What the hell is that second amp, something from an old movie theater? That thing looks awesome.
The amp driving a MagnaPlaner was listened to by several people and they said that they never heard anything so easy to listen to before. I never got to build a second channel, so the stereo effect never got listened to. It slewed in excess of 400 volts a second, I did not have the greatest of test equipment back then.
But Jacco why did you use the word stupid, that amp had a lot of peoples attention back then, including Fredrick Barrett, the person behind the Sequerra tuner. You seem petty to use such a pejorative term. I do not see your point, SORRY but I just feel it was un-called for.😛
The originator of this thread did not ask for anything but "what was the biggest"
Easy, read the MJ15024/25 datasheet ;
- Not meant to be used with rails way over 110Vdc.
- At 120Vdc rails, second thermal breakdown at anything over ~0.6A
Even attempting to reach the 746W level would terminate the output stage, all 20 of them.
Otherwise a fast transient would take care of it.
120Vdc rails are very dangerous, 250Vdc cans very exotic, and all that for an output stage that self-destructs.
Even a quarter century ago, the ticket for very high power was to go bridged/balanced.
750W from a pair of 250/300W amps is a stroll in the park, much safer rail voltage levels, cheaper parts, and a peak output current number that's more in line with continuous power level.
This forum is crowded with folks from India and Pakistan, who just crave to build amps of bizarre power levels.
Advocating the use of 120Vdc rails is not smart, in particular with devices such as TO3 Motorolas. (and anything other BJT than MJL4281/4302)
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I'm surprised that nobody has picked up a pair of AM radio transmitters from the last generation of tube gear and re-worked them as audio amps. From what I recall of the Collins 820D-1 I think it could be done as a DIY project. Conceptually, I speculate the biggest technical challenge would be rewinding a modulation transformer as an output transformer. Non-technical challenges would include floor space and the WAF.
Dale
Hi,
It was 300W mono, used 80 FETs,, two HT rails with 1.5 Farads on each, 2 1KVA transformer, 180Kgs, 1.8M Tall and ate 1800W just in idle.
It was not based on Nelsons design but on a large dynamic load I designed once.
The largest I had to design (Class B) was 10KW, in Class D 1.5MW, toys now days.
Hi Colin, thank you for the correction, my memory is not what it use to be.
Those amps did leave a lasting impression on me, I have always been curious about what was inside them, is the schematic for the 300W available to the DIY community - not that I need that kind of power.
Those amps did leave a lasting impression on me, I have always been curious about what was inside them, is the schematic for the 300W available to the DIY community - not that I need that kind of power.
Jacco just to being doing something in my spare time, and just because I have dealt with much more dangerous circuits than High Current plus and minus 120 rails and caps, I will attempt to learn something with the MJL4281/4302 you recommend....😛 How about a 1000 watter for our good friends from the sub-continent. Maybe you could kibitz on the design in a helpful way and make my day.😉
I wish Mr. Barrett was alive today and would give the world another Superbly Excellent State of the art, audio product such as the Sequerra Tuner, he would show you
for sure. But at least I will try.
I wish Mr. Barrett was alive today and would give the world another Superbly Excellent State of the art, audio product such as the Sequerra Tuner, he would show you
for sure. But at least I will try.
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At least one thing we're in agreement on : http://www.diyaudio.com/forums/pass-labs/148620-papa-watts-next-7.html#post2357131
Hi Colin, thank you for the correction, my memory is not what it use to be.
Those amps did leave a lasting impression on me, I have always been curious about what was inside them, is the schematic for the 300W available to the DIY community - not that I need that kind of power.
Itsmee,
Yes I think I planted the 300W on the photo page, I wrote it up for Wireless world.
Col
Great Minds run together😀
Jacco just for grins and ALL jokes aside, I am too old to start up a 750 or any other amp project, what is the max amp doable watt wise with Excellence as its core criteria?
Money not being a overwhelming impedance.
Dick Sequerra did the Marantz 10B before he did Sequerra FM 1, but cost was not a factor when he did it, the best design was.
Jacco just for grins and ALL jokes aside, I am too old to start up a 750 or any other amp project, what is the max amp doable watt wise with Excellence as its core criteria?
Money not being a overwhelming impedance.
Dick Sequerra did the Marantz 10B before he did Sequerra FM 1, but cost was not a factor when he did it, the best design was.
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