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High Output Preamp for First Watt SIT-3?

I'm new to the audiophile world and recently purchased a First Watt SIT-3 with Magnepan .7s.  I have a Mytek Brooklyn Bridge for streaming, though I prefer to play vinyl with my Mofi Ultradeck.  The Mytek serves as the phono stage (69dB gain for MM?), and I don't use a preamp;  the Brooklyn is connected directly to the First Watt. 

I understand that the SIT-3 is only 11.5 dB of gain, and that's extremely low compared to most amps.  I like most everything about the system except for the fact that I have the Mytek maxed out volume-wise many days.  Certain LPs are cut quieter, and I wish I had more power.  There are times streaming where the Maggies aren't getting to their sweet spot.  I realize the Maggies are a lower sensitivity speaker. 

What should I look for in a preamp to fully drive the SIT-3?  Eventually, I'd like to replace the phono stage instead of relying on the Brooklyn.  Is there a tube preamp featuring a phono stage with sufficient output to drive my amp in the $4k range?  Otherwise, I'm eyeing the Modwright PH 9.0 and a linestage preamp, realizing that this will probably be costlier.  I'm looking for a warm sound, not analytical but engaging. 

Any help is greatly appreciated.  I'm a working musician with a basic understanding of related electronics but little experience in this world. 

murphbass
charles1dad's avatar
charles1dad
10,250 posts
 
I find it pleasantly surprising that murpbass is getting the good sounding results relatively speaking. I recall from the Stereophile review the S.I.T.-3 put out less than 20 watts into a 4 ohm test load rather than the rated 30 watts. So on paper quite a bad match yet able to yield very good sound in ’some'  listening circumstances per murphbass. Impressive when you really consider the obvious handicap involved.

In my mind an excellent circuit and design execution by the iconic Nelson Pass (no surprise in that regard). Logic dictates that matching with a compatible speaker = sublime sound quality that joeinid alluded to earlier in this thread.
Charles
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almarg's avatar
almarg
9,670 posts
 
Hi Charles,

The reason for the discrepancy in power capability that you cited relates to the amount of distortion the ratings are based on.

JA's measurements in Stereophile indicated that:

Into 4 ohms (fig.5), the SIT-3 delivered 16.8Wpc (9.24dBW) at 1% THD+N, and 36Wpc (9.55dBW) at 3%.

And in the graph at the bottom of page 10 of the manual for the SIT-3 it can be seen that the amp can provide 30 watts with distortion of about 2.3%. The distortion being "dominated by second harmonic with a “negative phase”, the signature that we have come to prefer with the previous SIT amplifiers." Which would seem to be a relatively benign distortion characteristic.

Best regards,
-- Al
   
charles1dad's avatar
charles1dad
10,250 posts
 
Hi Al,
Usually JA uses 1% distortion/clipping as his reference point for measuring power output into a given impedance load.  Thus the <20 watts into 4 ohms I cited. However I agree with you that 2 or 3 % 2nd order harmonic distortion would very likely not be noticed or objected to in real world listening conditions. As Ralph (atmosphere) has noted on numerous occasions,  human hearing has much tolerance for 2nd order even distortion (but miniscule tolerance for higher odd order distortion).
Charles 
bigkidz
3,504 posts
 
An easy and cheap way to try would be a Counterpoint SA-3000 preamp.  Muscial, can be upgraded to sound as good as mostly anything out there, has a phono and very good in stock form.  Buy one cheap and take a listen.  Easy to resell if not but if you like it then send it to me for the upgrades - capacitors, resistors, volume control, take the transistor out, etc.  I have one in now for the upgrades.  Easy on tubes also.

Happy Listening.
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