Originally Posted by nkk /img/forum/go_quote.gif What is the difference between the Adcom Gfa-545 and the 5300? Other than power, is there a difference?
The main difference is that the 545 uses bipolar output transistors and the 5300 uses mosfets. Both are Nelson Pass designs. If the models are MK II or SE, then they were modified from the original design, in house, by Adcom.
Another difference is that the original 545 had some 100 volt driver transistors that could fry when the fuses blew. This usually occurred when trying to drive speakers that regularly dip below 4 ohms. the MK II used 150 volt transistors. The 5300 is better for this type of speaker load.
They're both class AB amplifiers but the 5300 will run in class "A" for the first 10 watts IIRC.
The 5300 was one of the first American amplifiers to be completely manufactured in China. Quality control problems are common and assembly is a notch below the 545.
The GFA-545 runs warm. The 5300 runs hot and you can use it as a small room heater.
Both amps have a similar sound. I haven't listened to the 5300 for any period of time, but from what I've read it sounds warmer than the 545 with a more compressed soundstage. Less detailed in the highs than the 545, but smoother. The bass is a little tighter. The midrange a touch more recessed. Opinions are equally divided as to which amp is preferable.
The GFA-545 has many modifications and improvements available if you search the web. These are said to take it to a whole other level.
Originally Posted by nkk /img/forum/go_quote.gif ok. So, then, what is the difference between the 545 and 5200?
I know that I could find this online, but I never really know who is a real knowledgeable person and who is just mouthing off. So, thanks for the reliable info.
What information are you looking for specifically? They're different designs that share the same heritage. FWIR the 5200 is just a lower power version of the 5300 with a smaller toroid and smaller value power caps. The series was made up of the 5200, 5300, 5400, 5500, 5502, and 5800 models. This series was designed about 8 or 9 years after the 500 series.
If you want to research Adcoms, you should visit diyAudio.com. Nelson Pass himself hangs out there regularly, so any information there on Adcoms would be accurate.
Another good resource that has more wheat than chaff is the Amp/preamp forum on audioasylum.com. Many professional amp designers and audiophiles hang out there as well and the information is usually accurate.