[jh4db536]

i really like the idea of 1 amp 1 box. it seems difficult to find something the right dimensions for this.

i did like those cases from europe, but the cost after shipping and vat ugh. i am trying to complete this project for under 1000; so far i have spent just over 800. i am trying to put 'value' in DIY and still get something very high performance and functional. this is the reason im only using 1 sigma22 for now...i can always upgrade to 2 later. I choose the JT attenuator even though it was a hefty step up in price from the dact or goldpoint and takes up more space. i learned from my apache that 24 steps just isnt enough.

i might go with the context engineering desktop or rack style since it's very easy to get any dimension. i am not sure how much it costs though not even a estimate. it looks very simple for the manufacturer to customize though so i hope it will fit the budget.

 

[linuxworks]

just to re-re-restate things, most one-box installs have hum.

strongly advised to go 2box.

 

[jh4db536]

thanks for the advice. i built another project before and it had the hum because it was in 1 box (no ground loop breaker either). the hum was very apparent (and annoying) in single ended mode. as soon as i switched to balanced (all else equal), the hum went away. i only intend to use all 4 boards with xlr i/o and i dont have any SE cans.

what do you think? i am really would like to avoid the cost of 2 boxes and particularly the umbilical cord. i hate the idea of umbilical cord/connector with a passion even properly and nicely implemented in the commercial amps i have. i havent seen a solution to this problem yet in all the builds i have seen. i would love a wireless energy transmission solution or something.

the only reason i want to have a separate enclosure for the PS is so that i can make a universal PSU box that i could use with any project. load it up with 2 sigma22, a sigma11 with interchangable gain/Volt out, and all my low current PS's

 

[linuxworks]

AMBs own gear is 2 box.

you draw your own conclusions. he could have built a 1box system just as well.

you can fight it or just accept it

I fought it, too; so I know where you're coming from. but trust us, the 2box solution is the better (measuring) one, to be sure. I'm quite certain. do the RMAA on a 1box and a 2box and you'll see.

 

[johnwmclean]

Put the trannie in it's own small box, similiar to a large wallwart in size.

 

[linuxworks]

Quote:

Originally Posted by jh4db536 /img/forum/go_quote.gif i would love a wireless energy transmission solution or something.

learn to play the guitar.

(LOL!!)

 

[Beefy]

Quote:

Originally Posted by linuxworks /img/forum/go_quote.gif just to re-re-restate things, most one-box installs have hum. strongly advised to go 2box.

But it is absolutely doable. For only $30-50 over a standard transformer, you can get a fully shielded unit from SumR. You will easily make that money back in reduced casework.

 

[linuxworks]

I wish there was a good a/b compare of the sumr trafo and a non shielded one in a 1box config. I'd love to see hum data. I'd love to be convinced. one-box sounds so much easier from a build POV. but I'm not convinced it will measure better. and isn't the b22 and b24 all about best in class, even at the measurement level?

ease of build comes 2nd, doesn't it, when it comes to ref class audio gear?

 

[Magsy]

Quote:

Originally Posted by jh4db536 /img/forum/go_quote.gif finally done that was long but i am sad it was fun stuffing the boards. i matched everything on the list down to q15,16. since i only plan to run 1 sigma22, i upgraded the heatsinks on it - this is serving only headphone duty. im still undecided on the chassis...

Hehe I know how you feel, when I finished the fourth board I'd had enough but then later I had an empty feeling that there was nothing left to solder in

I was not sad to see the back of the wiring however!

Build looks great and you are pretty close to some good times

I think one box is fine. Mine is not in its box yet but I have the trafo ~5mm away from the PSU board and only ~10mm away from two of the amp boards. I am in balanced mode and using HD650's but I have no noise whatsoever, at full whack with no source playing there is nothing but silence; its quite remarkable really, dead black.

I do have a Schuro shielded trafo but I'm not sure how good or not it is? It's all in german so I don't know the level of shielding but it does look high quality.

 

[Beefy]

Quote:

Originally Posted by linuxworks /img/forum/go_quote.gif I wish there was a good a/b compare of the sumr trafo and a non shielded one in a 1box config. I'd love to see hum data. I'd love to be convinced. one-box sounds so much easier from a build POV. but I'm not convinced it will measure better. and isn't the b22 and b24 all about best in class, even at the measurement level?

My M3 is a two box build, and a shielded unit from SumR still dropped the noise floor audibly.

I'm pretty sure n_maher fixed humming builds B22 with shielded SumR units.

 

[Magsy]

This is how my mess looks at the moment, I've had it like this for over 100 hours and it is silent!

 

[Helmore]

How well would it work to try and build an internal compartment in your box itself and then put the trafo and PSU in that separate compartment? A couple of aluminum plates should be enough to separate the trafo and PSU from the rest of the amp. A bit similar to this for example: http://www.audio-gd.com/enweb/pro/pre/C-2new/C2N5.jpg
Does anyone have any experience with this approach? Would it be (too) hard to properly implement and would the result be worth it?

 

[wink]

Aluminium plares are no good, they have the same shielding properties as air.
You need a grounded steel plate or a Mumetal plate for shielding.
Or distance - as in a 2 box solution.

 

[Beefy]

Quote:

Originally Posted by Helmore /img/forum/go_quote.gif How well would it work to try and build an internal compartment in your box itself and then put the trafo and PSU in that separate compartment? A couple of aluminum plates should be enough to separate the trafo and PSU from the rest of the amp.

As Wink said, aluminium doesn't actually shield magnetic fields.

Again, calling on n_maher's experiences, he had a one-box build that *nothing* fixed, until he popped a shielded SumR unit in there. It really is a fantastic fix if you don't want a two-box build.

 

[Magsy]

Quote:

Originally Posted by Helmore /img/forum/go_quote.gif How well would it work to try and build an internal compartment in your box itself and then put the trafo and PSU in that separate compartment? A couple of aluminum plates should be enough to separate the trafo and PSU from the rest of the amp. A bit similar to this for example: http://www.audio-gd.com/enweb/pro/pre/C-2new/C2N5.jpg Does anyone have any experience with this approach? Would it be (too) hard to properly implement and would the result be worth it?

If you are in the Netherlands don't bother messing around, buy mine ( Schuro - Preislisten für High-End Ringkerntransformatoren ) from Schuro, it is 41 euro and I know it works. I don't think you get a trafo for much less than that anyway