MrT

Overall Rating
 5 of 5

Value Rating
 5 of 5

Used product for
More than 1 year

Visitors rate this review
1.00 of 5, 1.00 votes

Price Paid:  $500.00 from used

Summary:
This is for the mkII, wich I have owned for about one years and have used with a variety of components such as Arcam CD72T, Marantz CD 6000 OSE, a few Sony ES cd players and speakers by Monitor Audio, Kef, TDL and Mission (Van den Hul cables)

Many reviews here note the fact that the DIA-100, being a direct input amp, really reveals the weekest link in your system, why matching is everything. It reproduces the sound of your cd player with great accuracy. In fact, the true strength of the DIA-100 is its ability to reproduce music totally "uncolored" with great imaging and a truly impressive soundstage! But beware if your cd player is on the lower end, then you surely will have to upgrade.

After having owned about 30 amps in about the same price range I have now settled for the DIA-100 mkII. I stongly recommend it to anyone who want to spend around 500 bucks on a used amp. You will not get anything better!

Strengths:
SOUNDSTAGE, imaging, excellent bass control, build quality and foremost PRICE (1000 $ retail was a bargain - 500 used is great)

Weaknesses:
Reveals even a minor flaw in the rest of yor setup. Get yourself a good cd player.

Similar Products Used:
Amps: Linn, Sony ES, Arcam, Rega, Copland, NAD, Marantz, Sansui, Pioneer Elite, Dared (tube) etc

Price Paid:  $200.00 from Craigslist.org

Summary:
I have this amp powering a set of vintage Acoustat Model II electrostatic speakers. They require 100W a piece, so the amp is putting out just enough power. I'm very happy with it so far. The sound is very, very clean. And the detail is great. If you can find them cheap, especially the Mk. II's, definetely go for it.

Strengths:
Great, clean sound. SOLID build. Looks great.

Weaknesses:
Limited functionality.

sellerjb

Overall Rating
 4 of 5

Value Rating
 5 of 5

Used product for
More than 1 year

Visitors rate this review
4.00 of 5, 1.00 votes

Price Paid:  $1000.00 from Park Avenue Audio

Summary:
This is a great piece of audio equipment - it is solid and basically indestructible...it worked beautifully with Linn Keilidhs, Harmonic Technology interconnects and Marantz CD63 SE. I spent over 3 years with this set up - it's beeen great.

Strengths:
Crisp, clear and articulate - a great value, I've seen them sold on eBay for less than $400.

Weaknesses:
Nothing fancy here - old fashioned, solid state, stripped down to the bear essentials type gear. For a no-nonsense direct input amp this is the way to go. It is 100% unadulterated amplification – nothing more or less.

hblee

Overall Rating
 5 of 5

Value Rating
 5 of 5

Used product for
More than 1 year

Visitors rate this review
5.00 of 5, 2.00 votes

Price Paid:  $995.00 from L.A.

Summary:
This is a tweak report on Acurus Dia-100 Dia-100 was my first hi-fi amp. I now have several other amps (TR and tube) that cost several times more, but I still keep it. It is my first love, and does not gobble up electricity nor tube life. My ealier tweak is posted earlier (auricap and capacitor adds). After I acquired the DIA-100 schematic from the Yahoo acurus user group (http://groups.yahoo.com/group/acurusowners/), I modified the following. 1. R2 (1K) signal-in resistor is changed to Kiwame 1K 2. R19 (68K) is replaced with Audio Note Tantal 68K. R19 is on the feedback path. 3. Feedback sound shaping (Feedback Onset) C6 (0.47 uF) and C7 (220 uF Non Polar) is replaced with 2 uF Solen and 470 uF Blackgate Non polar. 4. C1 and C2 input coupling caps are gone. It is now linked with good hookup wire (LAT). Actually, I took them out several years ago when I noticed my DAC is output capacitor coupled. 5. Power supply caps for each rail (+60V, -60V) is augmented with 6800uF, and 4700 uF, and most importantly with 220 uF Blackgate for each power supply lines to each channgel. So, I used 4 Blackgates. I actually cut the +V, and -V power lines to each channel in the middle and inserted the blackgates. In this way the Black gates are closest to the load (PCB) I know the sound of Kiwame, Tantal resistors and blackgates. Kiwame is warm, lush, no noise but lacks sparkling. Tantals make pretty sound that is best from voice to high frequency but attenutes the bass. Blackgates simply makes no noise. So the overall noise floor drops making one to hear minute details without "sh" sound. Dia-100 has huge unused space inside. So all these extra components can go in. DIA-100 is now up there with my other amps. The sh and "ch" sound is nowhere to be found but only pure prinstine highs exist. Somewhat sterile (not lively) voice/mid frequency that especially annoys at low level listening during the night became much more lively. Surprising even bass got more articulate. before it was undiscernible bass, now I hear melodies in bass. I am astonished in the way the new DIA-100 converys background sounds, reverberations and decay like good tube amps. You will hear effortlessly all the new sounds on the bass, and mid frequencies without any trace of grain. Simply it is no contest before and after the tuning. Dia-100 can now even be said sound like modern, high resolution, high power tube amp. Don't give up on the DIA-100. With a little tweak, it will ahame many amps that cost several times more.

Similar Products Used:
Krell, Musical Fidelity, PASS, DIY tube amps.

Discriminator

Overall Rating
 4 of 5

Value Rating
 5 of 5

Used product for
More than 1 year

Visitors rate this review
5.00 of 5, 2.00 votes

Price Paid:  $995.00 from Century Stereo, San

Summary:
This is my first review on this forum and I want to extend my sincere gratitude to all who have gone before me. I feel compelled to write this review because I think that I can shed some light on the debate over whether this amp is a clever design that produced an outrageously good deal, or an overly bright noise maker which makes an excellent door stop. From my experience it could be either depending on your luck. I auditioned the amp in the store's demo room where conditions and components had been optimized. I knew full well that I would not have a very good idea of how it sounded until I took it home and hooked it up to my Snells. Imagine my surprise when I took the unit out of the box and found that all of the letters on the face plate were double stamped! Can you say t-t-tuner? Of course I was too jazzed to stuff it back in the box without trying it out. I hooked it up and was immediately amazed at the detail I heard in the sound. Records sounded rich, full, and luxurious, but CDs sounded harsh and glaring. Since there was some doubt in my neophite mind as to whether this was a desirable state of affairs, I hung onto it for a few weeks. The sound did not change appreciably. I eventually found the time to exchange the unit, which the store was glad to do. The second unit looked AND sounded significantly different from the first! Gone were the d-double stamped letters, but more importantly the sound was flat. At first I was actually disappointed, but I soon came to realize that the previous amp had been too bright and the one I have now is pure and true. I have confirmed this by auditioning it with other speakers including NHT 2.9s which some find to be on the bright side. The 2.9s sounded natural and sweet. I will add that the DIA 100 had no trouble driving these notoriously power-hungry speakers to high output levels without apparent effort or excessive heating. I was auditioning a used pair of 2.9s and based on what I heard and have read I have decided to hold out for the NHT Fours which are coming out in a week or so. But I digress. What I have concluded from this experience is that quality control may not have been the best at Acurus. In a way it makes sense given the design. The amp has a single super-high gain stage which eliminates a preamp. The high current, high gain bipolar amp is a clever design in principle, but in the real world the sound could be several times (maybe even 10X) more sensitive to variations in the components in the gain stage. That hypothesis fits well with my experience, the differing observations reported here, and what I know about electrical engineering (I happen to have a Ph.D. in EE but it's not in analog amplifier design)! I will add that a DIA 150 reviewer stated that the amps were assembled by the U.S. military. In my mind that would explain why they are built like tanks, and perhaps also the double-stamped face plate and what seems to be questionable quality control. This amp has been with me for ten years so far and I have no intention of replacing it any time soon. I have never had any problems with it after exchanging the first defective unit. I may consider a separate subwoofer amp for the NHT Fours if the bass isn't solid but frankly I doubt I'll need one. The guy who owns the 2.9s was running 200 wpc Sunfire Cinema Grand Signature which retailed for $3500. I won't claim that the Acurus sounded as rich but I can honestly say that he was skeptical and that the performance of the Acurus with the 2.9s exceeded both of our expectations by a very significant margin. I can recommend this amp as an outstanding bargain on the used market.

Strengths:
Clever, simple design for excellent value Heavy duty design Natural sound (if you're lucky) Drives tough loads with ease

Weaknesses:
Annoyingly bright (if you're unlucky) No subwoofer out Assembled by U.S. military Questionable quality control

Similar Products Used:
Pioneer (ick), Proton (yuk!), Harman Kardon, 1980s NAD 3300PE Power Envelope integrated amp (pretty good)