[bulbuls]

I can get amazing sound by Two Input Basic Pot in a Box with Balance. Unbelievable price.
http://www.tubeaudiostore.com/twoinbapotin1.html

When do you need active pre?

Thanks.

[Clio09]

In my opinion you would need an active preamp if your system does not have enough gain. Today, most digital sources output in excess of 2V while most amplifiers reach full output near 1V. Suffice it to say that there is plenty of drive from the source to power the amp directly, so a simple attenuator in between the two like the pot in the box is all you need. There may be times due to impedance matching that an active buffer is preferable. While an active device it applies no gain. Nelson Pass actually wrote a very good paper on this topic that you should seek out.

Back in the vinyl days active preamps were more a necessity due to the gain required for phono cartridges, especially moving coil. At that time though full function preamps with built in phono stages were more the norm.

[pehare]

Not in my case w/one source.  When I bought my new RM10 MkII last year from Roger I figured I'd need a preamp or pot-in-the-box or lightspeed passive to get good sound but was overwhelmingly suprised by how well my Cary 303/300 CDP w/internal analog volume control worked & sounded running direct thru the RCA inputs (3V output on the Cary thru the RCA's is perfect in my case).  I immediately dumped my nice vintage Luxman FM tuner (there are no decent FM stations around here anyway).  It was like a happy accident but I remember Roger saying somewhere in threads that a CDP w/volume control was all that was necessary.  I often wonder if a 2V output CD player would be enough to get the volume I need?  Does more voltage output on the source equal more gain?

The longer I own this amp the more I appreciate it....cheers!

[Roger A. Modjeski]

Not in my case w/one source.  When I bought my new RM10 MkII last year from Roger I figured I'd need a preamp or pot-in-the-box or lightspeed passive to get good sound but was overwhelmingly suprised by how well my Cary 303/300 CDP w/internal analog volume control worked & sounded running direct thru the RCA inputs (3V output on the Cary thru the RCA's is perfect in my case).  I immediately dumped my nice vintage Luxman FM tuner (there are no decent FM stations around here anyway).  It was like a happy accident but I remember Roger saying somewhere in threads that a CDP w/volume control was all that was necessary.  I often wonder if a 2V output CD player would be enough to get the volume I need?  Does more voltage output on the source equal more gain?

The longer I own this amp the more I appreciate it....cheers!

Peter,

Glad you like the amp. I made it to be used directly with a high level source with the volume control external or internal. I see more players are having volume controls these days and for users who play only CDs that is perfect. Two volts is plenty as long as the CD is recorded at decent level and most are recorded pretty hot these days so there's plenty of signal there. More voltage output is like having more gain and if the internal volume control is all the way up when the CD gets to full level the amp will be well into clipping hence you will be getting all you can get and likely will never play it that loud.

I offer Pot in a Box for those who have multiple inputs up to 6 or just need a volume control. I find that the high quality volume control I use is every bit as good as the rather exotic solutions we see coming along lately. There will always be someone who wants to re-invent the wheel and someone that will buy it and rave about it. I know plenty about transformers and what I know does not lead me to build transformer attenuators and in fact steers me away from them and the many other solutions out there. Potentiometers sound fine as long as they are clean and if they get scratchy just clean them.

[jimdgoulding]

I used a CD player once upon a time to direct drive my active speakers.  A pair of cables and that's it.  Man, the sound was clean, clean, clean with tactile imaging altho a bit (no pun intended) under nourished.