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Client Feedback

ATI AT6007 Review

I am really enjoying my new ATI AT6007. This amplifier is top notch and I've had many amplifiers over the years. The highs and lows are crystal clear, no matter what speakers I use. I have easy to drive JTR 212HTR speakers but this amplifier delivers better overall dynamics, clarity and authority than my previous amps. I may need to order another ATI amplifier for the rest of my system. I've connected this amplifier to various loudspeakers such as Martin Logan, Bowers & Wilkins, Klipsch, Polk, DIY and BIC America speakers. The amplifier found the limits on most of them. The output power, headroom and volume was insane...I had to leave the room as the amp could go so loud and it wasn't even breaking a sweat!

Ralph was great and patient with me throughout the consulting and ordering process. I had a great experience but was hesitant on spending so much for an amplifier, but as the saying goes..."you get what you pay for". Ralph answered my questions and kept in touch even after I purchased the amp. This is a high quality amplifier and great customer service from Ralph at InterActive Home Systems. I am super grateful.

Thanks Ralph.

Alphonzo H.
Accokeek, MD

ATI AT4002 Review

We just upgraded our stereo system’s amp to ATI's AT4002 from a temporary Monoprice Monolith amplifier (200W/ch) fill in, and before that, we were using a Plinius 8200 MKII integrated amp (175W/ch) which in turn replaced an earlier Classe CAP 80. The upgrade to the AT4002 was transformative. Our listening system includes an Oppo 205 used as a preamp and processor,(Apple TV for Tidal Master), XLR cables to the ATI amp and the speakers are Polk LSIMs 707s (replacing for the time being a pair of Vandersteens 2Ce signatures moved to exercise room duty). The majority of listening is CD, and then SACD and some DVD-Audio, followed by Tidal master streaming (of lesser quality). In comparison to the Monolith, the AT4002 is significantly fuller and wider sounding, and the lows are much tighter and well defined.The AT4002 is really in a different class altogether, and is an extremely quiet unit. In the AT’s comparison to the Plinius, the Plinius is very good except for having less power and a very subdued/recessed lower end. Where I used to think the Monoliths were a very good value price point, the AT4000 series is now my performance value standard, especially for music listening.

In researching amplifiers, I targeted ATI for their performance value and warranty/build quality. I was unsure of where to purchase the amp, and whether I should consider ATI’s well reviewed AT522NC class D vs the A/B class AT4002. In reviewing online discussions, I noticed that certain contributors spoke highly of the ATI dealer in Nashua, NH (Ralph Keyslay - Interactive Home Systems). I contacted Ralph, and was immediately impressed with the large number of questions he asked of me regarding my use and other equipment before he would let me order a product. Ralph wanted to ensure that what I thought I wanted, would be a good fit for my use. He also had personal experience using both of ATI’s class D and the AT4000 series amps, knew the products very well, and was able to provide specifics as to what he heard as to the differences between the two. It was very easy purchasing the amplifier through Interactive, with excellent service and follow up. ATI was very fast in the shipping of the system, and in processing the warranty registration.

Peter W.
East Grand Rapids, MI

Thank you so much for being so helpful and pleasant throughout the purchase process of my ATI AT528NC amplifier with the rack mount kit. It has really been a pleasure working with you and I could not have chosen a better dealer to acquire this equipment from. I will make sure I refer any future purchasers to you - I doubt they could have a better experience anywhere else.

Krishnamurthy N.
New York, NY

ATI AT4005 Review

First, I want to express my sincere thanks to Ralph Keyslay, the owner of InterActive Home Systems. I initially had a great phone conversation with Ralph earlier this year regarding my desire to possibly purchase either an ATI AT4005 or AT525NC amplifier. Ralph took considerable time to inquire about my music/movie balance, my music tastes, my current equipment, my listening space and what improvements I wanted to achieve by upgrading to the ATI amplifier. After our phone conversation, Ralph answered a variety of additional questions via email. Later in the year, I decided to purchase the AT4005. I never considered another authorized dealer. Ralph essentially offered a concierge buying experience; from my first inquiry through my first experience listening to my new amplifier. He provided knowledgeable advice, free from any sales pressure, with my purchase satisfaction as his only goal. I highly recommend buying from Ralph. If I ever need another ATI amplifier, I will only buy from InterActive Home Systems.

In my opinion, amplifier listening experiences are hard to describe. My ATI AT4005 replaced a pretty good amplifier (Outlaw Model 5000). The best way I can describe my listening experience with my AT4005 is that this amplifier invites louder volumes, with absolute clarity. The dynamics are amazing not only in the peaks, but in the silences where the stellar S/N ratio shines. I first stress tested the new amplifier by playing a variety of Blu-Ray concert discs for 24 hours straight, so that all 5 channels could get a good workout. I usually was listening to these concert videos at higher than normal volumes (80dB – 85dB) in my modest-sized living room, the music was not fatiguing and the amplifier barely got warm. I find the sound quality in movies, TV, and music to be great as well. TV/movie dialogue is clear at all listening levels, regardless of the background sounds, allowing me to enjoy simple TV viewing at lower volumes. I comfortably listen to Tidal HD music (jazz, rock and blues) for many hours most days, enjoying the full depth and resolution that HD audio provides. This ATI amplifier is built like a tank, but with a very clean design. It has a lot of power, but it does not have to be played at high volumes to provide crisp, clear sound. I cannot imagine a listening situation that would cause clipping, before hearing damage occurred.

After 3 weeks of intense listening, the ATI AT4005 amplifier is a winner for me!

Robert F.
Orlando, FL

I can’t decide what I enjoyed more during my recent purchase of the ATI AT524NC amplifier. I was pleasantly surprised by the concern and honesty shown by Ralph that I get the product that I needed at a price that was fair. I was stunned how much the AT524NC has raised the bar in my home theater. But I do know that both of these have enriched my life and will return to Ralph at InterActive Home Systems to continue the relationship and future ATI purchases.

Jerry B.
San Clemente, CA

Hi Ralph - wanted to give you an update on the ATI amplifier we ordered from you, now that I’m back home. The amp was supposed to arrive on Monday March 25th, but it actually arrived on Friday the 22nd. That was fast and terrific! I got to help my brother James connect the unit and enjoy it before I left. The amplifier arrived in good shape. James is really pleased with his new AT525NC and has been really enjoying it!

We want to thank you for all your kind help discussing the technical aspects of the amplifier and guiding us through the purchasing process. It’s wonderful to connect with such knowledgeable, friendly folks like yourself that are patient and willing to take time to help their customer. Take care and thanks again.

James M. and Lynne H.
Rochester, NY

This is my second ATI amplifier that I've purchased through Ralph at InterActive Home Systems. He was helpful and attentive throughout both pleasant transactions and provided competitive pricing. I am very happy with my recent ATI AT4002 amp purchase and I believe this will be my end game amplifier. Thanks Ralph!

Steve B.
Boulder, CO

I’m writing to thank you Ralph for all your expert help during my ATI amp purchase. Your commitment to customer satisfaction is so impressive, in fact the best I’ve ever seen. It gave me complete confidence in ordering from you. I also appreciated your experience with ATI, your product knowledge as an electrical engineer and all your thoughtful follow-ups at every step. I’d be happy to recommend you with enthusiasm to anyone who’s interested in ATI products.

Tom J.
Menlo Park, CA

I would give Ralph my highest recommendation. He had the AT524NC amp in stock and got it shipped immediately after I made the purchase. Very fast and responsive service. Great price and he knows the ATI product line very well as ATI amps are the only products he promotes. Ralph answered all of my questions. ATI makes excellent amps. If you are looking to buy an ATI amplifier, Ralph at InterActive Home Systems is the man to get it from!

Jeff N.
Apex, NC

I did a lot of research before deciding to purchase an ATI AT6005 amplifier but I did not know where to buy it from. I spoke to several dealers before I found InterActive Home Systems during my search. I decided to give Ralph a call and I am so glad I did. He stood out from all the others I spoke with. The price he quoted was excellent and he took the time to answer all my questions. When the call ended, a short time later Ralph called me back to answer additional questions that were the type when initially asked I really didn't expect an answer for.

Having never done business with Ralph in the past and not familiar with his company, I was naturally concerned about sending a large sum of money on blind faith. After placing the order I was surprised to get the amp 4 days later. It was packaged very well. The initial invoicing was very quick, detailed and extremely professional. Ralph continued to follow up with me to address all my post purchase questions. He responds very quickly, by both telephone and email.

The purchase process exceeded my expectations. The ATI amplifier seems very well built and I am looking forward to many years of enjoyment with this powerful amplifier. I highly recommend Ralph at InterActive Home Systems.

Randall H.
Salt Lake City, UT

Recently I started researching power amps and found out about ATI and Ralph at InterActive Home Systems.

The offer to call you personally was irresistible. You where very generous with your time and based on your knowledgeable experience, I focused my research and subsequently went with your recommendation.

I received the ATI AT4003 amp much sooner then expected...thank you.

I connected the AT4003 between the Conrad Johnson ET3se and the Magico S1. Not expecting too much since the amp was cold and brand new, I turned the unit on and was speechless. Wow I did not know it could be this much better!

After a week of listening, I am even more happy. When I close my eyes, the speakers disappear and the sound stage opens up. The kick drum is tight, the violins sound full bodied and sweet, the bass is rich and also full bodied, the high notes do not sound shrill and you do not want to stop listening. It sounds real, not analytical.

My wife usually does not sit and listen with me, however, this time she did without saying a thing...she just enjoyed the music. I use the stereo system for home theater as well. We saw La La Land for the nth time and as long as the DVD player is set to stereo the voices where clear and easy to understand and you could not stop tapping your feet to the incredible sound track (a huge improvement over the Proceed amp). As you can tell, I am very happy with this amplifier and do not feel like I’m missing out on not having the D’Agostinos!

As I’m writing this, I’m listening to Tchaikovsky's The Nutcracker in a whole new dimension.

Ralph, thank you again for your great recommendation and service.

Roland R.
Santa Fe, NM

I called Ralph at InterActive Home Systems requesting help with amplification for my new theater room. He was attentive and listened to all my questions and patiently walked me through many options. In the end, I decided to roll the dice with two ATI amplifiers, sight unseen and have never heard them before. This was a tough decision and Ralph made it much easier. Based on our discussion, I also decided to go with a Marantz 8805 for the preamp and an ATI AT4007 amplifier for my Focal 1038 Be fronts and Focal CC 1008Be for center and four Focal Be for in-wall surrounds.

I also purchased an ATI AT528NC for the four Focal Dolby Atmos ceiling speakers and four outdoor speakers that I use on my patio and deck. I am very pleased with both my ATI amplifiers. The AT4007 is a beast. It has awesome imaging, clarity, no noise, power and dynamics that seem to go on forever. The build quality is also solid. The ATI AT528NC NCore amplifier does exactly what I need it to do.

In summary, both amps are awesome, but the real surprise in this business deal was Ralph Keyslay. His knowledge, friendliness, professionalism and desire to talk amplifiers, speakers and all things listening to music and watching movies related was a joy. He has good insight as to room set up, is not pushy and actually listens to my needs and made value recommendations. He is also aware of how a 'good deal' truly works and his customer service skills are impeccable!

I highly recommend Ralph and ATI amplifiers after many hours of listening enjoyment.

Brian D.
Spartanburg, SC

After doing some research online for a new amplifier, I had a few questions. I was looking for an amp to replace my existing class A/B amp. I had been a little hesitant about the new class D amps but was glad that I made the decision to move forward. Working with Ralph at InterActive Home Systems was great and he provided some excellent feedback. After doing some more homework, I ended up purchasing the AT527NC. This is a solid unit and is built with quality. The sound is amazing and it's super quiet, no distortion and plenty of power. It also runs a lot cooler than my previous amp. I can't wait for my next ATI amp purchase!

Chris R.
Charleston, SC

I am really happy with my ATI AT543NC 3 channel amplifier. I have all the power I need to drive my B&W 600 series speakers to insane levels. Doing business with Ralph was a pleasure. His product knowledge and patience allowed me to select the perfect amplifier for my home theater system. His prices were really good and I highly recommend purchasing ATI products from Ralph at Interactive Home Systems.

George W.
Port St Lucie, FL

I've had my two new ATI NC amps working in my system for about a week now and am very pleased. The AT543NC (500 watts/channel x3) is running my Triad Silver LCRs and the AT528NC (200 watts/channel x8) is covering Triad Silver surround and Atmos channels. I have headroom to spare and more. I have some HDMI handshake (DTV/Marantz/PJ related) and Control4 bugs I need to work through that are distracting me from running multiple DSP measurements, tweaking and truly critically listening, but I like what I hear so far with minimal room correction layered.

I will add that working with Ralph at Interactive Home Systems on the purchase of these new amps could not have been any easier. He’s very knowledgeable on the ATI products and asked me thoughtful questions about my room, my objectives and my other gear in the system to make good recommendations and ultimately help me to make the right purchase decision. Price was very good, and his communication after the deal, while having the amps built/shipped to me was great! 5-star experience! Thanks Ralph.

Greg F.
Conroe, TX

So far, I am very impressed with the ATI AT543NC amplifier. I use this amp to power my B&W 802D and B&W HTM2D center speakers. I had used the Emotiva XPA-1 monoblocks (500W) for a long time to power my 5 speaker system (rears are B&W 803D) and I had been happy with them – big, rich but neutral sound. Since one of my XPA-1 blew up, I was looking for a new amp to power my three front speakers. I was initially hesitant about ATI as my previous experience with class D amps was not good. I had previously tried Wyred for Sound class D monoblocks and they were basically terrible with high frequencies with my 802Ds – very unnatural and harsh sounding – seemed like a bad match for the diamond tweeters. I also just tried the new Emotiva XPA-DR3 amps (450W) with switching power and they also were exceedingly dry and I would say harsh with high frequencies (cymbals in particular) so I returned them.

The AT543NC doesn’t have any of that “digital” sound – in fact, there is no harshness at all and they sound much better than any amp I have heard before and much better than both the Emotiva amps I had in the past. The AT543NC sounds effortless and I could listen for hours without any fatigue. The sound is great throughout the entire range from excellent lows and mids to detailed, but still smooth highs. I am not sure how else to describe them, but if I did not know, I would never think that it was a class D amplifier – it sounds more like a class A amp. So I have been very happy so far during the first week of use. That is why I am thinking about getting another ATI class D amp, again from the great folks at InterActive Home Systems (ask for Ralph). This time an AT542NC to power the rear speakers as I listen to a lot of 5.1 recordings (DVD-Audio, SACD, Bluray).

Vladimir P.
Reno, NV

Placed a call to Ralph at InterActive Home Systems regarding one of the ATI class D amps particularly the AT523NC. This 3 channel 200 watts/channel amp complimented my Yamaha RX-A3060 receiver perfectly. I was a bit disappointed with the receiver initially after I purchased it running a 5.1.2 configuration where the internal amp on this receiver fell a bit short power-wise which left me wanting a more for mostly music. I added this amp and at low volumes there isn't much of an impact but once you increase the db to around -15db the additional power becomes really apparent. The improvement in headroom and sound quality is excellent and I'm very satisfied with my purchase and as an added bonus this amp runs really cool which is something I was looking for in an amplifier.

If you are looking for that something extra from your system take a look at ATI amps and speak with Ralph - he'll set you up with the proper amplifier to get the most out of your home theater system. Thanks again Ralph!

Eric S.
New Bloomfield, PA

This is my second ATI amp and my second time working with Ralph Keyslay from InterActive Home Systems. Clearly if my first experience were not positive I would not be writing about a second one. We originally purchased an ATI AT1202, a 120 watt, 2 channel amplifier in a slim chassis. It has worked flawlessly for years and continues to work, powering the rear surrounds. Recently, after conferring with Ralph, we opted for the N-core series, specifically the AT523NC to power the front L/R/C speakers. Another winner. Typical ATI - excellent engineering and build quality in a nicely executed, durable, no-nonsense chassis. All the features you need, and nothing superficial. We use it in triggered mode and it works great. No power-on thump, zero background noise, runs very cool (as does the classic AT1202), and provides outstanding amplification for movies and music.

Ralph is very knowledgeable, responds to questions quickly and thoroughly, and processes the orders immediately. Highly recommended!

Concord, MA

Ralph Keyslay provided exceptional service and was able to guide me to the best ATI amplifiers for my home theater space; an AT522NC and AT527NC. The ATI amplifiers are exceptionally well made and sound amazing. Detailed, rich tone, focused bass. The nCore amps being Class D sound incredible, never bright or veiled in any way. Plenty of power. Very happy customer!

Chad K.
Dallas, TX

Purchased an ATI AT543NC and AT544NC from Ralph at InterActive Home Systems: Received both amps within one week. He was very helpful in my decision and made time to discuss options and make recommendations over a few lengthy phone conversations. I really appreciated the personal touch. I installed the amps into my system yesterday and played around a bit. I am extremely impressed with them so far and very happy with the purchase and the process. I will say that my initial reaction is that these ATI amplifiers are the best I've ever owned and experienced!

Paul S.
Orland Park, IL

It's been a pleasure to add this incredible ATI AT6002 amplifier into my collection. I have run B&K amps for years and have my original one purchased in 1989 and it purrs like a warm kitten. Well, this AT6002 took center stage running a pair of Martin Logan Motion 60xts. If you don't have quality recordings then this amp is not for you, but if you are into top notch recordings then this amp should join your system. Tons of power and plays just like what was recorded, adding nothing but pure and loud audio! I run 16 amps and 13 speakers. My front speakers are Martin Logan and this amp rocks them no matter what I listen to. My mid speakers are Def Tec SR8080s and rears are from Audio Source, complimented by 2 Velodyne powered subs. In front is a PC350 Infinity with four Niles in wall and ceiling speakers. But my love is 2 channel stereo as my main listening pleasure and couldn't be happier with this cool running ATI AT6002 powerhouse; it's magical!

I was lucky enough to find and purchase this amplifier from a great guy; Ralph over at InterActive Home Systems. Very nice, knowledgable, patient, technical and spent a good amount of time with me, helping to select the right ATI amplifier for my system. A real pleasure to do business with him!

Bert H.
Sebastopol, CA

I contacted Ralph at InterActive Home Systems to ask him about the ATI NCore amplifiers. I was immediately impressed by his knowledge, friendliness and professionalism. He gave me a great deal and shipped the amplifier the same day! His customer service is impeccable! Now that I've had the AT528NC for a couple weeks, I can say that it's an incredible amplifier. I used to like amplifiers that were "warm" and were more forgiving of poor quality audio at the expense of enjoying my high quality music fully. I can say this new ATI amplifier isn't warm, but it sounds good with everything. It has a pure and clean sound, and is the most neutral amp I've had. It hasn't fully broken in yet per the ATI manual, so I assume things can only get better from here!

Bottom line: Ralph is awesome and I will buy my next amp from him. The ATI NCore amp is phenomenal and everyone should try one out.

Jared C.
Belton, TX

After ordering some new speakers (Philharmonic 3 by Dennis Murphy), I was quite excited to listen to them. Due to some unforeseen resource issues, they took over six months from order to delivery.

I installed the two channel system including an Oppo Sonica DAC, Emotiva XSP-1 preamp, and a diy ncore nc400 based amplifier. After a few minutes of adjusting the speakers to the proper triangle, etc., I fired up my favorite test song (SRV Tin Pan Alley). I had a wide grin, but alas, it was short lived as I suddenly noticed one channel cutting in and out. Utter frustration. I opened the amp and could not see any issues. No warning LEDs, connections seemed fine. Oh well, I remembered that someone had given me a Crown XLS1502 amp, so I swapped it in and fired up the music. Not bad. Sound stage not as wide. Bass was not as tight, flabby even. But, overall, very musical. Unfortunately, its too wide for my cabinet and I had tasted better output from these speakers.

Later that day, I visited the Linkwitz Lab website since I had made the Orions, LX521 and LXmini speakers. The LX521/LXmini doing HT duties. Siegfried Linkwitz was touting his new system setup which included the relatively new ATI AT528NC amp. Siegfried was gushing over both its sound and astounding electrical measurements. So, I did some Googling and found some very recent professional reviews that agreed in earnest with Siegfried Linkwitz. On one audio forum, a post said to go over to and speak to Ralph about the new amps. So, that is what I did. Actually, I sent an email and Ralph called me back within minutes. Ralph asked me tons of questions regarding my tastes in music, loudness, efficiency of the speakers, room, etc. We also discussed some old(er) audio equipment since we are almost the same age (don't ask). We both had a Hafler DH500 amp. What a beast! Ralph had some great stories and we had a pleasant conversation. I think Ralph thought the AT522NC would have been sufficient, but I was interested in the more powerful AT542NC. Very low pressure sales tactic.

I asked about the next steps and Ralph said he would send an invoice and a PayPal request. After an hour or so, I hadn't seen the email and emailed Ralph. Ralph called and said to look in my spam since he had sent it two minutes after our call. Sure enough, just as he said. I paid immediately. The next day, I got a paid invoice and later a shipping confirmation. Amplifier arrived three days later. Even though the ATI amp is Class D, it uses a linear supply (toroidal transformer), so its not "light". But not too heavy for a 500W/8 Ohm or 900W/4 Ohm amplifier. Very well built. Nice feel, good binding posts, etc.

I installed the amp in my system and immediately heard significant improvements. I've been skeptical about hearing major difference due to amplifiers, but this was proven wrong. The height and width of the soundstage was extended. Voices were highly stable. Low bass was tight and punchy. Mids were accurate. Not overly lush, nor strident. Highs were clear and uncolored. No background noise at all. Never strains (with 900W?), seems limitless in reserve. Gets a little warm to the touch. Very happy with both the experience purchasing through Ralph and with the amplifier.

Best regards,

Dale H.
Austin, TX

I recently had the pleasure of purchasing an ATI amplifier from Ralph at InterActive Home Systems. Ralph is very knowledgeable about his products and how they fit into my system. He provided rapid updates on availability, shipping, and checking back with me after the sale. I wish all vendors were this professional to work with, I would recommend Ralph without reservation!

I wanted to try a newer style Class D amplifier, so I purchased a 3 channel ATI AT523NC. I received the amplifier as promised and proceeded to install into a mixed home theater and music system with “old school” Thiel’s front (L+R) and center. I am replacing a Levinson 532 and older Linn amplifiers. I really liked the sound of the ATI, the midrange clarity and crispness is a nice improvement. I am keeping it in my system as is! The significant reduction in heat is fantastic and a key benefit I had hoped for. The other nice feature is signal sensing from standby to full on, it is flawless with the ATI and I think the best way to go in a system. I am convinced that the ATI AT520NC Class D series is the future for high performance amplifiers, I am sure I will add more as the channel counts go up!

Lou O.
Raleigh, NC

I purchased my first ATI amplifier (AT1506) about twenty years ago and it has performed flawlessly in various systems. Another brand multi-channel amplifier recently failed in my A/V system. Based on my satisfaction with the AT1506, ATI was high on my list for a replacement amplifier. A recent purchase of an ICE module based Class D stereo amplifier for my audio system convinced me that I wanted a lighter weight and cooler running Class D amplifier in my A/V system.

The ATI website described a five channel NCore based Class D amplifier that seemed to meet my needs. The authorized dealer list on the site led me to contact Ralph at InterActive Home Systems. I called him and inquired about acquisition of the AT525NC. Ralph promptly provided pricing and checked with ATI on availability. He found there would be some delay in getting the amp due to parts shortage because of high demand. I ordered the amplifier despite the delay. Shortly afterwards, Ralph again checked with ATI and found there was one eight channel version of the amplifier available. He offered me a great deal on it, I accepted the offer, and within a few days the new AT528NC arrived.

The new amplifier seems to be well designed and as solidly built as my old ATI amplifier. It appears that the new amplifier will likely be as good an investment as my old one. The audio quality was outstanding at initial power up. The sound is neutral and I cannot identify any sonic character that the amplifier adds.

Ralph was very knowledgeable, enjoyable to talk with and a pleasure to do business with. Based on my experience, I would recommend purchasing from him to others.

Richard B.
Macomb, MI

The ATI amps, AT543NC and AT542NC, went live Saturday. Wow! I hooked them up to a Classé processor and the Diamond Series 2 B&W speakers.

The material was Blu-Ray Chicago & Earth Wind & Fire live concert at the Greek theater 2004.

Absolutely awesome. The speakers were previously powered by Krells. The entire concert opened up in a way that I had never experienced before. All of sudden you’re listening to instruments that were not present in past listening. I can’t wait to start reviewing my collection of music.

The amps are also kicking butt with the Wi-Fi-streaming venue. If your ears are tired of listening to the same old sound, step up to the ATIs and have an epiphany in listening to your musical collection.


Lou R.
Bayside, NY

Hi Ralph, well...what can be said. The days of class A, A/B etc. are going away. Class D is the future. You may as well get on board...sooner or later.

THE BEAUTY and The BEAST! ATI AT542NC Stereo Amp. Grabs the sound with vice grip control...and does not let go. This amp is not for the meek! Yet, it is as natural and as airy at low output as it is at high listening levels.

My 300 watt per channel class A/B amps would start to get strained after about the 1/2 hour mark at high level into 4 Ohm loads. Not with this beauty. She is cool and in control until you can't take it any more or your drivers launch across your listening area into the adjacent wall!

As for Ralph taking care of me? Great people, straight up, honest! No B.S. If you have any questions, just ask him!! He is an electrical engineer, with a lot of knowledge on the ATI amps and technology in general. He was great and provided awesome service. Many Blessings to Ralph and ATI For the REAL DEAL!!

Mike A.
Tuscon, AZ

I recently purchased an ATI AT542NC power amplifier from InterActive Home Systems and would like to share my experience. From my very first inquiry I had the pleasure of working with Ralph Keyslay. Ralph provided me with exceptional customer service throughout the whole process. Ralph always answered my questions promptly and made me feel that I was a high priority. Let me give you a couple examples. I sent Ralph a question regarding the input sensitivity of the amp as it seemed rather high and I didn't think it would mate well with my DAC/Preamp. Ralph answered my question within half an hour saying that he would look into the matter right away. That very same day Ralph wrote me back to say that he had tracked down a technician and had him put the amp on the bench to measure the input sensitivity. Come to find out the stated input sensitivity in the published literature was incorrect. Now how many places you order equipment from are going to do that for you? When I actually placed my order and went to PayPal to send payment I had issues with PayPal trying to make me pay the 3% surcharge. It was 6 pm my time (9 pm where Ralph was) so when I shot off an email to Ralph, I wasn't expecting an answer until the following day. About five minutes later my phone starts ringing, and you guessed it, it was Ralph. Ralph then proceeded to walk be through the whole process until we got the order to go through correctly. After ordering Ralph kept me appraised of where my order was at without my ever having to ask. I was so impressed with Ralph I asked him if he sold anything else besides ATI amps because I was hoping to do business with him again. I can't give a higher recommendation than that.

The fact that you can get this much amplifier for the asking price is pretty amazing in my opinion. The amp conveys a sense of transparency and neutrality while all the while commanding brute force control over my Magnepan 3.7i loudspeakers. With 900 watts on tap into 4 Ohms the amp never sounds the slightest bit strained and drives the Magnaepans with aplomb. The top end is refined and never overly bright unless it is inherent in the recording itself. Build quality and aesthetics are quite nice too. I think ATI has stepped up their game in this regard over their past offerings. My only quibble about the amp is that ATI builds them upon order and it took four weeks before I received mine. But if this helps to keep costs down allowing me to afford an amplifier of this quality, then I can very well be patient and wait a few weeks.

Chris D.
Tacoma, WA

I’ve just completed a 100 hours or so on the ATI AT524NC and AT543NC purchased from you a month ago and thought I would send you a note just to let you know I made some very good decisions.

The first good decision I made, after auditioning amplifiers for several months, was choosing ATI. They met the price point and performance I desired. The second good decision was listening to your advice and council, finding the right person, in you, to answer all my questions, and selecting the AT5xx series.

As you’ll recall, these amps had to meet my requirements and some fairly tight wife-approval-factor parameters. I needed ample power and very detailed, uncolored sound. The wife needed it to be unobtrusive and well integrated into the cabinet in the family room, where the 7.2 system resides.

The AT5xx series delivers on all requirements! Smooth, easy, with very tight bass which gives the uncolored sound I needed with excellent transient dynamics. My B&Ws sing to their full potential and are very happy with the marriage. Due to their uniform size, and cool running nature, the cabinet is symmetrical (a wife thing) and silent, and I have no worries placing those powerhouses in a loose fitting, naturally convective enclosure.

I definitely could have spent more, or went with traditional class AB amplifiers, but to meet all my requirements in my 6500 cubic foot family room, I couldn’t have made better choices than Ralph at Interactive Home Systems and ATI Amplifiers!

Steve P.
Carrollton, TX

My ATI AT542NC amp arrived on schedule and was pressed into service immediately. It was more or less the first piece of my new system to arrive, so I’ve gotten to hear the changes as new pieces were added around it. The sound is really good! Not sure what I was expecting from my first Class D amp, but it definitely doesn’t have any objectionable “electronic” sounds like some Class D units are accused of. Plenty of grunt to drive my big speakers and quite stable. You might recall in our conversation that there was some concern about the bridged unit being uncomfortable with my Focal Sopra No. 3s that dip down to 2.75 ohms here and there (~1.5 from the amp’s point of view), but I’ve seen no issues at all.

Thank you for all your assistance and excellent service along the way – I really appreciate it!

Jeff J.
Wichita, KS

I purchased an ATI AT523NC amplifier from Ralph, owner of InterActive Home Systems. The amp is built like a tank and is extremely compact compared to other amplifiers I have owned over the years. I mentioned to Ralph that I would be operating the unit overseas (using 230V) and thought that I would have to purchase a power cable myself, with the plug for that country. Without me even asking, the amp came with the 230V power cable and correct plug at no additional cost...what service!. That was a nice touch.

This amp now powers 3 JTR speakers in my system. JTR speakers are highly efficient, but the dedicated power for the fronts has made a clear and significant improvement near reference level. No regrets at all in purchasing the AT523NC. The only negative is that the face plate design could use improvement, as it is has a very plain look.

It was a pleasure to work with and purchase from Ralph. I asked him many questions and he responded promptly at all hours of the day, each and every time with a level of patience and courtesy that you just don't find very often anymore. In my particular case, I needed the amp quickly and he went out of his way to get it to me much faster than the normal lead time!

John C.
Orange, CA

To: Mike Pontelle - ATI Vice President of Sales and Marketing
Subject: My New AT3007

Dear Mike:

Since our phone conversation a few weeks ago, I received my AT3007 and have had several days to listen to it and wanted to send my praises to you concerning the whole experience.

STELLAR!!! Yes, this experience has been a stellar one for our first foray into the world of purchasing High-End Audio and Home Theatre components!

First of all, kudos and serious praises must be given to Ralph, president of InterActive Home Systems, your longtime associate and the most knowledgeable sales person I have EVER had the pleasure of buying from and an asset to ATI!

As far as my AT3007, may I say you and your team have truly outdone yourselves with this remarkable piece of High-End gear! Ever since the days of your SAE amplifiers, I have been waiting for the day I was able to buy a quality, robust and neutral sounding High-End amp and I have found it in the AT3007! Whether listening to movie soundtracks or music, the AT3007 has given my wife and I an absolutely incredible listening experience and will continue to do so for a very long time, I'm sure. All of a sudden, we hear things that our previous amplifiers never even picked up. Besides sounding incredible, some of the other positives I've noticed about the AT3007 are it's truly small size considering it's sheer power output, it's beautiful styling and most stunning to me personally, your design in keeping the AT3007 cool at high current periods. I purposely played our DVD of "T3" at near ear-shattering levels in our 20' x 17' theatre room to see how hot the AT3007 would actually get and to my surprise, when I placed my hands on the sides of the amp, I could actually feel the rush of cool room temperature air rushing past my hands into the amp while all the heat was being forced out of the top! Brilliant! A convection cooling system which eliminates the need for a fan and really does keep the amp cool!

Yes, Mike, from the very first praises for ATI and the AT3007 from Ralph, to the actual hook up into my system and finally to the pleasure of using our new AT3007, I must say I will never buy another brand of power amplifier but ATI. ATI is to me today's SAE and actually owning an AT3007 is a moment I am savoring.

Keep up the GREAT work and thanks again,

Ron R.
Houlton, ME

Hi Ralph,

I've now had a few weeks with the AT2005, joined with a complimentary pre/pro and DIY high end speakers in a 5.1 AV system. This amp is very fast with exceptional resolution of detail. For action movies, at the listening position, it instantaneously brings my sweet but inefficient speakers (86 dB) from background dialogue in upper 60 dB's to measured peaks in low 90 dB's, sustained upper 80 dB's without any distortion or loss of clarity. I'm certain the amp still has headroom here, but my ears (and speakers) are viscerally satiated at that level without being left behind on the battlefield. The overlay of percussive blasts, shattering glass, and snarling monsters, etc., is very finely resolved. Musical detail is evident as well. For example, a snare can be easily identified as a stick, brush, center, edge, rim hit with/without delay, reverse delay, other effects, etc. Instrument tonalities and harmonics have depth and imaging accuracy without mush. Simply put, the AT2005 is fast, clean and true.

Build quality is commendable. While it's external simplicity will not qualify as a piece of display art (it's an amplifier, duhh), it is easy to see the attention paid to circuitry design and selection of quality components. The modular layout is solid and uncluttered. The balanced signal path has a dead silent noise floor, with absolutely no trace of hum or hiss. No extraneous noises arise from the amp chassis either and, well ventilated, it never feels hot to the touch. The sequential turn on of separate channels by remote trigger from my pre/pro is a nicely refined touch. Channels activate with quiet start up clicks and no other circuitry noise artifacts. "Sounds like the multiplex?" "Better" said the Wife - so the AT2005 gets to stay, only now, the pressure is on to chuck that old CRT for an HD widescreen that won't insult the fine audio.

Service from the ATI authorized dealer,, was great. Thanks, Ralph, for taking the time to personally answer my endless technical questions and ensure my satisfaction with the purchase process. The new amplifier, securely packaged, arrived straight from the production facility within a week of placing the order.

Hey Ralph - Sorry, but pictures of amplifiers alone are sooo boring! I have attached one of the front of my AV system with my ugly CRT (with its necessary center channel magnetic interference "scaffold" - ugghh). Notice how the home built cabinets and speakers all match in stained oak - helping to sneak this stuff past the Wife without much complaint, whheewww!

Thanks, again!

Mark B.
Boise, ID

Hi Ralph,

As promised, I'm sending you some pics of our Home Theatre system. My system components are:

  • 1 Velodyne HGS18 Subwoofer
  • 4 Definitive Technologies BP30 Bipolar tower speakers for mains and rears
  • 2 Definitive Technologies BP10 Bipolar tower speakers for surrounds
  • 1 Definitive Technologies C/L/R 2000 Center Channel Speaker
  • 1 ATI3007 Power Amp 1 Anthem AVM20B Preamp/Processor
  • 1 Mitsubishi 40" 40707 Big Screen TV
  • 1 Technics RS1506US Semi-Pro Reel-to-Reel
  • 1 Denon DP-DJ151 Digital Turntable with Audio Technica AT990 Cartridge
  • 1 Pioneer DVL-909 Laserdisk/DVD Player
  • 1 Nikkodo DEP-2000K Digital Processor/Voice Deleter
  • 1 Sony DVP-NC615 DVD Changer
  • 1 Onkyo Integra TA-2600 3 head/3 motor Cassette Player
  • 1 AKG K340 Headphones
  • 2 Tripp-Lite Voltage Regulators/Surge Suppressors
  • 1 APC Battery Backup for TV

So Ralph, these are the components that are presently in our main Home Theatre room. We also have another 2 complete Home Theatre 5.1 systems for our bedroom and one for our lower level living room, but they are not in the same league, though okay with the likes of Yamaha, Sony, Polk speakers, Hsu subwoofer, etc. However, the upstairs Theatre Room is where we have our main system. I'm sorry it took a while but the construction has been....difficult, as it's difficult to get good work for contractors anymore, it seems!

So, one more after this, Ralph. I hope you like them and I look forward to seeing them on your website, as I am, indeed, a satisfied customer!!!


Ron R.
Houlton, ME


I am really enjoying the power and civility of my AT3007. Thank you for taking the initiative to make this right for me. I am one satisfied customer.

Best regards,

Paul B.
Loveland, CO


My AT1202 amp arrived today. You exceeded my expectations! Thank you very much for your great service, technical expertise and speedy shipping.

George S.
Canton, MI

Hi Ralph:

I've had my ATI amplifier for a while now, an AT2005, and continue to enjoy it immensely! Everyone who has heard my system has been wowed by how great it sounds, and it's actually fairly modest as these things go. I absolutely attribute a great deal of that sound to the ATI amp. It never fails to deliver amazing dynamics, and barely gets warm no matter how hard I drive it. Dealing with you Ralph, was a pleasure. You were very informative, and the whole process was easy and fast! Before the ATI, I was going though an assortment of other amps, but now I don't feel the need to upgrade (although the new AT4000 and AT6000 are pretty darn tempting!). I guess that's why you rarely see them in the used market. Thanks Ralph, for keeping in touch with your customers.

Bruce L.
Seattle, WA

I purchased my ATI amp after doing extensive research and decided on the AT2005. I contacted Ralph through his website, and he immediately followed up with a phone call. He took the time to explain all of the benefits and features of this particular model amp. I found Ralph to be extremely professional, knowledgeable and passionate about his audio equipment. He was very easy to work with and kept me updated on the status of the order, confirming both when payment was received and when the amp shipped. I would definitely do business with him again. As far as the amp goes, I cannot say enough good things about it. I absolutely love it! 200 watts per channel (5) of honest to goodness American made muscle. Sure, it's not going to win any beauty contests, but that's not important to me. This ATI amp is all business (and weighs almost 80 pounds!) This was my first entry into the world of separates, and I couldn't be happier. Speakers were previously being powered by an Onkyo receiver. Moving to the amp is a night and day difference. Incredible headroom, dynamics, clarity, I can go on an on. It does not break a sweat and literally brings a smile to my face each time. It honestly sounds like a fog has been lifted, even without cranking up the volume. It was a solid investment and I look forward to enjoying this amp for many more years to come.

Victor M.
Boston, MA