PSU Questions
Hello,
I'm very interested by these cute modules for a multiamp setup.
http://schaeffer-ag.de/ makes ultra cool cheap custom cases (and they have a software for designing the front panels which talks to their CNC machinery).
So I'm already imagining 8 cute little boxes sitting on my shelf xD
However; a 300VA toroid isn't really the incarnation of "little" or "cute" (or "cheap" when you buy 8) so I wanted to ask you what was the tolerance of these modules wrt power supply ripple ; that's not mentioned in the datasheet...
I plan on building 6 or 8 little monoblocks ; each with its own power supply (besides these things have a balanced input, which is great) but for the mid and tweeters which need like 0.1-5 watts of average power I would rather use small R-Core transformers.
The Oofers would get a bigger supply of course.
So, would this be OK ? How much ripple can they tolerate without sound degradation ? How much PSRR ?
This, considering that with a smaller transformer, a power peak would take longer to recharge the PSU than with a big transformer...
I would not skimp on power supply caps. Are the BC-Component low-R snap-ins "audiophile-approved" ?
Do I need to make regulated PSU's (I'd make open-loop regs with just an emitter-follower so that would be easy and cheap) ? will this enhance the sound quality ?
Thanks for your answers !
Hello,
I'm very interested by these cute modules for a multiamp setup.
http://schaeffer-ag.de/ makes ultra cool cheap custom cases (and they have a software for designing the front panels which talks to their CNC machinery).
So I'm already imagining 8 cute little boxes sitting on my shelf xD
However; a 300VA toroid isn't really the incarnation of "little" or "cute" (or "cheap" when you buy 8) so I wanted to ask you what was the tolerance of these modules wrt power supply ripple ; that's not mentioned in the datasheet...
I plan on building 6 or 8 little monoblocks ; each with its own power supply (besides these things have a balanced input, which is great) but for the mid and tweeters which need like 0.1-5 watts of average power I would rather use small R-Core transformers.
The Oofers would get a bigger supply of course.
So, would this be OK ? How much ripple can they tolerate without sound degradation ? How much PSRR ?
This, considering that with a smaller transformer, a power peak would take longer to recharge the PSU than with a big transformer...
I would not skimp on power supply caps. Are the BC-Component low-R snap-ins "audiophile-approved" ?
Do I need to make regulated PSU's (I'd make open-loop regs with just an emitter-follower so that would be easy and cheap) ? will this enhance the sound quality ?
Thanks for your answers !
Use (e.g. 150W) electronic halogen lamp transformers, they work great with my ZAPs! As you can see in the pic I use quite big caps, as the smps doesn't rectify and filter the mains. So output of the SMPS is a 50Hz sine with 100kHz sine over it. You have to rewind the secondaries, which is not so hard (5 windings for 11.5V on my ones) as it sounds, or you're as lucky as I was and there are several windings in parallel which can be put in series.
BTW, those tinies drive a Scintilla (1 Ohm FR ribbon speaker) here!
Thomas
BTW, those tinies drive a Scintilla (1 Ohm FR ribbon speaker) here!
Thomas
Attachments
I got my SMPS here: www.reichelt.de , art# EL-TRAFO 150VA
They ship internationally, but they are only available in 230V input.
Conversion:
Check if and if yes how many secondaries are put in parallel. If you have 4 or even 6 you're lucky. Otherwise you have to rewind them. In my SMPS was a cap from prim. to sec., unsolder it.
Use high speed rectifiers, use big elkos as the halogen SMPSs are built up as cheap as possible and use DCed (had another look on a spare board I have) but unfiltered mains.
When I changed from toroidals to those there was no big difference apart from the fact, that these transformers don't hum!
They ship internationally, but they are only available in 230V input.
Conversion:
Check if and if yes how many secondaries are put in parallel. If you have 4 or even 6 you're lucky. Otherwise you have to rewind them. In my SMPS was a cap from prim. to sec., unsolder it.
Use high speed rectifiers, use big elkos as the halogen SMPSs are built up as cheap as possible and use DCed (had another look on a spare board I have) but unfiltered mains.
When I changed from toroidals to those there was no big difference apart from the fact, that these transformers don't hum!
Attachments
Hi Chris,
It certainly is a good start, and I'd recommend to go with the higher capacity caps (15,000uf/63V), and use that setup for the UCD180's, if you want to do something with a UCD400, just rip out the caps and replace them with the 10,000 uF/80 volt types.
The need for a UCD400 will depend on how efficient your speakers are, and how far the next door neighbour is.
For an efficient speaker like the Klipsch la Scala, the UCD180 is able to put over127dB SPL into your living room TDL (too Darn Loud), great sound stage, but possible damage to your ears. I only did this once, and although the neighbours were impressed, they asked me not to repeat the test....
Ity is imperative to keep both the signal and power supply wiring as short as possible, use heavy gauge wires for the power supply, and proper high quality wiring for the signal, however short.
There are no shortcuts to quality....
It certainly is a good start, and I'd recommend to go with the higher capacity caps (15,000uf/63V), and use that setup for the UCD180's, if you want to do something with a UCD400, just rip out the caps and replace them with the 10,000 uF/80 volt types.
The need for a UCD400 will depend on how efficient your speakers are, and how far the next door neighbour is.
For an efficient speaker like the Klipsch la Scala, the UCD180 is able to put over127dB SPL into your living room TDL (too Darn Loud), great sound stage, but possible damage to your ears. I only did this once, and although the neighbours were impressed, they asked me not to repeat the test....
Ity is imperative to keep both the signal and power supply wiring as short as possible, use heavy gauge wires for the power supply, and proper high quality wiring for the signal, however short.
There are no shortcuts to quality....
Arty123 said:
Hi Arty,
Thanks for the input. One point I disagree on, the ability to buy these modules is a big shortcut already
As far as the caps go I think I agree with you there too, why compromise this amp's quality for a future one that may never exist.. as a bonus the 63Vdc 15 000uF caps are a few dollars cheaper.
Wire.. planning on using silver plated stranded copper wire with teflon jacket. Nothing fancy just industrial stuff... 10 gauge will be used for the supply where I find I can't do without a wire.. more than overkill for this amp I think.
I'm going to cross my fingers and hope I don't need a soft start circuit with a 500VA Xformer but I do expect I'll be dissapointed, if so I'll add something later, like some tinfoil across the mains breaker.... yeah I'm kidding.
The need for a UCD400
You make a great point there and I'm well aware of it.There's not so much a need as there is a want, and I know my speakers would eat them up.
I'm running cerwin vega VS-150's, yeah I know, not audiophile but for what I listen to they do me proud.
Efficiency on them is 102dB @1W/1M, rated at 400W continuous but it seems people have happily run them with as much as twice that. That's not exactly the 104dB of your Klipsch la Scala's, but it's enough to tick the neighbores off just running the home brew 35W amp on the one speaker right now.
With the clean power of the amp I'd be more worried about detaching my retinas than going deaf, I love to blast it but never for very long, keeps the cops away, or at least by the time they get here they don't bother knocking if it's turned down already and they don't see a party.
I don't at all expect it to seem "loud" but I do expect some very clean power to be felt, all the way down the street.
I'd like to add what we all know already:
I used to run them off of a cheap pioneer receiver that had a very weak and heavily distorted 200W into 4ohms stereo, this was of course a class a/b amp.
You know the kind of commercial junk, you get one, maybe 2 good bass hits and then it seems like the rest are at half power?
(That's what disgusted me enough to bring me here anyway)..
So yeah my little 35watter class d doesnt' at all suffer that problem, even though it's only using a 48VA transformer, you've got to love it, the power is there when required, smooth and continuous, it handles pure sines with ease, up to clipping it anyway.
I'm also going to employ common mode chokes for the outputs because my speakers kind of like being far apart
I use 15' of 10 gauge monster cable for each one and I can't bring myself to cut it shorter.I'm going to go and hunt down the rest of the passives I'll need for the supply. Even though I'm using FRED rectifiers I will still bypass them. I may add a bleeder network or I may use a relay to short the caps directly after power off, so nothing extra loads it down while playing and for the fastest possible discharge afterwards, that could be a hard relay to find though.
Regards,
Chris
It seems that you replied about my "is small transformer OK" question !
I guess I'll make monoblocks with small transformers, cheaper and also easier to lug around.
Thanks.
I didn't mind my ex-neigbour listening quite loud to good music on his good hi-fi with the windows open. My new neighbour listens to **** on her crappy mini-stereo with the volume to the "maximum clipping" position, with all her windows open, and THAT ****es me off.
I guess I'll make monoblocks with small transformers, cheaper and also easier to lug around.
Thanks.
I didn't mind my ex-neigbour listening quite loud to good music on his good hi-fi with the windows open. My new neighbour listens to **** on her crappy mini-stereo with the volume to the "maximum clipping" position, with all her windows open, and THAT ****es me off.
Hi peufeu,
In your case with 8 monoblocks it would be insanely expensive to go bigger with the transformers just to get tighter regulation from them.
160VA is about right for a single UCD without starving it at all.
Going smaller and your rails droop a little more under load due to their regulation being worse but it will deliver the current required of it, it will only heat the transformer up more.
I hope that helps.
BTW I know how you mean, my neighbour has a 'blaster that's 100X's "louder" than mine. Not even a hint of bass. Just imagine what a 500W megaphone placed inside a plastic garbage can sounds like and you'd be pretty close. Gives you the urge to crawl under a bed and hide. They either play country or your typical 80's one hit wonders. I like to help them out by adding a little bass to it One day I'll freak them right out and play the same song in step with theirs, they won't know what's going on.
Chris
In your case with 8 monoblocks it would be insanely expensive to go bigger with the transformers just to get tighter regulation from them.
160VA is about right for a single UCD without starving it at all.
Going smaller and your rails droop a little more under load due to their regulation being worse but it will deliver the current required of it, it will only heat the transformer up more.
I hope that helps.
BTW I know how you mean, my neighbour has a 'blaster that's 100X's "louder" than mine. Not even a hint of bass. Just imagine what a 500W megaphone placed inside a plastic garbage can sounds like and you'd be pretty close. Gives you the urge to crawl under a bed and hide. They either play country or your typical 80's one hit wonders. I like to help them out by adding a little bass to it
One day I'll freak them right out and play the same song in step with theirs, they won't know what's going on.Chris
UCD modules and ultrasonic input?
Hi everybody
I am the happy owner of a pair of UCD180 modules (AD8620 version) for a month now. I didn't have the time to make them sing but they sure do look nice. God they are small! I didn't realize that until I had them in my hands
OK, now for the actual question. I have plans for using them with a NOS, filterless DAC (based on AD1865), and I was wondering how would the UCD feel about ultrasonic signal at the input?
Regards,
Calin
Hi everybody
I am the happy owner of a pair of UCD180 modules (AD8620 version) for a month now. I didn't have the time to make them sing but they sure do look nice. God they are small! I didn't realize that until I had them in my hands
OK, now for the actual question. I have plans for using them with a NOS, filterless DAC (based on AD1865), and I was wondering how would the UCD feel about ultrasonic signal at the input?
Regards,
Calin
Indeed, I expected them to be at least 2 inches tall. I've got myself the slimmest amp, in case I find some low profile caps for the PSU.classd4sure said:
So much for the filterless DACclassd4sure said:
Just joking. It's not that I'm I fan of NOS/filterless, in fact I haven't ever built myself a DAC before, but since this is my first attempt I would like to avoid drawing wrong conclusions. I don't know about intermodulation issues in class-D, if any, so I had to ask.Regards,
Calin
Hi again mr_push_pull:
Hi have DDDAC1543 nonos DAC feeding a four channel UCD180 amp as my secondary (?) system and it sounds wonderfull
I only hear HF distortion when my kids load DVDs on the transport
I don't want to offend anybody but I discovered that with this combo I've been able to use pure solid silver wire on the DAC without any known adverse effect and great "transparency", extension and slam.
Good luck
Mauricio
Hi have DDDAC1543 nonos DAC feeding a four channel UCD180 amp as my secondary (?) system and it sounds wonderfull
I only hear HF distortion when my kids load DVDs on the transport
I don't want to offend anybody but I discovered that with this combo I've been able to use pure solid silver wire on the DAC without any known adverse effect and great "transparency", extension and slam.
Good luck
Mauricio
(to buy Sikorel's)
Do you honestly feel that the UCD is better than *everything* else you have ever heard? For sure it's very, very good, but I would be suprised if the modules as stock are totally overwhelming some top of the line Krell or other class A gear
Pound for pound I think it's a winner design though. Personally I find it much better than my old Meridian 557 power amp (which is a fairly reasonable mid range hifi amp when it came out). I have heard a £13,000 Linn amp which I think sounded sweeter though...
Pound for pound I think it's a winner design though. Personally I find it much better than my old Meridian 557 power amp (which is a fairly reasonable mid range hifi amp when it came out). I have heard a £13,000 Linn amp which I think sounded sweeter though...
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