BEC Posted May 12, 2004 Share Posted May 12, 2004 I bought this diminutive amp just to try out the technology. The price of admission was around $94.00 shipped. It is a Griffin Technologies PowerWave Class T audio amp. Claims to be 15 W + 15 W (10 Hz 20kHz, 10W , 0.1% THD) In the picture it is sitting on top of a Dyna Pat 4 which is being used to drive it. The PowerWave weighs in at 6.5 ounces. Right now it is being used to power a pair of Lascalas to about 100 dbs at my listening position in the center of a 24 X 30 room. There is still some headroom there. I briefly ran it at 110 dbs. The PowerWave can be run in a completely digital (input) mode connected by USB to a computer or can stand alone as an amp driven by a pre-amp. I believe its main use was intended to be a way to connect better than the average computer speakers to a computer. How does it sound? Pretty good. I have only listened a couple of hours so far and am most surprised at the fact that the little amp is barely above room temperature. I am always impressed by efficiency in speakers or amps. I haven't really been able to fault it in any area so far. I know that the highs and mids are really where they should be, I have to think about the bass a bit more. Here is where I admit to a habit of mine. I expect certain things from equipment based on what I read before using said equipment. I have difficulty believing that a little amp like this one has the electrical "mass" to control a 15 inch cone. So far I think I may be hearing what I expected to hear and that is some lack of "tightness" in the bass. The bass is definitely there. Believe me, I have just spent 5 minutes with my head inside the bass bin of one of the Lascalas. It was LOUD and CLEAR. It is just somewhat different from my rather large solid state amp that is usually on duty. OK, I will say it. It sounds rather tube-like to me. Wish I had gotten this little amp before DaddyDee's gathering. I would have liked to hear opinions. Bob Crites Quote Link to comment Share on other sites More sharing options...
No Disc Posted May 12, 2004 Share Posted May 12, 2004 Interesting. Looks like a great way to pump audio from your computer though your high-end speakers. I wonder what class "T" is though. Quote Link to comment Share on other sites More sharing options...
BEC Posted May 12, 2004 Author Share Posted May 12, 2004 I think that the Class T is the TriPath technology that Leok has posted about. although TriPath is not mentioned on the Griffin Technology web site. They just call it a Class T digital amp. Perhaps Leok will chime in here to let us know if this unit uses the TriPath parts. Bob Quote Link to comment Share on other sites More sharing options...
Dflip Posted May 12, 2004 Share Posted May 12, 2004 Here is some infomation from the website: http://www.griffintechnology.com/products/powerwave/ About Griffin PowerWave: The PowerWave USB Audio Interface & Desktop Amplifier is a powerful and extremely flexible computer audio tool. With it you can record any mic or line input into your computer. Record your entire album collection to make CDs or MP3s. Hook-up a mic and musical instrument and turn your computer into a recording studio. But the PowerWave is also an integrated desktop amplifier. Use it to connect any set of home speakers to your computer. PowerWave makes a great compact amp for your MP3 player. It even enables the use of Apple Pro Speakers with any USB enabled computer. Flexible input, exceptional output, and amplifier power in one beautiful device, the PowerWave. With PowerWave, you can: Archive records and tapes to make MP3s or CDs Record instruments or voice into your computer Connect and power any set of home stereo speakers Attach Apple Pro Speakers to any computer Use as a standalone amplifier for iPod/MP3 player Zero latency monitoring for multitrack recording High quality RCA stereo inputs and outputs WHY INSTALL POWERWAVE?: There are a variety of reasons why PowerWave is preferable to the built-in audio on existing PCs or Macs. The inside of your computer is electrically very noisy. High frequency noise from many sources can degrade a computer's audio input and output quality. USB audio provides a far cleaner and more effective way of getting sound in and out of the computer. The audio A/D and D/A circuitry is external from the computer away from noise that degrades audio performance. All signals are carried to and from your computer digitally through the USB connection. The net effect is audio quality that is far superior to what people have become accustomed to from their computers. The Griffin PowerWave builds upon this advantage using the best USB audio codec (compressor/de-compressor) available. The PowerWave uses the identical codec used in the professional USB audio solutions that cost 5-10x as much. In fact most users and reviewers agree that the PowerWave provides superior audio input and output quality to these professional adapters. Further, software available only for the PowerWave allows you to customize your audio input and output far beyond what can be done with any of these high end products. Some of the other advantages of the PowerWave include: Isolates internal electrical computer noise The power supplies are full of transient noise from the CPU, hard drives, CD drives and other computer components. Built-in computer audio hardware can transfer that noise into the audio I/O. The PowerWave stays outside of your noisy computer system, attaching via the external USB interface. Eliminates "Ground-loop hum" Ground loops usually manifest themselves as a humming noise, often directly related to the frequency of the electrical system being used. In the United States, the hum is typically at 60Hz or a near harmonic, while in many European countries the hum is 50Hz (or a near harmonic). In addition, the nature of the electrical connections may also greatly exacerbate any possible radio frequency interference (RFI) that may be in the area. A "ground loop" can occur when at least two devices are connected to a common ground through different electrical outlets. Typically, audio/video signals use zero volts (0v) as the point around which all signals are compared and contrasted, with any appreciable voltage either positive or negative, representing the information being carried. This "zero level" is often called "ground", despite the fact that it rarely refers to a physical connection to the earth. The problem is that a piece of equipment plugged in to one outlet will probably have a slightly different "ground potential" than another piece of equipment plugged in to an outlet on a different house circuit. To prevent ground loops, all electrical grounds must be connected together. If you must connect your peripherals to two different power outlets that are on separate grounds, then you should use some method of isolating the signals and grounds from each other. There is a case to be made that a lot of the quality problems affecting audio or video electronic devices can be traced back to ground loops. Utilize industry-standard connections PowerWave incorporates standard RCA stereo and mini-jack connections, which eliminates potential problems caused by outdated proprietary hardware such as the older Macintosh PlainTalk design. By adhering to both the world wide computer standard 1/8" ports and standard stereo RCA connectors, PowerWave guarantees you'll be able to connect peripherals from around the globe. In addition, there is no commercially available PlainTalk extension cable, since it's an interface used only by Apple for its older microphones. With PowerWave, you can use practically every kind of extension cable on the market. Not only can you extend the audio connections, but you can also extend the USB cables for even more flexibility in usage and placement. Hassle-free expansion Many new Mac and PC desktop and portable computers are shipping without audio inputs. With PowerWave you can easily move one piece of equipment between two or more computers with no hassles at all. Simply unplug PowerWave from your desktop machine and plug it in your laptop; no drivers to install, no loss of expansion ports, no time wasted prying open the case and swapping cards in and out, and perhaps most significantly - no additional expense. SPECIFICATIONS: Minimum RMS Output Power per Channel: 15 W + 15 W (10 Hz Ð 20kHz, 10W , 0.1% THD) Input Sensitivity/Impedance RCA in (Line Level Mode) Ð15.0dBu , Greater Than 20kOhms RCA in (Mic Level Mode) Ð30.0dBu, 7000 Ohms Maximum Input Signal RCA in (Line Level Mode) 0.0dBu RCA in (Mic Level Mode) Ð15.0dBu Output Level/Impedance RCA out Ð2.0dBu , 600 ohms Frequency Response (20Hz 20kHz) RCA IN to RCA Out, Via USB Loopback +/- 1.0dB Total Harmonic Distortion (20Hz 20kHz) RCA IN to RCA Out, Via USB Loopback 0.03% Line Level Mode 0.07% Mic Level Mode Signal to Noise Ratio 85dB Residual Noise 72dB below nominal input level SYSTEM REQUIREMENTS: Mac OS 9.1 and above, OS X with USB port Windows 98SE, ME, 2000, XP, with USB port BOX CONTAINS: PowerWave computer amplifier AC Power Supply Speaker Breakout Cable 6-foot stereo mini-jack male to RCA male cable 7-inch stereo mini-jack male to RCA female cable USB Male A to B cable CD-ROM PLATFORMS SUPPORTED: Macintosh: Mac OS X Mac OS 9.1 or above Windows: Windows XP Windows 2000 Windows ME Windows 98 SE Quote Link to comment Share on other sites More sharing options...
speed3 Posted May 13, 2004 Share Posted May 13, 2004 Um, Pretty neat, but I can't figure out how you hook up regular speakers to it. I can't see any speaker level outputs on the back of the unit. How do you do it? For the price, it's an interesting solution. What a great way to be able to ditch those cheesy computer speakers and actually set up reall speakers with your PC. Quote Link to comment Share on other sites More sharing options...
No Disc Posted May 13, 2004 Share Posted May 13, 2004 What does the speaker breakout cable look like? Quote Link to comment Share on other sites More sharing options...
Soeren Basboell Posted May 13, 2004 Share Posted May 13, 2004 There is a general confusion about the class T principle, and it seems to me that Leo and I in this forum are the only ones who have worked with it since it was introduced in the audio field. I might be wrong in the following due to much secrecy and complexity involved, but the following is as near to the truth as I can get it. It was created in the days where Shannon and Nyquist were developing information theory and the second world war further accellerated the evolution. The idea was to use frequency as the variable and keep the amplitude constant but not as in classical FM modulation, as the frequency variations are far bigger than the signal bandwith and the relation between signal and output is more complex. Used in a transmitter it had a strong cryptographic effect as there is no defined frequency where you can listen. In the class T version the frequency swing is somewhere between 100kHz and 2MHz. So I think it is easier to say what class T is not: It is not a PWM, there is no fixed clock frequency It is not even necessesarily a digital amplifier; but is a classical tape recorder with HF premagnetization digital? In the time domain yes, in the amplitude domain no. This is just to visualize that the difference between digital and analogue is not always obvious. What it is a little bit more, or behaves like, is a FM transmitter. You can easily hear it with a Short Wave pocket radio if the amp is not well screened against HF radiation; much care should be taken making the layout. ----------------- Some of us are fascinated by this way of thinking and try to take it to its full potential, I also have an idea of how Tripath could make it even a little bit better from a high-end audio point of view. I think that the most fruitfull way of thinking at it, if you want to understand its nature, is to use the thesis of Thevenin: That anything in this electrical world can be seen as an EMF in series with a complex impedance, and instead of thinking at the EMF as most peple do, you should think more at the nature of the impedance. Søren Quote Link to comment Share on other sites More sharing options...
Cal Blacksmith Posted May 13, 2004 Share Posted May 13, 2004 ---------------- On 5/13/2004 6:31:47 AM speed3 wrote: Um, Pretty neat, but I can't figure out how you hook up regular speakers to it. I can't see any speaker level outputs on the back of the unit. How do you do it? For the price, it's an interesting solution. What a great way to be able to ditch those cheesy computer speakers and actually set up reall speakers with your PC. ---------------- I would guess it works like a separate power amp. The output level is controlled by the preamp or in this case your computer through the windows volume/ input output control panel. The unit has RCA input and output for line level and the breakout speaker connection to be used with their cable/adaptor. SEE PIC AT http://www.griffintechnology.com/downloads/high_res_images/powerwave_back_hires.jpg I have been looking for a better way to get sound into and out of my pc as I have a lot of vinyl to put on CD for use in the car. I am VERRY interested in how this unit works for you, LET US KNOW! Quote Link to comment Share on other sites More sharing options...
leok Posted May 13, 2004 Share Posted May 13, 2004 This amp may be based on the Tripath 15 Watt module (I can't remember the numbers). It may also have the dc input connection that I circulated a year or so ago to deal with dc offset and the input cap. If so, the technology is almost identical to the TA1101B I implemented in the P6D. Leo Quote Link to comment Share on other sites More sharing options...
BEC Posted May 13, 2004 Author Share Posted May 13, 2004 Here is a picture of the speaker break-out cable. Leo, Thanks for your comments. I think you have some excellent technology on you hands. I can think of lots of uses for this technology but probably nothing you haven't already thought of. One thing that sort of popped out at me (since I am a test equipment type guy) is the ease of building things like sweep generators using tripath. Seems to me that just adding a controlling chip and a keypad would make a nice programmable portable sweep/function generator that could directly drive speakers. Bob Quote Link to comment Share on other sites More sharing options...
leok Posted May 13, 2004 Share Posted May 13, 2004 Bob, I agree. Wnen I went to check out the Chorus-IIs that I eventually purchased, I took a little hand held signal generator and my amp. As a result, I found a midrange driver problem and knocked a bit off the price. Leo Quote Link to comment Share on other sites More sharing options...
Tweek Posted May 13, 2004 Share Posted May 13, 2004 speaking of which, i wish Yamaha would make a new CAVIT, one with MAC OSX support, and 6 descrete analog outputs for external powered speakers like the Ultra 5.1's i actually wouldnt mind if they just released new drivers for the 2 channel non-amplified version of the CAVIT, i need more high quality external sound options for an Apple notebook http://www.yamahamultimedia.com/yec/products/cavit/dpu50.asp Quote Link to comment Share on other sites More sharing options...
BEC Posted May 13, 2004 Author Share Posted May 13, 2004 Leo, What you said about testing the used speakers you were buying is also one reason I wanted this little amp. It seems that the best buying deals on older Klipsch speakers are on the ones that are: "dads old speakers that we have stored in the garage". Now with just a laptop or mp3 player and this little amp, I can power them up and know what I am buying. Bob Quote Link to comment Share on other sites More sharing options...
Daddy Dee Posted January 6, 2005 Share Posted January 6, 2005 Wanted to bump this back up to the top of 2 channel. I wasn't following was Soeren Basboell was saying in his post. Could anyone help me with that? Quote Link to comment Share on other sites More sharing options...
lvhobbs Posted January 7, 2005 Share Posted January 7, 2005 Thanks for the bump Daddy Dee. Amazon.Com has this amp for $74.99 under "New and Used" in NEW unopened box condition. Hard to pass up if it works as advertised. Any users of this amp comments pro or con? Quote Link to comment Share on other sites More sharing options...
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