Welcome home!Me finally back home(this time to stay)... 'been six long months wandering...
(hmmm...
...and I thought diyaudio was your home )
it would be fun even when I'm not home!@shaan: should we post some kind of warning about using SMPS with a PeeCeeBee? I doubt that most people pay much attention to the rating of these resistors. Not likely someone will etch their own, and then spend 100 Euro on a power supply, but there are plenty of cheaper SMPS that could cause the same problem...
400 Watt SMPS in the same chassis with a PeeCeeBee is like the proverbial 500 lb Gorilla... it will do what it will do...
http://www.diyaudio.com/forums/vend...lateral-mosfet-amplifier-171.html#post3543156
400 Watt SMPS in the same chassis with a PeeCeeBee is like the proverbial 500 lb Gorilla... it will do what it will do...
http://www.diyaudio.com/forums/vend...lateral-mosfet-amplifier-171.html#post3543156
Anything you can recycle or save from the scrap heap is a win, as far as I am concerned...i've been using my own diy smps rated 300w 40vdc output. using ir2153 and cannibalized part from broken psu pc, my vssa peeceebee still rock!
Did you read LC's explanation of what was happening to Miksi?
It's fun time!
My parts arrived yesterday from Mouser and today it's fun time!
So far I've assembled one board.
I had to enlarge the holes for the thick legs of the 2200uF Fine Golds, otherwise it's been a pleasure soldering this pcb. The gold plating is a nice touch and the solder flows easily.
For the rails I went with panasonic FR (Fine Golds not available from Mouser at this time) and the low ESR of the FR's might be a good thing to have at the rails.
The VAS transistors are not matched - one is 80 and the other measures 150 hfe. I simulated this difference and the distortion is a little higher but just for a very tiny bit, no worries about.
My parts arrived yesterday from Mouser and today it's fun time!
So far I've assembled one board.
I had to enlarge the holes for the thick legs of the 2200uF Fine Golds, otherwise it's been a pleasure soldering this pcb. The gold plating is a nice touch and the solder flows easily.
For the rails I went with panasonic FR (Fine Golds not available from Mouser at this time) and the low ESR of the FR's might be a good thing to have at the rails.
The VAS transistors are not matched - one is 80 and the other measures 150 hfe. I simulated this difference and the distortion is a little higher but just for a very tiny bit, no worries about.
Attachments
My parts arrived yesterday from Mouser and today it's fun time!
So far I've assembled one board...
So far you and IvanLukic are the first two online who assembled the boards! What Zobel resistor did you install? It looks a bit on the small side, so probably not a good idea to run any sine wave sweeps that way...
With respect, I don't think that is allowed in this forum, because of safety and liability issues.
Although some SMPS are adequately isolated from the mains, many are not, and so there is some small, but real danger that another diy newbie comes along at some time in the future, reads you post, and does something that turns out badly.
yes i agree with PMI, and this is Shaan thread about vssa peeceebee so i can not publish it here.
but if you really want to build it, i could send you details how to build. consider you know the risk, smps is danger and i'm not responsible for any damage.
send me your email address via private message.
but if you really want to build it, i could send you details how to build. consider you know the risk, smps is danger and i'm not responsible for any damage.
send me your email address via private message.
Hi PMI,
I totally agree with your safety concern. However, there is always scope for producing a dangerous creation wherever mains equipment is concerned and even more so with SMPSs. I also agree that this isn't the place to discuss such a design. shaan is doing a great job as it is
Thank you naf, I look forward to seeing what you have designed. I appreciate the risks, but have over 35 years experience in professional electronic design.
I totally agree with your safety concern. However, there is always scope for producing a dangerous creation wherever mains equipment is concerned and even more so with SMPSs. I also agree that this isn't the place to discuss such a design. shaan is doing a great job as it is
Yes, and it is hard for me to critique someone who is doing what I like to do myself... My personal feeling is that almost anything worth having, is also worth modding... coffee pot, audio equipment, car engine...
and any time something used and broken is reused, I consider that to be a plus. However, I also know what the likely consequences will be if you take it too far. Been there, done that.
As I type this, I have one of my test boards in front of me, with a dead VAS transistor, and a shorted mosfet, ready to do some repairs - I consider that part of my hobby, seeing how far I can push something b/f it fails. At the same time, I don't do that with the boards I listen to every day,
My intention with the p/s for this project is actually to go the other way, toward a cleaner and quieter linear supply (as I posted above, see pg 74), with a slower turn-on (longer turn on time), than a typical smps. Not so much to save the on-board resistors as came up in the VSSA thread yesterday, but to avoid exposing the on-board electrolytics to a large inrush current on power up, and also, to avoid any potential source of a "thump" on power-up.
A symmetrical design like PeeCeeBee, or VSSA is perfect to test that, because the rails draw about the same current at every stage, and the circuit should be stable during power up/down. This means that if you tune the power supply rise/fall time, you can reduce or eliminate one source of the turnon/turnoff noises.
That psu board is two-sided, but if anyone wants to etch their own, I will publish a single-side version which is electrically identical (somewhere else, not in Shaan's thread).
You are correct, I checked the datasheet just now. The 1W is the same size as a conventional 1/4 W metal film. In fact, I think I will add a few to my next order
edit:
And rated as flame-proof, which is even better.
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No, don't replace it. It is probably metal-oxide resistor. They are the same size as 1/4W carbon film or 1/2W metal film. These resistors are excellent, low inductance, thermally very stable (low drift).
Hi PMI,
I totally agree with your safety concern. However, there is always scope for producing a dangerous creation wherever mains equipment is concerned and even more so with SMPSs. I also agree that this isn't the place to discuss such a design. shaan is doing a great job as it is
Thank you naf, I look forward to seeing what you have designed. I appreciate the risks, but have over 35 years experience in professional electronic design.
hi currentflow, i will send you complete document on monday.
to make clear i'm not designer of this smps credit goes to nicolau who design it.
i just draw my layout to fit my part.