But what if there is no load, or low load and high line? For a production design one needs to look at these cases. As I said though, most 4148s and their ilk have a substantially higher breakdown voltage than the specification, and Hafler may have screened the incoming parts anyway.
I did, that question was for John C....
Cool !!
Don't see the point. Rest assured, it's been tried. For God's sake, Wayne, on those transformers it actually powered a pair of 82 dB/1W/1m loudspeakers in a room reasonably loudly, and was limited mostly by voltage rather than current ...
I'm all for healthy safety margins of at least 50%, but this is no competition who's going to overkill more.
Your delayed turn-on device would be as big as the amp itself.
Well i have found oversizing the transformer in pre-amps make a big difference, hence my suggestion ...
WAHAB said:
Hurt the bridge(s)
why el cheapo rectifiers , no soft start ? ...If it switches of the mains that would be fantastic, 20 amps breaker ! I love when the light dims to the music on large dynamic passages, give you a sense of the effort , makes the performance worthwhile...
wahab said:
That's totally contrary to what others and myself have found. I had mentioned going to a larger transformer because I found it made a difference when modifying the PSU on pre-amps ..
Just saying, ....
Lighten up Wave .....
Where's the dis-information ... i said you use SS @ home ( you do ) .toobs in the forum ( you do ) and anyway, this
Your sense of humor needs more feedback..............
My sense of humor tells me that it is kind of false sarcasm based on your selective reading: you see only what you want to see and claim as if it is the whole truth.
No matter how many smiles you add to offenses it is still sensed properly.
Pretty much (except "closed loop gain" should be "loop gain"). IIRC, somebody worked out the open loop gain of the DH120 is about 10000. The closed loop gain is about 20, so the loop gain is about 500.
Since the dominant pole is about 20KHz, everything will be fine as long as the next pole is above 500 * 20KHz = 10Mhz. Wait, what?! 10MHz!! I think you'll find poles well below that, hence the over-complicated compensation to try and keep it stable.
Wavebourn's way of looking at stability is actually better, and more general. I haven't analyzed the circuit properly, but suspect that C5 turns it into a 2'nd order system, rolling off faster than 6dB/oct to reach unity loop gain sooner.
Jeeeez
and i can't even tell you to go have a drink....
It was meant as a joke, same as to TL, his response was as such , yours .....
I guess i must have hit a nerve , What sensitive about having SS at home and no toobs ... ....
It s contrary only in appearance , actually this yield a more
powerfull PSU in respect of the output power....
2 x 45V AC/560VA ---> 2x125W/8R amp ---> 250 W total PWR--->2.24VA/W.
2 x 16V AC/120VA ---> 2x12W/8R amp ----> 24 W total PWR ---> 5 VA/W.
It was meant as a joke, same as to TL, his response was as such , yours .....
What's sensitive in something that I badly want, but can't afford?!
What's sensitive in something that I badly want, but can't afford?!
Undoubtly an AP2.......
What's sensitive in something that I badly want, but can't afford?!
OK... when is your Birthday ?
I have an experience electronics toob amp from Germany, supposedly as good as any waveborne
you can use it until you get over .@ WAHAB:
I guess you missed where i said the bigger transformer brought better sonics, i really never heard of going to a smaller transformer being better, there must have been some other situation involved or am i missing your point ..
I have an experience electronics toob amp from Germany, supposedly as good as any waveborne
Thanks, I better use Denon. You don't know what you are talking about.
Hey stop spreading disinformation .........
Thanks, I better use Denon. You don't know what you are talking about.
Back to the books. They are written by those who know and not worded well for those who don't. It is not encouraging Self describing even the IPS as too complicated to calculate without Spice. Neither book says anything about the impedance of the CM and what adding degeneration to it does other than lowering it. Neither book talks about the resistor between the CCS and the diff pair emitters. This tells me we went to the moon with rough guesses and breadboarding.
Maybe another misconception. Reading the WIKI page on Johnson noise. I thought it was also related to the material and the distribution of current through it. So, the reason for metal film or Hafler using half watt carbon film. The WIKI suggests it is only about the temp. From that, an old CC would be the same noise as a MF or silicon at the same temperature. Precision aside. Something else taught to me incorrectly in tech school?
Maybe another misconception. Reading the WIKI page on Johnson noise. I thought it was also related to the material and the distribution of current through it. So, the reason for metal film or Hafler using half watt carbon film. The WIKI suggests it is only about the temp. From that, an old CC would be the same noise as a MF or silicon at the same temperature. Precision aside. Something else taught to me incorrectly in tech school?
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If either book says adding degeneration (emitter resistance) lowers impedance of current mirrors, they are bad books, at least about that. And there are a lot of bad books (I mentioned one recent book on current sources and voltage references to Walt Jung and he said he'd gotten it and sent it back!).
Self and Cordell among others are reliable authors, technically, but neither one writes textbooks as such.It is more than likely that some things were taught wrong in tech school. But we're not going to be able to rectify all of those in here.
But you shouldn't feel bad. I had a smart guy, Caltech engineering grad and audiophile, say to me once that he preferred a certain brand of resistor because it had low thermal noise. He was not at all pleased when I said thermal noise per se was strictly a function of temperature and the resistance value. There are other noise sources in physical resistors but thermal noise is always present, pretty well-understood and well-quantified.
As far as noise, I just checked and Motchenbacher and Fitchen, Low Noise Electronic Design, can be had for under a dollar plus shipping from online sellers --- an amazing bargain. The later M. and Connelly is a whole bunch more and IMO not worth the tariff unless you have lots of dough.
The idea of a current mirror is that the output current should equal the input current (regardless of output voltage). So input impedance is low, output impedance is high, and both can be ignored. Emitter resistors are often added to improve the accuracy, especially if the transistors are not well matched. FWIW, doing so increases both the input and output impedances, but that's not the point.
Johnson noise is the noise one would theoretically get from a "perfect" resistor, and depends only on resistance and temperature. Real resistors have excess noise as well which depends on material, applied voltage etc. A good resistor will have noise only slightly higher than the Johnson noise, whereas a lousy resistor will have much worse noise.
Hey stop spreading disinformation .........
What?
Did you hear and measure my designs? - Status
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