Ultimate 4U 500mm Chassis - Who is interested?

[gary s]

That toroid will definitely not run out of steam with something like 30 amps secondary capability.

Just how I will do my PSU - CLCRC, you can't complain about 0.5mV ripple.

What value chokes did you use?

 

[2 picoDumbs]

I think I had 15mV ripple on my monster supply, but they were monoblock power supplies driving a 2A load per monoblock, not stereo

 

[ozorfis]

-Regarding ripple: I have to correct myself - it is 2.5 mV RMS at full bias (measured with Fluke 179)
- I used these chokes 10mH:
Blocked As the resistance is quite low I was afraid of a voltage spike caused by the high inrush current. But the softstart should have taken care of that. Although I will measure this later.....
- I did test with an old speaker and it was dead silent and sounding quite good
- adjusting distortion at the moment, which is a bit of pain as P3 does all kind of things on the BA-3 gain stage
- Soundcard is the awesome RME ADI-2 PRO FS and Software for FFT is ARTA Freeware: ARTA Download
- Pico has eagle eyes - the LEDs on the front I kinda forgot
- as some had mentioned: there are plastic feet included, which are good enough for me - also much more screws than needed, which is nice
- I should get some sleep now......

 

[2 picoDumbs]

Now time for a sound test.

 

[Blk Dynamite]

Good work so far, you have been very busy. That toroidal looks massive sitting in there, must be 1kva at least. Also notice you are using a CLC supply with the two iron cored chokes.

Have you had a listen to it yet?

Blk Dynamite - I am the opposite, have all the parts ready and boards loaded to do a Stasis build on my 1st enclosure.

Nice!! I shouldn’t be too far behind you hopefully. Also i was planning on using a similar clccc arrangement for the power supply. I want to stuff as many caps in mine as possible hence me wanting to see the chassis in person before I ordered more parts

 

[gary s]

In a message to me, Nelson mentioned not to scrimp on the PSU caps. I can see what you are saying as the big chassis mount can caps do quickly take up real estate in the chassis. I have some big air cored chokes instead of iron core I want to use in the PSU to see how they perform. I want to take my time and do a very neat job with the build - as it deserves it.

 

[Blk Dynamite]

Yup same here

 

[ozorfis]

There´s just no class quite as class A

Now time for a sound test.

I couldn´t resist converting it to stereo and give it a listen. Ohh boy there I am standing with goosebumps all over - best indicator for when things are right.

Yes I can hear humm up front in stereo and yes the distortion is higher than expected. But this result with my old speakers and without burn-in is very promising. I would describe it as relaxed and just real.

There´s just no class quite as class A

 

[2 picoDumbs]

Nice one.
Absolutely, Class A is where it's at.

Hum could possibly due to radiated hum field or ground loop.

The ripple on the supply was good, so see if you can fix the hum issue.

 

[ozorfis]

Thank you very much for all the good advice. I cannot hear the humm from my couch and it is knocked down to almost inaudible in bridged mode with ears to the speaker that is.

Sooo what I will do is listen to this amp while building the other one and move the transformer further to the front panel, by drilling some extra mounting holes in the base plate, I will also measure the distortion of the gain stage before putting it in this time around. Maybe I will measure the matched JFets from the shop just to be sure. Any improvements achieved in the 2nd build will be adopted to the first.

Life is good

Funkadelic - Maggot Brain [HQ] - YouTube

 

[2 picoDumbs]

You shouldn't be able to hear it at all.

My supply has 15mV ripple and it is dead silent with my ear next to speaker.

 

[2 picoDumbs]

Yeah funkadelic is cool.
Bootsy Collins

 

[AudioSan]

Hahah, sounds about right! So, are there feet? They might be 10mm. So, outside dimensions are gonna be 373 x 175 x 500mm W x H x D ???

No one was able to answer this?
Well. No the outside dimensions are 450mm wide, 180mm high (+feets) and 510mm deep (+ speaker connections)

 

[Mrdrewk]

@audiosan thank you very much! My boxes are due to arrive Monday. And this will help for furniture planning for sure.

 

[AlexRivera]

@Gianluca,

Will the Chassis be available in Silver Front Plate again?

I want to order 2

Thanks,
Alex

 

[Gianluca]

Hello Alex,


We only have black front panels left, silver ones are already sold out. Sorry!


If you don't mind having your front panels drilled but not reanodized after we can make a couple just for you. On silver front panels you are not going to see the difference anyway

 

[AlexRivera]

If you don't mind having your front panels drilled but not reanodized after we can make a couple just for you. On silver front panels you are not going to see the difference anyway

Thanks Gianluca, that works for me, what's the best way to put this order?

Should I go to the site, Order them in black, pay with paypal and make some notes about it or?

Thanks,
Alex

 

[Gianluca]

Try again now, you should be able to choose silver front panels

 

[AlexRivera]

Try again now, you should be able to choose silver front panels

That worked!!

Order is in, I'll send the money in a bit .

 

[HeyBill]

Got both chassis. Two of the covers had corner dings and lost paint where the box had been damaged. Minor problem. I will use them as bottom covers. Too much hassle for perfection. Not your fault Gianluca. They were well packed. Thanks again to everyone for the success of the group buy. Bill