The 3-Way Classic, update 2.
I have now listened to the 3-Way Classics fed by the PreFUNK + PwrFUNK combo for more than a week. My wife banning the sub-woofers was the right decision from an esthetic point of view. But it eliminated the 40 cm stand they where supposed to be mounted on and pushing them close to the wall did make the situation even worse.
The
power amp still had a faint thump occasionally at power-off even with my
P175 boards fitted. I did not have any thumps with the Hifimediy T1X4 board in my previous amp. I thought it was due to the P175
boards but Rod Elliot clearly state that "power-off muting is not
included in the design shown" and "whether you also need a power-off
mute is up to the constructor". I don't know why my previous amp was
thump-free and this is not but I do know that one thumpinator board for
the active XO (scavenged from my previous build) and two P175 boards doesn't prevent this one from thumping.
One problem is that my P175 boards are fed from a regulated power supply and they don't seem to collapse fast enough. I therefor decided to design and build a new board fed from an unregulated source. No fancy speaker protection just a simple thumpinator eliminating thumps at power-on and power-off. This is what I came up with (click the image for higher resolution).
The relays will activate after 3 to 5 seconds and deactivate as soon as the unregulated power source is cut. I connected it across the whole secondary winding of the toroidal transformer used to power the active XO (before the regulated power supply). Around 30V A/C is fed through J1, D1 act as a half wave rectifier. J2 is intended for a mute switch (not used in this build) and J3 for a power LED (turns on when the relays are activated). A simple circuit with the added bonus that it made it possible to remove the other three boards. The amp is now dead silent at power-on and power-off.
I have used a mixed bag of source material, Spotify and vinyl. The PreFUNK was built with vinyl in mind and vinyl really shine with this gear. The NOOLOM filters on the PreFUNK are perfect as an alternative to tone controls. The treble is there without being shouty in any way and I can listen for hours without fatigue. The mid-range is great, clean and neutral. I kind of miss the warmth of the W5-2143 but they work best as full-range speakers so it's a bit of an apple vs. orange comparison. The SB23NRXS45-8 sounds very different in this ported enclosure compared to my previous closed one. I like the sound of both, I tend to favor closed enclosures but I am also impressed by the level of bass produced in this ported configuration. It makes up for the loss of the sub-woofers.
I have had nine different pair of speakers in this room and the space is a nightmare from an acoustic point of view. All previous speakers has had their pros and cons. Some has worked great on low volume but not on high, some on high volume but not on low, some omnidirectional with a lack of sweet spot, and some directional with just a sweet spot, some sounds great with jazz but not with rock and so on. This setup, the 3WC fed by the PreFUNK + PwrFUNK combo is the first to do it all. Not perfectly but definitely good enough. I look forward to the day I can put them on stand mounts in a decent space.
A couple of lingering questions. My 3WC deviate quite a bit from the originals by Troels Gravesen. You might wonder witch one sounds the best? I have no idea because I have not heard Troels version but I have to assume that it is really good. I am very pleased with my result and I leave it at that. Another question is how my system finally measures? I really want to know but I would like to measure outside and the weather is horrible right now. I might have to wait until spring until I get a chance to do proper measurements. I will enjoy my subjective impressions until then. ;)
