See Post #162 from "thinking about the UCD modules" thread:
http://www.diyaudio.com/forums/showthread.php?threadid=66069&pagenumber=5
RS-components has 10000uF/63V Sikorels (and BHC, Rifa...etc), but they are expensive.
I had the chance to buy 8 pieces of 10000uF/100V Sikorel's from a dear forum mate (a "non-believer" I think) at a very convenient price. Look at "the market place" from time to time.
I will "super-regulate" my DAC for a better sound (I hope)
Good luck
Mauricio
tokki said:Only problem now, is that I keep getting internal servere error when logging into the webshop. So I can`t buy a pair of ucd400`s..
You could buy them from Eltek in Oslo? I have...
www.dynabel.no
need advice on ps caps and dc protection
Hi,
I am planning to build 2 (4channel ucd 400 amps), and i am a bit
confused. I read the entire thread but could not find any info on what i am looking for. The caps for the power supply that i found in my region
are united chemi-con smh series any good? also found elna lpo series
better than ucc caps?
Also found this for dc protection what do you guys think?
http://store.qkits.com/moreinfo.cfm/K4701
And last but not least, i looked at the specs. of the softstart module by Hypex and it is rated for 1500va max. but my tranny are 800va each.
can i still use only one or should i buy 2 ?
Sorry for the long post! And thank you in advance .
Gilbert
Hi,
I am planning to build 2 (4channel ucd 400 amps), and i am a bit
confused. I read the entire thread but could not find any info on what i am looking for. The caps for the power supply that i found in my region
are united chemi-con smh series any good? also found elna lpo series
better than ucc caps?
Also found this for dc protection what do you guys think?
http://store.qkits.com/moreinfo.cfm/K4701
And last but not least, i looked at the specs. of the softstart module by Hypex and it is rated for 1500va max. but my tranny are 800va each.
can i still use only one or should i buy 2 ?
Sorry for the long post! And thank you in advance .
Gilbert
Question about DC coupling:
I'd like to remove the input caps as well, but i'm a bit worried about this, so here's a few questions:
* DC IN means DC out - will the Hypex PS disconnect my speakers if this situation were to happen?
* The source I want to use is the new Denon 4306 - is it safe to assume there will be no DC offset on the outputs of the Denon unit? How about turn-on/turn-off DC?
* I have the 8620AD versions, will it give extra protection if things go wrong at the source?
It seems logical to remove them, as all commercial stuff has DC coupling caps on outputs and inputs anyway - I'd like to get that down to 1 of those caps instead of multiple.
Thanks for the input!
I'd like to remove the input caps as well, but i'm a bit worried about this, so here's a few questions:
* DC IN means DC out - will the Hypex PS disconnect my speakers if this situation were to happen?
* The source I want to use is the new Denon 4306 - is it safe to assume there will be no DC offset on the outputs of the Denon unit? How about turn-on/turn-off DC?
* I have the 8620AD versions, will it give extra protection if things go wrong at the source?
It seems logical to remove them, as all commercial stuff has DC coupling caps on outputs and inputs anyway - I'd like to get that down to 1 of those caps instead of multiple.
Thanks for the input!
t. said:Hi guys,
I finally got around to ordering a pair of the UCD modules, I decided to go for the 180ST mainly because their output is more than enough for my needs and I intended on trying some different op-amps
I've had a quick listen to them last night before fitting them inside the case and I'll admit I was rather impressed even with these units using the standard coupling cap and NE5532 op-amp, even at this stage in my opinion the sound is much superior to any of the little Tripath kits I've tried so well done to the guys at Hypex
The main thing I wanted to ask is have any of you guys compared the op-amps in these units, if so what are your honest opinions?
After looking at that nice neat board I don't fancy fitting and removing several types because the print looks a bit too delicate
I have AD8620,AD826,OPA2132 and a few others
Which ever type I use I will remove and link out the two electrolytics after the op-amp and fit 2.2uf Auricaps on the input if DC offset is not a problem with the newer op-amps
Just a note, I've often found AD8620 to be a bit bright when I've tried them in other projects, do they make the UCD modules slightly brighter than the standard NE5532's? I'm not a fan of an over bright or clinical top end
Any advice much appreciated
Hi,
Good for you, kicking yourself now for having waited so long?
I've gone from the 5532 to the AD8620BRZ, with and without caps.
The caps do add gross coloration, worth improving on.
The op amps, I couldn't at all call the AD "bright". The 5532 was far more so. It just became more natural, lost some harshness, smooth and fluent, so yeah I'd say the highs were less bright and more natural, but I've also found your power supply has an immense effect on this.
I find the highs with this kind of setup very easy to listen to. They just sound real.
As far as replacing them, you sure don't want to tug on them at all, small pads like that can lift easy, but it is well worth changing. I've had success doing mine using a heat blowing tip on my iron, but you have to be real careful the board is level and doesn't get nudged when you have it reflowed or things will slide around. Used forceps to carefully lift it off, easy as pie.
No need to make your post in every UCD thread btw
Regards,
Chris
Yves Smolders said:
It does have DC protection, if you hooked it up I guess so?
Measure the output of your Denon with a meter and see what it says, it should be something like .002 or .001. Verify with the rated specs of it, it should have that much information available to you.
You don't gain any level of protection with that op amp, rather it has low enough offset to make it useable.
Worth removing if you can.
Cheers
classd4sure said:
Hi,
Good for you, kicking yourself now for having waited so long?
I've gone from the 5532 to the AD8620BRZ, with and without caps.
The caps do add gross coloration, worth improving on.
The op amps, I couldn't at all call the AD "bright". The 5532 was far more so. It just became more natural, lost some harshness, smooth and fluent, so yeah I'd say the highs were less bright and more natural, but I've also found your power supply has an immense effect on this.
I find the highs with this kind of setup very easy to listen to. They just sound real.
As far as replacing them, you sure don't want to tug on them at all, small pads like that can lift easy, but it is well worth changing. I've had success doing mine using a heat blowing tip on my iron, but you have to be real careful the board is level and doesn't get nudged when you have it reflowed or things will slide around. Used forceps to carefully lift it off, easy as pie.
No need to make your post in every UCD thread btw
Regards,
Chris
You guys are too quick, I've got two replys as I was moving my thread to the UCD hotrodding, I should not have bothered
Yes, I have been putting it off but if you see how many diy amps I have already you may understand
I've no problem working with smd parts but the track does tend to lift after being heated a couple of times and I want these boards to stay neat
If the AD8620 are the way to go then I'll hopefully fit them later
I'm just drawing out a PSU pcb on the pc to etch out, I've got a few different type diodes I want to try out, last night I knocked up a pair of dual bridges using MBR20200's which seem to work nice, I've got the MSR1560's with and without bypassing snubbers etc
Regarding the coupling caps I've also never been fond of Auricaps in the past but it seems a few Hypex users like them so I should at least try them out, I may be surprised again and i do already have a couple of 2.2uf spare
BTW thanks for your advice Chris!
Yves Smolders said:
Hey that's even better, if it has too much offset, forget it and get one that doesn't, it's seriously worth it not to have a cap.
These modules are robust enough to handle that kind of an error, I've done it several times purposefully and it hasn't let me down, it's damn loud sliding live TRS jacks out though...
yuck. That's not really a DC issue as I see it anyway.
Here, dug this up for you:
"Jan-Peter
You must be below 50mV DC at the output of the amplifier. The gain of the UcD is 20 times (26dB). So the input DC must be below 2,5mV.......to be save 1mV would be the maximum.
Regards,
Jan-Peter "
Still applies unless you tweaked the gain, then do the math again.
50mV is also some sort of standard level of max acceptable dc output.
With the op amps I used I measure 3 and 4mV out of each module with no inputs plugged in and left floating, grounding them would likely lower it even more. With the inputs plugged into the pre amp/soundcard audiodock, output offset at the speaker terminals becomes less than 22mV, less than half the accepted "standard", nice.
Let me add my 2-cents as well, considering the fact that I've now had more than just the usual experience with these modules.
Modifying them to replace the NE5532 with a AD8620 and removing the coupling caps in the process is easily the most rewarding modification you can do. Furthermore it helps to replace the 470uF/63V caps with 1000uF/63V Panasonic FC.
Keep in mind though that no coupling cap is better than some exotic coupling cap from a well-known manufacturer; less components in the signal-path is the best approach. The only downside is the fact that you need to make sure none of your sources output DC, or it'll end up at the amplifier's output. If you're using the Hypex power-supplies they'll safeguard you from any damage, if not, then you could be in for popping speaker cones or worse, so better be safe than sorry.
I've recently built and documented the construction of a dual-mono UcD400 myself and also made above mentioned modifications, more about these, and the UcD400 in general, at the below noted link.
Believe the Hypex, class-D DIY amplifier
http://www.hardwareanalysis.com/content/article/1822/
Best regards,
Sander Sassen
http://www.hardwareanalysis.com
Modifying them to replace the NE5532 with a AD8620 and removing the coupling caps in the process is easily the most rewarding modification you can do. Furthermore it helps to replace the 470uF/63V caps with 1000uF/63V Panasonic FC.
Keep in mind though that no coupling cap is better than some exotic coupling cap from a well-known manufacturer; less components in the signal-path is the best approach. The only downside is the fact that you need to make sure none of your sources output DC, or it'll end up at the amplifier's output. If you're using the Hypex power-supplies they'll safeguard you from any damage, if not, then you could be in for popping speaker cones or worse, so better be safe than sorry.
I've recently built and documented the construction of a dual-mono UcD400 myself and also made above mentioned modifications, more about these, and the UcD400 in general, at the below noted link.
Believe the Hypex, class-D DIY amplifier
http://www.hardwareanalysis.com/content/article/1822/
Best regards,
Sander Sassen
http://www.hardwareanalysis.com
t. said:
You guys are too quick, I've got two replys as I was moving my thread to the UCD hotrodding, I should not have bothered
Yes, I have been putting it off but if you see how many diy amps I have already you may understand
I've no problem working with smd parts but the track does tend to lift after being heated a couple of times and I want these boards to stay neat
If the AD8620 are the way to go then I'll hopefully fit them later
I'm just drawing out a PSU pcb on the pc to etch out, I've got a few different type diodes I want to try out, last night I knocked up a pair of dual bridges using MBR20200's which seem to work nice, I've got the MSR1560's with and without bypassing snubbers etc
Regarding the coupling caps I've also never been fond of Auricaps in the past but it seems a few Hypex users like them so I should at least try them out, I may be surprised again and i do already have a couple of 2.2uf spare
BTW thanks for your advice Chris!
Hi,
Glad to help if I can.
I can't see you liking the sound of the Auricap anymore than you did before. I'm thinking most liked them as an improvement to the standard electrolytic... That's not to say not to try them again, but I think you'll end up using your favored caps whatever they are. Did you use RC snubbers for your schottkys?
Regards,
Chris
SSassen said:
Thank you Sander Sassen!
I'll have a look at your link now
When I used to use op-amps in cdp's I often found that a lot seemed to add a certain signature so I want to keep the UCD's as neautral as I can, my dac now has a discrete output, thats one of the reasons I was thinking about the AD8620 but if it works well in these modules then thats good enough for me
having no input caps would be ideal and my dac has an extremely low dc offset but I have a few friends that will want me to take the UCD's up to their place so they can compare it against their amps and use their own pre-amps etc
I'm going to make my own psu's once I can settle on some nice parts, some of my friends would not touch classAB so lets see what they think of classD
I have a pair of Holden and Fisher transformers, I'd like to try a pair of 600vA R-cores if they would make a worthwhile upgrade price wise at a later time
classd4sure said:
Hi Chris,
Well any help is always appreciated and you guys have had these units longer enough to know whats good and bad, classD is new to me
I'll give the Auricaps a try but I will probably remove them altogether when the amp is being used at home and add them when it goes to my friends, I've got other caps like 1uf Multicap RTX but their value may be too low
I did not try the snubbers across the schottkies yet, I just made the bridges up on veroboard so I could quickly try out the modules
Is it worth adding them on my pcb I'm doing which I hope to etch out
I love these caps, Jensens 
I just hate 95% of my material now... too revealing? No such thing! Recordings not up to par? Yes. Notice how spartan the supply is? Sounds great just like that. May tweak it later of course, few extra caps and that's about it.
I'm in the same predicament as you, I'd like it DC coupled for XLR and as far as bringing my amp anyway, odds are not many have XLR outputs anyway, they can use the RCA's AC coupled, one cap per channel. I haven't figured out an elegant way of doing that yet though.
Cheers
I just hate 95% of my material now... too revealing? No such thing! Recordings not up to par? Yes. Notice how spartan the supply is? Sounds great just like that. May tweak it later of course, few extra caps and that's about it.I'm in the same predicament as you, I'd like it DC coupled for XLR and as far as bringing my amp anyway, odds are not many have XLR outputs anyway, they can use the RCA's AC coupled, one cap per channel. I haven't figured out an elegant way of doing that yet though.
Cheers
