^OT
uhh Hummer? haha sorry they aint cool anymore cept in Russia. Oh BTW on they are (were) built in EU land. but you are correct on one thing ...it's all about the economy buying new 'junk' every year.
Im not against totally against switchers. my hobby and 1st job was designing them.
there are many forms of pollution and depleting the earths natural resources, but based on the simplistic thinking above im sure you need to do some basic research besides looking at a tail pipe.
uhh Hummer? haha sorry they aint cool anymore cept in Russia. Oh BTW on they are (were) built in EU land. but you are correct on one thing ...it's all about the economy buying new 'junk' every year.
Im not against totally against switchers. my hobby and 1st job was designing them.
there are many forms of pollution and depleting the earths natural resources, but based on the simplistic thinking above im sure you need to do some basic research besides looking at a tail pipe.
Last edited:
I edited my post just before your post, sorry.
No, the Hummer was never designed nor produced in EU land as EU engineers have great difficulty designing inefficient and unreliable cars:
https://en.wikipedia.org/wiki/Hummer
No, the Hummer was never designed nor produced in EU land as EU engineers have great difficulty designing inefficient and unreliable cars:
https://en.wikipedia.org/wiki/Hummer
Last edited:
civilian Hummers were for an image statement.. for old wealthy wanna be warriors, why did this come up anyway? oh yeah cars du jour for the image conscious buyer.
designing and building switchers are a lot fun, buts lots more involved than PCB layout for chip amps.
just like cars and trucks they have a purpose, and there are junky ones to be had for sure.
sorry Jean-paul don't take your prejudices and bad politics out on me,
designing and building switchers are a lot fun, buts lots more involved than PCB layout for chip amps.
just like cars and trucks they have a purpose, and there are junky ones to be had for sure.
sorry Jean-paul don't take your prejudices and bad politics out on me,
Last edited:
linear PS are still useful to engineers esp. to characterize class D audio circuits. they have a known quality and is one less thing you don't have to worry about in the lab.
Old school transformer supplies perform better and deliver better efficiency than modern smps - are you kidding? And what does make them more environment-friendly? The waste of copper and iron?
For your comparison, you should take a look at current developments of smps and their increasing efficiencies and not the cheapest ali baba stuff. On the other hand, has there been any significant progress with performance of mains transformers within the last decades?
Such statements sound like "the old times where the better times" - quite boring anyway.
For your comparison, you should take a look at current developments of smps and their increasing efficiencies and not the cheapest ali baba stuff. On the other hand, has there been any significant progress with performance of mains transformers within the last decades?
Such statements sound like "the old times where the better times" - quite boring anyway.
well you buy or design your chip amp supply +/- 35VDC @ 7.5 A with high surge capability and then we can compare. yes indeed a fine tuned unregulated linear can be pretty efficient.
your boring me too, Im surely aware of tradeoffs between PS tech. I've designed dozens of switchers from low power DC/DCs to high power off line.
your boring me too, Im surely aware of tradeoffs between PS tech. I've designed dozens of switchers from low power DC/DCs to high power off line.
I don't get the point why ******* someone on who is on SMPS a lot. An unregulated transformer supply is still not that efficient than a well made switcher. HF-ripple might be a concern at switchers, of course. If I need it clean, I'd go for classic copper, but without the need for high power. Linear regulation is mostly inefficient without a multi tap transformer at higher power needs. (I like the Prius, but yeah, this old Europe guys not lovin V8..)
Btw. why there's the need for high surge capability when having an excellent and fast active regulated power supply? The faster/better the regulation the smaller the bulk capacitance.
Can we please stay on topic? Thank you.
Btw. why there's the need for high surge capability when having an excellent and fast active regulated power supply? The faster/better the regulation the smaller the bulk capacitance.
Can we please stay on topic? Thank you.
Last edited:
Linear supplies have their place. A 300KW medium wave AM transmitter I was on the design team of used a 3 phase fed, iron core transformer and a 12 pulse rectifier. Efficiency was 97% or something ridiculous, power factor/line harmonics were great, and the cost/complexity was well below anything achievable by building a rack of switchers.
But for most "small" uses, switchers all the way. Smaller, lighter, less material usage, more efficient when you need regulation, cheaper usually, and EMI wise they're usually better than linear supplies as it's much easier to filter noise that starts at 60KHz instead of 120Hz.
doctormord - V8 cars make no sense until you get behind the wheel of one.
Sent from my Nexus 4 using Tapatalk
But for most "small" uses, switchers all the way. Smaller, lighter, less material usage, more efficient when you need regulation, cheaper usually, and EMI wise they're usually better than linear supplies as it's much easier to filter noise that starts at 60KHz instead of 120Hz.
doctormord - V8 cars make no sense until you get behind the wheel of one.
Sent from my Nexus 4 using Tapatalk
Yeah, 300kW is a different story, where you get 95-99% at a Pload of 0.5. But for smaller systems, <0.5kW there won't be that high efficiency. Anyway, how is your heat sink choice going?
Haven't got to it. Doing a project right now for a crew of people going to Burning Man, and the Wiener PCBs will be in any day now. Once all that's off my plate I'll be back on the 3251.
Sent from my Nexus 4 using Tapatalk
Sent from my Nexus 4 using Tapatalk
haha are you kidding me "EMI wise switchers will be cleaner" = FAIL
sorry it's not that simple
unregulated supplies feeding audio amplifiers work well with high 100-120 Hz ripple because the PSSR for most amplifiers (ones that use negative feedback) is quite good down low. not so much higher up. then the whole IMD mess (muli-tones indeed ) when you combine Class D and switchers, take a look with a spectrum analyzer,
now for regulated PS, its negative feedback can knock down 100-120 Hz very easily. The PS loop gain is gone before Fs >40KHz. so passive filters only.
a lot of folks don't consider the harmonics from secondary leakage inductance effects require snubbers and then shielding for really low levels >FCC class B. ALSO common mode noise can play havoc in the final application, and is mostly ignored by grounding in the conducted radiation bench test. Ive tested for FCC class B compliance.
this is an example of the reality in the lab https://youtu.be/BFLZm4LbzQU
I design these things too, I'm speaking from my own experience.
I worked several years at a company that built AM/FM broadcast transmitters. In an old FM product the amplifier B+, about 30-50V, was created with a big transformer, output rectified using SCRs to provide voltage regulation with LC post filtering into a big cap bank. This was followed by a bank of low drop regulators that filtered much of the 60hz/120hz/harmonic trash and permitted individual PA modules to have power cut for on-air replacement, then more LC filtering to remove the wideband HF trash that the linear stage didn't have the bandwidth to care of. It was a damn mess, but any trash on the PA B+ would cause AM modulation on the RF output and create spurious emissions.
In the successor product these were replaced with a bank of SMPSes, and we ran the PA's directly off them with no linear stage. Varying PA voltage was easy, 60/120Hz crap was minimized with feedforward compensation and a good feedback loop, and switching spurs could be taken care with easy passive filtering as they were at exact frequencies.
We had some old hats who couldn't believe that "those noisy SMPSes" would ever work, but the proof was in the results.
I ve been on EMI tests regularly for about 15 yrs. Never met a conducted radiation bench test😛
😛
yeah strike "radiated", it was a while back, my later work was in frequency sources PLLs DDS for radio tuners. ended up in a screen room again, testing phase noise, I had to explain each and every spurious source.
Last edited:
some of quasi resonant stuff is neat, passive filters can only get you `40 dB down on the whole. I know the trade offs can be balanced quite well😉 but putting a switcher in the clean camp category over a linear is stretching it quite a bit friend.
interesting I suspect the SCR pre regulator puts it in the switcher category but at a low frequency. the old Harrison Labs technology, (fig 11) that was the 1st sub optimum design error that took all those other band aids.
Last edited:
@infinia,
are you planning on making an own design for this amp or making a PSU design you will share with us?
are you planning on making an own design for this amp or making a PSU design you will share with us?
I already shared my PS design, but you didn't like it. that's OK by me after all its recycled gear from my stash.
im interested in what you guys will do, is that OK with you?
I reckon the PS isn't part of the system design process for some folks (devils details?)
im interested in what you guys will do, is that OK with you?
I reckon the PS isn't part of the system design process for some folks (devils details?)
Last edited:
Can't remember saying so, did I?
(I also can't remember that there was a particular design, would guess it was this +/-35V transformer. if so, nothing wrong with it, the discussion was about SMPS vs. Classic.)
(I also can't remember that there was a particular design, would guess it was this +/-35V transformer. if so, nothing wrong with it, the discussion was about SMPS vs. Classic.)
Last edited: