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 

Regarding the optimal ohm rating for the SIT3, the following is from Nelson Pass.

“The most popular impedance for the load is 4 to 8 ohms, which is the region where it measures best, and there is not a lot of difference between those two numbers. At lower, we see increased distortion, and at higher impedancethe distortion numbers don’t go up, but there is an increase in higher orderharmonics. It’s not a big deal, but you can play with this by putting some resistance across the speaker. Typically people play with resistor values from 8 to 25 ohms, and since resistors are cheap I recommend that you get several values to try. The type of resistor is not critical, but should be ratedat 5 watts or more.”


I have Avantgarde duo XD at 18 ohms. I use a Zu Audio 10 ohm resistor across my terminals to give the amp a resistance rating of 6.42 ohms calculated. 
Works wonderfully.

Hi. I used to own a sit-3 and had similar issues with the pre-amp. The best match I found is the COS Engineering D1 dac/preamp. Maximum output 8V (most pre-amp do 2-3V) and 0db gain. It’s one of the best dac I’ve ever used too. PM me if you wish to sell your SIT3 or are interested in knowing more about the COS D1.
Hi joeinid,
Thanks for posting that detailed explanation per Nelson Pass. Given atmosphere’s comments I wondered if thi applies to the S.I.T-3 (up to a certain point). In your case you prefer the sound with less than your speaker’s 18 ohm impedance load.

My speakers are 14 ohms and my amplifier seems to thrive with this high impedance. No doubt that this likely varies amongst amplifiers.
Charles
While it won’t matter in the case of @joeinid ’s 107 db speakers it’s probably worth mentioning that the SIT-3 won’t be able to provide much power into an 18 ohm or other very high impedance, regardless of whether or not a resistor is connected in parallel with the speaker.

For example, based on the amp’s 18 watt/8 ohm and 30 watt/4 ohm ratings it is probably capable of supplying something like 22 watts into the 6.42 ohm load he mentioned, corresponding to a 10 ohm resistor paralleled with his 18 ohm speaker. In that case, though, most of the 22 watts would be consumed by the resistor, and it can be calculated that only about 8 watts would be delivered to the speaker.

It’s a different story altogether in the case of @charles1dad ’s Coincident Frankensteins, which are optimized for high impedance speakers and I’m guessing would not need a resistor to provide good sonic results and close to rated power even with an 18 ohm load.

Best regards,
-- Al

@almarg

I totally agree with your assessment. Thank you for posting.

In my case, even 8 wpc is a lot for me.

It’s true that I’m wasting or throwing away power for the sake of keeping the SIT3 in its happy zone. So far the SIT3 is my favorite solid state amp on my Avantgarde although I enjoy others, just not as much.

Hi Al,

Thank you for the very clear (as usual) explanation. I suspected that different amplifier topologies respond differently (to some degree) with higher speaker impedances. You are correct, my SET amplifier (8 watts)  pairs beautifully with a 14 ohm speaker impedance. It seems the amplifier is just coasting along.

Charles

I do see frequently that Herb (and mostly Steve G.) will run inefficient speakers with low watt amps and say they sound fine and have plenty of volume, but I get a little wary when I start seeing actual customers trying to power inefficient speakers with 1/6/12/25wpc amps and not quite getting the results they were expecting.  Not everyone is running Zu or Klipsch or Tekton, and I'm not sure where the disconnect is.  Maybe what they consider an acceptable volume doesn't translate well to other peoples' listening habits.

Hi joeinid,

I know you've had some excellent SS amps in your system so your comment regarding the S.I.T.-3 is quite a compliment. I would not be surprised if you preferred it over Avantgarde's own sibling  amplifier.

Charles

@charles1dad 

Hi Charles,

 I don’t claim to have the best ears but I’m sensitive to too much or aggressive treble. Avantgardes beg to be driven by wonderful SET in my opinion. 
I’ve been told that the Avantgarde amps are especially wonderful for classical music but still have a bit of solid state sound. 
I do enjoy a Valvet E2se as a close second. Some of the less recent McIntosh amps like the 452 or 302 sound decent if a little bit flat. 
The Benchmark AHB2 is wonderful too for low to medium volume but it could need more break in. It’s very neutral but also very natural and dead quiet. Spooky details pop out of nowhere. 
The SIT3 is a warm, yet open and laid back presentation. The SIT3 is more mid hall perspective with beautiful vocals and piano. Because of its low gain, it’s also dead quiet and works superbly with various preamps. Best combo is CJ GAT2 with the SIT3. 

Do you believe the S.I.T.3 would improve SQ further if driving a 12 or 16 ohm speaker load (due to lower distortion) or is 8 ohms optimal for this particular amplifier?
If the amplifier begins making a greater percentage of higher ordered harmonic distortion into higher impedances, even though its THD might be lower, increasing higher ordered harmonics is never a good thing!


Have you seen a video of the inside of Herb's listening room in Brooklyn.  One thing it ain't is large.
Look at the Tetraspeakers.com site and any other Audio Industry.
I have known some top level Grammy winning artists. They normally do not involve themselves with any commercial enterprises unless they art financially invested (with the occasional exception of instruments from large companies). Tetra sells retail to all endorsing artists except Keith Richards for whom Adrian made a custom pair of Tetras for him to take on the road.

Thanks atmosphere,

The replies  from Al and joeinid (per Nelson Pass comments) were  clarifying explanations.

Charles

I don't know if this is in any way helpful.  I built the DIY version of the First Watt M2X.  I used my Cary SLP-98P preamp with it.  Lots of gain with front-panel level adjusters for each channel.  It sounded great.
There is an incredible level of "shoot from the hip" commentary about the SIT-3 and the Maggie 0.7 pairing. Yes - Maggies are notorious for being a tough load. But - as Vladimir Lamm put it to me a long time ago, "it's not about the watts , it's about the current". For those of you interested, I connected my SIT-3 to a pair of 20.7's I own and while they didn't blow the doors down, they ran the Maggies to satisfying levels. Earlier comments are spot on - Herb Reichert (whom I respect as a straight shooting reviewer), did in fact say the 0.7/SIT-3 combination was fantastic. So did Steve Guttenberg. So, armchairs reviewers can take a back seat to those of us who have actually experienced the combination. Several posters here have heard the combination or own it - listen to them. Forget the rest.
I have owned 3 open baffle speakers I love/d 2 of them. Which one didn't I? Magnepan 3.5Rs. I tried so many things, biamping, then active XO. After 2 frustrating years I replaced them with Emerald Physics KCIIs (open baffle, super efficient and about half the height,

EP is getting ready to move their factory and is blowing out available inventory. See USAudiomart for a couple of gems for pennies on the dollar


hth
I also have a SIT-3.  I recently sold my Magnepan 3.7i, but I can tell you I was surprised at how good the SIT-3 sounded on them within reasonable volume. I currently have Devore 0/96 (nominal impedance 10 ohms) and the SIT-3 doesn’t seem to be a great match for them. I recently got Tekton Moabs (4 ohms) and the SIT-3 is a very nice match and very musical combination.  The SIT-3 is a wonderful amp with the right speaker

kinara,

murphbass began this  thread by explaining in many cases he's been very happy with the sound quality (SQ) of his S.I.T.3 and Maggie pairing. He did however certainly cite  that there are some observed shortcomings as well. He wondered if it could be a lack of power "I wish I had more power" in certain situations or is more gain needed?

He straightforwardly was soliciting  input/suggestions on this forum regarding his dilemma.  IMO his generated some very informed responses and interesting dialogue and commentary. Posters did not dispute his claim of very good SQ with his amp/speaker pairing. Opinions were expressed and shared in regard to what might be suitable solutions to his 'stated'  concerns. I believe that murphbass gained some additional insight and appreciates the many  good responses he received.

So I don't understand your characterization of "shooting from the hip" which seems dismissive of what were well intentioned and thoughtful replies to murphbass's clearly stated concerns. I don't doubt you hear very good sound with your S.I.T. 3 and Maggie 20.7 but would this be your ideal long term amplifier for these speakers? It so then I hope they continue to provide you many years of listening pleasure.

Charles.

Charles, I apologize if that was the impression, there have certainly been some informed and cogent replies except that they were not addressed to the question at hand. I was just somewhat surprised by the fact that the subject heading - the search for a suitable high gain preamp for the SIT-3 quickly devolved from the first post into "you have the wrong speaker-amp combo". That was not what the poster was asking for or about, but since that appeared to way the thread was going, I threw in my two pennies worth on Maggies and their infamous power requirements. Frequently it's an issue of how the speaker behaves across it's impedance curve and the demands that makes on partnering amps. For example, driving Quad ESL 57's has never been about watts but finding amps that can cope with the ESL's wicked load impedance behaviour. After all, Peter Walker drove them with 15W amps. Similarly, I drive my Harbeth P3's with 10 watts (admittedly near field) from a Luxman SQ Integrated with great success. My SIT-3/20.7 run was simply an experiment, in normal existence , they are driven by 450W VAC amps, which is more appropriate. Someone once told me that "tube watts are not the same thing as SS watts and Class A watts are not the same thing as Class A/B watts". I think there's some truth to that. I am planning to match my SIT-3 up with Harbeth 30.2's but within a near field listening envelope and I am pretty confident it will work well, albeit not to head banging levels. I would still love to hear some thoughts from everyone on appropriate high gain preamps to pair with the SIT-3. The Modulus 3B has a ton of gain but customer service and reliability issues plague the Company. Happy to hear some input on that. Thank you.
Hi kinara,
I understand your point regarding the straying away from the original thread inquiry about high gain preamplifiers. I just believe that people were trying to point out that this wasn’t simply an issue of additional ’gain'  to solve the problem expressed by the OP. In fact he (murphbass) later in this thread came to the realization that adding more gain to his system via a preamplifier wasn’t the course he wanted to follow.

BTW kinara I do happen to share your appreciation of high quality low power amplifiers. I’ve been a very happy owner of an 8 watt 300b SET amplifier for over 10 years. I do readily acknowledge that it (terrific as it is) is not the right choice for everyone and speaker selection requires thought and scrutiny.
Charles
Murph, if you are still looking for a preamp I would suggest going back to Herb's review of the SIT-3 in Stereophile. He did indeed find a good match with the Maggies.

"The SIT-Maggie combo generated a distinctive, liquid, ribbon-tweeter clarity that also flattered sopranos in a way not bested by any other amp-speaker combination I've tried. Voices and instruments were no less there than they were with the Pass Labs XA25 or the Bel Canto Design e.One REF600M, and that's saying a lot—those amps make really SOLID sound with the Magnepan .7s. Wilder still, the SIT-3 generated more relaxed, natural detail and a bigger, better-mapped soundstage than I'd previously thought possible with these humble planars."

Given that success, look to Herb's preamp choices. He uses two -- the Rogue RP-7 and the PrimaLuna DiaLogue. He did not say which one was better in this case. You might send him an e-mail and ask.

- Robert
Chiming in late here, but would like to add that I have a SIT-3 that sounds wonderful with my Maggie 1.6.  Of course, I do not listen very loudly but at moderately high levels (guesstimating 90-95 dB) the SIT-3 sounds significantly better than my former 400 WPC Bel Canto Ref 500S.  Currently, I mainly use my Maggies with a 250 WPC McIntosh MC252 and don't appreciate any loudness or dynamic differences and in fact would ultimately prefer the First Watt.  

In OP's case I would audition the Pass Labs XA25 to replace the SIT-3.  I also had that amp and would switch back and forth between it and the SIT-3.  The XA25 sounds similar but plays louder at 20 dB gain.  It also opens up an easy trade-in option with Reno HiFi.
Thanks for adding to the thread, @eugene81 .  That's useful information.  I suspect that most of my listening centers around 85db, or at least that's were it sat on the day I checked.  I listen in a nearfield position because of the size of my room and so that I may mitigate some of the room's acoustic problems.  Of course, much of it is highly dynamic classical or jazz, so I'm getting up to adjust my preamp frequently.

Thanks to advice from @mglik , I purchased a used but low hours/refurbished Audible Illusions M3B.  I can't overstate the difference between my Mytek Brooklyn Bridge connected directly to the SIT-3 and the new arrangement.  Hard to say the objective sound of the M3B because my only reference point is my previous setup.  Perhaps a bit darker sounding?  The tubes do impart their magic.  I find myself turning the system up a little louder than previously when playing vinyl to reach the sweet spot- and the separation/clarity of instruments.  Streaming never requires the gain controls above noonish, but I can get close to the extent of the knobs' travel when playing quieter records.  Overall, a great improvement.

Still, a Linear Tube Audio microZOTL is on my list for the future.  I went with the M3B because the price was right, and the phono stage is good.  When I make the move to a MC cartridge, I will weigh purchasing the gold phono card vs a whole new preamp. 

@eugene81 I'm glad you mentioned the Bel Canto Ref 500S, because that unit and the mono block 600M were enticing.  I think the one you had actually delivers more current than the monoblocks, and Maggies seem to be current hungry.  But, I guess I can scratch those off my list! 

Thanks for the recommendation of the XA25.  I purchased the SIT-3 first because I was motivated by the limited supply (initially only 250?).  As a collector of all things music, I rarely sell back instruments/amps, etc.  The SIT-3 is special, and even if I temporarily take it out of the system, it was my first high end audio piece and will probably be with me forever.  I will consider the XA25.  If I change anything, or add options, it would probably be a high wattage amp.  I know conventional wisdom is Bryston with Maggies, but I think I need a more engaging/magical/euphonic amp.  So, that hunt continues, but I should reiterate that I'm pretty happy with where I'm at, thanks to advice received here. 

I took a power amp from my live bass guitar rig-  a QSC CX302- as an experiment.  It's 325 watts/channel @ 4 ohms- 10 times the power.  The fan was so ridiculously loud that it was laughable.  It was nice having more power on hand, but upon switching back to the SIT-3 after a few weeks, it was no contest.  I may not have the best tonal memory when switching pieces in and out, so quantifying differences is difficult.  Upon its return to my system, the SIT-3 thrilled me from note one, and it pulled me into the music, compelling me to listen for hours longer than I anticipated.  One lesson for me is that I will hear a clear audible difference between gear, sometimes showing distaste when it is outside what I'm familiar with.  It is through subsequent, in depth listening that I can truly value the swapped gear.  The first hours of the M3B were such a shock that I was unable to discern if I liked it! 

Thanks for all the input- you guys are the best!  I'm realizing much like life, this is a journey rather than an ultimate destination.  I'm geeking out on Quad 57s (haven't seen much anecdotal regarding the SIT-3 and Quads) and to a slightly lesser degree, Spatial Audio.  Most importantly, having fun and deriving much satisfaction from listening. 
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@tvad

I’m using a Supratek Cabernet with a SIT-3, it’s a really synergistic pairing. My speakers are Klipsch Forte III’s, however, which are very efficient.

The gain adjustment comes in handy on horns.
@charles1dad , The SIT3 improves with a lower ohm load, according to Nelson pass. using a 16ohm speaker, He suggests using a 4 ohm resistor across the terminals leads.
Its a different animal than most amps..
Good thread.  I don't have much to add, other than Charles mentioned Coherent speakers.  I am currently running a SIT-2 with Coherents and it is the best amp/speaker pairing I have personally heard.  I have the Model 10 (no longer in production), which is 94db efficient.  

Those Tetra speakers look awesome.  I remember that Stereophile article about Ron Carter's system and his Tetras looked stunning.  
I run an SIT-3 with 8 ohm Omegas and definitely got better performance out of it by dropping 8 ohm resistors in parallel with the speakers. I run it with both an MZ2 and Don Sachs Model 2, works well with both although obviously very different presentations.
@whoopycat,
Coherent Audio speakers seem to fly beneath the radar. All comments I've come across in regard to  them are consistently very positive.  
I have no doubt your audio system sounds beautiful with those speakers driven by the First Watt S,I,T. 2 amplifier.
Charles 
Gotta say, the XA25 is an excellent choice and shoots much higher than it is “rated”. Pass very conservatively rated the amp with a .01% THD wattage measurement, at the typical 1% THD measurement it’s actually over three times higher. It really is an excellent amp. Very high bias Class A operation, runs hot, but not a blast furnace. Best thing? For a Class A amp it’s tiny. But a power house. 
the SIT3 only requires 3V to full output/clipping. most digital sources exceed that alone. It’s a low gain amp and low power, but should be able to be driven by most anything. I have a SIT3 on its way and will be pairing it with the PASS XP12.
I am currently using the XA25 with it. Was told I just need to turn it up higher than most other amps, yet it will still be all attenuation as I’m coming off a DAC in balanced mode, 6V

@mikem,
If you are so inclined would you post your listening impressions/comparison of these two highly regarded amplifiers?
Charles
@charles1dad , Will do !  looking forward to breaking it in and hearing what all the fuss is about... !
Have a good weekend !

The SiT is a class A device with the transconductance qualities of a triode... so I would not define it as ’solid state" sound.

Now, the other amps... Maggies. I got 1.7s and 12s. Also got clone F4, F5, A2 and mono A5s. ( Plus a set of SiT transistors for the next amp).  And an ARC D70-II.

My preamp is a tube CJ that can swing 20V.

The SiT / Maggie combo will sound great at lower levels, but truly, they come alive with lots of power. Just like my F4 and F5 sound extremely good, when I plug in the A2 the music simply comes alive, not just the "sound of Aleph" but also the reserves of power: it sounds like an additional deep down octave came on line and the dynamic range snaps to life.

THAT, IMHO is the big difference: the lower power amps will drive the Maggies to good sound levels but you lack the dynamic range. Adding more, clean, power, lets you play at the same level but now you have dynamic range... it just sounds "louder" because the bass suddenly appears, also, the treble is cleaner as temporary peaks will not drive the amp into the harshness of clipping.

BTW, in my main system I’m currently driving the 1.7/A2 and Elac Unifi B52/F4. The F4 is fantastic (really needs those 20V from the preamp)... but ultimately the Maggies with 200wpc are the more satisfying sound - whole, top to bottom.

My advice to the OP:

(1) Your preamp should swing 20V.

(2) Get a pair of used Aleph 2s for the Maggies ( clones are fine ). If SS, it must be a class A amp... or perhaps a used ARC D115-II, VT100, etc... must have over 100 watts!

(3) Find a pair of efficient speakers for the SiT and post that here... because I’m also looking for that.

 

IMHO, the SiT and Maggies are a system for the brain... but sometimes, you need to feed your heart.