System Gain, Volume, and component matching?


I'm facing a bit of an unknown regarding proper gain matching of components and could really use some help in understanding this. First, with my current setup I typically listen at ~60 out of 99 on my Rowland Pre (maybe 90db or so). Here is what I believe my component gain structure is right now:
APL3910 4V output
Rowland 20db overall gain
JC1 amps 1V=28.3V out (56.6V max power)
Magnepan MG3.6 85db at 2.83V (4ohm load)

Am I correct in saying that to reach 85db at 1m on a continuous test tone, my pre would need to feed the JC1's 100mV?

If this is true, it seems that my pre would have to attenuate that 4V output from the APL a huge amount? But given the Rowland Pre's 20db overall gain, doesn't that suggest that: 1.) at max vol setting, Vout/Vin = 100? 2.) With APL outputting 4V, at max vol setting, the pre would be outputting 400V (no chance). 3.) If the volume knob is linearly calibrated, that would suggest that 4V per vol point (0-99) (no chance).

Could someone help me understand this? As I said earlier, I usually listen at ~60 out of 99 on the Rowland. I'm replacing the Rowland with another Pre that has 8db of gain (Rowland has 20db), and I'm sending my APL back to have a linear power supply upgrade which will drop output from 4V to around 1.5 to 2V. If I used the mathematical approach above, I wouldn't be worried about a thing. However, from a practical point, I currently listen at 60 out 99 on the Rowland, will be decreasing Pre gain from 20db to 8db, and will be reducing APL CD Player output from 4V to possibly 1.5V.

So, with those changes, am I going to be craving a pre that will "go to 11"? Will I run out of gain? And finally, I've heard people mentioning problems with too high of gain in a system causing certain distortions and very little (e.g. 7 to 9o'clock) control of volume, but is it possible to have too little gain when source is only a line level source with outputs in the 1+V range (No phono in system)?

Lots of questions in there I'm sure. I really appreciate any help in understanding this matter.

Thanks!!!

Jordan
128x128germanboxers

Showing 2 responses by drubin

Jordan, I can't comment on your precise situation, but I have an APL Marantz which, after a recent mod to get the AKM DACs and the new upsampler, has a very low output (around 1.2V I believe, which is less than you will have). I am using it into a Rowland Concerto pre and then into either Rowland 201s or a Primaluna Prologue 5. I'm listening right now (as I type) at a VERY modest level and the Rowland is set at 60.0. If I had less preamp gain, I think I'd be hosed. My advice is to have the APL mod done before you sell the Rowland, just to be on the safe side.
Jordan, the APL Marantz is less than a week into break-in after the upgrade but it is spectacular. Honestly, I can't believe the improvement. All the usual superlatives -- in another league, etc. -- apply, and then some. The man's a major talent.

I recently changed from Thiel to Harbeth speakers. I bought the 201s for the Thiels. The Harbeths don't need that kind of power and, with their more intimate presentation, I was curious to try a tube amp. Hence the Primaluna (which is not quite enough power, but it works). Both amps are great, but it's definitely apples and oranges.