| cowanrg |
so, im wanting to get a few projects done so i can clear out my basement of all the stuff. ive already contacted a guy that does machining to get a price quote on finishing my cases.
they were originally designed with an aleph2 monoblock in mind. but, after doing more calculations, it just seems like its going to be too hot. it will work, but it will just be HOT. i think the case would be like 80C or something like that (considering worst case scenario, room temperature, etc.) and thats for an 80 pound case, and i only get 100 watts :(
the truth is, my current speakers are power hogs and 100 watts really does nothing for me. i currently bi-amping with 2 220watt amps per speaker and its just barely enough to get them to the levels i want. so, a 100-watt monoblock is nice, but i would need something else to help it out, or go with a full active bi-amped system.
so, enter the UCD module. over the past month or so, ive read all the threads on the UCD180, 400 and 700. it was a LOT of reading. so i really dont have many questions. and im NOT going to ask "how will it sound compared to a pass labs amp?" that is something only i can figure out. but, my question is, what amp can i try out to get an idea of the sound quality? i dont want to drop much cash, i just want to get an idea of what im in for. i dont care how it sounds compared to the aleph2, i dont even know how that sounds yet. i just want to know, "will a UCD sound good with my speakers". thats all. ive heard of people building amp1's and such for cheap just to get an idea... does anyone have one of these for sale?
i know my cases are WAY overkill for the cooling requirements of the UCD modules, but i dont care. the heatsinks will be just for show. im considering doing stereo UCD700 amps (two of them). i mean, who not? plus, that would allow the case to maybe raise a few degrees...
plus, i have a couple 1.7KVA transformers that i was going to use for the aleph2's that have 45v secondaries, which would be right in line for the UCD400's.
so, am i crazy to abondon the alpeh2's and use UCD modules instead? |
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| MikeW |
| Yes you are crazy. You could put all 7 channels for your surround sound in one box. :clown: |
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| cowanrg |
haha.
hey mike, whaaaaaaaaats happening...
long time no talk. actually, i dont use a center channel, and i plan to biamp front and rears (currently i just biamp the fronts). so that would be 8 channels. and i use 4ft speaker cables on the fronts, so i need at least 2 amps, one left and one right...
i would be good with just a stereo amp. of course a double stereo (4-channel) would be cool, and do two of those. but with the price of the modules at around $250 each, that would be $2k in just modules. thats much more than i have to spend. so ill just do 4 for now...
but anyways, is it a crazy idea to abondon a pair of aleph2 monoblocks for UCD modules? |
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| ackcheng |
Oh! Man! you made so much effort to make it looks like Pass products! What a waste? I have heard Aleph 2 and it is really very good!
I have UCD400. While it is good too, but I find the bass is lacking - that is to my liking anyway. |
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| cowanrg |
| quote: | Originally posted by ackcheng
Oh! Man! you made so much effort to make it looks like Pass products! What a waste? I have heard Aleph 2 and it is really very good!
I have UCD400. While it is good too, but I find the bass is lacking - that is to my liking anyway. |
sure, there was a lot of effort to make it look like a real pass amp, BUT, it was never going to be an exact XA200 clone. it was going to be a very nice cloned chassis with an aleph2 inside.
so, putting something else inside isnt a whole lot different than having an aleph2 inside. neither are that the "original" was.
but, the ultimate truth is, 100 watts just isnt enough juice for what i need. if i built this amp as a 100-watt monoblock, i would end up getting another amp to drive the bottom end of the speaker too. it would mainly be just for show. it wouldnt be my main amp, it would be a tweeter amp. thats a waste of time to build a DIY amp that looks THAT good just to use it as a supplemental amp.
so, which amp could i get thats cheap to get an idea of how this class d stuff sounds? i heard the aleph2 was a little bass shy too. its not a big deal for me, i crossover at like 80-100hz and give ALL bass to my subwoofers, which handle it just fine. i just need clarity, soundstaging (very important), and imaging.
could an amp3 or amp6 give me that "taste" of whats possible with this new breed of class D? |
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| rha61 |
| quote: | Originally posted by ackcheng
I have UCD400. While it is good too, but I find the bass is lacking - that is to my liking anyway. |
it depends a lot on your PSU caps
put Elna caps and you will get big bass
alain |
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| cowanrg |
thats good to hear. not that bass is a huge concern, but i would rather my amps do what they should be doing!
i almost forgot about this thread. i guess if everyone though i was completely nuts i would have heard about it by now... |
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| lawbadman |
Hey Cowanrg,
I have similar questions you have. I too have power hungry speakers (MMG).
I was thinking about getting the Charlize as an intro to class D amps, since Nuuk's T-amp article on TNT stated that the Charlize sounds the best (not by a big margin though), and its not too expensive.
It would be nice to hear how it is compared to my tube amp. |
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| Yves Smolders |
| quote: | | I have UCD400. While it is good too, but I find the bass is lacking - that is to my liking anyway. |
I've changed block rectifier/2xBC156 22.000uF's for the Hypex HG (slitfoils)
Bass is a little more pronounced, but very tight!
@cowanrg,
Give it a go, buy 2 UcD400AD's. You have nice toroids just lying there, find 2 caps and a block rectifier and you're ready to test (without DC protection and such, but you can test them)
2x45V might trip the overvoltage though, however, I think I've read the overvoltage limit has been put higher again in the newest 400 batch.
UcD is something special, you need to hear it! I see you don't run a center channel, you'll love the UcD's, they image very well and super precise (got fooled more than once, I was thinking my HTM2 center was running between my 804's and it wasn't :eek: ) |
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| cowanrg |
well, how about this...
would you be interested in buying a second-hand amp from me? i was thinking about the amp6. its very cheap and not surface mount. they say the surface mount sounds better, but i just want an idea of how it sounds, not the final end result...
the charlize is too underpowered for me. its only 20watts, and would be $96 shipped. its too expensive for me to just play around with, and 20 watts isnt enough to do anything with.
so, it comes back to the 41hz stuff. the amp6 is only $40 plus shipping. its only 2x25w into 4 ohms, but its cheap :) also, if i had a place to unload it, i might entertain the amp1. its 2x100watts into 4 ohms and only $54 plus shipping. i would be willing to get one of those if i knew i could unload it and only lose a few bucks. the only downside, it needs to be built and its surface mount...
let me know. i want to get moving on this, and i just want to hear something first. unfortunately, the UCD modules are a bit pricey to just play around with. |
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| sinski |
| quote: | Originally posted by rha61
put Elna caps and you will get big bass
alain |
Can you say which Elna cap type is in your opnion the best for UCD modules ?
What about slit-foil from BHC ?
sinski |
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| cowanrg |
i need to add something to my post to lawbadman.
the amp3, amp6 and charlize all can be run from either 12v batteries or just a transformer (the amp6 has PSU onboard). this makes playing around and testing very easy! those might be the ones to go with...
Yves,
yeah, it would be nice to just buy a pair of UCD400's and play, but at $185 each, its a bit of a gamble. im sure i could get rid of them later, but still. i would rather know a little more about what im getting into first. however, if i didnt like it, i guess i COULD just sell them on here for the same loss as i would if i bought the cheaper ones. so, worst case i would be out like $50. hum, i might give it a thought.
im actually going to my favorite surplus store today to look at caps and a few other things. adios! |
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| Yves Smolders |
cowanrg,
I realize it's a "big" gamble. I took it too, on faith of what I read on this forum, and the good things I've read about a Van Medevoort amp that uses some kind of UcD, and of course the glorious posts on the forum.
For testing, I actually hacked my Yamaha receiver first. Took the power lines from the main amps to feed the UcD's... :xeye: - I was in love... Next I got a block rectifier and 2 large surplus 22.000uF cans and connected them to an old Akai transformer, listened to that until last week. Now the Akai's guts are ripped out and replaced by all hypex stuff (I wanted softstart/DC protection , it was the easy way to go) Vintage look for my class-D amp :D
You can always sell it later I guess, I'm sure some lurkers here might be interested in buying a completed amp.
You can also buy the ST versions, but i'm not sure it's the same thing. 180's would be a loss for you as they aren't powerful enough for you.
Maybe if you share where you live, you could meet up with another DIYaudio forum member that has a working amp? |
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| Yves Smolders |
@Sinski,
I only compared the BC 156 22.000uF caps to the hypex (BCC slitfoils) and the latter is better for me. Of course the comparison isn't exactly right, as I used basic rectifying and a much lower VA transformer with the BC's.
Bass is much tighter with the large 500VA toroid/hypex PS, and somewhat silkier sound (less "straining" to the ear, more relaxed listening) |
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| Bgt |
| quote: | Originally posted by Yves Smolders
BC 156 |
The 156's are very dull sounding caps. The 154's sound much better. Used the 156 also before I found the 154's. |
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| Yves Smolders |
| Sorry my bad, I have 154's. |
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| Bgt |
| quote: | Originally posted by Yves Smolders
Sorry my bad, I have 154's. |
Cannot imagine the slitfoils have better bass than the 154? Something else must be different/acounting for the better bass performance. Could be because they are 10000uf instead of 22000uf(154's). Faster response. Higher uF is not always better.
10000 is a sweet spot. |
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| sinski |
| quote: | Originally posted by Bgt
10000 is a sweet spot. |
10000 for two ucd180, or 10000 for each ucd180 ?
Or you mean using of multiple 10000 instead of 22000 ?
What configuration could You advice for one stereo amp with 2xucd180 ?
I don't need so much power, most important is sound quality and prat.
sinski |
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| lawbadman |
Hey cowanrg,
Which amp have you got?
I forgot about the amp1, the power output for the price is not too bad, plus good reviews, hmmmmm :scratch:
I am tempted to get it but I would need to buy a trafo for it, or find some way to get +/-35 from +/-45. |
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| cowanrg |
| quote: | Originally posted by lawbadman
Hey cowanrg,
Which amp have you got?
I forgot about the amp1, the power output for the price is not too bad, plus good reviews, hmmmmm :scratch:
I am tempted to get it but I would need to buy a trafo for it, or find some way to get +/-35 from +/-45. |
i currently use rotel amps for my main speakers. they are nice, but im sure they could be better.
whatever amp i decide to go with will replace those, so i want to make something decent.
i looked around my parts bin (huge) and found a few goodies! i already have transformers that will work (well, they are a bit high voltage, but i can defeat the overvoltage protection on the UCD's), and i found 12 2,200 200V caps. so, i could use 6 per amp for 13,200 per amp. that should be enough for testing at least. all i need is a bridge rectifier, but i have some of those laying around im sure.
i think i might just get a pair of UCD400's. if i dont like them, i can sell them. but if they work, i can use them and im not out any money.
lawbadman,
ultimately, i am interested in the UCD700's once they come out. maybe ill play around with the 400's to see what i think and end up selling them. if i do, ill let you know. im not sure yet though. if you end up wanting to get an AMP1, let me know, i would be interested in trying it as well. |
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| Yves Smolders |
@cowanrg,
Try them. The UcD180 and the UcD400 had the same gain, so if you want to keep them for back or surround channel duties they will do fine (depending on your setup of course, if your rears are full range, you'll be limited) - the caps will be marginal, but as long as you don't drive crazy basslines into high volumes you'll be OK I guess. What rotels are you using now? I'd love to hear if you can "beat" them! :D
@bgt,
I'm running 4x10.000uF slitfoils compared to the 2x22.000uF 154's. Of course I'm sure I have double the VA's than before, that could account for much! All my tests were at relatively low volume.
@Sinski,
Bruno P. once calculated the UcD400 sweetspot: 6250uF per rail per channel for 8 ohm loads (IIRC), double that for 4 ohm loads. But he used a very high duty cycle in his calculations - looking at the Hypex PS, I'd say 10.000uf/rail/module is indeed the sweet spot. BTW, this has been discussed to death in the massive UcD400 thread. It's becoming bible-sized lately :D |
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| classd4sure |
| quote: | Originally posted by Yves Smolders
@cowanrg,
Try them. The UcD180 and the UcD400 had the same gain, so if you want to keep them for back or surround channel duties they will do fine (depending on your setup of course, if your rears are full range, you'll be limited) - the caps will be marginal, but as long as you don't drive crazy basslines into high volumes you'll be OK I guess. What rotels are you using now? I'd love to hear if you can "beat" them! :D
@bgt,
I'm running 4x10.000uF slitfoils compared to the 2x22.000uF 154's. Of course I'm sure I have double the VA's than before, that could account for much! All my tests were at relatively low volume.
@Sinski,
Bruno P. once calculated the UcD400 sweetspot: 6250uF per rail per channel for 8 ohm loads (IIRC), double that for 4 ohm loads. But he used a very high duty cycle in his calculations - looking at the Hypex PS, I'd say 10.000uf/rail/module is indeed the sweet spot. BTW, this has been discussed to death in the massive UcD400 thread. It's becoming bible-sized lately :D |
I wouldn't say it's the sweet spot, that's of course what your ear likes best. That's just a designed spec for max ripple under max load conditions, which gets you the minimal value that will meet the requirement, and then rounded up to the next standard cap value.
There's ways of still taking advantage of even bigger cap banks, that doesnt' make it worth it though. Caps aren't cheap.
Regards,
Chris |
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| rha61 |
| quote: | Originally posted by sinski
Can you say which Elna cap type is in your opnion the best for UCD modules ?
What about slit-foil from BHC ?
sinski |
i've not tried BHC slit foil
The best Elna are the Cerafine , they have a very nice sound but are bass-oriented
alain |
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| classd4sure |
Hi,
Alain, Interesting to hear that my Cerafines are optimal for bass. You're pushing me to take that light bulb out and use a real soft start circuit, thank you.
Chris |
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| cowanrg |
thanks everyone.
i HOPE that these can beat my rotel. i mean, everyone is talking how great they sound and how they are beating up on a ton of high end designs. well, the rotels arent that high end in my mind. so, they should beat them. if they dont, ill get out of class d completely.
i dont run my speakers full range, so they wont be asked to do a LOT of bass, but i still like them to be punchy at the midbass frequences.
im having a problem finding appropriate caps to use for the supply. the ones i have will work for testing, but i dont really want to use them for the final amp if i decide to build it. the best ive been able to find at a reasonable price are nichicon 10,000uf @ 80V for $4 each. im really looking for 100v, because if i decide to go with the ucd700's later, i dont want to have to upgrade everything.
i found some nichicon muse FG's, but they are like $50 each. i would need 4 per channel for a 4 ohm supply, thast a lot on caps.
edit:
the lc audio predator psu looks good, but it only goes up to 60v, so i would have to get the special addition. i guess i could just drop the cash for the hypex PSU, but its PRICEY and its not carried in the states.
who in the states other than diycable and adire carries hypex stuff? adire is pricey and diycable doesnt have power supplies. |
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| Jan-Peter |
Hi,
We deliver worldwide! Please check our webshop......;)
The HG supplies are costly because we use Audio rated capacitors from BHC (Slitfoils).
Regards,
Jan-Peter |
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| cowanrg |
Jan,
how much would shipping be to the US for a pair of UCD400's? i just am looking for an estimate, not necessarily an exact amount. thanks. |
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| Jan-Peter |
We have two options;
By TPG post cost +/- EUR 32, takes 7 to 12 days.
By a courier TNT cost +/- EUR 55 takes 2 to 4 days
Since last week we can accept payments by Credit card!
Jan-Peter |
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| cowanrg |
when i get the quote back for building the rest of my case, ill have to consider this.
ill definately give them a full test run and see how they sound if i do get them. i have a few things to compare them against and have a pretty decent system. if they do what they are claimed to do, i will hopefully convert a few other skeptics too. |
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| classd4sure |
Hi cowanrg,
You've got to slow down, get a plan going.
Sounds like you wanted a good surround system of some sort and yet just want to try some class d, dont' care how it compares to anything, and most importantly be able to dump it when you don't like it. There's got to be a better way to go about this?
The most you'll be out is the cost of the module which you as you said likely would have no problem selling in the states.
Everything else is still good for any other amplifier.
Set goals, how many channels do you need just to experience the technology and decide if it's for you or not... just two right.
Don't let all these threads around here convince you into thinking all the tweaks need to be pulled out on them and all that. I'm confident the sound will exceed your meager expectations of it even in stock format.
You also don't need the very best hardware just to try it out, the UCD180 will be alot of power for you from the sounds of it, get the little 320VA transformer and run it in stereo with whatever cheap industrial caps you can find and a 2$ bridge rectifier, bolt it down to a piece of wood or sheet metal or stuff it in a used computer tower, who cares you're just trying it. Dont' even have to worry about soft start or protection just throw a 2 cent mains fuse in.
Then you can decide if you think it's worth sticking with, if it sounds good enough as it is, or if you need 5000$ capacitors in it with a 10kVA transformer and gold braid wires.
You can test this for a thousand or less I'm sure of that.
Regards,
Chris |
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| cowanrg |
chris,
im not sure if i was completely clear here...
im not simply planning to "toss" something together. i do have a plan, maybe im just not properly sharing it with you.
i already have a pretty impressive surround system, but im not totally happy with my amps. my fronts are being driven by a pair of rotel MB-1070's. they are biamped, and produce around 200wpc at 4 ohms, and since they are stereo, and one per speaker, im running passively bi-amped at around 400/ch. the speakers are magnepan tympani 1D's, which are pretty power hungry.
the rears arent as important for my purposes right now. BUT, if all works out, a pair of these amps for the rears wouldnt be bad either... but thats not taken into consideration.
SO, i currently have everything i need. i have all the amps and speakers, so its not like im building anything i dont already have.
so, in answer to your question, i only need two channels to evaluate the sound quality. i do this stuff for a living (i sell audio and do system consultation), so i have a "tuned" ear, or better yet im used to listening to amps on my system with the same damn songs ive heard 1 million times.
im not necessarily comparing this amp to "anything", im comparing it to things i have access to, and more importantly what i currently use. if it doesnt sound better than what i have, there is no use playing around with class D.
i dont plan on doing any tweaking or upgrading for just a test. i plan on using it in a "modest" form, that is, in a non-extreme application. i want to keep it pretty stock, but also not use inadequate parts either. just a basic textbook implimentation.
and i dont have meager expectations, they are actually quite high. i have heard a lot of things in my time, up to $1/2 million systems that have been properly designed in sound treated rooms. i dont expect THAT, but i expect it to live up to the hype in these threads.
the 180AD might be enough power to "test" with, its certainly not something i would keep if it sounded good. i would much rather use 400's. so, if im going to test them out, i might as well use 400's. that way, if i like them i can just keep them. either way, if i dont like it, i would sell them. but, i hope that wont happen.
hum, i wasnt quite clear about what i already have to test this thing. i have a TON of caps sitting around, and i was planning on using some i had laying around. i have various phillips, nichicons, some elnas (not enough for what i want to ultimately build though), and some others. i have high and low grade. i also have a bunch of bridge rectifiers, most 25-35amp, 600-1200V. the transformers will be 1.7kva toroidals with 45v secondaries. if i liked the sound and were doing it "for real", i would use better caps and a better power supply, maybe hexfreds or something.
i guess you may have thought that i didnt have parts at my disposal and i was planning on JUST buying the modules, and then trying to source all the other parts later. thats not the case. i have EVERYTHING i need to properly test these. i just want to see how they sound compared to what i have, and what ive heard. if they sound good, ill go from there, if not, ill sell them and not lose any sleep :)
i know i ask a lot of questions and seem new to this, but its just that im new to class d modules. ive been in this forum since '02 and have almost 2k posts. ive read a lot, im just not an engineer or an electronics major. so, some stuff i just dont get. but i know whats necessary to evaluate an amp. |
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| classd4sure |
| quote: | Originally posted by cowanrg
chris,
im not sure if i was completely clear here...
im not simply planning to "toss" something together. i do have a plan, maybe im just not properly sharing it with you.
i already have a pretty impressive surround system, but im not totally happy with my amps. my fronts are being driven by a pair of rotel MB-1070's. they are biamped, and produce around 200wpc at 4 ohms, and since they are stereo, and one per speaker, im running passively bi-amped at around 400/ch. the speakers are magnepan tympani 1D's, which are pretty power hungry.
the rears arent as important for my purposes right now. BUT, if all works out, a pair of these amps for the rears wouldnt be bad either... but thats not taken into consideration.
SO, i currently have everything i need. i have all the amps and speakers, so its not like im building anything i dont already have.
so, in answer to your question, i only need two channels to evaluate the sound quality. i do this stuff for a living (i sell audio and do system consultation), so i have a "tuned" ear, or better yet im used to listening to amps on my system with the same damn songs ive heard 1 million times.
im not necessarily comparing this amp to "anything", im comparing it to things i have access to, and more importantly what i currently use. if it doesnt sound better than what i have, there is no use playing around with class D.
i dont plan on doing any tweaking or upgrading for just a test. i plan on using it in a "modest" form, that is, in a non-extreme application. i want to keep it pretty stock, but also not use inadequate parts either. just a basic textbook implimentation.
and i dont have meager expectations, they are actually quite high. i have heard a lot of things in my time, up to $1/2 million systems that have been properly designed in sound treated rooms. i dont expect THAT, but i expect it to live up to the hype in these threads.
the 180AD might be enough power to "test" with, its certainly not something i would keep if it sounded good. i would much rather use 400's. so, if im going to test them out, i might as well use 400's. that way, if i like them i can just keep them. either way, if i dont like it, i would sell them. but, i hope that wont happen.
hum, i wasnt quite clear about what i already have to test this thing. i have a TON of caps sitting around, and i was planning on using some i had laying around. i have various phillips, nichicons, some elnas (not enough for what i want to ultimately build though), and some others. i have high and low grade. i also have a bunch of bridge rectifiers, most 25-35amp, 600-1200V. the transformers will be 1.7kva toroidals with 45v secondaries. if i liked the sound and were doing it "for real", i would use better caps and a better power supply, maybe hexfreds or something.
i guess you may have thought that i didnt have parts at my disposal and i was planning on JUST buying the modules, and then trying to source all the other parts later. thats not the case. i have EVERYTHING i need to properly test these. i just want to see how they sound compared to what i have, and what ive heard. if they sound good, ill go from there, if not, ill sell them and not lose any sleep :)
i know i ask a lot of questions and seem new to this, but its just that im new to class d modules. ive been in this forum since '02 and have almost 2k posts. ive read a lot, im just not an engineer or an electronics major. so, some stuff i just dont get. but i know whats necessary to evaluate an amp. |
Having mentioned cost a few times
Still, with all of that you had mentioned if the cost of the rest of what you want in your case was reasonable you'd consider trying it, and having mentioned cost a few times, I just didn't think you'd be someone with spare caps pushing the closet door open and thought the 180 would be cheapest overall to test with, using less expensive parts.
Anyway, I doubt you'll be disappointed with it, look forward to seeing what you think. I like how you plan on testing them and it might be a review worth reading:)
What do you have for soft starting a 1.7kVA toroidal? Something I hope.
Regards,
Chris |
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| cowanrg |
i mention cost because i dont like to waste money if i dont have to.
for instance, if i buy a pair of 180's and it sounds awesome, i would sell them at a small loss and get 400's. so, it would be silly to do that (in my opinion) when i could just buy the 400's in the first place.
im looking for "value", not cheapness, not "cost no object".
you didn't think i'd be someone with spare caps? hehe, you should check out the links in my signature sometime :) thats a very very very small portion of what i have. i have a 20' x 20' shop full of stuff, i only have a small pathway to walk to the workbench and thats it.
i hope i like these amps, it would save myself a lot of hassles! plus, i find it interesting that no one yet has discouraged me from trying these... there is usually SOMEONE that says "thats stupid!". but not here, no one seems to think its a bad idea. i hope they are right.
ill do something for a soft-start on the 1.7kva, havent really thought about it yet. WHATEVER i build, ill need a softstart for it, so i might do the lcaudio one, or the one hypex sells. there are several on the market. or maybe ill just get a variac and use that. who knows, its a small detail. |
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| classd4sure |
| quote: | Originally posted by cowanrg
i mention cost because i dont like to waste money if i dont have to.
for instance, if i buy a pair of 180's and it sounds awesome, i would sell them at a small loss and get 400's. so, it would be silly to do that (in my opinion) when i could just buy the 400's in the first place.
im looking for "value", not cheapness, not "cost no object".
you didn't think i'd be someone with spare caps? hehe, you should check out the links in my signature sometime :) thats a very very very small portion of what i have. i have a 20' x 20' shop full of stuff, i only have a small pathway to walk to the workbench and thats it.
i hope i like these amps, it would save myself a lot of hassles! plus, i find it interesting that no one yet has discouraged me from trying these... there is usually SOMEONE that says "thats stupid!". but not here, no one seems to think its a bad idea. i hope they are right.
ill do something for a soft-start on the 1.7kva, havent really thought about it yet. WHATEVER i build, ill need a softstart for it, so i might do the lcaudio one, or the one hypex sells. there are several on the market. or maybe ill just get a variac and use that. who knows, its a small detail. |
Variac will work. I used a 100W lightbulb just to throw a test together, it works but obviously limits the bass a great deal, that's good though, I have a great idea what it sounds like, what I want it to sound like from here, and everyone who's heard it thus far and found it lacking power will be blown away later and think I pulled something out of my hat :)
The little pathway, must be where you twist your cables?
I think you're in for a slight shock anyway, doubt you'll have ever seen value like this.
Regards,
Chris |
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| cowanrg |
| quote: | Originally posted by classd4sure
Variac will work. I used a 100W lightbulb just to throw a test together, it works but obviously limits the bass a great deal, that's good though, I have a great idea what it sounds like, what I want it to sound like from here, and everyone who's heard it thus far and found it lacking power will be blown away later and think I pulled something out of my hat :)
The little pathway, must be where you twist your cables?
I think you're in for a slight shock anyway, doubt you'll have ever seen value like this.
Regards,
Chris |
yeah, i do the lightbulb thing. i have a power cord that has a light bulb built into it that i use for testing stuff. i guess i could just do that. but i would rather listen to it in all its glory :)
well, that little pathway is all i have right now, but its not always been like that. i just havent had much time lately, and i have acquired a bunch of "stuff" from various places that will all be sold. i dont twist cables. i leave them straight :)
well, im optomistic for sure! but i hope its not JUST value, i hope its great sound too. thats REALLY what im looking for. but i also dont want it to cost $10k. |
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| Yves Smolders |
cowanrg,
You can always start with the lightbulb in series and then short it out with a (heavy) switch to see what the thing can do :D
It's interesting to see someone from "the business" testing the hyped DIY modules.
I've mentioned my DIY work a few times in a high-end store I like to visit here in Belgium, they just chuckle a bit and give me the "poor boy, he doesn't know what he's doing" look...
At least you keep your mind open to test these modules.
BTW, I'm not sure if you are aware, but if you test the UcD400's and they live up to the hype, but lack power somewhat, you can still try to bridge them - of course i'm not sure it will do any good for magnepans, because of the low impedance. UcD400's are limited to 20A of current, drive them under 4 ohms and the max. power output goes down.
I'm looking forward to your tests!
Yves
PS. If you haven't sold "transformer 2" on your DIY site yet, it's ideal to test UcD's, 42v secondaries! I tried with a classic transformer also, although a bit smaller. sound and mid/high ranges were almost identical, bass was there, but weak and slightly loose in comparison with the 500VA toroid i'm using now. |
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| cowanrg |
| quote: | Originally posted by Yves Smolders
cowanrg,
You can always start with the lightbulb in series and then short it out with a (heavy) switch to see what the thing can do :D
It's interesting to see someone from "the business" testing the hyped DIY modules.
I've mentioned my DIY work a few times in a high-end store I like to visit here in Belgium, they just chuckle a bit and give me the "poor boy, he doesn't know what he's doing" look...
At least you keep your mind open to test these modules.
BTW, I'm not sure if you are aware, but if you test the UcD400's and they live up to the hype, but lack power somewhat, you can still try to bridge them - of course i'm not sure it will do any good for magnepans, because of the low impedance. UcD400's are limited to 20A of current, drive them under 4 ohms and the max. power output goes down.
I'm looking forward to your tests!
Yves
PS. If you haven't sold "transformer 2" on your DIY site yet, it's ideal to test UcD's, 42v secondaries! I tried with a classic transformer also, although a bit smaller. sound and mid/high ranges were almost identical, bass was there, but weak and slightly loose in comparison with the 500VA toroid i'm using now. |
well, people that work in those stores arent interested in the next new thing unless its THEIR thing. thats not a bad thing, i worked in a high-fi store here that was pretty high-profile. ALL THE TIME, people would bring stuff to show us, many were real commercial companies. so those people see a TON of products, and quite frankly, most were junk. the worst was people that would bring in their home-brew cables. they were always the same cable, silver or silver-plated, teflon tubes, twisted or braided. and it always sounded the same, worse than all the commercial interconnects. i dont want to start a cable debate (im a fan of cables), but everyone would try to make their own, and completely missed the boat.
i thought of bridging the amps if they arent enough power, but i would probably just end up getting the 700's, because they are supposed to sound better. plus, my speakers are 4 ohm, so bridging isnt the best option there.
i guess that transformer would work if the toroidals dont. unfortunately, i only have one of them, and i will be building monos so that wont work. i will keep an open mind and test it all out! im curious too. |
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| cowanrg |
alright!
i cleaned up my shop, now its able to be used!
i ordered the spare parts needed to complete the "test". its going to start basic, and i can upgrade it later if i see any potential. so if any nay-sayers (such as myself at this point) are curious, in a couple of weeks i will have a test pair of monoblocks made and i will compare them with various things and see how they sound. im pretty excited.
about how long does shipping take from these guys? if its awhile, i should probably order it now... any ideas? |
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| Jan-Peter |
Shipping option TPG Post --> 8 - 15 days.
Shipping option TNT (courier) --> 3 - 5 days.
Jan-Peter |
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| cowanrg |
well, they still havent shown up yet, hopefully they will show up this week (its been over 10 days already :( ).
but, in the meantime, i have built a pair of chassis for them with power supplies. so, my test rig will have 1.7kva transformer, with 45v secondaries (unloaded), 13,200uf total capacitance (per supply) with dual 35A bridge rectifiers.
they look like this: |
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| cowanrg |
and the power supply:
(not fully hooked up of course) |
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| Yves Smolders |
Watch out with 45V secondaries - i remember from the UcD400 thread that the older modules sometimes went in protection mode because the voltage is so close the the maximum. A spike on the mains, or a bit too high mains voltage, and they shut down.
Maybe the new modules can handle a bit more, I'm not sure.
I hope you get them soon, your test enclosures look very industrial and dramatic :D |
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| cowanrg |
yes, the voltage will be close. by my voltage does NOT fluctuate here. plus, i run dual power conditioners by furman that smooth everything out and get rid of spiking. its very stable.
the cases serve their purpose :) they are just the stripped down case thats in my avatar. its just minus the sides, top, and front. it will be pretty empty, but whatever. |
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| Yves Smolders |
Well ok, you're obviously a much more experienced DIY'er than I am, I don't need to tell you what to be careful of!
I'm just wondering if you'll like the modules!
PS. I've listened to a pair of B&W 802D last weekend... :eek: :eek: :eek:
Amazing speakers... |
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| cowanrg |
yeah, the 802D's can be pretty amazing speakers, if they have the right equipment with them. they have great potential.
i have 2 pairs of 803D's right now. i worked at a place that sold b&w and they gave us a good deal when the new diamond series came out, so i bought a couple pairs. they are just taking up space right now... im not a big enough b&w fan to keep them.
HOPEFULLY these modules will show up this week. counting saturdays (the post office moves mail on saturdays), its been 14 days now :( so, jan said 8-15 days, and its definately at the longer end of that. |
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| Yves Smolders |
Yeah, the 802 is a large speaker and yet it sounds like it's "not there" at all.
I'm so jealous :D - B&W 800 series is my kind of speaker.
If they are in your way, I'll happily pay the transport fees to send them over to me :Angel: ;) That's what... $20.000 just sitting there! :wow:
What do you think about the 803D? Some people think it outperforms the "old" N802.
I have a couple of "old" N804's and N805's, and the HTM2 centre... Been thinking to upgrade these to 804S, but it seems not worth it... I'm happy with the sound, right now i'm looking into a new receiver to run as pre/pro, I'll use the money there.
Strangely enough, Nautilus speaker still remain at a good price on ebay and such. About 15-20% off the list price, which is what I paid for them in the first place.
Some people forget that the "oldies" still are excellent value for money :D
Must... fight... upgraditis... |
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| cowanrg |
IMO, the 803D's are pretty similar to the old 802's, with slightly better power handling, and a cleaner top end.
ok, so today i got my UCD modules, woohoo. i eagerly opened up to the box and everything appeared to be there.
since i had the test rig all built and the power supply running and tested, it was pretty easy to get music playing out of these things. right now, i only have one up and running. it makes music, and thats about as far as i got in regards to quality. i will have to let it burn in for a little while and do more testing before it gets played on anything decent. right now, it only gets played on crappy speakers or a dummy load.
well, here comes the bad news. it plays music, but there is a nasty little hum/buzz coming out of it. its pretty small, but still unacceptable to be in my main system. i need to track it down. i saw some threads on here talking about it. i havent really tried a whole lot yet. i have attached a picture showing the setup. the wires are messy, i know.
basically, i have a pretty standard linear supply. nuetral and hot lines come from the inlet, go into the transformer (thanks guys for helping me figure out the wiring), then out with the primaries to the rectifier bridges, then to cap bank. from here, i have tried two things. ground directly to a star ground on case (as seen), and i have also tried directly to the amp. it was worse without the star ground. the RCA hack ground goes to the board and so does the ground for the binding posts.
there is LOUD noise if i get my hands anywhere near the power wires or the input wires... if i get my hand within a foot or more of the input wires, there is a LOUD buzz... is this normal for these types of amps? i have read a LOT on these, but i didnt read anyone specifically say if theirs was dead quiet or not. most people expect a slight buzz or hiss, but i like my stuff to sound the same with no signal as it does when its off. i like a black background. is this possible with these, or is there just too much noise?
or maybe im doing something wrong in the hookup. see atached picture for any suggestions. i did move the transformer like a foot farther away with no chance in noise. the noise increases when i start getting my hand closer, touch the heat spreader, touch the case, or get my hands close to any wires. also, the hum is VERY loud when nothing is connected...
(p.s. - i dont have the heatsink attached to anything right now. im running it for less than a minute at a time or so, and with VERY low signals. it will have a heatsink) |
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| mac |
| quote: | Originally posted by cowanrg
well, here comes the bad news. it plays music, but there is a nasty little hum/buzz coming out of it. |
I have 3 UcD modules in each of my two chassis and have zero noise/buzzing problems. I suspect that you may have a ground loop with your wiring scheme. You appear to be using single-ended inputs. Did you tie input pins 2 & 3 together? Also, make sure your outputs are isolated from the chassis. |
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| cowanrg |
| quote: | Originally posted by mac
I have 3 UcD modules in each of my two chassis and have zero noise/buzzing problems. I suspect that you may have a ground loop with your wiring scheme. You appear to be using single-ended inputs. Did you tie input pins 2 & 3 together? Also, make sure your outputs are isolated from the chassis. |
as SOON as i saw this post, (i was researching possibilities), i JUST thought about the single-ended thing. i DIDNT tie 2+3 together. ill try that right now and see if that does it...
thanks! |
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| cowanrg |
uh oh...
i connected the signal ground to the -signal (J3), and NOTHING changed. it was the exact same buzz, maybe louder. i even took the RCA jack off the back panel completely to make sure it wasnt touching (it wasnt), and that didnt change anything.
one thought, i dont have the earth ground connected on the IEC inlet. could that help? i usually lift it to solve any potential ground issues. |
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| mac |
Don't know if this slightly blurry photo might help. Pins 2 & 3 both go to input signal ground (not tied to chassis ground). Pin 1 goes to input positive. I have supply ground tied to a star ground point on my chassis and also have the AC receptacle ground tied to the same point.
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| mac |
| The other thing you may want to try is shorting the input to your UcD module. If the noise goes away you have a ground loop with your source component. |
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| cowanrg |
well, i tried a few things. i modified the star ground to now include the earth ground on the IEC inlet.
that did nothing...
BUT, i tried what you said about shorting the input to ground, and now its silent... there is NO noise coming out of it at all. but, its really really noisy if nothing is connected. i made a cable awhile ago that is an RCA interconnect that is shorted out at one end, just for this purpose. and when i disconnect it, the amp hums again. when its plugged in, it stops humming and is silent. is that normal?
thanks for the help!
edit:
i re-read what you said about having a ground loop at the source component... im not quite sure i understand how to fix this. i had the earth ground lifted before and that didnt do anything. how else could i have a ground loop issue? also, the humming/buzzing happens with NOTHING connected, just a bare amplifier without an input. even if i just disconnect all the input wires to the jumpers, it still buzzes. |
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| Jan-Peter |
....hm, your setup is wrong;
- remove the star ground.
- ground the circuit ONLY at the cinch gnd tab to the chassis ground.
- use a screended wire, or at least twist the wires.
- when you like to use an asymmetrical connection connect -symmetrical to gnd.
Better to use;
- use symmetrical screened wires.
- use a symmetrical input XLR, whereby pin#1 is connected to chassis.
- make an asymmetrical to symmetrical cable whereby at the side of the cinch the screen is connected to -symmetrical, and then to the GND of the cinch.
When proper wiring you will have NO hum and NO noise.
Jan-Peter |
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| mac |
| Looks like you've got JP to help out. I'm sure he'll be able to get you up and running. Good luck. |
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| cowanrg |
| quote: | Originally posted by Jan-Peter
....hm, your setup is wrong;
- remove the star ground.
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done.
| quote: |
- ground the circuit ONLY at the cinch gnd tab to the chassis ground.
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this confuses me a bit... by "cinch" tab, i assume you mean the quick-disconnect tab on the UCD module itself? that connects to chassis ground? where is chassis ground? doesnt that imply i would have a star ground?
| quote: |
- use a screended wire, or at least twist the wires.
|
by "screened" i assume you mean shielded. where do i need to use shielded wires? everywhere, or just on the signal wires?
| quote: |
- when you like to use an asymmetrical connection connect -symmetrical to gnd.
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i got that part. i connected pin 2 to pin 3 at the RCA input jack. i dont use balanced connections (my processor doesnt have them), so i will never need an XLR jack.
| quote: |
Better to use;
- use symmetrical screened wires.
- use a symmetrical input XLR, whereby pin#1 is connected to chassis.
|
see above. ill just keep 2 and 3 connected.
| quote: |
- make an asymmetrical to symmetrical cable whereby at the side of the cinch the screen is connected to -symmetrical, and then to the GND of the cinch.
|
you kinda lost me there. im still not sure what you mean by "cinch". but i am guessing you mean a shielded cable, where the shield is connected at one end (the UCD module end) with the shield connected to - input, and ground to ground, and signal to +input. right?
| quote: |
When proper wiring you will have NO hum and NO noise.
Jan-Peter |
I can only hope so!
but i am still confused as to what my grounding scheme should be... i have covered the asymetrical (XLR, single-ended, whatever you want to call it) issue. i have grounded (or connected) pins 2 and 3 together at the RCA jack ground tab.
but im still confused about how to ground the actual module and the chassis ground thing. i am using dual primaries and dual rectifiers. should i connect the 0V taps together and just use a single rectifier? how should i go about wiring this thing up.
| quote: | Originally posted by mac
Looks like you've got JP to help out. I'm sure he'll be able to get you up and running. Good luck. |
i sure hope so! thanks anyways. |
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| Jan-Peter |
Cinch is RCA.
The best is to connect chassis ground at the input RCA connector. In you picture you can solder a small wire from RCA GND to the nearest screw. In this cas you have ground the amplifier at the input side. Twist the signal wires, and connect at the UcD180 the -symmetrical to GND of the UcD180.
Jan-Peter |
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| cowanrg |
| ok. i understand that. if im only grounding the amp here, i would just float the ground thats connected to the supply? |
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| Jan-Peter |
You must ground the amp only at one side! Never use star grounding, which fool that has designed.....
JP |
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| cowanrg |
well, thats exactly what i have... |
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| cowanrg |
| quote: | Originally posted by Jan-Peter
You must ground the amp only at one side! Never use star grounding, which fool that has designed.....
JP |
well, there are a lot of fools on this forum then... star grounding is a common practice from what i thought. but if there is a different and better way to do it for your amp, ill learn. its obviously not working for me now.
OK, so lets get this straight... i have a power supply, that looks just like the picture mac posted. i have 3 connections coming out of it. do i connect THAT ground to the UCD module? or JUST the RCA tab ground?
edit:
i just followed the directions on the supplied manual diagram, and only added a star ground AFTER i got humming. |
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| Jan-Peter |
There is no need to ground at the center of the capacitors. Please ground only at the input of your RCA connector.
You can very easy test it in your setup, remove the star ground. Connect a wire from the RCA GND tab to the chassis. And connect -sym at the UcD180 module to GND.
Connect the center of you capacitors ONLY to the GND of the UcD180. Remove also here the star ground.
JP |
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| cowanrg |
| quote: | Originally posted by Jan-Peter
There is no need to ground at the center of the capacitors. Please ground only at the input of your RCA connector.
You can very easy test it in your setup, remove the star ground. Connect a wire from the RCA GND tab to the chassis. And connect -sym at the UcD180 module to GND.
Connect the center of you capacitors ONLY to the GND of the UcD180. Remove also here the star ground.
JP |
yes, i tried that... and the module didnt turn on. i dont have a star ground anymore. the only way it turns on is when i have a wire connected from the center of the cap bank to J5 on the UCD board.
the only other ground connections i have are: from the speaker terminals to the UCD board (necessary), and from the RCA ground tab to the UCD board (-sym, and input ground).
thats the ONLY grounding thats going on. |
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| Jan-Peter |
Watch our website, unther Applications. We will put today some drawings how to proper wiring the UcD module in a met case.
Jan-Peter |
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| cowanrg |
| quote: | Originally posted by Jan-Peter
Watch our website, unther Applications. We will put today some drawings how to proper wiring the UcD module in a met case.
Jan-Peter |
ok. its late here and im going to get some sleep. ill mess around with it again tomorrow. it just seems strange that im having problems (not being a complete beginner, i have working amps that i built from scratch that run fine). and i see so many beginners tossing these things together in a few hours on wood boards and just hand-wired together without problems. it must be something simple. tomorrow, ill try the other UCD and see if maybe it has a problem. |
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| Jan-Peter |
Have a nice sleep.....:angel:
Jan-Peter |
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| cowanrg |
| i almost forgot to thank you for your help. so, thanks. |
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| classd4sure |
It may not be "correct", but I was able to drive the module single ended with non inverting input to + RCA and inverting input to RCA ground, the module's signal ground was left to float, grounding it to inverting input produced alot of hum.
Having the modules wired out of phase in stereo produced alot more hum on one channel over the other. Wiring them in phase produced equal levels of hum (the same as on the quieter channel previously). Any attempt at grounding the signal ground to the star point produced noise/hash, which remained the same regardless of where that ground was brought.
Point is: Star grounding for the simple supply as per the data sheet works equally well for me in balanced or unbalanced provided the signal ground is left to float (with or without shield attached), which I guess then grounds it through the power GND /star point and so is obviously not ideal. |
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| lne937s |
Is it just me, or do the capacitors look like they are wired kind of oddly? Is there a ground between the rectifiers?
maybe it's just hard to see in the pictures... |
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| Jan-Peter |
Guys, please check this link; http://www.hypex.nl/docs/wiring.pdf
Drawing: Interfacing unbalanced source / balanced amplifier
The RCA connector must be a female instead of a male.
I hope this will give enough information.
Regards,
Jan-Peter |
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| Pasi P |
Thank you Jan-Peter.
Your drawing is very clear but i just want to ensure that this new grounding method is also best in supply with 4-pole caps.
Wiring of supply connection attached. |
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| cowanrg |
| quote: | Originally posted by classd4sure
It may not be "correct", but I was able to drive the module single ended with non inverting input to + RCA and inverting input to RCA ground, the module's signal ground was left to float, grounding it to inverting input produced alot of hum.
Having the modules wired out of phase in stereo produced alot more hum on one channel over the other. Wiring them in phase produced equal levels of hum (the same as on the quieter channel previously). Any attempt at grounding the signal ground to the star point produced noise/hash, which remained the same regardless of where that ground was brought.
Point is: Star grounding for the simple supply as per the data sheet works equally well for me in balanced or unbalanced provided the signal ground is left to float (with or without shield attached), which I guess then grounds it through the power GND /star point and so is obviously not ideal. |
hum. that all makes some sense and i will have to try it. Jan's diagram is nice and all, but thats exactly how ive been doing it. its nothing new, and its stuff ive tried. ive had enough grounding problems in my day to know what to try...
ill give yours a shot. one question though, is your amp quiet now? did you get it to work without any noise?
lne937s,
ill take a better picture of the wiring as i have it now. im not sure what you mean "ground between rectifiers". ill take a better picture and detail how its hooked up a bit better. |
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| Jan-Peter |
| quote: | | Jan's diagram is nice and all, but thats exactly how ive been doing it. |
You have to remove the mains ground, of course only if you have a double insulation transformer! (=tested with 4KV). With an asymmetrical connection and connection to mains ground you will have groundloops......
All our amps wired in the symmetrical way and with the special symmetrical to asymmetrical cable are DEAD QUITE (even when we turn up our passive preamp to the maximum volume and the SACD player in PAUZE mode).:angel:
Jan-Peter |
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| cowanrg |
well, i think i figured it out.
i did what classd4sure said and floated the signal ground. it really didnt help much, so i just attached it to the chassis, and it was quiet with nothing connected. however, when i connected ANYTHING to the rca, i got a small hum. just guessing randomly, i connected the earth ground to the same point on the chassis, and now its dead quiet. so, thats good.
im going to do a bit more testing in the next few days.
i did notice one thing thats strange... i connected an 8ohm 100-watt dummy load to the speaker terminals and put a pretty good signal into the amp. i was getting around 15vac on the outputs (so just shy of 30 watts of power) into the dummy load. i heard a wierd noise. i put my ear very close to the UCD module and heard the music very very faintly coming from what i assume to be the coil... and when i looked at the light bulb (the one i have in series with the main in place of a fuse), it was glowing every so slightly. is that just the nature of having a light bulb in line with the mains? or does the amp itself create a little bit of noise? |
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| classd4sure |
| quote: | Originally posted by cowanrg
hum. that all makes some sense and i will have to try it. Jan's diagram is nice and all, but thats exactly how ive been doing it. its nothing new, and its stuff ive tried. ive had enough grounding problems in my day to know what to try...
ill give yours a shot. one question though, is your amp quiet now? did you get it to work without any noise?
lne937s,
ill take a better picture of the wiring as i have it now. im not sure what you mean "ground between rectifiers". ill take a better picture and detail how its hooked up a bit better. |
Dead quiet, always has been. I was in a quest for perfection so I tried different schemes with what I had (still not using connectors) and everything was worse. So I drove it for weeks like I told you, signal gnd left to float but it still grounds via the module and power gnd which is tied to star point/center tap/static screen/earth and is dead quiet with a 102db efficient speaker only a slight hiss is ever heard with the ear less than a foot from the tweeter. Sounds like you're doing it my way after all.
Grounding the shield/signalll gnd to chassis at any point still produced mild noise, but not hum.
So it works, but I see the key difference as my way references the input to the output, while JP's way is the preferred opposite.
Right now I'm using fully balanced so it's not a concern, but I'll be further experimenting myself, as I'm building a much better supply, more like yours. Parts should be here now in fact, see ya later:)
Actually before I go, JP are you advocating no earth ground at all in the amp? What do you do with the static screen, leaving that disconnected gave me an ugly imbalance.
Regards,
Chris |
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| Jan-Peter |
| quote: | | Actually before I go, JP are you advocating no earth ground at all in the amp? What do you do with the static screen, leaving that disconnected gave me an ugly imbalance. |
When you have an earth ground connection -----> use balanced input ;)
Because the UcD-modules are having a tru balanced input (instrumential input design!) you can take the advantage to use this.....
Jan-Peter |
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| Bruno Putzeys |
Hi,
I sense some confusion. When JP writes "don't ground at the power supply" he means: don't connect the PSU ground to the chassis. But you *should* of course have all 3 wires going from the PSU to the amplifier :)
Here's the full recipe for wiring up an RCA chassis part:
*Use non-insulated RCA chassis parts. They will serve as the chassis connection for the whole amp. You don't want to have the whole amp floating in the chassis or you'll get one heck of a buzz when you leave the inputs open.
*Make no other chassis connection elsewhere, but otherwise wire the whole thing normally.
*Preferably use shielded twisted-pair cable, such as microphone cable.
*Tie pin 1 of the module's input connector (J7) to the RCA signal pin using one of the two conductors.
*Tie pin 3 of J7 to the RCA ground lug using the second conductor.
*Tie pin 2 of J7 to the RCA ground lug as well using the cable shield. This step insures the amplifier is no longer floating with respect to chassis.
This method insures that any ground currents flow through the shield, not through the "cold" wire on pin 3.
If you have a substantial personal preference for using 3 separate wires instead of a shielded twisted pair, at least twist the 3 wires together.
The problem with unbalanced (RCA) connections is obviously the sensitivity to ground loops. Because of this, you should not connect the chassis to mains earth. Instead, follow double-insulated construction methods on the primary side for safety.
There are a few tricks to make an RCA input "pseudo differential" using the differential input of the UcD module, but I'm afraid to "float" them here because that will cause more confusion. Besides, the above description is the most solid because using uninsulated RCA parts also keeps your amps from RF break-in.
Having said all that, it is always best to use XLR inputs and build a "converter cable" (see new doc on Hypex site) that extends the differential sensing trick all the way to the pre outs. |
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| Bruno Putzeys |
| quote: | Originally posted by classd4sure
Actually before I go, JP are you advocating no earth ground at all in the amp? What do you do with the static screen, leaving that disconnected gave me an ugly imbalance. |
We're advocating using XLR inputs.
Unbalanced inputs will only work acceptably when all devices are floating (or only one is grounded). Otherwise you're bound to run into ground loop problems at some stage. This has nothing to do with this specific situation. It's the same in all unbalanced gear, except when people buy modules they have someone to ask how to solve their grounding problems :)
I thought having differential inputs would immediately solve anyones problem, but I forgot the human factor. One more wire is one more source of confusion. |
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| cowanrg |
classd4sure,
thanks again for the help, it all works great, and now i understand what is going on and why i had hum before. i didnt hear any noise at all from my speakers, but my shop isnt exactly the quietest place in the world. i only settle for absolutely silent, even a slight hiss is a bad thing. i use 6ft tall line arrays and with my ears, even the slightest hiss i can hear in the room. i ususally keep my amps on all the time too.
Bruno,
thanks, that is the explaination i was looking for from the beginning. in all the other projects ive done before, it is very different. im used to having the RCA jack completely isolated and having a star ground. so, this was just a bit new to me.
also, i was confused when jan said not to ground to the center of the caps. i was curious how the unit would work. but now i get what he was saying...
having the unit rely on balanced (XLR) inputs is nice, but there are plenty of people out there that use single-ended. i use single-ended only because most home theater gear is NOT balanced, and if it is, its VERY pricey. plus, i have pretty expensive interconnects and once i buy them once, i dont want to replace them all for balanced.
could either Jan or Bruno address my "issue" with hearing the music through the unit itself? is this just because im using a light bulb in series, or is there another issue at hand? thanks! |
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| Bruno Putzeys |
Ferrites have a property called "magnetostriction". When subjected to a strong magnetic fields, they shrink (just a tiny little bit). So when you run an audio frequency current through them, they vibrate and produce sound. It's the same thing that makes the line coil in a TV whistle.
Ferrites formulated to exhibit this effect to an extreme degree are sometimes used as acoustic exciters in ultrasonic welders.
(You might have found that some linear amplifiers also manage to produce acoustic output. There, the output transistors themselves are the culprits. Silicon devices are piezoelectric and many transistors "sing" audibly with the voltage, not with the current.) |
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| Bgt |
| Ground/earth between the 4 caps. is a valid way of doing the earthing/grounding and there is absolutely no humm. You'll have to use it with floating input RCA plugs than. No earthing at the mains input, that will cause groundloops.What noise/humm? RFI problems....absolutely not. |
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| cowanrg |
| quote: | Originally posted by Bruno Putzeys
Ferrites have a property called "magnetostriction". When subjected to a strong magnetic fields, they shrink (just a tiny little bit). So when you run an audio frequency current through them, they vibrate and produce sound. It's the same thing that makes the line coil in a TV whistle.
Ferrites formulated to exhibit this effect to an extreme degree are sometimes used as acoustic exciters in ultrasonic welders.
(You might have found that some linear amplifiers also manage to produce acoustic output. There, the output transistors themselves are the culprits. Silicon devices are piezoelectric and many transistors "sing" audibly with the voltage, not with the current.) |
ah ok. so this is just something that happens with this type of amp? its not a big deal, it only happens when its cranked up louder, so you would never actually hear it anyways.
| quote: | Originally posted by Bgt
Ground/earth between the 4 caps. is a valid way of doing the earthing/grounding and there is absolutely no humm. You'll have to use it with floating input RCA plugs than. No earthing at the mains input, that will cause groundloops.What noise/humm? RFI problems....absolutely not. |
well, its working without hum now, so ill leave it alone. i DID have it hooked up how you mention though, and it didnt work right. so, ill leave it as is. |
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| mac |
| quote: | Originally posted by cowanrg
classd4sure,
thanks again for the help, it all works great, and now...
Bruno,
thanks |
Glad to see that you resolved your problem. |
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| cowanrg |
| quote: | Originally posted by mac
Glad to see that you resolved your problem. |
i just got back from the store picking up the last bits and pieces so i can finally bring them up into my main system and test them out. i will now be using twisted shielded cable for the input, and actually have rubber feet on the bottom of the case so it doesnt scratch my rack all up :)
it will be interesting to see how a 1.7kva transformer feeds these things. my speakers arent exactly easy to drive (84db efficient, large room, and 4 ohm). |
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| classd4sure |
Hi,
I"ll have more to say about the grounding later /questions whatever, once I've reviewed all material..
Great to see you back here Bruno.
Cowanrg, if you want a real kick try the amps with different speakers and see how much it makes them all sound the same, effortlessly. |
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| cowanrg |
| quote: | Originally posted by classd4sure
Hi,
I"ll have more to say about the grounding later /questions whatever, once I've reviewed all material..
Great to see you back here Bruno.
Cowanrg, if you want a real kick try the amps with different speakers and see how much it makes them all sound the same, effortlessly. |
im going to try a few different combinations of grounding now that i know what works, just to learn a bit more about grounding for these amps.
im not sure what you mean about it making all speakers sound the same. i think thats a bad thing... i have a few pairs of speakers in my house, and they all have their good qualities. im not sure if any of them would sound at all similar with ANY amp. my magnepan tympani 1D's are pretty unique-sounding and i would hate for them to sound like my B&W 803D's, and vice versa.
maybe you mean it just universally makes speakers sound their best. thursday is when ill get a chance to hopefully listen to them on my own speakers and form an impression. |
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| Yves Smolders |
I'm sure thats what he means... maximizing virtually any speakers performance.
I'm very interested in the 803D performance compared to your other amps...
My modules also needed a little bit of time to "settle in", it could be psychological, but I left them on for a day or 2 at normal volume levels and they got better, more coherent. |
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| classd4sure |
| quote: | Originally posted by cowanrg
im going to try a few different combinations of grounding now that i know what works, just to learn a bit more about grounding for these amps.
im not sure what you mean about it making all speakers sound the same. i think thats a bad thing... i have a few pairs of speakers in my house, and they all have their good qualities. im not sure if any of them would sound at all similar with ANY amp. my magnepan tympani 1D's are pretty unique-sounding and i would hate for them to sound like my B&W 803D's, and vice versa.
maybe you mean it just universally makes speakers sound their best. thursday is when ill get a chance to hopefully listen to them on my own speakers and form an impression. |
No what I mean is that they'll sound the "same" (within reason). The amp is frightningly independant of load, and so the load attached doesnt' seem to affect the sound much, not like you'd normally expect it to. You'll see what I mean if you try it.
BTW you may have great hearing but my speakers are 102dB efficient and you _need_ to be no less than a foot away from the tweeter to hear the hiss. If you hear it from further away I trust it's imagined. Anyway I'll let you discover it for yourself, but that's what you can expect if you've got it working right.
Regards,
Chris |
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| Yves Smolders |
Yeah it's really low noise, it's amazing at that...
My B&W's aren't efficient speakers, but with the Yamaha DSP-A2 there was noise from the tweeter, audible about 30cm away.
The noise is still there, it's being generated by the noisy opamps/volume control of the A2...
However if I turn it off, it all but disappears... ear against the nautilus tweeter reveals a little noise, when very quiet... and even then it's not like broad-spectrum noise, it's different than your usual amp noise. |
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| cowanrg |
right now im getting NOTHING from the tweeter, even with ear touching the driver almost, it sounds the same as when it's off, so thats good.
i bought shielded cable yestertday that i still havent installed, so that will be just extra caution so that there is NO noise going on. |
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| Yves Smolders |
Awaiting your first listening results, sir!
Yves |
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| cowanrg |
| quote: | Originally posted by Yves Smolders
Awaiting your first listening results, sir!
Yves |
me too!
i need to build the second monoblock tonight and then they will both be running. it will only take about 2 hours or so to get the second one fully working. so, hopefully tonight ill have some listening time, but tomorrow until i start forming an opinion. |
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| cowanrg |
something just came to me...
im building TWO of these things, and i only have a lightbulb for one. i was using the light bulb as the softstart, but i only have one. i could easily just buy another bulb and base, but is there something else i could do for a quick soft start?
i plan on getting the LC audio ones for the real amps when i build them, but i dont have them yet. can i just put a resistor or something in series with the transformer for a down and dirty soft start? |
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| lne937s |
40 ohms of resistors (25w or higher) and a momentary switch- press the momentary switch for a few seconds before switching on the PSU, then release the switch.
oh, just to be clear- have the momentary switch/resistors bypass the main power switch/ running parallel to the switch. |
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| pburke |
| quote: | Originally posted by Yves Smolders
2x45V might trip the overvoltage though, however, I think I've read the overvoltage limit has been put higher again in the newest 400 batch.
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I'm trying to get some details on that, because I would like to build some UCD400 amps using off-the shelf Plitron audio transformers, and those come with 30V, 45V and 60V secondaries. They are so expensive, I don't even want to ask them for a custom wound 42V unit (at that point I'll go with the 60V and build some UCD700s instead, spending the extra $ on the modules and not the custom winding of a toroid).
So if I do want to go with the 45V I will have at least 63.5V DC on the rails (my wall voltage is actually 124 some nights, so I am going to be above that value by a bit). Has anyone built UCD400s with such a transformer?
I've never built a big power amp, only preamps and other low voltage stuff, so this may be a dumb question related to this: is there a way to lose a few volts in a PSU without a) vaporizing some resistors, or b) screwing up the sound of the thing? I guess anything that could drop the voltage in such an application would be a component that is bound to generate a lot of heat.
I'm kinda torn between UCD400 and UCD700 right now, and the 42V transformer secondaries requirement makes the decision rather difficult (and no, I don't want to use the 40V Avel transformers from partsexpress if | | | |
