Would it be feasible to use the transformers from an old welding machine. I found on in the dumpster at work. Brand new never plugged in. It is 3 phase so I can not use it to weld with no 3 phase power available. Would the indidvidual transformers work to power a monster amp?
It would be nice to put this thing to some good purpose.
Tad
It would be nice to put this thing to some good purpose.
Tad
cbdb said:
You need "The Good-ol-boy" network in your area, or one of the catalog/internet surplus dealers. When I lived in FL, I got most of my stuff at Skycraft and out of a handful of surplus catalogs which I don't even know still exist. Today, Jim Tanner (Dallas area) keeps me supplied - I get first crack at whatever comes in. Larger batches of inventory get diverted to his buddy at BG Micro, where I got a second batch of heat sinks from - and some 75V caps as soon as they hit the website. They're for a future build - outside the scope of what I'm up to now. Apex Jr. has some trafos that will work - especially if you double or quad them up. You just have to keep your eyes peeled, buy up potentially useful stuff in anticipation, and design around what you can get.
tryonziess said:
How good are you at rewinding? Toroids are easy - those big monster EI's aren't. Not only that, but trafos for chargers and welders don't use very high quality iron and run it way the heck up the BH curve. Iron losses are high and they make a lot of racket. So you'd probably end up needing a new primary as well as secondary. I would find better candidates for an audio amp.
For a big power supply or some other menacing application like making hydrogen from salt water - go for it!
tryonziess said:
Turning it back into water vapor, of course! I thought all kilowatt amp builders were also pyromaniacs.
Take two bored college students with no money - one a Chem major the other an EE. Allow them to have all the free electricity they want in the dorms. Transformer is too low a voltage to build a decent amp with, but very high current. When all the 6.3V electrolytics have been turned into bits of paper, get out the bucket of salt water and a couple two liter bottles.....
Probably not practical after 9/11, but back in '86 we got some mileage out of it.
we use stepdown transformers on site for safer working for our tradesmen.
240:55-0-55Vac to run 110Vac power tools.
They are available from 500VA to10kVA and all are EI.
would a 2 or 3kVA do for audio?
240:55-0-55Vac to run 110Vac power tools.
They are available from 500VA to10kVA and all are EI.
would a 2 or 3kVA do for audio?
Exactly what are you going to use for smoothing capacitors on this monster. With this much juice the ripple will be rather large. Are you going to water cool the thing.
Tad
Tad
AndrewT said:
Those have possibilities. If you used just one 1KVA unit, it would be good for an old-school CS800 clone (like a Dirty Harry) running off 240V. You'd put two in series to run of 120V, but that would be getting big and heavy for the same power.
Now if you put two in series and ran the primary from 240 like it's supposed to, you'd have quad rail +/-80 and 160. That would make a killer class H. You'd need 3kVA total (more if you want overkill) and 240V operation would be desirable because that amp would be bigger than 2kw/ch at 2R. More like 2kw/ch@ 4R and 3kW/ch at 2R.
tryonziess said:
20,000-30,000 uf per rail, at whatever voltage you run at. It has to do with the time constant between the rail cap and load. More is not needed. Ripple will end up being the same percentage of rail voltage. Store-bought pro amps get by with less (10-15kuF), but that assumes 4 ohms not 2 (even though they advertise 2 ohm power).
If you run your big amps class H or G or D or whatever, they generate no more heat in operation than an old-school 94 pound 1977 Peavey CS-800 running bridged into 4 ohms. Cooling for that requires a large heat sink and a 105CFM fan. No problem.
Whooooohhoooooooooo
Well, today is my lucky day !!!
I found a ALTO MISTRAL 6000 for $150!!
The previous owner saiz that the protect light stays on all the time.
time to get my hands dirty 😛
on my way out the door.. figured i'd share the good news 😛
quick specs i dug up...
maybe while im in there....
Long story short...
Need to find the schematics now and get to
Well, today is my lucky day !!!
I found a ALTO MISTRAL 6000 for $150!!
The previous owner saiz that the protect light stays on all the time.
time to get my hands dirty 😛
on my way out the door.. figured i'd share the good news 😛
quick specs i dug up...
maybe while im in there....
Long story short...
Need to find the schematics now and get to
Re: Whooooohhoooooooooo
Nice grab...pics...we need to see the guts. I'm curious how many outputs, size of transformer, heatsink design, many questions.
Good find. 🙂
Adrculda said:
Nice grab...pics...we need to see the guts. I'm curious how many outputs, size of transformer, heatsink design, many questions.
Good find. 🙂
Ok...
i just got back...
the amp isnt in town and is at a buddies place that tried to fix it, but he closed it as soon as he opened it and said that he was in way over his head. Hes got some sort of backyard garage band sorta deal and hes got quite a few amps that either partially working or blown, and apparently he tossed 2 Mackie's last week !!
Those could have been perfect donors for power supply and chassis as well. It was getting dark and my flashlight was a bit weak, but deffinately stumbled across a "gold mine" 😀
I told him that i will be back tomorrow to go through them and see what i can do for him as he agreed that if i fix 2 or 3 for him i can have the rest of them!
i just got back...
the amp isnt in town and is at a buddies place that tried to fix it, but he closed it as soon as he opened it and said that he was in way over his head. Hes got some sort of backyard garage band sorta deal and hes got quite a few amps that either partially working or blown, and apparently he tossed 2 Mackie's last week !!
Those could have been perfect donors for power supply and chassis as well. It was getting dark and my flashlight was a bit weak, but deffinately stumbled across a "gold mine" 😀
I told him that i will be back tomorrow to go through them and see what i can do for him as he agreed that if i fix 2 or 3 for him i can have the rest of them!
Re: Whooooohhoooooooooo
This could well be a genuine 4ohm capable amplifier based on that info.
falling to 1400W into 4r0 is only a loss of <0.4dB. This is superb performance and confirms a good output stage and a good PSU as far as peak current output is concerned.Adrculda said:
This could well be a genuine 4ohm capable amplifier based on that info.
You can buy that amp new for $535 (US) or just under $600 Canadian. Still think you can build your own cheaper?
Steve Dunlap said:
That amp retails for a bit over $1100 out here
You are overlooking freight, Customs, taxes and the profit margin for most retailers is 30-45% mark up !!
Steve Dunlap said:
How many end up here looking for the "cheaper" way?
The lucky ones become engrossed in this forum and spend 99% of their time chatting and dreaming, plotting and planning, advising and posturing. They don't want to get the hands dirty, no time, money, space, motivation to do, just to talk.
The unlucky ones start building stuff, become better at it, buy more gear, buy more parts, build more things - eventually run out of space in their house (even though wife, family, kids and friends have long departed). Still, the need to build something new drives me...err I mean "them" relentlessly onwards to the next project and the next after that, so on and so on.
Cheaper should be a censored word here.
Adrculda said:
That is the price with markup. It is not unusual to find new pro equipment for half of list. You pay taxes on parts also. And freight and customs. Unless you buy mail order and don't get charged taxes, but that also applies to amps.
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