Dynahi driving speakers!!!
Apr 5, 2007 at 2:46 PM Post #47 of 58
Quote:

Originally Posted by cotdt /img/forum/go_quote.gif
Yes I think you are right rsaavedra. You can mod it to disable the protection mechanism.


No but this incident scared the hell out of me already
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I think the power supplies should have that protection as they do. The manufacturer should know where their limits are after all. Unless I come across some higher sensitivity bookshelves I won't use the Dynahi to drive my current speakers, just in case.


Eagerly waiting for that 100w pure class A speaker amp design from Gilmore.
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Apr 5, 2007 at 2:47 PM Post #48 of 58
Just a thought, I suppose you could mod it to remove the protection circuitry, but wasn't it designed in there for a reason?
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You might just want to look into getting a beefier power supply, and not run the risk of blowing something for real.
 
Apr 5, 2007 at 2:51 PM Post #49 of 58
Quote:

Originally Posted by rsaavedra /img/forum/go_quote.gif
Eagerly waiting for that 100w pure class A speaker amp design from Gilmore.
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Why not convert your amp to the Dynamight? It will have 4 times the output of whatever the Dynahi has. Use one power supply for all four amp boards. It will get loud for sure, maybe even enough to destroy your speakers.
 
Apr 5, 2007 at 2:59 PM Post #50 of 58
Quote:

Originally Posted by cotdt /img/forum/go_quote.gif
Why not convert your amp to the Dynamight? It will have 4 times the output of whatever the Dynahi has. Use one power supply for all four amp boards. It will get loud for sure, maybe even enough to destroy your speakers.


I'm very happy with my Dynahi as it is, in single ended mode for headphones. Also, remember the Paradigms do have 4 ohm impedance in some frequencies. Not exactly comfort zone for the Dynahi circuit, not even the Dynamight I would guess.

I think it's better to simply stick to a circuit that has been designed from scratch having in mind very low impedance loads like speakers'. So to drive speakers on a regular basis at sustained, loud enough volumes (for me 85 dB on average at 10 feet,) and with no worries for the amp circuitry or power supplies, it better be a speaker amp.
 
Apr 5, 2007 at 3:04 PM Post #51 of 58
Quote:

Originally Posted by rsaavedra /img/forum/go_quote.gif
I'm very happy with my Dynahi as it is, in single ended mode for headphones. Also, remember the Paradigms do have 4 ohm impedance in some frequencies. Not exactly comfort zone for the Dynahi circuit, not even the Dynamight I would guess.

I think it's better to simply stick to a circuit that has been designed from scratch having in mind very low impedance loads like speakers'. So to drive speakers on a regular basis at sustained, loud enough volumes (for me 85 dB on average at 10 feet,) and with no worries for the amp circuitry or power supplies, it better be a speaker amp.


The circuits for the dedicated speaker amps (Class A linear) are not very different from that of the Dynahi. The difference is mainly in the power supplies. So I don't see a point in building them because simply giving the Dynahi the right power supplies would accomplish the same thing.
 
Apr 5, 2007 at 3:14 PM Post #52 of 58
Quote:

Originally Posted by cotdt /img/forum/go_quote.gif
The circuits for the dedicated speaker amps (Class A linear) are not very different from that of the Dynahi. The difference is mainly in the power supplies. So I don't see a point in building them because simply giving the Dynahi the right power supplies would accomplish the same thing.


Yes, but notice what Dr. Gilmore indicated, that Dynafet could easily be scaled up to 100 watts of pure class A power. The Dynahi circuit as it is, and with the heatsinking I have at least, is probably not prepared or scaled properly to handle that amount of power, no matter how powerful the power supplies.

To drive speakers with the amp boards I have I could certainly simply get more powerful power supplies as bperboy suggests. Maybe even Condors, they have a 28V 10 Amp version (I have the 28V, 2 Amp version.) But still, I'd rather see Dr. Gilmore's 100w speaker amp circuit first. As soon as he publishes it with some measurements I'm sure I'll want to build it.


PS. By the way I just checked the Condor specs pdf file again, it does indicate these power supplies have "Short Circuit Protection: Automatic current limit/foldback."
 
Apr 5, 2007 at 3:37 PM Post #53 of 58
Yes, the limiting is certainly current-related as you found above. What I was trying to describe in my post above is that I've seen devices which basically build heat as current draw increases and when they reach a certain point they shut down. Either way the idea is the same, when demand for power gets too high they shut down before damage occurs, or at least that is the hope.

Regardless I'm glad to hear that nothing was permanently damaged in your amp. That's always a heart stopping moment when the music just stops!
 
Apr 5, 2007 at 3:43 PM Post #54 of 58
Just as a side note you could probably find some full range drivers that are 16 ohms and build some horns to give you ~100 db sensitivity as well as a higher ohm load.
Thats just if you want a fun little [
rolleyes.gif
] wood project
 
Apr 5, 2007 at 4:09 PM Post #55 of 58
Quote:

Originally Posted by n_maher /img/forum/go_quote.gif
Regardless I'm glad to hear that nothing was permanently damaged in your amp. That's always a heart stopping moment when the music just stops!


I wonder if the heart actually stops, maybe that's exactly what happens. It felt like a very short moment of absolute panic.

You know right after sound stopped but the led was still on, first thing I did was to turn off the amp. Then after a couple of seconds I turned it on, led was on again, but still no sound. Turned it off immediately. My entire mind was racing through all what I had to do to fix the damaged power supply (I was assuming it had been damaged.) First I would diagnose myself if I could do anything on it, maybe it had its own fuse. Maybe it was a capacitor blown, maybe, maybe, maybe... If I couldn't figure out what was wrong in the PSU, I would need to use a local electronics guru. I'm not in the US but in Venezuela, so sending such a heavy thing to Condor for repair would probably cost more than getting a new one. Couldn't use the warranty because it lasts for 3 years, expired some time last year. All of this thinking took about 1 second, and I kept looping on it for the following minutes. Not sure when, but at some point during all of that my heart started beating again
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Apr 5, 2007 at 4:13 PM Post #56 of 58
Quote:

Originally Posted by phergus_25 /img/forum/go_quote.gif
Just as a side note you could probably find some full range drivers that are 16 ohms and build some horns to give you ~100 db sensitivity as well as a higher ohm load.
Thats just if you want a fun little [
rolleyes.gif
] wood project


I've thought about it, it would certainly be a fun project. But I don't have room for such speakers. Have room for a dedicated stereo speaker amp though
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Jul 12, 2018 at 10:16 AM Post #58 of 58
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