I've got this transformer.....check it out!

[mpmarino]

Please guys, project ideas are welcome...

I found this thing in a telecom power supply my company was surplusing. It's gotta weigh 70 pounds..AT LEAST! The power supply was 'conservatively' rated at 60a 52v. I am assuming this thing can do 3KVA without breaking a sweat.

I was playing with the primaries today and I am happy to say I've got a few options. The secondaries are center tapped. As a bonus the PS had 4 38000uF 60 volt caps! I can get any of the following all before rectification:

20.5v + 20.5v
23.3v + 23.3v
39.8v + 39.8v

I wouldn't mind building a 4 channel version of ......

This would be for my line arrays presently under construction ..4 ohms on the tweets..6 ohms on the mids. Whadya think of a 4 channel Aleph or Aleph-x. I can pretty much get all the heat sink I need so that's no worry. Maybe a class a/b on the higher voltages...or maybe an Aleph on the higher voltages? ...is that too high for the Aleph?

I feel like I have a LOT of potential here. Any ideas?

 

[paulb]

Do you know what the current rating of each of those secondary arrangements are? The lower voltage arrangement, (especially if it has more current than the others) would be best for a Class-A.
Better start looking for heat sinks.

 

[mpmarino]

I am purely guessing at all specs. I just know what the device it came from was capable of. The wire on the secondaries is ..in my estimation..8ga. You can barely bend the cable with 1 hand! As I look at this transformer..it just looks 'larger than life' to me.

 

[Nelson Pass]

Looks to me like you can build any kind of killer Class A
you want.

 

[rcavictim]

I pulled apart some telco battery plant (48V) chargers years ago and got three double-C core xfmers out of each one much as you describe except the primary was 208-230 volts with several taps.
I made a very nice portable arc welder with one and later added a second xfmer in parallel for more welding current. Mine have faraday shielded primary or secondary windings which would be a nice touch in an audio amp application. I don't know what anyone at home would need with that much audio power for though.

 

[azira]

Woww, looks like a whole lot of iron for a line array. I'd love to see what kind of amp you hook it up to
--
danny

 

[mpmarino]

RCAvictim,

Hmm, your probably right. No-one in his right mind would 'need' that much power for home use. In fact, I don't even need this computer I am sitting at!


..............so what the heck, why not take it all the way!


Marc

P.S. The thing is so heavy, I may one day call myself "transformervictim".

 

[Super_BQ]

Common Find for Me

I come across these large types of transformers all the time. I normally find them in these huge refridgerator size rectifiers for telecommunications. The units are very old and because of the shape and appearance of these transformers, I don't even bother looking at them. Instead, what I do take are the rather large size heatsinks inside these rectifiers. Sometimes I get arrays of CG type capacitors.

Another thought is the chemicals used in these transformers. PCBs is known to be cancerous - only if the transformer is old enough.

With the measured voltages, my guess it could make a good 25w/ch Son of Zen amp.

BQ

 

[markp]

No PCBs in that type of transformer. PCBs are in the encased type of transformer.
I've got a similar unit that has wire that looks like bussbar, about 3mm thick and 5mm wide! It weighs at least 60lbs. and has dual primaries and dual secondaries of 60VCT.

 

[Circlotron]

I think PCB's (polychlorinated biphenyls) are/were in old-type transformer oil. Some kinds of oil-filled paper capacitors too.

 

[mpmarino]

I am pretty sure you guys are right on with the PCB's. They 'were' used in old high voltage (KV) transformers for cooling and insulation.

As far as the looks of the thing, I couldn't care less. It delivers and thats all I care about. It was made in 1986, by the way...so it's not a complete dinosaur.

I have never built an amp before..never even considered it. I have built tons of speakers though. When I saw this forum I said 'wow'! I can put a Pass amp together! I acquired a handful of lm3875's to put a couple of Gains together to get my feet wet.javascript:smilie('')
hot

I am pretty blown away at the options on the Pass stuff. I have spent endless hours combing and still can't get a full grasp on it. I want to probably go with the aleph for it's simplicity.I have created a photoshop layout of the Briangt aleph layout and will probably etch my own boards.(I hope Brian doesn't mind Does anyone have issue with that layout? I am leaning toward using IRFP450's as I can get 'em real cheap. From what I have read they will work just fine.

I really could use some direction as this is a large undertaking for me at this time. I have a huge power source available and do NOT want to waste it. I will be building it for my line arrays but as we all know..they will not be my last pair of speakers. I want to build an amp to keep me happy for some time to come..no matter what speak I am building/using. I will always bi-amp actively so I would like to go 4 channel. Given the voltages I have available, and the fact that heat sinks are not an issue, what is the most Aleph (reasonably, that I can plug into a average electrical circuit) possible? I have attached a pic of the board layout in progress. I will be using the 'iron-on' toner transfer method...which has worked well for me in the past. Any input?

This will be a looong process as my personal and work situation is VERY demanding.

Thanks,
Marc

I must add the following: Thank you Mr. Pass for making it possible to even consider this!