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Old 30th March 2013, 03:36 AM   #71
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Quote:
An umbilical carrying 2300VDC is decidedly unsafe.......It can be done safely.....We routinely have a 45kV umbilical in the lab.
It can be done. I used to maintain some laser systems that ran 25 KV at 1/2 Amp through the same umbilical that carried the cooling water. These laser systems ran 24/7 and failed often, sometimes quite spectacularly, but never because of the umbilical cable. Check out the X-ray machine in your dentist's office. That movable X-ray head that gets shoved right next to your face runs on 75 to 100 KV.

I built my 845SE on two seperate chassis, one power supply, and one stereo amp. The power supply is the smaller of the two, but the heaviest. I used test probe wire rated for 5 KV and ordinary Cinch-Jones plugs for the umbilical. Only 1100 volts though.....

Quote:
Thoughs landfall chassis a really pricey.
Not when you consider the cost of the other parts. I am building an amp in a Landfall box. Why, because 40 pounds of 200 watt tube amp goes into a 3 RU box that will see some mechanical abuse. A thin Hammond or Bud box will bend under the pressure.....No, I won't park a truck on it, just put it into a portable guitar rig.
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Old 30th March 2013, 12:42 PM   #72
Magz is offline Magz  United States
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Quote:
Originally Posted by tubelab.com View Post
It can be done. I used to maintain some laser systems that ran 25 KV at 1/2 Amp through the same umbilical that carried the cooling water. These laser systems ran 24/7 and failed often, sometimes quite spectacularly, but never because of the umbilical cable. Check out the X-ray machine in your dentist's office. That movable X-ray head that gets shoved right next to your face runs on 75 to 100 KV.

I built my 845SE on two seperate chassis, one power supply, and one stereo amp. The power supply is the smaller of the two, but the heaviest. I used test probe wire rated for 5 KV and ordinary Cinch-Jones plugs for the umbilical. Only 1100 volts though.....

Yes, I agree it can be done, in the proper environment. I've worked in an analytical chemistry lab for the last 32 years, we have lots of very HV equipment such as mass spectrometers and inductively coupled plasma spectrometers, and in a lab environment where users are degreed professionals and there is no chance of children touching or dogs chewing or drunken party guests probing that is accepted practice. I however am not as comfortable having that type of voltage accessible in a home environment.

So...the HT will be in one box because that's what's safest and (secondarily) that's what will fit in the space allotted...it's my Midlife Crisis, after all
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Old 30th March 2013, 01:07 PM   #73
Magz is offline Magz  United States
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I've layed the components out on an 18"x22"piece of posterboard to see how they'll fit (see pic).

The filament trannie will go under the big 733A trannie (inside the box, bolted to the back plate) so it's not on the posterboard. The two white spaces are for the 833 B+ choke (back corner) and the OPT (front right corner). I think I might upsize slightly to 19"x23" for a bit more breathing room. Since the 369KX and 733A transformers, the 833 first choke and the OPT will be on top of the box I have a little more room than it looks.

Good thing I'm using the AOT1N60 driver setup in the schematic, there's no way I'd fit another stage of tubes and their associated peripherals in there, nor could I fit a bridge of 3B28s with their filament supplies for 833 B+. As it stands, the driver board will be fit into the white space near the tube socket and the rectifier boards will go along the side walls of the box.

The input from the preamp will come in on the left front side directly beneath the 6E5P tube socket. The output will exit on the right front side directly beneath the OPT. The left and right monoblocks will be mirror-imaged to achieve the shortest and most direct signal path from preamp to amp to speakers.

The fan shown will be located under the 833, which will be enclosed in a 6" OD pyrex glass tube with a vent cap on top.

This thing is about 80% power supply!
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Old 30th March 2013, 02:25 PM   #74
Funker is offline Funker  Germany
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Hi,

Quote:
Insanity indeed - but a good crazy!
100% agreed!

Only crazy people create crazy projects.

@Magz: Good luck with your unbelievable project!

73
Wolfgang
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Old 30th March 2013, 04:02 PM   #75
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Originally Posted by Magz View Post
I've layed the components out on an 18"x22"piece of posterboard to see how they'll fit (see pic).
My rule of thumb, (sometimes painfully) learned from many electronics projects since I am able to hold a soldering iron: Plan the area needed for your layout carefully, then increase the estimated area by a factor of 1.5 to avoid problems that are difficult to solve later on...

Rundmaus
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Old 30th March 2013, 09:20 PM   #76
nhuwar is offline nhuwar  United States
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Originally Posted by Magz View Post
my Midlife Crisis, after all

Hey Magz, I'm right there with you. Sorry if I came across wrong.

Its a great project and I wish you the best for it.


One day I'll be building my own mid life crisis amp. Hopefully in my late thirties. Hey I'm impatient, Lol.

What will this beast be driving?

Nick
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Old 30th March 2013, 10:11 PM   #77
Magz is offline Magz  United States
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Originally Posted by nhuwar View Post
Sorry if I came across wrong.

No Sweat. I appreciate the interest and suggestions.


Quote:

What will this beast be driving?

Nick
These Infinity RSIIb speakers, circa 1984.

They have been gutted and rebuilt by me with separate external crossovers in boxes behind the speakers, and new EMIM midrange diaphragms made by Apogee Acoustics in Australia. All wiring is Cardas copper Litz in Teflon.

They like power.
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Last edited by Magz; 30th March 2013 at 10:15 PM.
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Old 2nd April 2013, 01:34 PM   #78
nhuwar is offline nhuwar  United States
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Quote:
Originally Posted by Magz View Post
No Sweat. I appreciate the interest and suggestions.




These Infinity RSIIb speakers, circa 1984.

They have been gutted and rebuilt by me with separate external crossovers in boxes behind the speakers, and new EMIM midrange diaphragms made by Apogee Acoustics in Australia. All wiring is Cardas copper Litz in Teflon.

They like power.
Very nice.



Keep us posted on your second mortgage, LOL.
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Old 2nd April 2013, 03:38 PM   #79
Magz is offline Magz  United States
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Update: Just ordered two 18" x 22" x 4.25" chassis from Landfall in plain brushed aluminum finish. Once I have made all the appropriate holes and cutouts and tested things, I will disassemble and send them back to Landfall for finishing in the finish and color of my choosing.

I think that's a really nice service to be able to get the finishing done by the same vendor after I have cut it up - I don't need to worry as much about minor mishaps marring the finish in that way. Also, unlike Front Panel Express, the panels can then be anodized on the cut edges for a more finished look.
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Old 2nd April 2013, 07:00 PM   #80
hpeter is offline hpeter  Europe
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have you been considering other big tubes?
tri tetra penta ?
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