Whom are you quotting, Jacco? I have not written "we do not wish" (but Halcro did)! 😀
Regarding 15A - this is too low value in case the amp works with speakers with impedance dips to some 2.2ohm, and there is a lot of them - Wilson Maxx, BW801 Matrix, Thiels etc. etc.
The 200/400W amp must be capable to deliver much more than 15A, as current limitation is pretty audible (one of the worst distortions).
Regarding 15A - this is too low value in case the amp works with speakers with impedance dips to some 2.2ohm, and there is a lot of them - Wilson Maxx, BW801 Matrix, Thiels etc. etc.
The 200/400W amp must be capable to deliver much more than 15A, as current limitation is pretty audible (one of the worst distortions).
Bob Cordell said:
Thanks Bob,
So you own a Juli@, nice sound card. Probably, this one could also be used in my setup, as this card is form the same manufacturer (ESI), and has roughly equal specs.
As for plans making the S/W available, as a matter of fact, I did have such plans, 5 years ago, and selling it for $50. But after working continuously for 3 years on this project, 'm getting a little bit tired, a kind of 'selective burnout'. So, the S/W still isn't finished yet.
For example, making it compatible with a larger number of sound cards (who is gonna pay all these cards, including a Lynx L22?) and the various versions of windows, improving the human interface, writing help files and documentation. Last but not least, implementing copy protection and a 30 days try out period. As you see, still a lot of work to do.
Maybe I should find a partner to finish this work and to bring it to market.
Cheers, Edmond.
john curl said:
I think i have something with +/-100 volt rails and peak current exceeding 200A for short brusts, in production from several years...
Workhorse said:
Hello WorkHorse
When you say 200A for short bursts , what is the duration of the burst.
Regards
Arthur R
Workhorse said:
Hello Workhorse
Can I ask you what the max continuous current the amp can deliver for say a 5 minute duration.
Regards
Arthur R
Workhorse,
I can produce 550A for more than one hour at 150kW. With plasma spraying gun rather than amplifier 😀
I can produce 550A for more than one hour at 150kW. With plasma spraying gun rather than amplifier 😀
Workhorse said:
Hello Workhorse
The amp with +/- 100V rails , and lets say 8ohm load and 4ohm load of 5 minutes of continous operation.
Regards
Arthur R
but i think amps were under discussion
Our Induction Furnace is capable of generating eddy currents of order greater than 1000A...for continuous, until the Conductor itself melts....
😀 😀 😀 😉
PMA said:
Our Induction Furnace is capable of generating eddy currents of order greater than 1000A...for continuous, until the Conductor itself melts....
😀 😀 😀 😉
PHEONIX said:
With 8 Ohm =9[Rails sags to +/-96VDC]
With 4 Ohm = 15[Rails sag to +/-88]
These are continuous, until the temperature protection kicks in...
In my case ,The 200A peak current was measured by applying direct short circuit across the output, with an input signal of 100hz with 100mS single brust duration...[Of course power supply filtercapacitance plays a vital role in sourcing large amount of current]
We also have beasts like these from various companies
http://www.lds-group.com/docs/display_product.php?product_item_id=446
Unfortunately, all manufacturers seem reluctant to publish data unless one registers or request it by mail. I do remember seeing an amp for this purpose on ebay one and with very impressive capacity.
The only figure I managed to find was from one manufacturer who mentioned their old linear shaker amps now being replaced by switching ones. The text mentioned power dissipation up to 170 kW into the cooling water for the biggest linear amps.
About welding cables, no haven't tried that, but I once used very short interconnects made from power cable for Ericsson AXE phone switches. That was thicker than most welding cables I have seen. 🙂
http://www.lds-group.com/docs/display_product.php?product_item_id=446
Unfortunately, all manufacturers seem reluctant to publish data unless one registers or request it by mail. I do remember seeing an amp for this purpose on ebay one and with very impressive capacity.
The only figure I managed to find was from one manufacturer who mentioned their old linear shaker amps now being replaced by switching ones. The text mentioned power dissipation up to 170 kW into the cooling water for the biggest linear amps.
About welding cables, no haven't tried that, but I once used very short interconnects made from power cable for Ericsson AXE phone switches. That was thicker than most welding cables I have seen. 🙂
john curl said:
Hi John,
You sound like the Hyudai salesman who claims that his SUV has more cargo space than the BMW SUV 🙂. One spec by itself does not tell the whole story. Bottom line is that Stereophile deemed it their Amplifier of the Year, not yours.
Although I would liked to have seen stronger continuous 2-ohm performance from the Halcro, 266W continuous into 2 ohms at 0.02% THD is nothing to sneeze at, and obviously disproves your assertion that VFETs are not suitable or robust for high power amplifiers.
It is unfortunate that JA did not measure the burst power of the Halcro, like he did with yours. That would have told a much more interesting story. I'm sure that you appreciate the importance of the burst power capability.
With the data available, we can only speculate as to the origin of the 266 W limitation of the Halcro into 2 ohms on a continuous basis. My speculation is that it is due to the switching power supply, as opposed to some limitation imposed by the use of VFETs. Your speculation is that it is deliberate hard current limiting in the output stage. They are both just speculation.
One interesting thing about switchers is that they are essentially constant power devices over a wide range. It is very possible that Candy has incorporated a long-term safety control system into his switcher to protect the amplifier when subjected to abusive loads on a long-term basis, where the rails are actually reduced in a deliberate and controlled fashion when appropriate. This approach, if used, would preserve the desired short-term high-current capability in a fairly elegant way. Anyway, this is just speculation. There are other VMOS amplifiers out there, some in the professional arena, that disprove your assertion that VFETs are unsuitable for high-power amps.
I don't recall the Halcro going into a violent ultrasonic oscillation and blowing a fuse when it was hooked up a certain way. We all have our vulnerabilities, John.
Cheers,
Bob
Folks, I don't think that you understand why hard current limiting is a problem.
It is NOT continuous current that is required, but short term for a few milliseconds.
Of course, just like Halcro implied, very high sustained current would damage speakers and might even start a fire. However, dynamic impedance conditions occur in many loudspeakers that require the amps to put out large peak current for short periods.
For example, my WATT 1 loudspeakers drop to 1/2 ohm at 2KHz. Drive that sometime, with an anemic amp!
I am using the Halcro as an example of a potential oversight, that I cannot afford to miss, and still be able to drive difficult loads properly.
It is NOT continuous current that is required, but short term for a few milliseconds.
Of course, just like Halcro implied, very high sustained current would damage speakers and might even start a fire. However, dynamic impedance conditions occur in many loudspeakers that require the amps to put out large peak current for short periods.
For example, my WATT 1 loudspeakers drop to 1/2 ohm at 2KHz. Drive that sometime, with an anemic amp!
I am using the Halcro as an example of a potential oversight, that I cannot afford to miss, and still be able to drive difficult loads properly.
john curl said:
John, I don't think that you understand that the Halcro may not be hard current limiting. That is my whole point. There is simply not enough information in the Stereophile review to conclude that the Halcro has hard current limiting. Period.
No-one here is disagreeing with the need for an amplifier to be able to deliver high bursts of current in brief bursts. And no-one here will argue that your amplifier is lacking in that department - it is a fine performer there, and it is truly great that JA showed those burst power measurements for your amp.
Cheers,
Bob