2. analog
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Newbee help- Volume low even at full preamp volume-???

Guys- my first turntable- Dr. Feickert Firebird- arm- TTW jelco- cart Charisma MC-2: Specs-
:Cartridge Weight: 12 gCartridge Body: aluminiumCantilever: sapphireStylus: super fine line contact nude diamondVertical Tracking Angle: 20 degreesCoil: pure iron crossed-coil with single crystal high purity copperOutput Voltage: 0.42 mV at 3.54 cm/sec. Internal Impedance: 14ohmsFrequency Response: 20 –25,000 Hz ± 1 dBChannel Balance: better than 0.5 dBChannel Separation: better than30 dBDynamic Compliance: 10 um/mNRecommended Loading: 100 –1,000 ohmsRecommended Tracking Force: 2.0 g ± 0.1 gTracking Ability at 315 Hz / 2 g: 80 uMRecommended Tonearm Mass: medium
Phono preamp- Rogers PA-1A
Preamp- Wyetech ruby-
Ok- I set the Rogers Phono Pre per Charisma rec.-"We would suggest you to try the 100 Ohm and 10K Ohm of the resistive selection. Capacitance is sensitive to moving magnet cartridges, but not moving coil."

I get very low volume even with the Wyetech preamp at full volume- Please help a Newbee out- What am I doing wrong??thanks gary



fluffers
jmcgrogan2's avatar
jmcgrogan2
6,346 posts
 
Hi Gary, first, do you have the interconnects plugged into your MC input on your Rogers PA-1A? If not, then remove them from the MM inputs and put them on the MC inputs.
Second, you can do as griiffithds suggest, and use all 12AX7's which should provide 15 dB more gain.
If this still doesn't provide enough gain, have the tubes checked out, make sure they are reading okay.
rcprince
3,077 posts
 
Agree with griffithds and jmcgrogan2, check to make sure you're using the right input and switch out the tubes.  I think that using the 12AX7 tubes as suggested above will help, as 50 db of gain from the 12AU7s might not be enough for your cartridge.
sbank's avatar
sbank
3,381 posts
 
How much gain does the Rogers phono stage put out? If I understand from above the 12AU7 puts out 50db gain, but switching to the 12AX7 results in 65db gain...correct? If so, 65db should be plenty of gain to drive the .4mv output cartridge. 
Absolutely no need to consider switching to a moving magnet! You've got a simple wiring error or a bad tube in all likelihood.

And for god's sake, never any need to turn the volume all the way up. If you pass 2:00 and it's not plenty loud, usually something is setup incorrectly.
Cheers,
Spencer
fluffers OP
78 posts
 
Thanks guys- I bought the Rogers used and the guy sent a mishmosh of sovtek tubes so I guess they are no good- 
I am going to order a new set of 12ax7- So the question is which one do you guys rec. I get- thanks again for all the help!!!
kijanki's avatar
kijanki
4,432 posts
 
65dB = 1778
0.42mV x 1778 = 0.75V

Still low - needs about 8.5dB more to get to standard 2V. Am I missing something?

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