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Gear / Technical Help => Playback Forum => Topic started by: BCostigan on March 12, 2005, 07:24:06 PM
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I've been thinking about building one....not that I can do it any cheaper or even better than those out there but it's snowing again and I'm bored. :)
My plan is to feed 3-4 hubbell hospital grade duplex receptacles each with a 250VA isolation transformer. One duplex receptacle would be supllied buy 2 250VA isolation transformers connected in paralell. This duplex receptacle would be designated for the amp(s). I would also have some sort of resetable overcurrent protection @ 15A. This would all be in some type of hammond enclosure...not sure which one yet.
What do you guys think? I'm trying to decide if I want to make it the size of a component and have it with everthing else.....if so the chasis would be 17"x10"x4". Would it be better on the floor?
I'm also working on the "blinky light factor". Power indicator led, toggle switch on/off, volt/amp indicators (trying to find some lighted analog ones :) )
Any ideas on how I can best do this or even where to find some of the parts is VERY appreciated!
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I think it's a great idea.
check out the jon risch balanced power conditioner:
http://www.geocities.com/jonrisch/catch2.htm
he has some parts listed in his paper.
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very cool Brian! go for it...
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I think it's a great idea.
check out the jon risch balanced power conditioner:
http://www.geocities.com/jonrisch/catch2.htm
he has some parts listed in his paper.
+T for that. I think tracking down the right parts is gonna be the toughest part!
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Equitech sells blem transformers. Here's the link:
http://www.equitech.com/products/seconds/seconds.html
5A is a little low for many amps; I'd like a little more headroom in there.
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Equitech sells blem transformers. Here's the link:
http://www.equitech.com/products/seconds/seconds.html
5A is a little low for many amps; I'd like a little more headroom in there.
Thanks for that link. +T
One of the transformers elbarto listed is rated at 8A. 8A should be plenty for me even if I get a center, sub, and surrounds and crank the whole system. Even with all speakers being driven my amp shouldn't pull more than 700 watts or 5.8A. This leave me with 2.2A for CD/DVD etc which is plenty.
The enclosure is troubleing me. What do you guys think? If it were you would ya want the unit on the floor or in your rack? The size of the transformers is kinda throwing things off........
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Well....here's what I've decided on so far:
Enclsure:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=4660&item=3880323760
Transformer:
part#798.1202; 115primary/115secondary; 1000VA toroidial isolation transformer
http://www.toroid.com/standard_transformers/isolation_transformers/isolation_commercial.htm#Data
Volt meter (blinky light fun factor):
http://www.martelmeters.com/products.php?cat=16&action=detail&id=83
The front face will have:
crome toggle that turns the whole unit on/off
blue led power indicator
voltmeter listed above
10A panel mount replacaeable bus type fuse
Rear panel will have 6 hospital grade duplex receptacles.
I'm thinking for an increased fun factor I could add 6 more toggles and indicator lamps (one per outlet) so that I could turn individual components on and off.....maybe even fuse them individually based on manfgr. specs for max current draw.
This is gonna be fun! ;D Now to appropriate the funds to build this thing....looks like the parts cost is about $400 ($300 minus the voltmeter). :-\
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Brian,
I know that some power supply thingies I have seen have shyed away from using a lot of lights/etc. as they believe it could introduce noise into the signal?
Just a thought. Not sure what with all the blinking lights and all if that is a concern on a power conditioner. I'd rather have a bleak black box with an on switch than a fancy blinky one that introduced noise. ;D
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Brian, since you're the electrician, I'm sure you can answer this one: Why not use a PTC resettable type of fuse? Are they not as safe as glass fuses or some other kind that actually "blow" and need to be replaced? Are they meant for smaller currents (more in the 1A range, than the 10A you propose)?
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Good point Nick! I was actually thinking I'd need to add another small xfmer for the lights etc due to voltage constraints.....good call no blinky lights! (well one non blinky 120v indicator)
Matt.....quite honestly I'm not too familiar with PTC fuses. I decided to go with a bus type fuse because:
it's cheap, effective, and fuses are readily available
A resetable option leaves the window open for operator error.
By operator error I mean than people (myself included from time to time) usually just keep resetting and triping the device until the problem gets "cleared" or the overcurrent device burns out. Forcing the operator to change the fuse gives them time to think "hey....maybe somethings wrong".
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Good points on the resettable fuse too Brian...
I'd be interested in seeing what you can make this for cost wise... sounds like a fun project none the less. What is your highest cost now sans blinky lights?
Are the hubbell receptacles now the most costly part? Being our resident electron mover and shaker, I ask you, what is it about these "hospital grade" receptacles that makes them so expensive? I just wonder if other specialized receptacles used in other applications other than in the hosipital where clean power is a must are any cheaper but of similar build quality, etc.
Does the "toroidial isolation transformer" somehow clean and hold the power? I am so n00bish I feel dumb asking that question :P 8) I do know that my amplifier has one though ;D
Then again, I know virtually nil about electrical stuff so who knows ;D
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Cost is still about $400 with voltmeter $300 without. I was going to power the voltmeter off the load side of the xfmer terminal bus....I guess I could put one on the line side as well but it's cost prohibitive.
Hospital Grade receptacles. There are 3 "grades" of receptacles: standard (what most folks have in their house), commercial, and hospital grade. Hospital grade receptacles are just the most rugged well made of all 3 categories. Hospitals have their own set of standards for elec, gas, plumbing etc. that are more strict compared to most buildings. All installations but be of the highest quality for obvious reasons.
Hubbell just has the most respected name in the business. If the local supply house quotes me a significantly better price on another brand I'll go with them. I don't expect to pay more than $10 per duplex.
If anyone wants me to build this for them I'd be happy to! You just buy the parts I'll donate the labor as I'd like to make a prototype and maybe try selling these.
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Hubbell just has the most respected name in the business. If the local supply house quotes me a significantly better price on another brand I'll go with them. I don't expect to pay more than $10 per duplex.
Thanks for the good explaination! I've seen those wall recepticals priced so high ($49 (http://www.psaudio.com/products/powerport_overview.asp)) that I was curious why not go with a lesser known brand that is also hosipital grade ($15ish (http://store.yahoo.com/electricalsupplies4less/basiwiwistsi.html)).
Neat stuff..!
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Brian,
Here is more to chew on;
http://www.marinco.com/hospital.htm
I'm clueless to pricing, quality comparison, availability, etc. I just thought I'd throw this out there as another possible source for you.
Thanks Moke. I'm also wondering if I should hard wire the unit or use a female IEC connector......
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IEC
That's what I figured too.....the cost keeps going up!
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Then you can experiment with power cords ;D
I personally would like no lights on the front... The lights on my Moon gear burn holes in my retinas and that's annoying. I'm all for gear that can go into stealth mode.
And I'd make it sit on the floor. But that's only because I'm out of room in my wife-approved armoire!
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I've thought about that... But I'm a little slutty when it comes to gear, who knows how long I'll own this thing. Unless I find something completely reversible, resale will suffer..
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If you are thinking about a bulk order on the torroids, count me in for one.
If you are thinking about selling completed boxes, PM me a quote.
One question about balanced power.
If we isolate from ground do we loose shielding or run a ground "around" the iso-xfmr ?
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If you are thinking about a bulk order on the torroids, count me in for one.
If you are thinking about selling completed boxes, PM me a quote.
One question about balanced power.
If we isolate from ground do we loose shielding or run a ground "around" the iso-xfmr ?
PMed ya.
The transformer doesn't do a thing for grounding issues. The transformer pysically isolates the current carring (neutral and "hot") from the source. Grounding isn't privy to the wonders of induction.
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If you are thinking about a bulk order on the torroids, count me in for one.
If you are thinking about selling completed boxes, PM me a quote.
One question about balanced power.
If we isolate from ground do we loose shielding or run a ground "around" the iso-xfmr ?
PMed ya.
The transformer doesn't do a thing for grounding issues. The transformer pysically isolates the current carring (neutral and "hot") from the source. Grounding isn't privy to the wonders of induction.
That is, it is not supposed to be. ;D
Ground-induced voltages make thunderstorms pretty.
What I meant was, are you lifting the ground or are you grounding component to conditioner to wall, passing ground through ?
It was a common, older practice (dangerous, too) to not connect ground and pass "balanced power."
If ground leg has no current, then no induction is possible, of course. But.......
Which brings up anothe question, are the hospital outlets GFIs ?
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If you are thinking about a bulk order on the torroids, count me in for one.
If you are thinking about selling completed boxes, PM me a quote.
One question about balanced power.
If we isolate from ground do we loose shielding or run a ground "around" the iso-xfmr ?
PMed ya.
The transformer doesn't do a thing for grounding issues. The transformer pysically isolates the current carring (neutral and "hot") from the source. Grounding isn't privy to the wonders of induction.
That is, it is not supposed to be. ;D
Ground-induced voltages make thunderstorms pretty.
What I meant was, are you lifting the ground or are you grounding component to conditioner to wall, passing ground through ?
It was a common, older practice (dangerous, too) to not connect ground and pass "balanced power."
If ground leg has no current, then no induction is possible, of course. But.......
Which brings up anothe question, are the hospital outlets GFIs ?
After a few of our PMs I'm not sure what I'm doing anymore! :P
No....I had no intentions of letting the chassis "float". I was planning on using standard grounding practice. The chassis will be grounded but will not be used as the main grounding means. I'm still open to the best method to ground this thing.
The outlets will not be GFCI protected. I can't think of any reason to.....unless the chassis was floating but it won't be.
Just want to give Bob a public thank you and +T for helping me via PMs!
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Bout to fire up the new power conditioner...I wil let you all know what I think in an hour or so...
BPT 1.5 I think it is, used I paid 470 fwiw.
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How did this work out?
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Absolutely, the best purchase I think I have ever made sound-change wise. The model I got was a Balanced Power, BPT 1.5 I think, the smaller one, with upgraded litz wiring and some other voodoo stuff inside. I got it for 450 shipped off of audiogon. The background is BLACK, it was pretty black before but wow! Noise which I didn't even realize was there until I didn't hear it anymore is history. I will write a bit more tomorrow, but wow, wow, wow!
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Hey did this ever get built?
I've been toying with the idea of building something, perhaps with just power conditioning and circuit protection up front, leaving room in the box for an iso tranformer to play around with that in the future.
Thoughts? Ideas? Potential pitfalls?
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if anyone is interested, i have bunch of line conditioner/stabilizers that i have collected over the past couple of years. ebay is killing me so i dunno what to do with them... they are by TOPAZ and i have them in varying power ratings. most of them are brand new. i think the smallest one i have was ~$650 new and it is 1.5KVa. i also have a couple of 2KVa units as well.
i also have some medical grade 220v>110v isolation x-formers.
here is some good info:
Posted by Jacques (A) on February 13, 2005 at 08:49:39
In Reply to: Isolation Transformers? posted by dalcorn on February 9, 2005
at 19:44:00:
Ten year ago, I had to test for EMI our airborne predictive maintenance
computer. I used Topaz 1000W ultraisolation transformer between the mains
and the testbench.
Another time, I made EMI conducted susceptibility testsfrom the mains, and
I had the habit to set an ultraisolation Topaz transformer between the mains
and the LISN (Line Impedance Simulation Network). My main goal was to get
rid of any external source common mode perturbation, in order to make
correct measurements from the standardized CM signals I injected, but not
the neighbor...
Ultraisolation transformers are built this way:
primary and secondary are split in several sections, and completely
separated. Primary cores are surrounded by an insulated copper foil (which
does not short itself thanks to covering insulation. This primary shield is
connected to the ground inlet. Then, another non-self-shorting insulated
copper foil separates the primary/ secondary coils pairs. This shield is
connec ted to the transformer chassis. Then, a third set of
non-self-shorting insulated copper foil surrounds the secondary coils. This
shield is connected to the ground outlet.
A heavy-gauge small coil links the ground inlet to the transformer
chassis, and another heavy-gauge small coil links the ground outlet to the
transformer chassis.
A non-insulated copper foil is used as a magnetic shield/short around the
transformer.
A sheet of steel separates the primary and secondary case.
The result : superb common mode insulation, up to 140dB (!) at 1MHz. Why?
Because, done as it is, the capacitive coupling between the primary and
secondary coils is quite zero (<0.00001pF, yes!), and furthermore, the
symetric construction avoids that some CM noise be changed into differential
noise.
feel free to drop me a line
nism
i would love to part with some of these x-formers and would do it for a real good price...