[Hooster]

I was wondering how compatible the battery powered Monica 2 DAC is with a passive pre-amplifier? Are any figures regarding Monica's output impedance available?

I would love to use Monica with a passive pre and my power amplifier that has a 2V RMS input sensitivity and an input impedance of 11kohms.

I know the Monica will never be able to drive this amplifier to it's full output through a passive pre (I believe the output voltage of the Monica is around 0.7V) but I can easily live with that. I am more worried about loss of high or low frequencies.

While I am here, is Monica compatible with 24-bit/48kHz data from a DVD player as well as the 16-bit/44.1 kHz data from a CD player?

I would love to use Monica with a passive pre.

[roymail]

I recommend you either call or email your questions to Vinnie.  He will gladly answer them and advise you on your concerns.  And, trust me on this, he knows what he's talking about, so I'd go with whatever he recommends.  You can go to "redwineaudio.com" and get all the contact information.

-- Roy

[Hooster]

Thanks Roy. I know Vinnie is very busy and I prefer not to contact him directly unless I am really going to buy something. I am still undecided as to what direction my system will take in the near future and I am not ready to make a firm descision regarding what to do. I would prefer to just let this question sit here on the forum. I have been in contact with Vinnie directly before and he has been extremely helpful.

Since many people have viewed my queston and there has not been a concrete answer I guess the answer must be that the combination I propose will not work very well.

If anybody is using the Monica 2 with a passive pre I would appreciate some words regarding their experience. I would also like to know what the Monica's output impedance is.

Thanks

[BobM]

I have a Monica II that I built myself. I had some troble getting good dynamics out of the unit (both with battery and with direct AC). I wound up putting a sizeable capacitor (6800uF) on the board where the power comes in. This helped quite a bit but the DAC is still not what I would call "dynamic".

Now given that most passive preamps suffer from the same issue (lack of dynamics) I would say that this is not a great match-up. I'm sure it will certainly sound nice on chamber music and soft jazz and such, but may not cut it for large scale orchestra and rock and roll.

Enjoy,
Bob

[Vinnie R.]

Thanks Roy. I know Vinnie is very busy and I prefer not to contact him directly unless I am really going to buy something. I am still undecided as to what direction my system will take in the near future and I am not ready to make a firm descision regarding what to do. I would prefer to just let this question sit here on the forum. I have been in contact with Vinnie directly before and he has been extremely helpful.

Since many people have viewed my queston and there has not been a concrete answer I guess ...

Hi Hooster,

I apologize for not responding sooner..

The output of the Monica 2 uses passive I/V conversion via a resistor (I believe it is approx. 2k).  If your amp has an input impedance of 11k (on the low side) with 2V RMS input sens (more than the max output of the Monica) and you want to use a passive preamp in-between, I don't think this would the best combo.

Using the Monica 2 with a passive preamp DOES work well, but I recommend that your should have a higher input impedance and lower input sensitivity than the one you are using.

For your situation, the Ack! dAck would be a very good choice.  It is a battery powered, NON-OS dac, but uses an opamp output stage (biased into class A) that has a very low output impedance.  
Check out: www.ack-industries.com

Regards,

[Hooster]

Thanks, Bob and Vinnie. I appreciate your help very much.

I love this hobby.