Monitor/Speaker Amplifiers

I bought my first PL300 in 1981 while stationed overseas in the USAF. Still have it 40 yrs later with one re condition last year. I have another I bought of E-Bay in excellent physical shape but sent it off too for recondition & up date. They both are 120WPC With .003THD. I have them bi-amp into a pair of Polk RtiA9 tower floor speakers. The music the amps push is clear live like. I like almost everything about them other they could use a external power switch. I have third one also that someone rode hard. I keep it on the shelf for parts as needed. I would recommend this amp for anyone wanting to get into High-Fi.

the a.r.t. sla1 in a nutshell is "thinnish, but incredibly articulate with exceptional separation between channels!" when pushing 90 db spl sensitivity drivers that meter out @ 6.7 ohms (not 8 like posted), the 100 watts rms per side easily created deafeningly loud audio, and the amp doesn't appear to break up before my ears tap out. the most noticeable improvement was in the stereo sound field both "widening" as well as an apparent "more accurate stage placement," meaning the instruments/voices sit in the pan stage where i put them on the dial, and LCR mixing just sounds terribly lacking now. my ONLY complaint about this amp is a VERY QUIET buzz that exists even when inputs are disconnected, and ground lift makes no difference. this buzz is consistently ~ -100 db @ 1 meter, regardless of front volume pot settings, and does not increase with current push. it is only noticeable in a quiet treated studio when there is NO other noise. the cat meowing drowns out the buzz.... despite the buzz and thinnishness, i still call this a 5 star amp, because it sounds better (read as more transparent with better staging) than power amps twice the price. i am so happy with this unit, that i will be BORROWING a bryston 4b pro off a friend to verify that the extra $800 (used in CDN funds) has enough merit to validate the upgrade. there is OCD, and then there is PRO-CD; below are my attempts to be pro-cd with backstory and testing: i bought the a.r.t. sla1 as a temporary amp until i can afford either a bryston 4b pro or the avantone cla-100. i have a small home recording studio with the following signal chain: win 7 pc (i have lots of legacy firewire hardware that is incompatible with win10) echo audiofire 12 sound interface (on par with rme fireface for d/a & a/d conversions) audient nero monitor controller (passes null tests down to about -105dbFS, INCREDIBLY transparent) a.r.t. sla1 power amp for monitor set 1 cla-10 mid-hi's (avantone's replica of the infamous yamaha ns-10's) running full range (passive crossovers) twin polk audio 10" powered subwoofers toggled to check subsonic frequencies. i have done quite a bit of room measurement and treatment using s.m.a.a.r.t. v7 and a rta-420 calibration mic. there is still work to be done, but i've got main reflection points, ceiling cloud, and rear deflection/diffusion handled fairly well with a mixture of roxul afb and fabric. in a nutshell, i've got my playback room to the point where the only real issues are a dominant bass node @ ~47 hz and a secondary @ ~70 hz - both of which go away with subwoofers off. for sake of comparison, i'll be comparing it to the denon avr-788 in "direct" mode (no eq or processing), the rotel ra-810A (flat eq), and the crown xls 602. i tried to find a frequency response chart of this unit but failed - just going by ear i would GUESS that there is a -1 or -2 dip between 80 & 250 hz, and then it would be above unity by a db or two from 1khz to 5khz, then the top seems a tiny bit diminished as well, but this is all speculative! as anyone who travels down the audio fidelity road knows, this is a game of diminishing returns, and the returns on high investments are NOT linear, they degrade logarithmically, so i can say with confidence that anyone who wants great fidelity will not be disappointed with this unit! below are the direct comparisons between various amps i own: when compared to the denon avr-788 (home theater amp), it was improvements in all fields (using pre-amp in's, bypassing denon's pre amp phase), but when using the denon with the on board pre amp (in direct mode) i found the denon to be a bit fuller in the low mid range. but very "flat" sounding compared to the improved staging and brighter upper midrange. when compared to the rotel, the "colouring" of the rotel has never been more apparent! to be fair, i was unable to bypass the pre-amp/eq stage on the rotel, so for this i compared apples to fruit trucks. the rotel dramatically "smooths" out the top end, boosts the lower mids, and has a bit less staging. this comparison really doesn't count because the two amps are engineered for totally different tasks - the art sla1 is meant to stay out of the way, whereas the rotel is very opinionated about how sound should sound. the rotel is more "pleasant" to listen to for it's "hifi" eq stance, but is TERRIBLE for critical audio work. the rotel sounds amazing with my b&w 601's as it "fixes" the deficiencies of that speaker, but the sla1 just makes the b&w's sound "boner tone." (the b&w 601 s2's ARE boner tone speakers, ie: deficient bass & mid bass, exaggerated top end.) finally the most fair comparison was between the sla1 and crowns xls 602: even though the sla1 is about 1/4 of the power output of the 602, both amps could reach deafening levels in my room. i incorrectly assumed that the larger headroom of the crest meant that it would sound better at high volumes. the opposite was true! the crown had quite a bit of staging issues, ESPECIALLY at higher volumes. the sla1 was WAY more linear in its staging throughout all volumes. at matched volumes (roughly) the sla had better stereo separation, and much "faster" response in the higher frequencies (quite noticeable in ride bells and hi hats). the crown DID fill in the lower mid bass area better but at higher volumes an apparent loudness curve in the crown really kicks in and the bottom end becomes "murky and saturated." the sla1, while i complained about the "thinnishness" earlier, definitely retained that characteristic through the different output volumes. in conclusion (if you made it this far), the a.r.t. sla1 was a temporary purchase that MAY just be my final amp, at the VERY least, it is a wildly overqualified unit for my 2nd monitor chain. what started out as a short term placeholder amp will now HAVE to be a/b tested against its more expensive cousins before i can justify the expense! i've attached a photo of my setup taken right before i bought the sla1.

I have a nad c-352 with wharfedale 9.5 speakers, a rotel cd player, everything linked with good cables, and I also have an old quad 33-303 in almost-new condition. While the nad sounds wonderfully for a built-in amp, when I add the quad to the system, the improvement is spectacular. The vocals with the quads have a much more realistic consistency, all mids are more clearly audible, the lows are deeper and more solid, instruments are more transparent. It's truly impressive to see an old unit with such qualities, even if the quads seem more powerful than the nad (2x45w vs 2x80w for the nad). You can feel the air moving in the room with the low end of the quad, something the nad can't achieve. That's why I can easily understand the popularity of these units even today!!!

I've had my Crown D75 for about seven or eight years. It came into my hands in an unlikely fashion and I have been using it in a variety of ways since I got it. It is a compact dual channel power amplifier, good for power monitors that may be unpowered, or for using it as an head for a bass or guitar cabinet. It has both XLR and 1/4 inch outputs to send to a cabinet or speakers and it also has connections for speaker wire. In the front of it there is a headphone jack and a power switch. It then has a volume knob for each channel with green and red LEDs to show output level and overloading. I have used this amplifier successfully in a few ways. Right now I am using it to power a pair of Yamaha NS-10M studio monitors and it works flawlessly for this. In the past I have used it as a bass and guitar head by plugging my instrument into it and sending the amp to a speaker cabinet. While I didn't get as much juice out of it in this application that I would have liked, it did the job. I used it for mostly bass guitar as this worked much better than guitar. However, this unit is probably really designed to power studio speakers, and works best in this application. The price won't make you dig too deep, and I'm not sure you can find too many of these around, but if you can find one and need a compact power amplifier for your monitors, I definitely recommend it! While not extremely versatile in its use by any means, what it does do, it does it well and has a pretty good amount of power for a single rack unit.

The right channel gave up on me after only one year. Luckily for me, the reseller replaced it for me even though I had no warranty anymore... It had expired some days earlier! But one year later the problems came back: Crackles and signal dropouts, both on the right and left channels. Very annoying for monitoring and listening. It seems to be a well-known issue of this product, which the resellers tend to keep to themselves... Despite its good audio quality, I advice you against it! I would certainly not buy it again. I would go for some active monitor speakers.

The D-45 is a 2 35 watt amp with 4 Ohms and another 2 25 watts at 8 ohms. You can purchase this amp now much cheaper than you could when it first came out which makes it a steal now and a must have. You can rack this amp up and it will only take up one rack space. It is very durable for the road in case you are a traveling musician. The D-45 has 2 channels and 2 XLR or TRS inputs but it has no DSP. That is the main difference between this model and the more expensive models from Crown (no DSP). This Class AB+B amp will provide you will all of the power you need to get a great sound out of your set up in no time. There is no set up process involved and it is very easy to use. When I was using this for my system I made sure that I had some very good cables to go along with it to give my sound the best possible sound that I could give it for an affordable price. This amp only cost around 700 dollars now and was a little more when it first came out. Crown makes some of the best amps and when they came out with this one I was very skeptical at first with it not having DSP. Crown drops this amp with a full coverage 3 year warranty in case something happens but I don’t think anything can happen to this amp because it is built like a tank. The 3 knobs that are on the front are very easy to turn and they are not the type that will break off it you put too much force on them. This amp could last you a long time. I have used many Crown amps and the D class amps they make are some of the best out.

The Bryston 4B SST Pro is a stereo power amplifier, and at that is one of the best of it's kind. I've used this power amp with a pair of passive ProAc Studio 100's at the studio where I work. These aren't our main monitors, rather we set them up occasionally as an extra choice for engineers, and the power amplifier that we always used in the Bryston 4B SST Pro. I don't know a whole lot about the background of this power amplifier, but everyone at the studio agrees that it's one of the best they've used before. Sometimes we'll also use these with our Yamaha NS-10m's, but for the most part they are used with the ProAcs. This is a pretty heavy piece of equipment, so we tend to keep it and one spot, as it does take up about three to four rack spaces if you wanted to keep it in a traditional rack casing. The 4B SST Pro has an array of different connections for you to choose from, starting with dual XLR-1/4" jacks, and followed up with RCA and traditional speaker cable jacks for hooking up your monitors. I'm not sure exactly how much power these deliver, but it should absolutely be enough (maybe even too much) for your passive monitors. These days most monitors out there won't require an external power amplifier since most of them have one built in, but there are still plenty of monitors out there that will require a power amp. Especially in a professional studio environment, it's extremely important to have a good amp to go with your passive monitors. With the Bryston 4B SST Pro, you're getting one of the best power amps available. The only downfall is the price, but as always you get what you pay for, and what you get here definitely lives up to the price if you can afford it!

The Bryston 2B LP is a stereo power amplifier that I have used in the recording studio to power up a set of passive monitors. This is a pretty powerful amp, but isn't overbearing - it's got 60 watts per channel at 8 ohms and will fit in a single space in a rack casing. I'm unsure what type of connections it has since it was already connected and ready to go in the professional studio where I used it, and there really wasn't any reason to get back there and switch connections or anything like that. It does have a ground lift switch on it, which I didn't need to use. The amp does seem to be built extremely well, and built to last as well. I think that as long as you don't bring it around too much and treat it right, that this is an power amp that could last a seriously long time. The speakers that I used the Bryston 2B LPs were a set of passive Tannoy monitors, and it did a perfect job of getting power to them. We didn't have the levels up the entire way, and didn't really want to find out what would happen if we did! The studio had them preset to the amount that they usually do and that they had experimented with, do I didn't see a reason to mess with that at all. Bryston has built up a pretty good reputation over the years, and if I'm not mistaken they have been around for a pretty good amount of time. I haven't used all that many other models made by Bryston, although I have used one or two. It's hard to say if this was the best one that I've used without trying them all out with the same monitors in the same room, etc. Either way, in the space that I did use the 2B LP, it was flawless in it's performance and didn't present any issues. While there are a lot of different stereo power amps to choose from, if you're looking for a mid level priced one that packs the sound of those more expensive than itself, the Bryston 2B LP is definitely something worth checking out.

The Crown D150A is a stereo solid state power amplifier. I have used it for powering passive studio monitors in the recording studio. Each channel delivers 75 watts of power, and like the name states, the whole unit gives 150 watts. It is quite basic in make up as it simply has two volume knobs on the front for each channel and has connections in the back. It has 1/4 inch connections and that is pretty much all that it has in terms of connections. It is a rack mountable piece of gear and will take up three rack spaces. As far as getting the job done, this amplifier will definitely power anything up to 150 watts that you would want to use it with, whether it be a guitar amp or a set of studio monitors. I would say that it is definitely best suited for use with speakers rather than a guitar amp, but it will work either way if you need it to. The unit is built well and is decently heavy, so it isn't anything that you would want to be moving around too often. Since it gives off a lot of power, it has a radiator system to keep it cool and for this reason it is heavy. The Crown D150A also has LED lights to show if your levels are clipping and has an on/off button with another LED as well. The price of the Crown D150A is usually reasonable, but will vary as you can only find these used since they are no longer being made. If you can find one of these it isn't something that you need to jump on, but will definitely get the job done well if you are looking for a reliable power amplifier that can get up to 150 watts.

The Samson Servo 200 is a power amplifier that will give you a great amount of power for your midsized speaker chain. You can use it for studio monitors too but for the best performance I suggest sticking with using it for your speaker chains in live events. There are 100 watts for each side of this amplifier at 4 ohms and 200 watts mono at 8 ohms (bridged). This amplifier is very clean and quiet and will make your speakers a lot louder and warmer than they naturally are. It has RCA inputs and ¼ inch inputs to connect to your speakers. You can rack this unit but it will take up two rack spaces. It has 3 LED meters to read your levels easily no matter where you are. We could even see the levels from across the stage. We have been using this amplifier for over a year now for some gigs and we love how much louder it gets our speakers. It is not for larger venues or speaker chains though. The more speakers you have means you will need to upgrade to a different device similar to this one. The most attractive thing about this amplifier is the price, it is very affordable and it does a great job for the price that it cost. I have used many models of speaker amplifiers but none of them at this price. I was very skeptical purchasing this unit because I did not think that it could possibly be that good for as little as it cost but boy was I wrong. This unit delivers a great amount of power for your sound. I would purchase this again if needed. The only thing that I would change about it would be to make it one rack space because it does not seem to need to racks. They could have made it smaller and still had the same amount of power.

I bought the P120 mostly because I needed an 88-key weighted keyboard with great portability and cost-efficient quality. I bought it at Guitar Center for $1099, excluding accessories. The P120 is very light and easy to move, which is a plus for any keyboardist who travels frequently for gigs. Also, the majority of the sound samples are great for the amount of money that the keyboard costs. The grand piano patch sounds great in the lower register, and the e. pianos and clavichords sound fairly good as well. The touch of the keys is also very good, if you're used to playing on weighted models. Playing high notes can sometimes be a pain, especially if the sound feeds through an amp. Be sure to turn the mid high and high ranges on your amp lower if you do decide to go that route. Also, the church organ and strings sounds are pretty cheesy by themselves. The guitar sound isn't much better. The user song mode is limited (two tracks) and you can only do three. This is definitely not a model to get if production and beats are the focus; the P120 is strictly a performance tool. The body design is fairly modern, especially the silver model. Seems to be pretty durable, although i haven't had it for very long. All the connections are on the side of the keyboard as opposed to the usual location in the back. Comes with a clear, stylish stand that looks very good. Overall, the P120 is a good instrument for the performing keyboardist who doesn't like a whole lot of bells and whistles that add weight and confusion to the instrument. The P120's purpose is simple: to create a great playing interface that enables the player to jam to his or her heart's content. Its light weight makes it very portable, and you should be good to go with a stand and amplifier setup. This review was originally published on http://www.musicgearreview.com

The Adcom GFA-5800 is a stereo power amplifier for your passive monitors. I don't own this but I've used it at a studio with a set of Tannoy 8's I believe. The amp seems to do a great job of powering these monitors, and the owner of the studio mentioned that it's the best amplifier he has heard from the monitors, which is something that can make a big difference. You connect your monitors via speaker cable and can plug your sound source in via an unbalanced RCA connection or a balanced XLR input. It's a pretty big power amplifier and shouldn't be in a spot where you're going to need to move it often. It is rack mountable but will take up something like six spaces it seems as it's really gurthy. I'd recommend just keeping it on the floor behind your desk so it's out of site but still doing it's job. It's not like you're going to have to change any settings on it - just keep it plugged in and let it do it's job. I believe that this is the first power amplifier that I've used from Adcom, so I can't compare it to any other power amps from them, but it seems like the GFA-5800 is a solid power amp for passive monitors in the studio. Again, it depends on the monitors for sure, but I know from experience that Tannoy 8 monitors sound great with this. He had a different power amp in there before if I wasn't mistaken and it seems like the Adcom definitely sounded better. I have no clue what this will go for or how hard it might be to find. In general when it comes to power amplifiers, you're probably not going to want to spend the effort to seek one out specifically, but if you come across one of these used, it's probably worth a second look if you need a power amp.