Well now, this certainly gives us something to talk about........
I've enjoyed reading the recent post.
Like many humans, I'm a little timid when it comes to hanging out with the really, really big boys. Then again, I don't think of myself as a little girl in the school yard, or Fred as a bully coming to take my candy. BUT, I was mortified to see the pcb momentum fall off so rapidly after Fred's prior posts. It seemed that if we proceeded with the pcb purchase that we'd be sued by Nelson Pass, or that we'd torch our speakers, or at the very least, the end of the Earth was at hand. Fortunately, hifiZen (Chad) came on board as chairman and the momentum has gathered once more.
Now Fred shows a softer side:
Fred, I'm pleased to read your statements regarding the educating of us less fortunate. And, if you don't mind me asking, what's wrong with a little "hand holding".
It's been a pleasure hanging with you folks.
John Inlow
I've enjoyed reading the recent post.
Like many humans, I'm a little timid when it comes to hanging out with the really, really big boys. Then again, I don't think of myself as a little girl in the school yard, or Fred as a bully coming to take my candy. BUT, I was mortified to see the pcb momentum fall off so rapidly after Fred's prior posts. It seemed that if we proceeded with the pcb purchase that we'd be sued by Nelson Pass, or that we'd torch our speakers, or at the very least, the end of the Earth was at hand. Fortunately, hifiZen (Chad) came on board as chairman and the momentum has gathered once more.
Now Fred shows a softer side:
Fred, I'm pleased to read your statements regarding the educating of us less fortunate. And, if you don't mind me asking, what's wrong with a little "hand holding".
It's been a pleasure hanging with you folks.
John Inlow
Halojoy,
all you need to do is use a variac and work your way up monitoring currents, voltages, input and output waveforms. You stop when things get too weird. Here you may want to give full power to the input and low power to output to see a more realistic picture.
As far as what happens I don't need a simulator to predict a few boiling plate outcomes. Peter didn't know a priori what would happen and didn't like what happened when he shortened the output of his A75 to ground but that didn't stop him from either building it, using it, and enjoying it, right Pete?
What happens if you drop a 50 lb barbell on your turntable tone arm? I have a more colorful parallel but I voluntarily
myself. Bottom line:who cares?
More interesting would be to know what happens if one drives the amp single ended. Maybe when Fred takes a break from BS-ing he could tell us mere monkeys.
shorting + and - outs: since dc should be about equal there should not be a high DC current flow, bias current should continue to flow to the preferred -15v, on the ac side however things will probably go nuts, generate huge transients, self oscillation or whatever that will claim the life of the components in short order.
shorting 1 out to ground: will probably do what it does on 110% of the amps in the world, kill the output devices and very likely dump PS voltage on the speaker.
These catastrophic scenarios should probably be investigated just so that people know what to expect but that should not discourage anyone from building the AX.
all you need to do is use a variac and work your way up monitoring currents, voltages, input and output waveforms. You stop when things get too weird. Here you may want to give full power to the input and low power to output to see a more realistic picture.
As far as what happens I don't need a simulator to predict a few boiling plate outcomes. Peter didn't know a priori what would happen and didn't like what happened when he shortened the output of his A75 to ground but that didn't stop him from either building it, using it, and enjoying it, right Pete?
What happens if you drop a 50 lb barbell on your turntable tone arm? I have a more colorful parallel but I voluntarily
myself. Bottom line:who cares?More interesting would be to know what happens if one drives the amp single ended. Maybe when Fred takes a break from BS-ing he could tell us mere monkeys.
shorting + and - outs: since dc should be about equal there should not be a high DC current flow, bias current should continue to flow to the preferred -15v, on the ac side however things will probably go nuts, generate huge transients, self oscillation or whatever that will claim the life of the components in short order.
shorting 1 out to ground: will probably do what it does on 110% of the amps in the world, kill the output devices and very likely dump PS voltage on the speaker.
These catastrophic scenarios should probably be investigated just so that people know what to expect but that should not discourage anyone from building the AX.
Actually shorting one output to ground shouldn't be catastrophic since a current limiter built around Q4 and Q9 (on latest schematic) should protect the outputs like in a regular Aleph.
I asked the question before, and Nelson replied that if you make shure that you don't connect the outputs with a ground you don't really need it. So I'm not using it in my Aleph X.
I asked the question before, and Nelson replied that if you make shure that you don't connect the outputs with a ground you don't really need it. So I'm not using it in my Aleph X.
jh6you said:
RTFM...? Read The F-king Manual...?
http://info.astrian.net/jargon/terms/r/RTFM.html
--
Brian
Thanks grataku.
The answers in your post, give a good indication of what will
happen in the case of shorted output. Yes, I did test using a
variac.
I am a little sad, though. It seems that you really do not care to
much about these issues. This could suggest that it is not
necessary to deal with them. I think that is not correct.
Don't get me wrong. I would not want to discourage anybody to
build the Aleph-X. Is it not a good idea to make this amp more
bulletproof?
Peter,
The values around the current limiter Q4 and Q9 should be
reconsidered. I do not think it is wise to leave the current limiters
out of the circuit.
Regards
The answers in your post, give a good indication of what will
happen in the case of shorted output. Yes, I did test using a
variac.
I am a little sad, though. It seems that you really do not care to
much about these issues. This could suggest that it is not
necessary to deal with them. I think that is not correct.
Don't get me wrong. I would not want to discourage anybody to
build the Aleph-X. Is it not a good idea to make this amp more
bulletproof?
Peter,
The values around the current limiter Q4 and Q9 should be
reconsidered. I do not think it is wise to leave the current limiters
out of the circuit.
Regards
Till, you should know by now that Zen output is capacitor coupled so you can short it. It's different with Aleph X.
rtirion,
I want my circuit to be as simple and pure as possible, so that's why I leave the current limiter and input protection Zeners out of a circuit. I also hope it might improve sonics a bit. When my A75 40V DC hit the speakers I was left out with $500 driver replacement bill. Guess, some people never learn on mistakes.
rtirion,
I want my circuit to be as simple and pure as possible, so that's why I leave the current limiter and input protection Zeners out of a circuit. I also hope it might improve sonics a bit. When my A75 40V DC hit the speakers I was left out with $500 driver replacement bill. Guess, some people never learn on mistakes.
Till. rtrion and others,
as Peter corrected me earlier, there is a current limiter in the aleph, I went back, RTM, and so, though I will not try that while my oris horn is hooked up, single out to ground should not be a problem the output could pretty much be 1/4. Although I am not absoultely convinced. 2 outs to ground should be equivalent to shorting the 2 two outs together, things there could get more tricky to predict and perhaps more damaging.
My point was simply to illustrate that with a rational approach these problems can be dealt with, and that freaking out over these issues is counterproductive.
I am done talking about it, my next report will be factual, as it should have been for the people in a more advanced stage of the construction. Although I have a PhD in a different field, I am not an EE (TG), so lot will be rediscover of hot water for which I expect to get cremated by some of the more electronically oriented members but hopefully my struggle will create some momentum and generate new and useful info.
Of course there are many people that could do it right now. Or beat me to it.
as Peter corrected me earlier, there is a current limiter in the aleph, I went back, RTM, and so, though I will not try that while my oris horn is hooked up, single out to ground should not be a problem the output could pretty much be 1/4. Although I am not absoultely convinced. 2 outs to ground should be equivalent to shorting the 2 two outs together, things there could get more tricky to predict and perhaps more damaging.
My point was simply to illustrate that with a rational approach these problems can be dealt with, and that freaking out over these issues is counterproductive.
I am done talking about it, my next report will be factual, as it should have been for the people in a more advanced stage of the construction. Although I have a PhD in a different field, I am not an EE (TG), so lot will be rediscover of hot water for which I expect to get cremated by some of the more electronically oriented members but hopefully my struggle will create some momentum and generate new and useful info.
Of course there are many people that could do it right now. Or beat me to it.
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