john curl said:
Because it was you who started discussing rectification problems. I'll continue kicking lightly potential barriers in the Syn08's thread, meanwhile. 😎
I understand now, but it is a 'bit over the top' for these power supplies. What amazes me is that so many resist JUST using hi speed, soft recovery diodes to eliminate the source of the crossover artifacts in the first place.
No, Jan, I just made a mistake in your relationship with the mike designer. That is all. I stand by my knowledge of microphone design.
john curl said:
You assumed he was my friend because I agree to him. If that isn't prejudice, I don't know what is.
Actually John it all falls into place for me now. You assume someone is my friend because I agree with him. This says a lot about you.
We are critical of Mr Bybee because of physical facts. You agree with him because he buys you lunch and takes you in the Bentley: he is your 'friend'.
Enlightening.
Jan Didden
Jan, please don't be that way. I have known and WORKED WITH Jack Bybee for about 15 years now. I do NOT design his quantum devices, BUT I know a lot more about them than you do, because I use them and have taken them apart. Until you have actually TRIED something, maybe you should not bother me with your opinions about Jack Bybee.
Now as far as the microphone engineer is concerned, I regret jumping to the opinion that you knew him well. You seem to so easily take his opinion over mine, that I presumed that you were colleagues in some fashion. Where is the prejudice in that?
Now just for completeness, there are ways around what Schoeps considers a 'noise barrier' due to acoustic resistance. IF you knew more about microphones, you would know this too. However, there is more to noise than just that.
For example, how many dB is the electronics noise floor below the microphone-preamp noise floor? 6dB? 12dB? 20dB? Over what range of frequencies is this S/N? It won't be constant. Do you know? Do you care? Do you know what each dB range that I listed means in context to what CAN be the best possible?
Now as far as the microphone engineer is concerned, I regret jumping to the opinion that you knew him well. You seem to so easily take his opinion over mine, that I presumed that you were colleagues in some fashion. Where is the prejudice in that?
Now just for completeness, there are ways around what Schoeps considers a 'noise barrier' due to acoustic resistance. IF you knew more about microphones, you would know this too. However, there is more to noise than just that.
For example, how many dB is the electronics noise floor below the microphone-preamp noise floor? 6dB? 12dB? 20dB? Over what range of frequencies is this S/N? It won't be constant. Do you know? Do you care? Do you know what each dB range that I listed means in context to what CAN be the best possible?
john curl said:
I'm not a mike engineer. What I noted is that a sucessful mike manufacturer told me that there is no money in trying to get lower noise preamp/buffers because the diaphragm is the limiting factor. I did assuming he is not lying through his teeth; in fact, there were enough people in the audience to call him on that if he did (and they did, harsly, on a number of other issues).
Therefore I wonder why all the humdrum about mike preamp noise; isn't that logical? Do you understand this reasoning? What does that have to do with considering someone a friend, collegue or competitor?
By implying that I said something because it came from a friend you are deliberatly placing me as someone who believes everything from a friend - unfair, and even ironic in the light of your constantly bringing up 'friends' which wich you have lunch, phonecalls, car rides.
And this is the last I say about this. You can have the last word, lets see how you handle that.
Jan Didden
Anyone can hear a "perfect" preamp, if they wish, a more perfect one than the Blowtorch. Merely connect the source directly to the power amp.
On the other hand, some might consider anything without proper tone control less than perfect.
The CTC-BT doesn't have it, nor does my Classé Omega preamp, the Ayre KX-R i'm saving up mulla for lacks it as well.
I've kept some spare storage room in the cases of the second Omega pre that i've been building myself, in the event that i finally run across something that fits the bill or gawd forbad, i think up something myself.
Pretty much given up on waiting for a contemporary commercial specimen to appear, and i really really detest having to conform to the hurd.
Seen the latest blasphemy champagne popper, Stuey ?
The CTC-BT doesn't have it, nor does my Classé Omega preamp, the Ayre KX-R i'm saving up mulla for lacks it as well.
I've kept some spare storage room in the cases of the second Omega pre that i've been building myself, in the event that i finally run across something that fits the bill or gawd forbad, i think up something myself.
Pretty much given up on waiting for a contemporary commercial specimen to appear, and i really really detest having to conform to the hurd.
Seen the latest blasphemy champagne popper, Stuey ?
I have run my low voltage sources that way, straight into the power amps.
A bit loud for a conversation, so I had to turn the tuner off if someone knocked at the door.
A bit loud for a conversation, so I had to turn the tuner off if someone knocked at the door.
john curl said:
Why should I RESIST driving Ferrari?
I don't. I'm Ok with my Nissan Armada.
The same with rectifiers. Why should I solve a problem that I did not create yet, if other problems have higher priorities?
interview question
Ok it’s better to be helpful so here’s a little example from my interview questions.
In the figure with no additional information, what is the small signal AC gain? You can assume that resistor values can be chosen so that incidental properties of the transistor don’t matter.
ANS: ~(Vs-Vo)/Vt or ~40(Vs-Vo)
To the first order it does not matter which transistor or on any of its properties. A simple but profound result a gain of 40 per volt of drop no matter what. The fact that there is a T term in Vt also directly leads to PTAT (proportional to absolute temperature) biasing. If the interviewee insists on knowing the beta even after being told it does not matter they usually end up being sent on their way.
Ok it’s better to be helpful so here’s a little example from my interview questions.
In the figure with no additional information, what is the small signal AC gain? You can assume that resistor values can be chosen so that incidental properties of the transistor don’t matter.
ANS: ~(Vs-Vo)/Vt or ~40(Vs-Vo)
To the first order it does not matter which transistor or on any of its properties. A simple but profound result a gain of 40 per volt of drop no matter what. The fact that there is a T term in Vt also directly leads to PTAT (proportional to absolute temperature) biasing. If the interviewee insists on knowing the beta even after being told it does not matter they usually end up being sent on their way.
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Re: interview question
I would say, very technological, production - specific answer is needed.
This is the whole spirit of American education: Engineers are less scientists, but more knowledgeable technicians prepared to work for companies making money on electronics.
scott wurcer said:
I would say, very technological, production - specific answer is needed.
This is the whole spirit of American education: Engineers are less scientists, but more knowledgeable technicians prepared to work for companies making money on electronics.
Scott, your circuit is confusing a little bit as it looks like R1=R2=R, transistor would be in saturation. Also you might mention that Vo is dc operating point and the question might be what is the small signal AC gain at relatively high frequencies?
dimitri said:
The R's can be different but the transistor is definately not saturated there is at least a Vbe of Vce. Any midband frequency would do. It's an illustrative example gm = Ic/Vt and Ic = Vs-Vo that is something a new graduate should know.
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