While the speaker and amplifier are individually good products, as a pairing they aren’t compatible IMO. The assessment of roberjerman is on the mark. If I were in this situation I’d keep the First Watt S.I.T-3 and purchase a more suitable speaker for it (higher sensitivity with an easier to drive speaker impedance load). This amplifier delivers less than 20 watts into a 4 ohm load. The maggies (83 db sensitivity) need more than this to perform at their best. Yet if matched with an appropriate speaker according to owner feedback the S.I,T.-3 will sing will superb sound quality.
Murphbass which do you cherish more, your Maggie’s or the S.I.T,-3? I believe that your amplifier is the better of the two products and offers more sonic performance potential upside ultimately. I readily acknowledge that this is simply my humble opinion. In summary I don’t believe this is exclusively a "gain" issue.
With the appropriate speakers, the SIT3 is sublime. I’m sorry but the Magnepan speakers are not the right pairing. Everything said by the others is right on. Maggies need a lot more power to sing. The SIT3 may be difficult to replace in the future so I vote for a new, highly efficient speaker to mate with it.
I have Avantgarde Duo XD which are 107db efficient. With a resistor across the terminals to bring down the resistance that the amp sees (the SIT3 prefers to see 4-8 ohms), its been a revelation. A wonderfully engaging amp. Keep it and get new speakers.
Thanks for all of your input. I purchased the SIT-3 first because I was intrigued by early reviews and wanted to purchase one before the limited supply ran out. I've always wanted planar speakers and was aware of the low sensitivity of the Maggies as well as the low wattage of the First Watt. So, yes, a mismatch guided by two separate thoughts.
I wouldn't have gone down this road if not for a few factors: Herb Reichert sang the praises of this specific combination, saying the SIT-3 made him appreciate the .7s 'a lot more' and called them 'beguiling' in this context. Steve Guttenberg used the term 'magical,' I believe.
The Maggies are 4 ohm, the SIT-3 puts out 30 watts/4 ohms. I was concerned and asked my Maggie dealer if I could demo the speakers with my amp. They wouldn't accept my request (because it would be too much of a hassle to connect/reconnect) and mentioned that since the .7s are a special order, I was unable to return them in the event that I did not like them in my system/room. So, I demoed them with a lower wattage amp that sounded anemic at times. Yes, I bought the amp with this knowledge! But, honestly, they sound great together. Not knowing why, I can guess that it is the high current capability of the SIT-3.
I am thinking of temporarily using one of my pro power amps to hear the Maggies properly powered. I have limited space in my listening room but will consider a high sensitivity pair of dynamics. Avantgarde is a bit out of my price range. I am curious about SET amps as well and have been looking at speakers that work well with them.
If anyone has read this far, I appreciate the input and take your advice. But, if there is anyone out there with this or a similar combination of components, perhaps they could weigh in with additional feedback. Like I mentioned, I'm at the cusp of where I want to be. Many hotter LPs and digital files sound fantastic. I can coax a bit more streaming a lower level file with Fidelia or my UAD interface.
Additional high sensitivity speaker recommendations in that $4k and under price range (used is fine) are greatly welcomed.
Here are a few brands of very good quality and reasonable pricing that I believe will work very well with your amplifier or an SET amplifier. The S,I.T.-3 is capable of world class sound quality if driving properly selected speakers.
1 Coherent Audio (Canadian) their "Prime" model range.
2 NSM Audio Model 100.USA.
3 Tekton "Perfect SET" speakers.USA.
4 Vaughn Loudspeakers. Various models. USA.
5 Decware Audio has numerous models. USA.
Depending on the type of music you listen, e.g., jazz, blues, folk, etc., I think you’ll find the Omega Super Alnico Monitors quite a good match with the SIT 3 or any other low power SET/SEP amplifier. The Magnepans basically present a constant 4ohm resistive load to the amplifier so load is not as much of an issue. You just need enough gain to make them sound loud enough depending on your room size.
Regardless of its output, putting a dedicated preamp in front of your power amp will not make the power amp output more power. It may well change, and likely improve, the overall sonic presentation, but your decibel levels won't change. I can't think of a planar speaker that will work with your SIT; but there are open baffle speakers that will (e.g. Spatial).
Excellent comments by the others, and I certainly agree that the pairing of the SIT-3 with the Maggies is not ideal from a power capability standpoint.
Regarding the original question, however, depending on what phono cartridge you are using, and assuming (as I suspect) that the gains of the Brooklyn Bridge are similar to those of the Brooklyn DAC (as measured by Stereophile), based on my calculations it appears that for many recordings on LP you may be falling several db short of being able to drive the SIT-3 to its 30 watt/4 ohm power capability, even with the volume control at max. (Although you certainly should be able to do that when using the Brooklyn Bridge as a DAC). Meaning that when playing many LPs you may not be able to drive the amp to output levels of more than say 10 or 15 watts, depending on the rated output of your particular cartridge. I could be more specific if you let us know the make and model of your cartridge.
In which case a simple and inexpensive solution may simply be to insert something like an Antique Sound Lab Line Two DT ($450) between the BB and the amp. I used its predecessor model (the Line One) for a while some years ago while my main preamp was down, with fine sonic results. And I see no technical incompatibilities that it would present with your equipment, in terms of impedances, gain, etc.
Good luck. Regards,
You can construct an excellent audio system with either speaker or an amplifier as the initial step or base. I’ve done it both ways and so have other experienced audiophiles/music lovers. My current system (10 years) is amplifier first in approach and has provided pure listening joy. The S.I.T.-3 is a superb foundation to build an audio system around. IMO the Magnepan.7 is a good audio product, the S.I.T.-3 is an exceptional audio product. I just feel that between the two this First Watt amplifier takes you further up the sonic /high quality sound chain.
Hi Jose ( @jg2077 ),
No, I don’t see a Speltz autoformer as being helpful in this situation. As you most likely realize it is mainly useful where it is desirable for an amp to be presented with a higher load impedance than the speaker would present by itself. But in this case, where maximizing the amp’s power capability is particularly important, the maximum power capability of the amp into an 8 ohm load is considerably less (18 watts) than its capability into the Maggie’s 4 ohm impedance (30 watts). Also, Maggies present a flatter and therefore more amplifier-friendly impedance curve than many and probably most other speakers having 4 ohm nominal impedances.
The thinking behind my earlier post was motivated by the OP’s statement that ...
I’m at the cusp of where I want to be. Many hotter LPs and digital files sound fantastic. I can coax a bit more streaming a lower level file with Fidelia or my UAD interface.
... coupled with my suspicion that depending on the particular cartridge he is using he may very well not be able to utilize a considerable fraction of the 30 watt capability of the amp when playing many LPs, even with the volume control at max. If so, inserting some additional gain in the signal path, such as with the simple one-tube line stage I cited, may result in performance that is satisfactory for his purposes.
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.
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.
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).
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.
I had to chime in... I agree with others that it's a poor speaker / amp mismatch. I have been using a pair of 40 w mono tube amps for a few years. I pair them with a few lower sensitivity speakers and they were good, but when I connected a pair of Heresy III up they were such a much better combo. Plenty of power on tap they are so efficient. I have had them 2 years and amp going to move up to a Forte or maybe larger in the future.
I heard a pair of the Forte III with the new Luxman 10 watt tube amp and it was scary lifelike. I had a "non audio" buddy with me and he was blown away at how life like it sounded.... don't sell that amp what ever you , it just needs the right speaker to be jaw dropping
You may have to try a few different speakers but it will be worth it
I also have the combination of a First Watt SIT-3 and Magnepan .7's. Like the OP I also made this choice largely on the basis of the Herb Reichert and Steve Guttenberg reviews. In my case I also have a similar sized listening room (10.5' X 12.5') to that of Herb Reichert, so I knew that I would not need as much power. In my space, the combo is absolutely wonderful at the listening levels I prefer. To the OP I would recommend checking out the Supratek line of preamps as possible high gain options. I have a latest generation Supratek Chardonnay and it is a wonderful combination with the SIT-3. Of course YMMV.
Your thread has generated many good responses and viable solutions for your dilemma.
1 keep the amplifier and speakers and add a high gain preamplifier.
2 Keep the Magnepans and acquire a more powerful amplifier for them.
3 Keep the S.I.T.-3 and acquire suitable higher sensitivity/efficiency speakers.
Which direction is more appealing to you as a long term choice?
+1 Charles. I would also like to know what phono cartridge is being used. With that information and the information that has already been provided a determination can be made as to approximately how much of the amp's power capability is not being utilized on many recordings, with the volume control set at max.
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?
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.
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.
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🙊
Great info. Quads have always been on the 'list.' There's a lengthy thread on the Hoffman forums about which amps make them 'sing' that I bookmarked yesterday but have yet to read. Does 'sand' refer to silicon and transistors, the graininess of solid state or something else?
I was a working musician until the coronavirus cleared my calendar. Fortunately, I'm also an essential worker. The Maggies don't reproduce the lowest octave(s), but in some sense, it is the truest representation of acoustic and electric bass I've heard. My audiophile friends tease me about being a bassist yet not getting the support from my system.
Greg- I was hoping to hear from someone with the .7s and SIT-3. Encouraging to know that you are liking that setup with a good preamp to match. Similar room, too!
Didn't see your latest post until I'd left a reply. Anyway I feel you made a good decision when all is factored in. There are truly excellent higher sensitivity dynamic speakers available (I listed a small sample a couple of days ago). I don't believe that you will miss the Magneplan speakers.
I also believe you'll love SET amplifiers if you decide to go that route. As with mglik I'm a devoted SET aficianodo.
One other suggestion.. The CAF 2019 “Best sound at Show” included the following components: MicroZOTL Z10 Integrated Amplifier, Spatial Audio M-3 Sapphire Speakers, Lampizator Amber 3 DAC. Given that you own Magnepan .7 speakers you must enjoy that very transparent, open airy sound. Your Mytek DAC is a good piece but you need to reassign the Mytek to just DAC duty. The 2 most open and airy preamps I’ve heard are the Dodd Audio Battery preamp (truly special) and any on the MicroZOTL preamps. The Dodd is not produced anymore but can purchased used for 1200 to 1500. The MicroZOTL’s are still being made and are sold by Linear Tube Audio. My guess that the aforementioned preamps paired with your Mytek DAC, Sit-3 AMP and a set of Spatial Audio M-3 Sapphires would make a truly magical system. If your a follower Terry London, you might run this combination of kit past him. Herb Reichert as also reviewed many of these pieces. Good luck in your synergistic search,
I’ve also had issues with the gain, using the Brooklyn as a preamp.
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.Back in the 1970s Radio Shack made a number of low power transistor amps, varying between 1 and 6 watts output depending on the model. You'd be surprised how much power than can actually be; Radio Shack did well with these amps and made sure they had plenty of fairly efficient speakers on hand to take advantage of that power. These little amps have an ardent following to this day; I own one myself and can vouch that they sound surprisingly good (when properly refurbished), and just like the Pass they have a predominate 2nd harmonic as part of their distortion signature.
So you need more efficient speakers. One of the reasons this amp doesn't have a lot of gain is its meant for speakers of greater efficiency where the gain simply isn't needed. There's been a lot of good advice here- get that amp on a speaker that has good efficiency and the results will be excellent. There isn't a reason why resolution has to take a back seat to efficiency either- so I wouldn't worry about that. To keep distortion down though and yet still make reasonable power, I'd be looking at an 8 ohm speaker rather than 4 ohms.
To keep distortion down though and yet still make reasonable power, I'd be looking at an 8 ohm speaker rather than 4 ohms.I wasn't aware that distortion could be a function of a speaker's impedance. Or, at least, I assumed a lower impedance speaker driven by a solid state amp wouldn't stress the amp as much as a higher impedance speaker playing at a similar SPL. Tube amps, I'm guessing, could be a different story?
What's the theory behind lower distortion from higher impedance loads?
@murphbass **All** amps make lower distortion into higher impedances. You can see this in their specs. You might think the difference to be 'negligible' but the distortion components involved are higher ordered harmonics. Since the ear uses these to calculate sound pressure, it is more sensitive to them than almost anything else, since the ear has about 120-130dB range! So that small increase is **huge** to the human ear.
The ear converts all forms of distortion into tonality. Higher orders are heard as brightness and harshness and are why solid state amps sound bright. But put them on a higher impedance and they sound smoother and more detailed both at the same time.
Tubes work better in this way into higher impedances too, as does class D. If **sound quality** is your goal, your amplifier investment dollar will be better served by a speaker of higher impedance that otherwise performs the same.
Thanks for your responses. It is nice to have my energy returned.
Subjective is the word. Since you like how the SIT-3/.7 recreates the lower frequencies and the planar sound, the ultimate solution is getting an Electrostatic Sound Solution rebuilt pair of Quad 57s. This may be the last speaker you ever buy. Especially since you already, lucky, own one of the best amp matches for the Quads there is and, probably, the best First Watt amp made. When I said "sand amp" I was referring to silica or silicon. However, the silicon-carbide-based JFETs in the SIT-3 may be the best application ever of a sand amp. This amp creates a midrange to die for with very little SS glare and a solid bass. And 57s create a midrange that is, to this day, the industry standard. Many, many speaker designers use them as a gauge to guide their developments.
Regarding your MoFi MM cartridge, it seems to be a very good one. I don't think the 3mv output is an issue. Industry standard loading for MM phono stages is 47ohms which is appropriate for almost all MM cartridges.
I raved about the Audible Illusions M3A/B. That stands. Though still a SET guy, I think a good SS amp and good tube preamp is a great combination. You already have a great, maybe even classic amp. Why not go for a great and classic preamp like the Audible Illusions M3A/B with an excellent SET phono stage?
As said, you fortunately own about the best SS amp ever designed. Cherish it.
If you want to have a second system or alternate speakers my only suggestion is to go with a little known Canadian company-Tetra Speakers. I own their $16K Phoenix TZs and their $1500 entry level 120Us. Tetra's designer, Adrian Butts, is very much like a great musical artist in his ability to capture the "rightness" in a speaker unlike any speaker brand I have ever experienced. This is clearly reflected in the many great musical artist using and endorsing his speakers. From Keith Richards to Herbie Hancock, they all make similar comments. When going to Tetraspeakers.com, the first image you see is Keith Richards who says: "They're not just ANY pair of speakers"! If I sound like I am selling Tetra speakers, I am. I want to turn all friends on to Adrian's work. I have been at this quest for the "right sound" since I was 18. And a professional in the Audio Industry for almost 40 years. I have never heard a speaker company who is able to consistently capture the essential soul of the music anywhere close to Tetras.
Adrian sells direct so, even though I put on my salesman hat, I make no money for my recommendation. Owning his entry level 120Us made me just one of the many musicians who own and adore Tetras regardless of the level. All Tetras have the house sound just increase in their output.
I do long for Quad 57s and am clear about my recommendation. But my Tetras make me not anxious to get another pair or Quads. As much as I love the Quads, I love my Tetras more. There is no other Audio Industry company of any kind who have this kind of amazing and terrific endorsements. The Tetra speaker website is one-of-a-kind and a convincing testament. Check it out. BTW-I use a SET 300B amp to run my Tetra Phoenix TZs. Not the last word in Rock but, like you, I am very happy with the match even though my First Watt M3 gives me more bass and a fuller sound, I adore the "magic" of the SET. All Tetras work well with 8 watts of 300B.