SMSL PA400 GaN 500W

[jmc06]

I'm currently very confused about which impedance setting to use on the PA400 when driving the Linton 85th (rated at 6 ohms, 4.5-meter listening distance). The PA400 only has two impedance settings (4 ohms and 8 ohms), and when I asked the manufacturer, they didn't provide a clear answer.

 

[NTK]

I'm currently very confused about which impedance setting to use on the PA400 when driving the Linton 85th (rated at 6 ohms, 4.5-meter listening distance). The PA400 only has two impedance settings (4 ohms and 8 ohms), and when I asked the manufacturer, they didn't provide a clear answer.

With impedance dropping below 6 Ω between 80 - 300 Hz, if it were me, I'd run the amp in the 4 Ω mode.

Source: https://www.erinsaudiocorner.com/loudspeakers/wharfedale_linton_85/

 

[jmc06]

With impedance dropping below 6 Ω between 80 - 300 Hz, if it were me, I'd run the amp in the 4 Ω mode.

Source: https://www.erinsaudiocorner.com/loudspeakers/wharfedale_linton_85/

Thank you for your reply, but if I switch to the 4-ohm setting, wouldn't it be pretty much the same as the V3 Mono? From what I see, the main difference between the PA400 and V3 Mono lies in their 8-ohm power output. The PA400 delivers 200W into 8 ohms, while the V3 Mono outputs 120W into 8 ohms. At 4 ohms, the FOSI V3 Mono and PA400 are essentially identical. If using the 4-ohm setting, does that essentially negate the PA400's advantage?

 

[NTK]

The PA400 4 Ω output power is only rated to 250 W. If you look at output currents, 250 W @ 4 Ω is 7.9 A, 200 W @ 8 Ω is 5 A, and for the bridged mode, 500 W @ 8 Ω is 7.9 A. I think it is pretty evident that the max rated output current of the PA400 is roughly 7.9 A, which limits its output into low impedance loads.

 

[EJ3]

GAN is getting a lot more interesting if it's becoming economically competitive. ...Amplifiers are already "good enough" so if newer technology can give us more wattage per dollar, that's great.

There are already amps rated for more power than you can get from a regular power outlet...

The (small) 1968 or 70 (or so) home that I bought has ALL 20 amp power outlets throughout the home & had only a 100 amp service box. I changed to a 160 amp service box & split up some of the overhead lighting (which was wired in such a manner [clustered together in the attic, with one lead from there going to the breaker box]) and retained the all 20 amp outlet feature of the home.
In the living room there happens to be 2 twenty amp outlets within 8 feet of each other on one wall that are NOT on the same circuit.
Care to guess which wall is the back wall that my Tri-Amped over 1000 watt RMS a channel (4 Ohm) 2.2 stereo system is along?

I do wonder if they had a kiddie pool in the living room & were using timed grow lights on a track to do hyroponig gardening of some sort back in the day?

 

[EJ3]

Thank you for your reply, but if I switch to the 4-ohm setting, wouldn't it be pretty much the same as the V3 Mono? From what I see, the main difference between the PA400 and V3 Mono lies in their 8-ohm power output. The PA400 delivers 200W into 8 ohms, while the V3 Mono outputs 120W into 8 ohms. At 4 ohms, the FOSI V3 Mono and PA400 are essentially identical. If using the 4-ohm setting, does that essentially negate the PA400's advantage?

1. No harm will be caused by using either output ohm switch selection (unless you plan on using the volume control set to max [but then, it is very highly likely that the issues that occur will NOT be related to the ohm switch settings);
2. Changing the ohm switch selector does NOT change the total power available, but the 8-Ohm selection will increase the amp's Voltage gain and will require a slightly lower volume-control setting for the same output level;
3. Something not usually mentioneded is that changing from 4-ohm to 8 ohm (or the other way around) changes the way the amp damps the speaker's back-EMF and hence bass performance.
The 4-Ohm setting will damp more--that is, the amp has a higher damping factor--and the bass will sound tighter, less 'bloomy', while the higher setting will damp less and allow the bass to sound 'fuller'.

Try the other setting for more than a few minutes; you may prefer the sounds.

18HURTS (from the AVS forum) makes the TRUE (but lengthy) explanation perfectly clear here (proving whether one needs or does not need further edification on the subject [warning: like many things, it's a bit complicated]):
18Hurts
4,983 posts · Joined 2015

#4 · Jul 18, 2022
A bit of clarity, lower impedance does not make it "louder"

Watts are volts X amps and the lower impedance something is, it draws more amps. For example, an 8 ohm speaker at 2.83volts is one watt while a 4 ohm speaker at 2.83V is 2 watts, a 2 ohm speaker at 2.83V is 4 watts a 1 ohm load at 2.83V is 8 watts etc. Well, at the ultimate basic it is but speakers are not pure resistors so their impecance varies depending on frequency. If you look at the impedance sweep of a speaker, say 8 ohms you'll notice the impedance varies from around 6 ohms minimum (if it is correctly rated) to a high of 30, 40 or higher ohms at certain points. Typicallly, impedances rises with frequency with impedances over 10 ohms being common over 10KHz.

Clear as mud? Hey...you asked!

Impedance has nothing to do with speaker efficiency, how many dB you get with a specific unit of power applied (commoly 1 watt) You can get an Elac coax bookshelf speaker at 4 ohms that outputs 82dB at one watt or a JTR 212HTR that was tested to put out 105dB at one watt/one meter. You'd have to punch out 23dB of gain with amplifiers into the Elac to make it even with the JTR. 200 watts gives you that gain so crank it up that high to get even with the JTR at one watt... Yeah, the Elac requires 200 times the power to give you the same output as the JTR!

Of course, you put 200 watts into an Elac bookshelf speaker for any length of time you'll smoke the voice coils and kill the poor thing--of course. You can't get a barrel of SPL out of a shot glass after all. This is why you can't take any random speaker and just keep throwing power at it until you get there. Eventually, things overheat, cones move too far and the soft bits hit the hard bits and the air pump fails.

Your confusion stems from percieved loudness with the same amplifier. I call it the "Best Buy trick" Amble on down to the big box store, look at a pile of speakers and you have a switch box. Say you have the exact same speaker but one of them is 4 ohms while the other is 8 ohms. The 4 ohm speaker will be "louder" because it is pulling more power from the same amp at the same signal level. Manufacturers know this, louder is better so 4 ohm speakers are "louder" but not more efficient but they will sell better if you don't understand. Another stunt is to increase bass response, have it go lower. The issue with that is a small box will limit the efficiency of that bass response. OK, make it the same size as your 8 ohm competition but run it at 4 ohms to gain 3dB of output then throw away that 3dB of output gain by using a less efficient woofer in the same space but it extends deeper! You can either get "louder" or "deeper" for a box the same size and it will do that at Best Buy with the switch box. For the win!

Think about it, most retail audio equipment is purchased that way--no secret there. A lot of more basic recievers, the big sellers won't deal with 4 ohm loads for long because it is pulling twice the amps from the power supply, generates a ton of heat and is less electrically efficient and creates more amp distortion than 8 ohms. Well, if you drop it to 6 ohms you'll get almost 2dB "more" SPL and it won't kill the loss leader Black Friday recievers...for the win!

Tin foil hat off... I can't blame the big box companies from doing this, the customers don't know, understand and really don't care so rock on! Realsitically, if a speaker company actually cared, they would point this out by giving accurate ratings for sensitivity (2.83V, 2.00V, 1.41V) and say they go with 2.83V they should also give it as an efficiency rating at one watt. The Elac would be rated 85dB @ 2.83V and 82dB one watt/one meter if they wanted to be accurate. Rots O Ruck finding that level of accuracy in audio... Heck, this is over the head of most "reviewers" not to point out what the actual efficiency is to keep an even playing field. Yeah, it is up to YOU to understand this--welcome to audio, keep em in the dark and feed them BS...the mushroom effect.

So if you actually care and really want to know. Look up what speakers specs actually mean and learn the difference between sensitivity and efficiency and how it is effected by impedance. I can purchase 2 ohm sub drivers and 16 ohm pro sound compression drivers and mix them together. Although they both can be rated the same in sensitivity, the sub driver is being driiven 8 times harder than the high impedance compression driver so the sensitivity rating might be the same but the efficiency rating is 9dB different. Make sense?

In summation, if you want it "louder" at the same power level, that is called efficiency--not sensitivity. Sensitivity makes sense because that is what you get when connected to an amplifier in the real world. This is why you can mix 4 ohm woofers with 16 ohm compression drivers, the 4 ohm sucks up 4 times the power but that is a good thing--makes it "louder" while the high impedance compression driver is being driven less so it won't overwhelm the woofer. This is day one of speaker building 101, use impedance to get more even response. My line arrays I built in the garage have 6 ohm woofers impedance, 13 ohm mids and 7 ohm tweeters (dozens of drivers wired that way) The difference between the mids and woofers is over 3dB as I used impedance to "turn down" the mids and boost the bass. I rate those speakers as 6 ohms although most of their output is well over 8 ohms. This is how speakers are designed.

For a person just getting into this, you should learn the difference between sensitivity and efficiency and why each spec is important. Speaker impedance and how low it dips is very important when connecting amplifiers to drive them. 8 ohm speakers that don't drop below 6 ohms can be driven by anything but a 6 ohm speaker that dips to 3 ohms or lower requires high current amplification. Waaaay back in the day, had an older friend that owned Infinity Kappa 9 speakers that were rated "4 ohms". He had a Marantz integrated amp that was rated for a 4 ohm load so it should be fine--right? Wrong! The Infinity Kappa 0 dipped below 1 ohm and the Marantz overheated and shut down within minutes! He had to purchase a monster amp that weighed almost 90 pounds to handle the 1 ohm dip and he was really pissed! They called the Kappa 9 "amp killer" for that reason. A horrifically and poorly designed speaker if there ever was one. Infinity went broke, Harmon bought them out and attempted to fix the bad design and eventually gave up. I really liked the sound of those speakers though, that poor amp would get HOT when cranked up in rock star mode so I can see why they dumped the design eventually. Most people don't want to pony up the bucks for a 1 ohm atable amp--I get it.

Hope that helped more than it hurt--my advice is to look up a text book style source that fully explains all speaker and amp specifications, what they mean and how they apply to what you desire. You can't just jump on a spec or two and go by various ramblings of forums--you need to get the specifications down, fully understand what they mean and then narrow down your choices with and educated and critical eye. You don't want to get "Kappa'd" :

So relax, get some text book education under your belt and go. Putting up a poll of two completely different speakers won't help you--you will get an answer but what good is the wrong answer when you don't know how to ask the question? Too many variables, the math won't work so time to get rid of those variables. Welcome to such a crazy hobby, things get complicated when mixing electronics, air pumps and how energy works together--such is life. Enjoy!

 

[EJ3]

I'm currently very confused about which impedance setting to use on the PA400 when driving the Linton 85th (rated at 6 ohms, 4.5-meter listening distance). The PA400 only has two impedance settings (4 ohms and 8 ohms), and when I asked the manufacturer, they didn't provide a clear answer.

Personally, I run mosty 4 OHM no matter what (I have no speakers whose rating says that they are higher tha 8 ohm & all of my amps can handle 2 ohm [and, if you check, solid state amps that can handle 2 or even 1 ohm, do NOT have a special selector for 2 or 1 ohm {that, there is a clue}]), no problem.

 

[Roland68]

I purchased two PA400s to replace my FOSI V3 mono amplifiers, driving my Linton 85th in the living room (listening distance 4.5m) and the Klipsch RP600 Mii in the bedroom (listening distance 2.5m).
They'll arrive this afternoon, and I hope for a favorable outcome. I appreciate their aesthetic design, and I have greater confidence in SMSL's circuitry. I consider SMSL a superior brand compared to Fosi and Topping, as they don't blindly pursue static specifications. (Although early SMSL products, like Topping, did obsessively chase extreme static metrics—a tendency that made me overlook the brand. Fortunately, SMSL seems to have moved away from that approach. Naturally, in this forum environment, such a shift wouldn't earn them favorable reviews.)

May I ask where this view of SMSL comes from?
SMSL is a brand that, with relatively little innovation, builds devices based primarily on chip manufacturers' evaluation boards and designs and then optimizes them based on measured values. This is especially true for the newer GaN amplifiers.
But your view clearly shows that SMSL has good marketing.

 

[sharkinswamp]

Hi, as far as I understand, it’s better not to use the PA400 in mono mode with 4 Ohm speakers? I’m also wondering if one PA400 would be enough for ELAC Vela 408.2 speakers, or would I really need two of them?

 

[Roland68]

Hi, as far as I understand, it’s better not to use the PA400 in mono mode with 4 Ohm speakers? I’m also wondering if one PA400 would be enough for ELAC Vela 408.2 speakers, or would I really need two of them?

One should be perfectly sufficient. If you need two, you probably have speakers that are too small, or you need a subwoofer.

 

[Evo42]

For any one who wants to give one a try it's on sale with additional coupons around 400usd pre taxes on AliExpress at the moment.

 

[mocenigo]

I purchased two PA400s to replace my FOSI V3 mono amplifiers, driving my Linton 85th in the living room (listening distance 4.5m) and the Klipsch RP600 Mii in the bedroom (listening distance 2.5m).
They'll arrive this afternoon, and I hope for a favorable outcome. I appreciate their aesthetic design, and I have greater confidence in SMSL's circuitry. I consider SMSL a superior brand compared to Fosi and Topping, as they don't blindly pursue static specifications. (Although early SMSL products, like Topping, did obsessively chase extreme static metrics—a tendency that made me overlook the brand. Fortunately, SMSL seems to have moved away from that approach. Naturally, in this forum environment, such a shift wouldn't earn them favorable reviews.)

What do you mean by "blindly pursue static specifications"?

 

[mocenigo]

GAN is getting a lot more interesting if it's becoming economically competitive. ...Amplifiers are already "good enough" so if newer technology can give us more wattage per dollar, that's great.

True, but the higher efficiency, together with the increased noise, is the reason GaN is ideal for the power supplies, not the amplification circuit proper.

And it SEEMS like there may be potential for more total wattage for pro applications. But maybe not... There are already amps rated for more power than you can get from a regular power outlet...

Yes, I see GaN good for pro applications — and for this use case also in the amplification circuit.

Just for fun, I went on the Mouser website (Electronic component distributor). There are some GAN Fets that cost more than $1000 each, and even some MOSFETs that cost more than $1000 each!!! (There are also some GANs for a couple of dollars and I don't have a feel for what kind of specs you need for a class-D amp.)

I am curious to see which ones, and for which applications they are intended.

 

[sharkinswamp]

One should be perfectly sufficient. If you need two, you probably have speakers that are too small, or you need a subwoofer.

Right now I have one already, but I ordered a second one just as an experiment, because it surprised me so much that I even sold my AB class Musical Fidelity M6si, which was my “friend” for about 2 years. As I understand, mono mode isn’t really suitable, because mono only supports 8 ohm loads, and that can even be harmful for the amplifier itself. But I still want to try bi-amping, or mono but not in bridged mode.

 

[F1Fan72]

Still no idea why SMSL do not put 12v triggers in their products..

 

[Loba]

Right now I have one already, but I ordered a second one just as an experiment, because it surprised me so much that I even sold my AB class Musical Fidelity M6si, which was my “friend” for about 2 years. As I understand, mono mode isn’t really suitable, because mono only supports 8 ohm loads, and that can even be harmful for the amplifier itself. But I still want to try bi-amping, or mono but not in bridged mode.

If in mono bridged mode, what happens if load drops to say 6.3 ohms?

 

[LumiAudioNut]

If in mono bridged mode, what happens if load drops to say 6.3 ohms?

I’m currently running a pair of SMSL PA-X’s (virtual clones of the PA400) in mono mode powering a pair of very inefficient 4 ohm Magnepan 2.7I’s. They’ve been operating fine for a few months now. I also have tried them with a pair of 4 ohm (3.2 ohm minimum) R3 metas on several occasions with no issue. Also, I’ve been using a pair of SMSL PA200’s to power some Kef L50 metas for months (also with no issue).

 

[Loba]

I’m currently running a pair of SMSL PA-X’s (virtual clones of the PA400) in mono mode powering a pair of very inefficient 4 ohm Magnepan 2.7I’s. They’ve been operating fine for a few months now. I also have tried them with a pair of 4 ohm (3.2 ohm minimum) R3 metas on several occasions with no issue. Also, I’ve been using a pair of SMSL PA200’s to power some Kef L50 metas for months (also with no issue).

I am running a pair of PA200 to power B&W DM3000 which is known to dip to 6.3ohms. wondering if to upgrade to a pair of PA400 for more headroom on bass when I blast music in my living room which is about 35m2.

 

[LumiAudioNut]

I am running a pair of PA200 to power B&W DM3000 which is known to dip to 6.3ohms. wondering if to upgrade to a pair of PA400 for more headroom on bass when I blast music in my living room which is about 35m2.

I feel like my dual mono PA-X’s (similar to PA400) have a lot more headroom than my dual PA200’s. But these are sighed tests….

 

[Serg-hi-res-83]

посмотрев на официальном сайте сравнение обеих моделей закрадывается подозрение что это одни и те же усилители просто более старая модель имеет ниже напряжение питания усилительной части. взаимопроникновение каналов 75дб это позорно для техники такого уровня в обеих моделях.