Thinking Out Side Of The Box - The Copper Box 2A3

[Spectral Morn]

As some of you are aware I have my own online magazine and sometimes items that come in for review require extra careful system/component matching in order to get the most out of them (1). Over the years I have been asked on many occasions why I keep so many bits of audio equipment at home, some of which don't get used that often and my answer is simple in order to give me as broad a range of items to be able to review other kit with; especially if there should arise incompatibility issues.

Recently I have had to take out of storage a pair of old reference speakers Ruark Equinox's in order to review a low powered 300B amplifier. It was just not able to drive my Anthony Gallo Ref 3.1 speakers, though it made a stab at it. The Ruark's are wonderful speakers but when the Gallo's came along I abandoned them as frankly the Gallo's are better speakers (they still are) but re using the Equinox's has made me appreciate them in a whole new light and especially in light of another left field audio encounter.

http://i549.photobucket.com/albums/ii364/davros124/004_576x768.jpg

Deciding to use the Gallo's as my references has by necessity meant I have had to use higher powered solid state amplification of 75 to 100 watt valve amplifiers (2) However with the Ruark's in the system I decided to revisit a failed experiment in which I had borrowed a DIY, sort of clone, low powered valve amplifier (can be used as either an integrated or power-amplifier) with quite interesting results now.

The first time round it was a total bust, flat lifeless sound, no drive at all. It was driving the Ref 3A Dulcet's which can be just too awkward for some low powered valve amps. Though they have sounded fantastic on the end of some; such as the Ecofan 6A3 amplifier.

In some audio circles in Northern Ireland there has been for many years hushed whispers about the amplifiers built by a certain member of the ulster orchestra, products of his own individual audio journey; which has for the most part kept him away from conventional audio retailers. I must confess many years ago (20 or so) at feeling a tad frustrated that he and a few of his colleagues kept away from buying kit from the business I worked in at the time. However I can now say I see why; or maybe I should say I can hear why that was.

There was three amplifiers built by this gentleman, all based on part or whole on Audio Note amplifiers using Audio Note parts. One uses 211 valves, one 2A3's and the other....well I am not sure enough to say. However they were all called Copper Box as the cases are made from Copper.

The amplifier I have been using recently is the Copper Box 2A3 which I am told had quite an online following at one time, even having a website devoted to it (now closed down). This amplifier comprises, or so I am told the front end of an Audio Note On-Gaku and the back end of an Audio Note Neiro.

It is 7 watts a channel, class A, 2A3, parallel single ended,valve rectified design with solid point point to point internal construction, switched attenuator volume controls (separate left and right) and front mounted 1 to 3 inputs and 1 direct input for direct connection to a pre. I can't tell you much more than that technically (hopefully the photos will).

http://i549.photobucket.com/albums/ii364/davros124/030-1.jpg

http://i549.photobucket.com/albums/ii364/davros124/032-1.jpg

http://i549.photobucket.com/albums/ii364/davros124/033-1.jpg

It has been built front to back, with as short as possible cabling from the inputs to the volume controls to the pre to the power amplifier section. The transformers and rectifier are shielded in their own box from the rest and the case is made from copper.

http://i549.photobucket.com/albums/ii364/davros124/015.jpg

http://i549.photobucket.com/albums/ii364/davros124/010.jpg

http://i549.photobucket.com/albums/ii364/davros124/012.jpg

http://i549.photobucket.com/albums/ii364/davros124/009.jpg

http://i549.photobucket.com/albums/ii364/davros124/007.jpg

http://i549.photobucket.com/albums/ii364/davros124/008.jpg

How does it sound ? In a word lovely, powerful, dynamic, detailed, open, musical with great poise and delicacy and the bass is very good too. There is also very little noise too. I have to say this has been a real eye opener and it has really forced me to think outside of the box I have been operating in for quite a while now. Don't get me wrong there has and is nothing wrong with where I have been but this amplifier is I fear going to force a rethink (hence thinking outside the box) of the hard to drive speakers, high powered amplifiers approach I have been taking recently.

To broaden this out a bit and really the main thrust of this post, would the membership care to share your occasions for thinking outside of your own particular audio boxes?

Regards D S D L

**NB** All photos Copyright Adventures in High Fidelity Audio 2011

(1) Its not always possible to slip a component in for review into ones reference system and it work from the off/sound as good as it can. Quite often I think the reason items reviewed elsewhere don't do as well as they should is failure to take this into account, not being able/or flexible enough to make changes to do so, or items not being run in properly.

(2) Bat Vk 75 (75 watts) Music Reference RM 200 (100 watts)

[Welder]

Talk to yer man Eric van Voorst. He knows a thing or two about thinking outside the box…..well just thinking in fact he seems pretty good at :stalks:
He’s not going to go down well here is he :lolsign:

[Spectral Morn]

Talk to yer man Eric van Voorst. He knows a thing or two about thinking outside the box…..well just thinking in fact he seems pretty good at :stalks:
He’s not going to go down well here is he :lolsign:

Would help to know who he is. A link would be useful.


Regards D S D L

[Welder]

There you go. Sry, i thought you would have seen his intro;
http://theartofsound.net/forum/showthread.php?t=11349

[Spectral Morn]

There you go. Sry, i thought you would have seen his intro;
http://theartofsound.net/forum/showthread.php?t=11349

Cheers missed that :doh: wow :)


Regards D S D L

[Welder]

Wow indeed ;)

[Reid Malenfant]

To broaden this out a bit and really the main thrust of this post, would the membership care to share your occasions for thinking outside of your own particular audio boxes?
Yes, i can do that but not yet with an amplifier - you'll have to wait for those :eyebrows:

Ok, so i'm in the process of designing a new pair of loudspeakers. These will be the last pair of front speakers that i'll use on my system, i may well make other oddities for surrounds or whatever.

To cut a rather long story short i can't use ports in the enclosure because i can't make them big enough to flow enough air without causing turbulence & consequently distortion. If i make them bigger then the first port resonance where it'd act like an organ pipe will be in the passband. I can't use any passive radiator that i know of that can be purchased.

So i'm going to make my own passive radiators with the parameters that will make the enclosure work. Here is what i made back in 1996 (http://theartofsound.net/forum/showpost.php?p=215387&postcount=23) to fit to a different enclosure & it worked perfectly on the first try! It doesn't look very pretty but i can make sure the new ones look the part. What you see there is the remains of two 16" motorcycle innertubes cut up & bolted & glued together with an aluminium plate & MDF as the frame ;)

If that's not thinking out of the box i don't know what is :eyebrows:


E2A:- That copperamp is a thing of beauty!

[Spectral Morn]

Interesting Mark, very interesting.


Regards D S D L

[John]

I heard these awhile back at Tim's
http://www.pmc-speakers.com/product.php?mode=view&pid=22
Using a 400 watt amp They go down really low and very detailed but the sound was sluggish, it might of been system synergy, but I left not very impressed by them.

[SPS]

How does it sound ? In a word lovely, powerful, dynamic, detailed, open, musical with great poise and delicacy and the bass is very good too. There is also very little noise too. I have to say this has been a real eye opener and it has really forced me to think outside of the box I have been operating in for quite a while now. Don't get me wrong there has and is nothing wrong with where I have been but this amplifier is I fear going to force a rethink (hence thinking outside the box) of the hard to drive speakers, high powered amplifiers approach I have been taking recently.

To broaden this out a bit and really the main thrust of this post, would the membership care to share your occasions for thinking outside of your own particular audio boxes?

Regards D S D L




i too when down a very similar route, but i started with higher efficency speakers whilst learning about valve amps at the same time, the two go hand in hand

my route has taken me to single ended amps which in my view is where the best sounds are.. with matched speakers.

that amplifier looks very nicely built and will sound much better than most

and i would also guess that it could be improved on....

most of the guys that i know that make their own amps have all been down the solid state/ low eff speaker route.
if ending up with lower power valve amps and that in turn is thinking outside the box...well.. alot think outside the box.. its just that not many with shop bought kit can /wants to believe what can be achieved, so our comments are not understood

to me its just experence of different types of kit and knowing what sounds the most real

the trouble is the very best kit is expensive... and usually diy like that copper amp

[The Black Adder]

Risen from the grave.

Just found this... wow, what an unusual amplifier. I must have missed this back in 2011. Never seen one before.