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
Thanks to all for the replies. I have been reading the massive LS Attenuator thread with great interest. (I will probably get to the end of it by 4th of July). I would love to try it but the only catch for me is that I need a remote control.

I think a reasonable path would be to try the cheapest passive I can find in my system. If it works and I like the nature of what I am hearing, I could then upgrade to a better passive and keep the cheaper one as a back-up. (while selling my current pre-amp).

Even if I don't like it, trying one is definitely something I should experiment with.
Definitely worth a try Sam for the money, compared to the cost of a good active preamp.
The sound you'll get with a passive pre in your setup will be honest to the source, the frequency and dynamic range of it will not be limited, and it will be uncoloured, with zero distortions, you may love it.
If not then the search begins to find what all the different actives preamps will bring to the sound, as they all sound different.

With a passive friendly system such as yours, and probably more than 75% of other owners, here is a quote from Nelson Pass who calls it like it is. (one of the true gods of audio).
Cheers George

Nelson Pass,
We’ve got lots of gain in our electronics. More gain than some of us need or want. At least 10 db more.
Think of it this way: If you are running your volume control down around 9 o’clock, you are actually throwing away signal level so that a subsequent gain stage can make it back up.
Routinely DIYers opt to make themselves a “passive preamp” - just an input selector and a volume control.
What could be better? Hardly any noise or distortion added by these simple passive parts. No feedback, no worrying about what type of capacitors – just musical perfection.
And yet there are guys out there who don’t care for the result. “It sucks the life out of the music”, is a commonly heard refrain (really - I’m being serious here!). Maybe they are reacting psychologically to the need to turn the volume control up compared to an active preamp.

..
To get the same transparency and gorgeous sound you could spend thousands on an expensive pre-amp or spend a few hundred for the Lightspeed. It all depends on how much you like to throw away your money. I personally like money and LOVE my Lightspeed.
If you need a remote, a Tortuga LDR passive is the way to go. I had one in my system for a couple weeks and I was very impressed.
Thanks for the great responses on this thread. I definitely want to try a passive. I have arranged to borrow a simple volume pot to put in my system to see if the gain is sufficient. If it is, then I will pursue a better one to try out.

I would love to try the Lightspeed but my listening room is in the family room so a remote is essential.

The concept of the passive makes so much sense. In my case, the preamp is not in the same class as the rest of the gear so the benefits could be substantial.