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
Hi Murph,
I have pretty carefully read your posts. I relate to your perspective on music playback. Until recently I was a working musician and have made a living as an audio consultant and dealer. I own one of Nelson Pass’s “kitchen table” creations, the M3. Believe the SIT-3 is one of his better works. And there are two main issues, as you mentioned. Speaker and amp combination are the “two hands clapping” in any system. And the preamp is “the heart”. Central is your feeling of how the music sounds. If you like the Maggies you are not going to get that open sound from any other speaker that works for you other than a legendary pair of Quad 57s. It is counter intuitive, but if the SIT-3 and the .7s work for you they work. But the First Watt should be an excellent match with the 57s. I would save your money and stay with what you have. BTW you have one of the best TTs for $2k out there in the MoFi. And the your digital is said to be terrific although I am not a digital guy. An excellent phono stage and, according to TAS Editor’s Choice for many, many years as “the best at any price”, is the Audible Illusions preamp. The model with the phono stage is the M3A or M3B. I own and adore my M3B. A new one is $5200. But you can get 90% there with a factory refurbished one for around $2500. One of the fortes of the AI is that they are a SET design using only one tube per channel for the preamp and for the phono stage. And a SS amp is normally smoothed off by a tube preamp-let alone a SET. I know Dan Wright very well. I did an audio show with him. You can’t go wrong with one of his preamps but I prefer the AI. Unfortunately, a SET amp is a bridge too far for the Maggies. I am an all SET guy for life. Unmatched musicality with the right speakers. As good as the First Watt is, it is still a “sand amp” and has a SS sound.
But if all those wonderful reviewers and YOU love this combo, stick with it. Some day, or now, you may want to get Quad 57s. I joyfully lived with my 57s for 10 years and still miss them. But something you don’t get with 57s or .7s is dynamics and slam. This can be helped by adding a subwoofer. I would only use a Rel. They only make subs and they hook up directly to your amp making for the best connection. Surely, you may be more able to better push the Maggies with a higher power amp but adding an AI will give you substantially more gain and adjustable gain for MM. Matching amp with speaker is about the toughest thing in a system and if you, mostly, like what you have, be happy! Some day, you may want to get a SET. Ultimately, there is nothing that compares. SS amps try to sound more like tube amps and multi tube amps are trying to sound more like SETs... mostly.
Al- I appreciate you running calculations on my setup. The cartridge is a MOFI Mastertracker. 3mv output. That's substantial, no?

https://www.mofielectronics.com/mastertracker-cartridge
I was curious if the amp was seeing the full potential input signal (and therefore outputting a full 30 watts). 

Last night I listened to the Speakers Corner issue of Aretha Franklin's 'Live at Fillmore West.'  It was very/too loud when the Mytek was maxed out.  However, my listening tastes are varied.  I listen to classical chamber and solo works, acoustic jazz (50s-60s and up), rock, new grass, reggae, pre war blues, Grateful Dead, electronica, post punk and more.  A rock album with limited dynamic range mastered in a normal to hot range is great on my system.  Many classical pieces don't fare as well with this setup.
I have always expected to have at least two setups to cover various genres and listening needs.  Planar speakers have a midrange, imaging and other qualities that I don't think I'll find in dynamics.  But, I don't think planars will 'rock' like dynamics will.

Without going into my life story and why my listening room is (temporarily) limited (11 x 13, I believe), I do have to settle on one system for now until my situation changes. 

My local dealer carries McIntosh, Klipsch and Primaluna.  My tastes are toward a more euphonic presentation.  I would love to hear what the Maggies sound like with a robust power amp, but I imagine a solid state amp such as the often paired Bryston would leave me cold.  Same for Wyred4Sound and Class D.  Maybe a tube preamp would mitigate that.  If Nelson Pass's other (higher power) amps are anything at all like the SIT-3, I'd like to hear them.  But, I'm guessing the SIT-3 is unique, the First Watt stuff underpowered, and do I want to heat up my room with an XA, nevermind the expense? 

I know I was the one who started the thread asking about high gain preamps, but I don't like the idea of fixing a problem based on my other mismatched components.  It seems like a better idea to find a synergistic combination.  Your responses have shown me the light.

I think I'll listen to the sentiment of most of the contributors to this thread and build around the better of the two variables:  my amp.  I like the idea of having a high efficiency speaker on hand when I add an SET amp. Since it's hard to demo most of what's out there, I really appreciate everyone's recommendations.  I can sell or store the Maggies, but ultimately I'll be looking at 3.7s or higher when I have more space.  I have tube guitar amps from the 40s (!) through the 70s that sit unused in the attic.  I'm a bit of a hoarder.  Hoping to fund my system through trading rather than collecting pieces that aren't listened to. 


Here is an analysis of approximately how much of the amp’s power capability can and can’t be utilized in this situation when playing LPs, based on the cartridge’s rated output and the gain structure of the system:

Stereophile measured the gain of the SIT-3 as being 11.3 db, which corresponds to a voltage multiplication of 3.67x. For an amp having that gain to provide an output of 30 watts into 4 ohms, which corresponds to 10.95 volts, an input of 10.95/3.67 = 2.98 volts is required.

Mytek’s description of the Brooklyn Bridge states that “Brooklyn Bridge is identical to Brooklyn DAC+ in terms of audio circuits and performance but has the addition of a built-in Network Streamer.”

Stereophile’s review of the Brooklyn DAC+ states that “the DAC+’s feature set, which includes MQA and a built-in moving-magnet/moving-coil phono stage, is largely the same as the original Brooklyn’s.”

Therefore it appears likely that for MM phono cartridges the Brooklyn Bridge provides gain that is similar to what Stereophile measured for the Brooklyn DAC, namely 55.6 db. That corresponds to a voltage multiplication of 603x.

As stated above Murph’s cartridge has a rated output under the standard test conditions of 3 mv. A gain of 55.6 db will boost that to 0.003 x 603 = 1.81 volts, **if the volume control is at max.** That of course falls well short of the 2.98 volt input the amp requires to be driven to full power.

Since for a given load impedance power is proportional to voltage squared, the percentage of the amp’s 30 watt/4 ohm rating that is being used when the cartridge is supplying its rated output, and the volume control is at max, is:

(1.81/2.98) x (1.81/2.98) = 0.37 = 37% (!)

The corresponding power supplied by the amp when the cartridge is supplying its rated output is 0.37 x 30 watts = 11.1 watts (!!). Meaning that almost 2/3 of the amp’s power capability can’t be used for many recordings without additional gain being provided.

The peaks of various recordings can of course be either somewhat greater than or somewhat less than the standard LP test conditions. But this analysis appears consistent with Murph’s observation that there isn’t enough gain in the setup to support LPs which aren’t “hot.”

And given his earlier statement that he is “on the cusp of where I want to be” it seems to me that replacing the speaker or the amp is not necessarily called for, despite the mismatch in power capability. If neither of those things is done, what is called for is providing additional gain between the Brooklyn Bridge and the amp. 12 db or so should be adequate. The simple one-tube line stage I linked to earlier provides a gain of 22 db.

Best regards,

--Al


Mglik, ,
You make some very compelling points. When all is said and done subjectivity rules. You have to choose what ’you’ feel sounds best and provides the most enjoyment and satisfaction,. Murphbass says he’s on the "cusp" of what he wants with his current audio system make up. So it’s quite conceivable that the addition of system signal gain could put him where he wants to be. We are discussing what ’he’ wants.

With the right cartridge (which Al has asked about and rightly so) the suggestions posted here of various high gain preamplifier/line stages could be the solution in this specific scenario. I have to acknowledge that from murphbass’ perception (not mind or anyone else) he is quite close to his objective.
Charles
Don’t look down on Klipsch. I have owned Martin Logan stats and my Maggie 1.7is are sitting in a box. I had a 200 watt amp when I was using the Maggies. Right now I am using Klipsch Heresy IVs with the Pass Xa-25 with a c-j ET3se. Sound is more solid and dynamic. Very musical! BTW would love to try your Sit-3🙊