1. Home
  2. amps-preamps
  3. 1400932591

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
georgehifi's avatar
georgehifi
4,966 posts
 

05-30-14: Sruffle
In the meantime, I will be borrowing a passive to determine if using one is even feasible in my system. Thanks for all the comments. This has been a great thread!

Definitely worth a try with your system, to hear it at it's most transparent, dynamic and extended from top to bottom.
Just make sure the one you try has a 10kohm or 20kohm logarithmic (A taper) pot inside it.
And that your interconnects are <100pf (picofarad) per foot capacitance, which quality ones usually are.

Cheers George
mapman's avatar
mapman
15,679 posts
 
How are people liking the Tortuga's these days?

I like the concept and approach and have seen some good reviews but have not heard these.
sruffle OP
41 posts
 
Well, I made the leap. I replace my modded Acurus RL-11 with DIY passive that uses the Tortuga LDR3V2 board. I received it this weekend and gave it a trial run Saturday and Sunday. My first reactions were mixed. Because I was juggling taking care of the kids and getting used to the remote I didn’t really get a good feel for the sound but I will say that I wasn’t bowled over right out of the gate.
The second night I was able to sit down and really dig in. I am not a reviewer but my impressions were:

1) Lower noise floor – I listen to a lot of live Grateful Dead and this was particularly noticeable on several live recordings.

2) Increased detail

3) Better tone and timber - on jazz recordings, horns and saxes seemed more pure and free flowing. Additionally some glare was removed from my system.

This was exactly what I was hoping for. One thing that I did realize is that the Acurus has a great remote. I am going to order an Apple remote to see how I like it.

I was looking for some of the typical characteristics that critics of passives highlight. Other than not liking the remote as much, I didn’t sense any deficiencies. Maybe I will in the future but for now I am very happy with the decision to go this route. This is a great component to build a system around. The money saved from upgrading the preamp can now be put into a DAC upgrade somewhere down the line.

Again, thanks to all the responses on this thread. This has been a significant upgrade for relatively minor dollars that will give me much listening pleasure going forward. I may post some more impressions after further listening
More to discover