2500W will be OK for 2-channels, but you can't fit more than 1800W in 2U case. For single channel use half power.
Regards
its okay Apex, my available chassis's height measures 7". I think it's 3U, right?
Now, the only problem that I might be encountering is the power transformer.
Sorting some electronics stalls in Zhenshen China, what I always find are their 24v-0-24v 400W torroidal trafos. I guess, there would be no available transformer having such secondaries in the market, unless it's especilly wound.
By the way, how do you really compute for the current rating of the transformer's secondaries from its wattage specification? Is it thru ohms law?
Let's say the given transformer secondary voltage is 80-40-0-40-80 @ 2500 watts, then its secondary current, by ohms law, should be: 2,500/160 = 15.625A.
Am I right? please correct me if I'm wrong.
Thanks Apex and best regards.
>Joel
Philippines
Now, the only problem that I might be encountering is the power transformer.
Sorting some electronics stalls in Zhenshen China, what I always find are their 24v-0-24v 400W torroidal trafos. I guess, there would be no available transformer having such secondaries in the market, unless it's especilly wound.
By the way, how do you really compute for the current rating of the transformer's secondaries from its wattage specification? Is it thru ohms law?
Let's say the given transformer secondary voltage is 80-40-0-40-80 @ 2500 watts, then its secondary current, by ohms law, should be: 2,500/160 = 15.625A.
Am I right? please correct me if I'm wrong.
Thanks Apex and best regards.
>Joel
Philippines
A 7" case is 4U. You should be able to fit almost any trafo in there.
The easiest and cheapest way to get 80-40-0-40-80 is to put two 40-0-40 trafos in series. Or four 20-0-20's.
Current rating is by ohms law - but the AC current does NOT equal the DC load current.
The easiest and cheapest way to get 80-40-0-40-80 is to put two 40-0-40 trafos in series. Or four 20-0-20's.
Current rating is by ohms law - but the AC current does NOT equal the DC load current.
hi wg_ski,
so how true is the way I compute it in AC? is the 15.625A more or less correct?
I need the current rating of the trafo, as most of the manufacturers in the Philippines require the voltage and current specs when I make an order.
I see, my chassis is a 4U then. Actually, I took the dimension from the chassis of my GFA-555 ver1, but longer in dept for longer heatsink as I'll make this project with 6 pairs of output Qs.
Thanks dude for clarification.
Regards,
>Joel
Philippines
so how true is the way I compute it in AC? is the 15.625A more or less correct?
I need the current rating of the trafo, as most of the manufacturers in the Philippines require the voltage and current specs when I make an order.
I see, my chassis is a 4U then. Actually, I took the dimension from the chassis of my GFA-555 ver1, but longer in dept for longer heatsink as I'll make this project with 6 pairs of output Qs.
Thanks dude for clarification.
Regards,
>Joel
Philippines
Actual DC current draw at full signal will be 13.5A. AC will be 1.8X this, or about 25A. This would translate to a 4kVA trafo! You will not likely draw full power - even if the PA is blasted to distortion. In practice, if it's sized to about half of this you're ok. A store bought amp would size it around 1/4 - or a 8-900VA unit. A big toroid like this can handle a factor of two "overload" for hours, and a factor of 10 for at least a few minutes. And nothing to blow out catastrophically like switchmode supplies can - it's only limited by temperature rise. 15 amp rated current would be more generous than most.
Member
Joined 2002
apex, i have a story about a carver like the one in your first page http://www.diyaudio.com/forums/solid-state/162408-900w-h-class-pa-amp-limiter.html#post2112275
Carver amp has no weight to it at all, I remember going to dj, and yes i wa sreally young grade 8 but loved helping out and learning how to do the job, i was nuts about it. ANYWAYS at the end of the job, i was told to help pack up unplug things and clean up. As i was packing up i lifted up one amp and it was so heavy 🙁 then i went to pick up the carver and it was soooooooo light. i was amazed at how lout and powerful it was, then i learned it was a smps amplifier ( of some sort ) also hear they were ticking time bombs too!
Moral of the story, never judge a amplifier by its looks 🙂 lol
Carver amp has no weight to it at all, I remember going to dj, and yes i wa sreally young grade 8 but loved helping out and learning how to do the job, i was nuts about it. ANYWAYS at the end of the job, i was told to help pack up unplug things and clean up. As i was packing up i lifted up one amp and it was so heavy 🙁 then i went to pick up the carver and it was soooooooo light. i was amazed at how lout and powerful it was, then i learned it was a smps amplifier ( of some sort ) also hear they were ticking time bombs too!
Moral of the story, never judge a amplifier by its looks 🙂 lol
hi wg_ski,
how about an EI trafo 80v-40v-0-40v-80v @ 15A, would that be fine?
Thanks,
>Joel
Philippines
And like JL said, it's a ticking time bomb. The circuit presented in this thread is a lot more reliable than the Carver Cube.
There is such a thing as building them too light and too cheap.
Why wouldn't it be? The only real probelm with EI cores is weight. Large ones have as good a regulation as a toroid.
Hi andrewlebon,
hm, someone with colored finger nails is holding that heatsink. Girlfriend, wife? 😀
hm, someone with colored finger nails is holding that heatsink. Girlfriend, wife? 😀
Pre amp for H900
Hi wg_ski,
thanks for the great insights.
by the way, will Nelson's B1 FET buffer match this h900 amp?
how about impedance matching?
😕
Hi wg_ski,
thanks for the great insights.
by the way, will Nelson's B1 FET buffer match this h900 amp?
how about impedance matching?
😕
Hi Apex,
I have here MUR860G ultrafast, 8A/600V, power rectifier (TO-220) by ON semiconductor. Instead of SFA1603, can i use 2 pcs of this in parallel for an equivalent of 16A current rating...?
Thanks,
>Joel
Philippines
I have here MUR860G ultrafast, 8A/600V, power rectifier (TO-220) by ON semiconductor. Instead of SFA1603, can i use 2 pcs of this in parallel for an equivalent of 16A current rating...?
Thanks,
>Joel
Philippines
@ Apex,
one thing more, can I substitute 1N4007 for the BAV21 diode?
Regards!
>Joel
Philippines
one thing more, can I substitute 1N4007 for the BAV21 diode?
Regards!
>Joel
Philippines
Use single MUR860G, peak current is much more than 8A,
1N4007 can't be use, diode must be fast recovery over 200V rated.
Regards