Passive preamp w/Rogue Medusa and Rega DAC


All,

I have become intrigued with the concept of a passive pre. At the moment, I think my preamp is the weak link in my chain. Key system components are MacMini-Rega DAC-Acurus RL11 pre-Rogue Audio Medusa-Fritz REv 7 speakers. At this point I am not ready to shell out the cash for a good active but thought about experimenting with a passive. I have concerns whether a passive will work in my system. Here are the basic specs on the DAC and Amp:

- Rega DAC: 2v output, 600 ohm output impedance
- Rogue: 200K ohm input impedance, Input sensitivity: 1.0V RM
- Fritz speakers 89db, 4 ohm
- Cables are all 1 meter or less

My concerns are the output impedance of the DAC is high (but the input impedance of the Rogue is very high and I can' figure out if the gain on the Medusa will be sufficient to run a passive.

Given the high input impedance of the Rogue, I think it will work with the DAC but am not sure. Based on the above, does it look like there are any limiting factors that would prevent a passive from working?

Any comments are appreciated. Thanks.
sruffle
Sruffle, where are you located? You might get someone close by to hook up a lightspeed to your set up to see if you like it or not... Just a thought.

The remote control issue bothers me and can be a pain sometimes. At times, I set the volume and leave it. Other times I get volume ADD, and thank George for introducing some sort of physical activity into this hobby besides moving speakers an inch, daily.

I'm working on some sort of remote control device... Rubber band around the volume knob connected to a servo? There's got to be a way to make something remote controlled to move the volume knob.
I've had a few customers who have taken it on themselves to add their own remote volume controls to their Lightspeed Attenuators, like these aftermarket ones.

[url]http://www.ebay.com/sch/Consumer-Electronics-/293/i.html?_from=R40&_nkw=Remote+volume+control[/url]

[url]http://www.ebay.com/itm/ALPS-Remote-Motor-Volume-Potentiometer-Control-Adjustment-4CH-50KA-/331214708402?pt=US_Amplifier_Parts_Components&hash=item4d1def5eb2[/url]

They can be coarse in their action. And the remote buttons don't last.
I cannot afford to use them as for me they're just not reliable enough especially the hand sets.
With the Lightspeed being very reliable as it is, and at the low shipped price it is, I don't need or can afford to have returns coming back because of these after market remotes, from companies that look like their here today gone tomorrow, then spare parts become a problem as well.

The only companies that make good quality ones are the big boys Sony, Yamaha, Panasonic, ect and you cannot get these quality ones for the small manufaturers like me.

Cheers George
Why wouldn't you just upgrade your dac to something like the Benchmark DAC 2 which can be run direct into your amp.

Personally, I think your DAC is the weakest link by far...especially if you consider how much more the DAC impacts the sound.

I'm not saying that a pre amp isn't important, but just because a pre amp is old, doesn't mean it's a weak link.

With a DAC, it's a completely different story. Newer dacs are making great strides and I wouldn't count Rega as a trend setter in that realm. (I've owned their digital products in the past and found them acceptable, but not state-of-the-art.)
His Rega dac get some good raps, even over the Benchmark, in some of the a/b's done.

But you are right Labtec going direct with a dac or cdp that has a digital domain VC is the only way to better the transparency of good a passive pre.

You just have to watch that digital domain VC's are used in the top 75% of their full output, otherwise you can run the risk of "bit stripping". EG: 16bit resolution down to 14bit then 12bit and so on the lower you go with them, if he has very efficient speakers he may not even be able to get to 75% let alone over it, before it becomes too loud for him.

This is when a good passive attenuator is the next best in transparency, as the remote controled digital domain VC of the dac/cdp can be full up then with no risk of "bit stripping", and the volume then set by passive pre attenuation.
And then you can still use the remote volume of cdp/dac within it's top 25% so you can adjust it from your listening chair.

Cheers George
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