George, is it your view that the Buffering used in preamps, and passives like the BENT, The Truth, or the First Watt B1 is there for handling worst case scenarios - long or high capacitance interconnects, or amps with low input impedances, but where the ICs are low capacitance (Cardas GR 12p/ft) or high input impedances (100kohm)that a bufferless approach will always be superior? That is how I read it, and that something like the LSA is about as good as you can get in not altering the source signal to the amp.
Lightspeed Attenuator - Best Preamp Ever?
The question is a bit rhetorical. No preamp is the best ever, and much depends on system context. I am starting this thread beacuase there is a lot of info on this preamp in a Music First Audio Passive...thread, an Slagle AVC Modules...thread and wanted to be sure that information on this amazing product did not get lost in those threads.
I suspect that many folks may give this preamp a try at $450, direct from Australia, so I thought it would be good for current owners and future owners to have a place to describe their experience with this preamp.
It is a passive preamp that uses light LEDs, rather than mechanical contacts, to alter resistance and thereby attenuation of the source signal. It has been extremely hot in the DIY community, since the maker of this preamp provided gernerously provided information on how to make one. The trick is that while there are few parts, getting it done right, the matching of the parts is time consuming and tricky, and to boot, most of use would solder our fingers together if we tried. At $450, don't bother. It is cased in a small chassis that is fully shielded alloy, it gets it's RF sink earth via the interconnects. Vibration doesn't come into it as there is nothing to get vibrated as it's passive, even the active led's are immune as they are gas element, no filaments. The feet I attach are soft silicon/sorbethane compound anyway just in case.
This is not audio jewelry with bling, but solidly made and there is little room (if any) for audionervosa or tweaking.
So is this the best preamp ever? It might be if you have a single source (though you could use a switch box), your source is 2v or higher, your IC from pre-amp to amp is less than 2m to keep capaitance low, your amp is 5kohm input or higher (most any tube amp), and your amp is relatively sensitive (1v input sensitivity or lower v would be just right). In other words, within a passive friendly system (you do have to give this some thought), this is the finest passive preamp I have ever heard, and I have has many ranging form resistor-based to TVCs and AVCs.
In my system, with my equipment, I think it is the best I have heard passive or active, but I lean towards prefering preamp neutrality and transparency, without loosing musicality, dynamics, or the handling of low bass and highs.
If you own one, what are your impressions versus anything you have heard?
Is it the best ever? I suspect for some it may be, and to say that for a $450 product makes it stupidgood.
I suspect that many folks may give this preamp a try at $450, direct from Australia, so I thought it would be good for current owners and future owners to have a place to describe their experience with this preamp.
It is a passive preamp that uses light LEDs, rather than mechanical contacts, to alter resistance and thereby attenuation of the source signal. It has been extremely hot in the DIY community, since the maker of this preamp provided gernerously provided information on how to make one. The trick is that while there are few parts, getting it done right, the matching of the parts is time consuming and tricky, and to boot, most of use would solder our fingers together if we tried. At $450, don't bother. It is cased in a small chassis that is fully shielded alloy, it gets it's RF sink earth via the interconnects. Vibration doesn't come into it as there is nothing to get vibrated as it's passive, even the active led's are immune as they are gas element, no filaments. The feet I attach are soft silicon/sorbethane compound anyway just in case.
This is not audio jewelry with bling, but solidly made and there is little room (if any) for audionervosa or tweaking.
So is this the best preamp ever? It might be if you have a single source (though you could use a switch box), your source is 2v or higher, your IC from pre-amp to amp is less than 2m to keep capaitance low, your amp is 5kohm input or higher (most any tube amp), and your amp is relatively sensitive (1v input sensitivity or lower v would be just right). In other words, within a passive friendly system (you do have to give this some thought), this is the finest passive preamp I have ever heard, and I have has many ranging form resistor-based to TVCs and AVCs.
In my system, with my equipment, I think it is the best I have heard passive or active, but I lean towards prefering preamp neutrality and transparency, without loosing musicality, dynamics, or the handling of low bass and highs.
If you own one, what are your impressions versus anything you have heard?
Is it the best ever? I suspect for some it may be, and to say that for a $450 product makes it stupidgood.
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- 1866 posts total
That is correct, buffers are there to drive long interconnects, and or low input impedance amps. There is no perfect buffer they all sound different As there is no perfect interconnect they all sound different, unless the amp is so low in input impedance then this puts all interconnects (within reason) on a level playing field I keep comming back to this, plug the cd player straight into poweramp ( with more than 47kohms input impedance) with good quaity 1-2mt interconnects, this is the perfect transmission of the cd players sound (save for the interconnects signature), then put in the Lightspeed Attenuator without buffer and see how little it influences that sound compared to any other active pre or buffer. Cheers George |
George, maybe you can help me figure something out. I was using the Lightspeed with a pair of monoblocks that supposedly had a 10k input. Theoretically this would not be an ideal match for the Lightspeed, but I heard nothing out of the ordinary. Any explanation for this? The link shows a schematic for the circuit. http://electra-print.com/singleended_a2.php |
I assume you are using the input that is full range not the one with the roll off at 70hz. The diagram actually shows it's 27k input impedance this together with the 1uf coupling cap (yuck) gives a 5hz -3db roll off, the opamp is a 14watt chip amp that has an input impedance of 5megohm, you could change the 27k for 82k and you will see it will sound better. And go lower theoretically as the 82k resistor now with the 1uf coupling cap (yuck) will now go down to 2hz -3db but you will not hear this as the interstage transformer and output transformer cannot go down this far anyway. But don't switch on the amp without the Lightspeed attached as that will let the chip amp see only the 82k resistor and chip amp may complain, when the Lightspeed is attached it sees the 7k odd of the Lightspeed and it will think everything is fine still. Cheers George by Georgelofi |
- 1866 posts total