. The change in output impedance between the two cases was around 0.01 ohms.
 
If damping factor is about damping the speaker then the series impedance of the speaker itself must be included. This will be nearer 8 Ohms than 0.08. I reckon DF is an irrelevance.

OTOH there may be other consequences of output impedance that have nothing physically to do with 'damping' per se.

Anyway how were you changing the output impedance of the amp? Do you have feedback around the output stages?

(BTW what's 'slam' sound like?)

Paul
 
analoguekid said:
Get rid of yer electrostaics and you might find out :D
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Mmm. I could be wrong here, but I thought electrostatics had transient response like pretty much nothing else on earth (except in the really deep bass obviously), because the diaphragm weighs basically nothing.
 
Changing the output inductors has a significant effect on the output impedance. One inductor might have a low DC resistance, but has a lower saturation current and be less linear than another.
 
PeteH said:
Mmm. I could be wrong here, but I thought electrostatics had transient response like pretty much nothing else on earth (except in the really deep bass obviously), because the diaphragm weighs basically nothing.
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Yes pete transient response, but they don't move the air as much and so as I undestand it don't have what Issac calls Slam
 
Changing the output inductors has a significant effect on the output impedance.
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So you don't use feedback to the far side of the filters?

I think that many amps that have super DF figures and stabilising output inductors are measured before the inductor.... Obviously trickier in a Class D.

'transient response' is a bit 'all things to all men'. ESLs don't have great high frequency extension, OTOH you can't hear high frequencies. MC speakers often have all sorts of sparkly stuff going on at the top, when you switch to an ESL it sounds dull. But the cymbals sound right. So I think the sparkles are probably spuriae.

If you didn't have to meet CE and other regs would you need output inductors on a Class D? Why not use the same argument as the non-OS DAC?

Paul
 
Paul Ranson said:
If you didn't have to meet CE and other regs would you need output inductors on a Class D? Why not use the same argument as the non-OS DAC?
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Because people don't appreciate having their tweeters blown up by having 50V switching at several hundred kHz to few MHz region....
 
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Isaac Sibson said:
Not necessarily just caring about the numbers.

During some recent testing with prototypes, we tested several different variations with different measured damping factors, and there was a noticeable difference. Some people preferred the lower damping factor case, I preferred the higher damping factor case as it had greater slam. The change in output impedance between the two cases was around 0.01 ohms.
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i really don't know how to deal with a DF parameter - my current amp quated as 18 (eighteen) and it dealt with my former B&W speakers much better than EC pre-power combo.............
 
Croc - like any single technical specification of an amplifier, on its own it may not tell you as much as you'd like about how something will sound. Also, the DF of an amplifier will vary with frequency (quite significantly), so different quotation frequencies and different speaker loads (different peaks/dips in impedance trace) can result in quite different results.
 

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