[andyr]

Hi Hugh,

For WAF reasons (hehe ... and so I can swing the upgrade to LFs!!  ), I am planning the transmogrification of my 3-way active setup - which currently involves 3 boxes - into a single box roughly 1' square by 2' high.

(Transmogrification is a fair-dinkum word but I can't help feeling it actually means doing a sex-change operation on a moggie like yours!!    )

At the base of this "tower" will be 4 power trannies (here we go again!!    ), with a steel divider above, to stop magnetic interference with the amp modules.

My issue is ... can I have these 4 power trannies arranged horizontally on the floor of my case - in each corner - or will this allow transformer coupling ... in which case, I should arrange them as 2 horizontal (in opposite corners) and 2 vertical (in opposite corners)?

Obviously, the shorter the height of this amp/XO case the better but I do have the luxury of allowing for 2 x 160VA trannies to be mounted vertically, if this is better.

Regards,

Andy

[AKSA]

Hi Andy,

You got it - as you mount trafos left to right, orient each 90 degrees to the previous to ensure magnetic LOF don't interact.

Best for hum.......

Cheers,

Hugh

[andyr]

Hi Andy,

You got it - as you mount trafos left to right, orient each 90 degrees to the previous to ensure magnetic LOF don't interact.

Best for hum.......

Cheers,

Hugh

Hi Hugh,

But I'm not mounting the traffos in a line ... I'm going to mount them at the four corners of the base of the case.

So what do I do relative to each corner? .... put two at each pair of opposite corners like each other?  IE. at the NW and SE corners, I mount the traffos horizontally, and at the NE and SW corners, I mount them vertically, as the hypotenuse across adjacent sides? 

Regards,

Andy

[AKSA]

Andy,

if you plan to mount them at the four corners, and you are using a steel barrier around each (??) then diagonals the same orientation as you say, and thus adjacents would be 90 degrees turned with respect to each other.

I actually doubt it will be important if you are mounting them more than with width of 2 trafos apart.

Cheers,

Hugh

[jules]

Interesting proportions Andy! No only should it look good but you'll also have the advantage/challenge of working in three dimensions rather then the usual two dimensional case.

Will you be using three layers or using the large top section as a sort of cube for both the amps and the pcbs for the actives?

jules

[andyr]

Interesting proportions Andy! No only should it look good but you'll also have the advantage/challenge of working in three dimensions rather then the usual two dimensional case.

Will you be using three layers or using the large top section as a sort of cube for both the amps and the pcbs for the actives?

jules

Hi jules,

I'd love to be able to brag that I thought of that "form factor" but in fact I stole it from marcus!    Xept he just roughed up a box out of MDF offcuts ... whereas I will make mine look much nicer! 

My current thoughts are to just have 2 compartments - the one at the base containing the 4 power trannies, with a steel divider on top, to isolate the trannies from the upper compartment.  Power supplies will be mounted on top of this divider, XO PCBs on the back of the upper compartment and 2 AKSA heatsinks vertically on the front of the case.

Binding Posts will be on the front of the case (directly below the amp heatsinks) - so I will need only very short speaker cables going straight (forward) to the speakers - and the 2 RCA inputs (one from Sub Out for the bass drivers and the other from Tube Out for the other drivers) and the IEC power sockets etc. will be on the back of the case.

I'll build a frame out of 3mm aluminium angle, then the side panels and the top will bolt to this frame and the front and back panels will have piano hinges at the bottom, so they can hinge outwards for repair.

Regards,

Andy

[jules]

Clever, Andy ... and Marcus. The hinge feature will be great for access. You'll be able to make endless mods with great ease  . It's sort of tower computer inspired layout I guess [?]

jules

[aurelius]

Xept he just roughed up a box out of MDF offcuts ... whereas I will make mine look much nicer!

I'm shattered Andy

The MDF, as you so coarsely describe it, is redgum veneer particle board... If only I had have gotten around to installing the fronts, the tops, the solid redgum buttons and varnishing the rest, it would have looked quite good   The problem with audio work is that you can actually get them to be functional well before they are aesthetically pleasing.  Truely a problem when you are as lazy as myself.

It's sort of tower computer inspired layout I guess [?]

More inspired by those big, bloody expensive solid state Australian amps that people were raving about a few years ago... can't remeber their name

I really like the form factor... it makes it look like a piece of furniture.  Mine was constructed as 3 layers, with 15V EI-core transformers and power switch snubber in layer 1, 4 x torroids and the power switch in layer 2, with the remainder of the case being the four amplifier modules (2 per heatsink)  installed vertically at the back, plus the orion active crossover at the front.

BTW, my transformers were installed almost touching each other... I must confess to being a little confused about the concern for transformer coupling each other's fields... what's the risk? Imposing 50Hz hum on top of? 50Hz power? I can understand that if transformers were being used for different audio channels that low frequency crosstalk may be a concern, but if you are multi-amping, all transformers belong to the same audio channel.

A word of advice on building an amp this way.  Always ask yourself, "If component x breaks, or I wish to switch it out, how can I get to it easily".  In trying to create as compact and pleasing a form factor amp as possible, I ended up making something that is about as easy to mod as your average laptop.

I will be, in fact, redesigning the case, almost like a little chest of drawers as such:
Level 1 (bottom): Full 400W UcD stereo power amp sharing a single transformer for stereo subwoofers (sorry Hugh - I mean no disrespect).
Level 2: 4 x 160VA torroids for AKSAs, with power switch and power umbilicals coming out the back, terminating on Neutril PowerCon locking connectors (1 per amp channel).
Level 3 & 4: Stereo 55W AKSA amp modules and rectification/filter boards.
Level 5: Orion ASP and subwoofer crossover & AKSA Feed forward power supply.

In the original design, I eliminated the need for interconnects between the ASP and the amplifiers, but it came at a considerable ease of use expense.  I am confident the new design will be much more flexible.

I think I will try curved fronts with mitred edges for each "drawer".  Should scrub up pretty nice.

[andyr]

Xept he just roughed up a box out of MDF offcuts ... whereas I will make mine look much nicer!

The MDF, as you so coarsely describe it, is redgum veneer particle board...

A thousand apologies, marcus!   

It's sort of tower computer inspired layout I guess [?]

More inspired by those big, bloody expensive solid state Australian amps that people were raving about a few years ago... can't remeber their name

Holcros?

Regards,

Andy

[andyr]

BTW, my transformers were installed almost touching each other... I must confess to being a little confused about the concern for transformer coupling each other's fields... what's the risk? Imposing 50Hz hum on top of? 50Hz power? I can understand that if transformers were being used for different audio channels that low frequency crosstalk may be a concern, but if you are multi-amping, all transformers belong to the same audio channel.

I will be, in fact, redesigning the case, almost like a little chest of drawers as such:
Level 1 (bottom): Full 400W UcD stereo power amp sharing a single transformer for stereo subwoofers (sorry Hugh - I mean no disrespect).
Level 2: 4 x 160VA torroids for AKSAs, with power switch and power umbilicals coming out the back, terminating on Neutril PowerCon locking connectors (1 per amp channel).
Level 3 & 4: Stereo 55W AKSA amp modules and rectification/filter boards.
Level 5: Orion ASP and subwoofer crossover & AKSA Feed forward power supply.

Hi marcus (seriously, this time!!  ),

Re. transformer coupling ... surely the 'high', 'medium' and 'low' frequency bands are just as much 'channels' as L & R?  So you don't want modulation between 'high' and 'low', for instance?

And do you have a divider between 'drawer 4 (AKSA modules & PSes)' and 'drawer 5 (the XO & its PS)'?  If so ... why, pray?

And finally ... are you driving a pair of subs as well as those twin 10" Peerless XLS woofers?    Whew!! 

Regards,

Andy

[aurelius]

Holcros?

Halcros... Nice construction... a bit over priced for my taste!

Re. transformer coupling ... surely the 'high', 'medium' and 'low' frequency bands are just as much 'channels' as L & R?  So you don't want modulation between 'high' and 'low', for instance?

I guess so... I would have thought that the crosstalk would be so down on dB compared to the main signal that it would be comparative to residual out-of-band signal after XO filtering...  No real experience though... pure speculation.  I'm sure Hugh could offer some real insight.

And do you have a divider between 'drawer 4 (AKSA modules & PSes)' and 'drawer 5 (the XO & its PS)'?  If so ... why, pray?

I don't in my current set-up, but will in the future.  Why?

Construction ease is one reason; the other is unfounded and unscientific paranoia, coupled with a pinch of gullibility and too much disposable income...  pretty much par for the course for a participant on an audiophile website 

And finally ... are you driving a pair of subs as well as those twin 10" Peerless XLS woofers?    Whew!! 

I am not now, but may in the future.  I will start with a pair of Linkwitz Thors (12" Peerless XLS), but will probably entertain myself at some point in the future with Steve Deckett's Imperial SO.

[AKSA]

Construction ease is one reason; the other is unfounded and unscientific paranoia, coupled with a pinch of gullibility and too much disposable income...  pretty much par for the course for a participant on an audiophile website

I thrilled with inner delight when I read this.......

My golly, Marcus, 'Et tu, Brutus'??? 

The external field of an EI is maximal at idle;  quite the reverse of a toroid.  So, if using EIs, there is good sense in separating them and orienting adjacent trafos at 90 degrees to prevent augmenting the fields, which are considerable;  but no such issue with toroids.

Cheers,

Hugh

[aurelius]

 

My golly, Marcus, 'Et tu, Brutus'??? 

Wrong Emperor Mr Dean!  To any who might take offence at me poking fun at myself and our hobby, I would refer you to Marcus Aurelius Himself; "Reject your sense of injury, and the injury itself disappears." 

[AKSA]

Indeed, or, a modern day equivalent of Eleanor Roosefelt's famous comment:

'People can only hurt us if we allow them to'.

Cheers,

Hugh