Sunday, 1 March 2015

Light and sound levels

As my avid reader will have surmised, music is my preferred art form.   Not that others have no place, but it's music that moves me the most often, and the most effectively.  And it's the art form to which I contribute, in my modest and amateur way, via my flute.

And so it's this, I imagine that drives my interest in hi-fi.  I like to listen to music at home, and when I do, I like it to sound as realistic as possible.  I have listened to enough hifi equipment over the years (I used to trade in it in my spare time), to know that they all sound different, regardless of what the measurements will say, and I have a good idea of what is good and what isn't.

I have been happy with my current stereo for a while.  The key component is the speakers, they come from here, and to my ears they are hard to beat.  They aren't cheap, though.  The amplifiers I have been using are these Bantams from Temple Audio.  They are very cheap compared to the speakers, and you'd imagine that they could sound rough, but they don't.  They rank amongst the very best I have ever heard at any price.  They are based on recently-developed digital amp technology.

There is only one problem with them, which is that they don't go very loud.  And here we come across a problem of English usage: I don't mean that they only play at very modest sound levels, I mean that they don't go very loud, even with the Bastanis speakers that are quite sensitive.   And there is some music that just needs to be played loudly.

When you turn up solid state amps too loud, they start to clip the waveform, which presents as a harshness to the sound, that makes them sound like they're playing loudly, even if they're not.   The more you overdrive them the harsher they sound as more and more of the waveform gets clipped.

It's quite noticeable at concerts that the music is playing much louder than I listen to at home, without any form of harshness.   What's more, my ears are not what they used to be.  Distant and and mid-field crickets no longer form part of my soundscape, and bats that I used to listen to as a lad now flutter silently overhead.  And a tinnitus left me by an unfriendly ear infection needs to be drowned out as well.

So I have resolved to replace my amps with more powerful ones.  I have chosen these, the NCORE400 amp modules from Hypex electronics, that use the same digital concepts as the Temple Audio Bantams, and have been well-received by the DIY community.  They come in kit form - amp and power supply, you have to put them together, and you can get nice housings for them on the commercial market.  I chose these ones from Ghent Electronics in China.  Putting them together is a bit like plumbing - just a bit of soldering involved, nothing too tricky.

(I suspect that these amps are the ones used in the B&W Zeppelin, since the amps are round - a strange shape for an amp unless it's going into the Zeppelin, and Hypex do supply the amps for it.  And Hypex are explicit that they don't want OEM enquiries for the amps, so perhaps B&W have an OEM exclusive.)

Here's the two amps and power supplies, all nicely wrapped in anti-static bags, laid out ready to mount in the case, and a pic of the modules installed.

Here's what the back panel looks like, and the finished article.

Now when I first plugged it in and turned it on, I did so with the top off the box.  Experience has taught me that if anything is going to go wrong, smoke or other evidence is more quickly and easily seen with the electronics exposed.  I also wired in an old cheap speaker since something that can dump 400 watts of audio into a loudspeaker when it's working properly, could do a lot of harm if it's not working properly.

Click went the switch and phut! went the spark.  Odd, but after that the amp seemed to operate OK, and subsequent switchings on and off gave rise to no spark.  It all seems to work fine.  But then then next day, turning it on from cold produced another spark.  So I contacted Hypex tech support: "is it supposed to do that?"  "Noooooo!"

So this aspect of the project is on hold while we resolve what's going wrong.  Looks like a dodgy power supply to me.  Meanwhile I'll put the other amp together and see if the problem reproduces.


Tim Trent said...

I find I can't stop this bubbling to the surface:

G E E K !

I feel so much better now.

Mark In Mayenne said...

You're right of course! Nerd would do as well :)

James Higham said...

Bastanis seem good. fidelity obviously good. I had Celestion Dittons at one stage, also not bad.

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