is a bank holiday in the UK and found some time to do some
further work on the amp. I totally agree with you, the speaker
itself can dramatically change the final result along the
source-preamp-power amp-speaker line.
speakers are 3-way, closed cabinets, tuned roughly at 40Hz
and go down to 30Hz (~ -3db), so yes, the change is not
so noticeable but maybe slightly better. However, since
I used my Mundorf aluminum/oil capacitors, I think that
the midrange sounds a bit clearer now, but maybe all these
changes are a bit subjective and due to the fact that we
expect better sound clarity by using better components.
Anyway, enough with rumbling, here's my review on the amp:
listening to the amp for over a week now, I can say that
it is definitely a very good amp, with pleasant sound, wide
frequency band, punchy bass, realistic mids and crisp highs.
I am using it in a full diy, flat response, system and have
no response issues whatsoever. The build is simple enough,
the components are of very good quality, and once you follow
the instructions carefully no problems should arise. The
bias which can cause anxiety to many who have seen caps
exploding or resistors catching fire due to dodgy pots,
should not worry at all with the use of a multi-turn pot.
The circuit is very stable and once you bias it as suggested,
the amp will happily deliver clear, detailed and pleasant
attached a few new pics of the final build, where you can
clearly see the dual mono configuration, with a 300VA toroidal
transformer, two 35A rectifier bridges, a total of 27200uF
capacitor bank and 100nF mkp bypass capacitors for each
channel. The dc protection circuit has separate grounds
even though the two channels are built on the same pcb.
As a result the two channels do not share ground along the
line from the input to the output, and the elimination of
the crosstalk is remarkable. The only changes I did are
the spade connectors that made the assembling a bit easier
and the use of a better quality input capacitor, notably,
I have used a 4.7uF Mundorf aluminum/oil capacitor which
in my opinion offers slightly clearer mids, and in theory,
lowers the cut-off frequency of the high-pass filter in
the input stage.
many cheap but questionable in terms of reliability kits
that have over flooded e-bay, I think that these modules
worth every penny and are a very serious option for somebody
who wishes to build an amp that can keep and enjoy for many
years. Of course with your help Mike, and your response
is too much appreciated.