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In the Forum: Melquiades Amplifier
In the Thread: Planning my DSET
Post Subject: Fleshing out the design a little more...Posted by anthony on: 7/29/2015
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 Romy the Cat wrote:
 anthony wrote:
 Then the AC-DC conversion on the first floor, filter caps and output transformers on the third level with the amplifiers sitting proud on top.  I don't want to see any caps or transformers...just valves.
Possible, even I like more the idea of separation of PS and control circuit on the different chassis. The vertical towers work very well with SS amps. With tube and particularly with input choke DSET you will have a lot of LF vibrating high mass element and you won’ be able to quite them down. But this is juts might personal take. What is non-personal and absolutely certain is that you can’t put the last cap in your PF at the different floor then your tubes. The caps need to be right there in very close proximity to tube. If you chose to have large caps then the accommodations need to be made. If you have unlimited heights then you can make the 2 floor of the caps and the third of the tubes. 

Yes, I think that the separation of the PS and amplifier is very important to make this all work to properly.  I have fleshed out the design a little more.

First of all the footprint has been increased from about 300mm square to about 400mm square as there was just no way to get all of the OPT's close to their power tubes with the smaller size.  As it is now there is spare room up top with the valves and I am considering whether to introduce a curved roll-off from the top surface to the sides rather the the square "industrial" look.  I am not sure.  I will have to draw it to see what it looks like.

As drawn below, each mono-bloc will stand somewhere around 1m tall.  I think that this will work well when you consider that the Upperbass Horn will stand about this tall and I plan to snuggle each mono-bloc in behind and immediately beside the horn stack, and with the speaker cables coming out at a little under that 1m height I can keep the speaker cables very short.  If I keep the amps in nice and close to the horn stack perhaps all I will see of the amplifiers from my seat will be the tubes thus helping to make a visually large audio system seem a little smaller when seated.

Notice that not all of the components are shown in these sketches.  The OPT's (in an off-yellow/light brown) have not been chosen so I do not have exact dimensions and have used cuboid of approximately the right size.  All the filter caps are shown, but the smaller caps for the bias are just randomly placed in their approximate positions along with a few of the associated components.  There should be plenty of room under the top plate for amplifier components (caps ans resistors) and if necessary I can spill into the vacant space of the layer below for parts of the crossovers.


DSET Tower - Early Days #1.jpg


You can see that I plan to use vibration management in two places on the amplifier:  firstly under the entire amplifier with a constrained layer platform sitting on springs so that hopefully vibrations above 5Hz or so are not transmitted from the floor to the amplifiers;  secondly using the same system internally for the power supply which I intend to keep highly isolated from the amplifier section above it.  The brown three layer sandwich is the constrained layer platform but I have not drawn the springs.


DSET Tower - Early Days #2.jpg


In the shot below you can see the placement of the OPT's.  They are very close to the centrally located large filter caps and only a few inches from their respective tubes keeping the B+ voltage lines short.  You can also see the Bourns potentiometers (in blue).  I plan to have these situated behind two little drop down doors.  This way I keep the knobs out of eyesight.

DSET Tower - Early Days 3.jpg


Lastly, this shot shows the location of the smaller filter caps for the bias and a little more of the location of the large B+ filter caps.

DSET Tower - Early Days 4.jpg



AC and DC wiring may be able to be transported from the power supply section to the amplifier section inside one or more of the eight chassis columns.  Perhaps run a PVC tube up the centre of the column and glue some rubber grommets at the entry points and the wiring would be neat and tidy.  I am not sure sure of the electrical consequences of running the wire inside a number of steel bars, but hopefully it will be ok.

Opinions and insight are appreciated.

Regards,

Anthony
EDIT:  Not sure why the images are not showing up properly.  Romy?

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