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Customer Galleries
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Upgraded Mono Amplifiers
Markus has updated his old DIY mono power amplifier. There used to sit a 150W MOSFET amplifier module
Now it has been replaced with two of our amplifier module from the Shop page: PA3CCmkII, TIP.
The power supply is a transformer of 2 x 30Vac giving a rail voltage of +/-42V + 4 can capacitors + bridge rectifier
The stack of amplifiers for each loudspeaker. The loudspeaker is passive crossed between
tweeter and mid-range and active between woofer and mid. The active crossing is a Cabre at 450Hz.
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Some commends from Markus:
1. "Now I am very satisfied with the result! (On the first sight they seem to be equal to the class A amplifiers)."
2. "The sound in the given application, driving the 38cm Jamo with a crossover frequency of 450 Hz, is definitely
(I can say definitely now after some hours listening) the same as the class A. I tried them before as bass drivers
to decide, if the elimination of the old amplifier was necessary - and it was worth the change."
3. "I did a one to one comparison between the class A and the PA3CC and there is a clear difference in the high range.
The PA3CC is sharper than the class A. But on an extremely high quality level and after this listening I connected
again the two amps to the bass and did not hear any difference there."
Elaborating "sharper":
The sound is different and it is a subtile difference that is difficult to describe. My wife is musician and she compared
the difference to actors on the stage of a big theater with an attitude of slightly "overpronouncing" versus the "normal"
sound of speech. The PA3CC is clean and precise and the class A seemes to miss details at the first moment after switching.
But the other way round it gets clear that it is not anything missing, but you hear the "sharper image" more in the forefront
in the same way as you hear the "overpronouncing" of the actor on the stage.
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After this "review" I coulden't help myself - I had to send this mail to Markus:
Okay – thank you for the elaboration of the difference.
The difference of sound stage that I discovered was under difficult loads. The load was a pair of Martin Logan CLS electrostatic
– so I would say it depends on the load of your driver represented to the amplifier. I always recommend going for a low ESR
(internal resistance of the capacitor). You will easier get low ESR by parallel coupling of many “smaller” capacitors than “only”
two big ones. Capacitors do dry out over time and this is also going much faster at higher temperature – I see some “old” FRAKO
types in your amp…
Normally I would recommend 100nF over the two of the diodes in the bridge rectifier AC1 to -V and AC2 to –V. This will take
out the switch noise from the diodes.
AND NOW THIS - Markus:
Thank you for sharing your expertise with me. I have put a higher quality power supply (and put 100nF over the two diodes) in the amp
and got a better sound result. I compared it with the Class A amps again today and it was interesting to hear a difference - without
being able to find out what the reason for this difference was. They have a natural - and neutral sound with precision. While piano
seems more natural in this comparison, the human voice has a little more presence with the class A.
I am very satisfied and I will strongly recommend the PA3CC !
Thank you Markus for following my advice to upgrading your power supply - you got the reward...
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