| BlairHatcher |
Hi,
at present I am building 4 gainclones for use in an active system.
I have measured the drivers and have calculated the values of R & C to correct for the rising impedance response.
Am I correct in using these values for the zobel on the amps.
Also is which of these are prefered sonically.
1: Power Amplifiers mounted in the loudspeaker cabinets but long interconnects required.
2: Power Amps mounted in cabinets but long speaker cables required.
Any help Appreciated.
TIA
Blair |
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| Bill Fitzpatrick |
Many would say that Zobels are not needed with active crossovers. I'm not sure where I stand.
IMO, longer speaker wires are preferable. |
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| phase_accurate |
Every amp profits from decent loads. Personally I would use Zobels also with active speakers though I don't know how large a difference it would make. But I would definitely take a smaller cap on the woofer Zobel, than the formula gives for achieving a really flat impedance curve. Correctly dimensioned they tend to get quite large and people are then tempted to make quality compromises in order to keep the price down.
Regarding amp placement. I don't think that there is a definite answer since both have advantages and disadvantages and it is quite a personal decision how much weight is given to each property.
Personally I prefer speakers with built-in electronics because I regard the amp/speaker combination as one system so it should definitely be packed together. Out of the two variants - a.) airtight electronics-assembly built into the box (i.e. woofer compartment and b.) electronics in a seperate chamber - I prefer the second because it is technically better even tough the box gets larger.
Regards
Charles |
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| Nuuk |
I have tried both long speaker canles and long interconnects and have not yet decided which is best.
If you go for long interconnects, ie amp close to drivers, I suggest keeping the electronics out of the speaker cabinet. I used to have my amps close to my drivers but in separate housings. The speaker leads were about 1/2 metre from amp to driver terminals.
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| Mr Evil |
A zobel to correct for rising driver impedance isn't really necessary in an active system A zobel to provide low impedance termination for RF may be necessayr on the other hand, although you could well get away without one, especially if the speaker cables are short.
Sonically, long speaker cables provide theoretical advantages, but it really depends on too many factors to say overall. The things I would be most concerned with are noise pickup from long line-level cables, or more difficult load presented to the amp by long speaker cables. |
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| GregGC |
I'd say that long (relative word) speaker cable would be better. Long interconnects would pick up noise and having in mind the output impedance of most CD players and the capacitance of some interconnects (especially when long) you may crate a LF filter that will start cutting the high frequencies at bellow 15 kHz (1k/10nF), which is not good at all, especially for the HF speaker. Not so critical with the speaker cables(unless they are of exotic/strange type).
/Greg |
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| Nuuk |
| quote: | | Long interconnects would pick up noise |
Not in my experience Greg! I used 2.5 metre interconnects, sheilded with kitchen foil, and they were dead silent. ;) |
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| GregGC |
Nuuk,
What I said was a general statement. Some places have really high level of EMI and RFI so, compared to long speaker cables I think long interconnects would be much more susceptible to noise. Also 2.5 m is on the short side, I think. They could be much longer depending on the layout of the room. So why create inferior conditions that could potentially give you headache down the road.
/Greg |
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| carlosfm |
Speaker cables should be as short as possible, even if you have to use longer interconnects.
This is my own experience, and also talking recently to a friend of mine that sells hi-fi(-end) and makes demos, installs equipmend, listens every day 6 days a week, he confirmed it.
Amps become more unstable driving long(er) cables, while long interconnects don't affect the sound so much.
And don't worry about picking interferences, because I use 5 meter shielded interconnects and without music playin' there's silence.;)
As for the zobel, try it with and without, I have a feeling that you need it all the same.
With a direct speaker you will have the amp driving directly the drivers' voice coils' inductance.
My Epos ES11 speakers have direct woofer (no crossover) and the zobel made quite a difference for the better. |
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| Nuuk |
Don't forget the other factor here. That is with the longer interconnects, you probably won't get away with a passive pre amp.
In my active system, I had the active crossovers with the volume control right next to the CD player, then the 2.5 metre interconnects, then the amps and speakers. The active crossovers also provided the drive for the interconnects so no extra (pre amp) circuitry was needed. ;) |
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