Hi,
I wasn't sure in post11, but I have gone and drawn a single ended ClassA with constant current sink. Then bridged a pair of these.
The peak output power is limited to Iq^2 * Load impedance.
Short the output and the current is Iqpk and power =0.
It is immune to the effect of an output short.
I wasn't sure in post11, but I have gone and drawn a single ended ClassA with constant current sink. Then bridged a pair of these.
The peak output power is limited to Iq^2 * Load impedance.
Short the output and the current is Iqpk and power =0.
It is immune to the effect of an output short.
No, Actually I believe photo was taken in Alaska. But....I spent a year in Keflavik,Iceland and observed the lights. I'll bet with the recent solar activity they have been real wild up there in Norway.They could be seen here in the states as far south as Kansas. Not a very common sight for Iowa 
Bless
Dave
BlessDave
Yes, the amp output will be shorted by the jack, I am sure of it. Some pictures are needed to explain..
On the socket the contacts are close together. When the jack is inserted, first the tip (left channel) comes into contact with the ground of the socket. Push it in more and the tip comes into contact with the right channel output and ground of the socket simultaneously causing a short. Since all headphones use stereo jacks, we are stuck with it and have to work round it.
Headphone impedance goes down to about 32 ohm for normal headphones. So output impedance of amp needs to be much lower than this. I wasn't keen on overload protection schemes because they seemed to be detrimental to sound quality. So I was going for a brute force approach.
Andrew, that sounds interesting, but I am still new to this, do you have any schematics?
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
On the socket the contacts are close together. When the jack is inserted, first the tip (left channel) comes into contact with the ground of the socket. Push it in more and the tip comes into contact with the right channel output and ground of the socket simultaneously causing a short. Since all headphones use stereo jacks, we are stuck with it and have to work round it.
Headphone impedance goes down to about 32 ohm for normal headphones. So output impedance of amp needs to be much lower than this. I wasn't keen on overload protection schemes because they seemed to be detrimental to sound quality. So I was going for a brute force approach.
Andrew, that sounds interesting, but I am still new to this, do you have any schematics?
Hi,
search single ended ClassA amplifiers.
Start with the Pass site. He shows a CCS version and he also shows bridged in there somewhere.
D. Self also discusses single ended, but there are many others, even in here.
I agree, that plug does short between poles!! Terrible design and yet "Professionals" use it much of the time in their TRS connections.
I must add that a push pull amplifier that is bridged is not immune to a short. It self destructs unless protected.
search single ended ClassA amplifiers.
Start with the Pass site. He shows a CCS version and he also shows bridged in there somewhere.
D. Self also discusses single ended, but there are many others, even in here.
I agree, that plug does short between poles!! Terrible design and yet "Professionals" use it much of the time in their TRS connections.
I must add that a push pull amplifier that is bridged is not immune to a short. It self destructs unless protected.
Yes, a TSR "Tip-Ring-Sleeve " jack can short (or a the very least briefly misconnect) the output. If everything is perfect no two contacts will ever touch th same segment during insertion -- but in the real world repeated insertions and extractions.
TSRs are nasty things anyway because they are used in so many places that potential for plugging one into a place where it emphatally ought to go is always a concern.
TSRs are nasty things anyway because they are used in so many places that potential for plugging one into a place where it emphatally ought to go is always a concern.
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