2. amps-preamps
  3. 1304036269

help me to understand the gain

I have a problem that the gain is too high. I can only turn the volume knob to 7 o'clock position, with the 0 at 6 o'clock. I am sort of ok when using my computer where I can lower the volume in iTunes. But from my CD player, I cannot.
I am using Maverick Audio DAC, PrimaLuna Progloue 3, McCormack DNA-1, and B&W CDM9NT.

CDM9NT - 90db sensitivity
PrimaLuna - gain 12db(4x), input impedance - 100k Ohm, output impedance - 2800 Ohm
McCormack - input impedance - 100k Ohm, 150Wpc RMS into 8 ohms (21.8dBW)

is that my equipments are out of synergy? I just bought a pair of Zu which is 101db sensitivity, does that mean it will be a even bigger problem? should I buy another preamp with less gain, or should I buy another amp with less power output?
gte357s
onhwy61's avatar
onhwy61
5,249 posts
 
I not saying what the problem is, I'm offering a solution. If he keeps the Zu speakers he should redo his preamp/amp. If he gets rid of the Zu, he just needs new speakers. Which is easier and less expensive to implement?
czbbcl's avatar
czbbcl
1,752 posts
 
Agree with the resistor change in the pre-amp or the
attenuator suggestion.

Chuck
jeffreybehr's avatar
jeffreybehr
805 posts
 
Gte, you have TWO problems. First is that you have about 130 more Watts of power than you'll need for your Zus. Second is that your poweramp has about 30dB TOO MUCH gain. Too much gain amplifies preamp noise (and the thermal noise inherent in the resistors in any attenuators) excessively and resticts volume-control movement. (At 12dB, your preamp does NOT have too much gain.) DIYaudio.com recently issued a newsletter about gain structure. I can't find it online; if you'll e-mail me at jeffreybehr(at)cox(dot)net I'll forward it.

Nelson Pass, with his FirstWatt amps, recognizes the general problem of too much system gain and solves it with one poweramp, the F4, with ZERO Voltage gain. Read about it at http://firstwatt.com/index.html . It has plenty of power for the Zus and looks to me like a great choice.
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gte357s OP
281 posts
 
I tried connecting the DAC directly to the amp, the sound is not good. I also try to lower the volume on the DAC. Although it gives a more usable range for my preamp, it has a small impact on the sound. Lowering volume on iTune sounds better.

I think it is usable as long as I use iTunes, but the next thing I will change would be the power amp, or I will get an integrated. I will get the Zu this week and see how it work.

BTW, tube amps are expensive. I want to keep the budget around 1000, and there are very limited choice. Maybe I will start and thread about suggestions.
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