4401
4401
Second life
Let's put things clear : modified and refurbished, the 4401 is now a high-end killer. After I have replaced the output stage transistors the preamplifier has reached a new level of performance. First thing I noticed when I turned it on is the silence. With the volume control at full throttle you cannot hear the slightest hiss. Secondly this thing lets flow pure music without coloration or veil. Crystal is the word that pops to mind. And dynamics too.
I did further measurements : output voltage, various sine and square waves. Most noticeable facts are the total absence of phase shift accross the audio band which means that bandpass is probably very wide. Reference waveform can be seen on top trace, 4401 signal bottom trace. They are perfectly aligned. You will also notice that this souped-up Bose 4401 is capable of swinging 15 volts accross it's outputs, to be compared with the timid 7,0 volts RMS stated by Bose on the specs sheet. Let's call it a 4401 under steroids. You can check out the distorsion and performance report here and compare with the Bose specifications, figures speak for themselves don't they ?
After a 30 minutes warmup / break-in session
I carefully listened some CDs I know well from a reference player. I use these
very high
quality monitors for checking units that I build or modify, these
speakers have no mercy with anything connected to them and all I can say is
that I'm enjoying a damn lot what I am hearing.
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