| beppe61 |
Dear Sirs,
I understand that UcD modules come with some sort of current limiting circuits.
Anyone who knows which are the values for the 180 and 400 models?
I am still undecided about which to try.
Also a suggestion for the better voltage rails choice would be very welcome and valuable.
Thank you so much.
Kind regards,
beppe |
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| beppe61 |
In the datasheet I think it is what is mentioned as ACTIVE CURRENT-LIMITER.
Anyway no figures on the Ucd 180 and 400.pdf datasheets.
Kind regards,
beppe |
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| Yves Smolders |
Download the PDF's from Hypex:
UCD400: Current Limit 20A, stop mode after 40ms
UCD180: 10A stop mode (limit mode available) |
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| beppe61 |
| quote: | Originally posted by Yves Smolders
Download the PDF's from Hypex:
UCD400: Current Limit 20A, stop mode after 40ms
UCD180: 10A stop mode (limit mode available) |
Thanks a lot Sir.
Please excuse my lazy question but I have been overwhelmed by the size and number of replies of the 3Ds on the UcD modules in this forum.
I wonder if somewhere there is something like FAQ pages.
Anyway the current capability of the 400 is very impressive.
I think I will try that one.
Thank you very much again.
Kind regards,
beppe |
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| Yves Smolders |
It sure is impressive!
It means you have the full potential of the modules (400W) available at 4 ohms, and even further down it's still very good!
I don't have the numbers anymore...
Yes, the 180 and 400 threads are incredible. It contains a lot of information, but it can't be "read" anymore, it's too large.
About rails for the UCD, I'm running the 500VA toroid & HQ power supply from hypex itself, with amazing results on my speakers. |
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| beppe61 |
| quote: | Originally posted by Yves Smolders
It sure is impressive! It means you have the full potential of the modules (400W) available at 4 ohms, and even further down it's still very good!
I don't have the numbers anymore...
Yes, the 180 and 400 threads are incredible.
It contains a lot of information, but it can't be "read" anymore, it's too large.
About rails for the UCD, I'm running the 500VA toroid & HQ power supply from hypex itself, with amazing results on my speakers. |
Thank you sincerely again Sir.
I did not catch which precise model of the two you have.
Nevertheless I wonder how they have measured that 20A figure (i.e. load, ms, etc.).
Anyway, very impressive.
I am extremely curious about class D.
I believe it has the potential to revolutionize the audio market.
And big advantages as well (efficiency, dimension, weight, low heat generation, etc.).
Thank you very much again.
My best wishes,
beppe |
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| Yves Smolders |
Beppe,
You don't have to "Sir" me, I'm not a knight or such :-)
I have the UCD400AD models, unmodded, running a pair of B&W Nautilus 804 speakers. |
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| fokker |
| quote: | Originally posted by Yves Smolders
It means you have the full potential of the modules (400W) available at 4 ohms, and even further down it's still very good!
|
is it possible that the current going through the mosfet isn't 1 for 1 going through the load? if so, maybe the instataneous power from those modules is much less? |
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| classd4sure |
fokker you should read the AES paper on the Hypex website on UCD and you'll know the answer to that question.
Cheers |
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| beppe61 |
| quote: | Originally posted by Yves Smolders
Beppe,
You don't have to "Sir" me, I'm not a knight or such :-)
I have the UCD400AD models, unmodded, running a pair of B&W Nautilus 804 speakers. |
All right Mr. Smolders.
I understand that Nautilus speakers are highly transparent ones.
Any defect in the sound should be very evident I think.
Thank you very much for your kind and valuable advice.
Kind regards,
beppe |
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| classd4sure |
| Hey Yves, you said unmodified, though I trust you've removed the AC coupling electrolytics? Same here, also 400AD's, they're outstanding just with the AC couplers gone. |
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| beppe61 |
| quote: | Originally posted by classd4sure
Hey Yves, you said unmodified, though I trust you've removed the AC coupling electrolytics?
Same here, also 400AD's, they're outstanding just with the AC couplers gone. |
May I ask you which speakers are you driving with them?
Which amps have you already compared with your UcDs?
I heard of people selling their high-end amps in favour of DIY creations based on UcD modules.
Thanks a lot.
Regards,
beppe |
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| fokker |
| quote: | Originally posted by classd4sure
fokker you should read the AES paper on the Hypex website on UCD and you'll know the answer to that question.
Cheers |
questions are sometimes asked other than to get answers. |
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| classd4sure |
| quote: | Originally posted by fokker
questions are sometimes asked other than to get answers. |
Yeah if you're trolling, you're right though, it really wasn't worthy of an answer, that's why what I gave you was more along the lines of rtf. :rolleyes: |
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| Yves Smolders |
| quote: | | Hey Yves, you said unmodified, though I trust you've removed the AC coupling electrolytics? Same here, also 400AD's, they're outstanding just with the AC couplers gone |
Nope, I'm really running them unmodified! I have thought a lot about shorting the AC couplers, but I'm unsure about my Denon 4306 (acting as pre) having good quality DC free outputs...
If my amp is on and I turn on the Denon later, there's a very very quiet click... |
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| Yves Smolders |
@Beppe,
Yes, I was in the market for a high-end amp to match the N804's, as they weren't sounding like I heard them in the shops... Of course I knew that before, those puppies are quite hard to drive and I would need good clean power.
Then I found out about UCD here, and though, hey why not give it a try.
And really, it's money well spent. I've never looked back. There could be better stuff out there, but I don't think there is at the price I paid!
Regardless of sound, "power"-wise they are extremely good. Lots & lots of power, high amperage available when needed.
And soundwise well... just buy a few UCD400AD's and be turned to class-d! |
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| classd4sure |
| quote: | Originally posted by Yves Smolders
Nope, I'm really running them unmodified! I have thought a lot about shorting the AC couplers, but I'm unsure about my Denon 4306 (acting as pre) having good quality DC free outputs...
If my amp is on and I turn on the Denon later, there's a very very quiet click... |
That little click is probably the settling of the receiver's output coupling cap and you don't need two in series. see if you can measure a milivolt or less at the output of the receiver, it'll probably be zero.
Try one module DC coupled and measure it's DC output level, if it doesn't look too bad , say less than volt or so, try it with a cheap speaker, you should see it drop to within spec of 50mV, probably less.
With the newer 400's you can just let the amp warm up for a little while and then use the DC trip pot on the daughter card to fine tune it to zero.
If you should need to keep it AC coupled upgrade with a film cap at least. |
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| m.parigi |
Beppe, I'm Italian and I live in Torino (well, close enough... Chieri). I've built a 6-channel power amp based on unmodified UCD 400.
It sounds awesome with any kind of load: I own both ribbon speakers (Apogees) and horn speakers (Avantgarde) and the sound is always fantastic.
If you want to send me your coordinates via email we can arrange for meeting and having some listening sessions...
In Italian:
Mandami per mail le tue coordinate, così ci possiamo sentire e/o incontrare!
Here's a picture of my amp with only 2 channel power supply installed... |
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| m.parigi |
| ...and here is the power supply for the remaining 4 channels. |
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| beppe61 |
| quote: | Originally posted by Yves Smolders
@Beppe,
Yes, I was in the market for a high-end amp to match the N804's, as they weren't sounding like I heard them in the shops...
... And soundwise well... just buy a few UCD400AD's and be turned to class-d! |
Actually a very solid recommendation.
Thank you very much Mr. Yves.
Kind regards,
beppe |
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| beppe61 |
| quote: | Originally posted by m.parigi
Beppe, I'm Italian and I live in Torino (well, close enough... Chieri). I've built a 6-channel power amp based on unmodified UCD 400.
It sounds awesome with any kind of load: I own both ribbon speakers (Apogees) and horn speakers (Avantgarde) and the sound is always fantastic.
If you want to send me your coordinates via email we can arrange for meeting and having some listening sessions...
In Italian: Mandami per mail le tue coordinate, così ci possiamo sentire e/o incontrare!
Here's a picture of my amp with only 2 channel power supply installed... |
My sincere congratulations for your amp.
Very well built indeed.
You have personal mail.
Thank you very much for your extremely kind invitation.
Kind regards,
beppe |
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| fokker |
| quote: | Originally posted by classd4sure
Yeah if you're trolling, you're right though, it really wasn't worthy of an answer, that's why what I gave you was more along the lines of rtf. :rolleyes: |
you should try to get more maturity because you badly need that. Grow up a little bit.
I asked the question in order to get the poster to think about it a little bit, as the current going through the mostfet is shared by the capacitor in the filter and the load, assuming no cross conduction.
apparently it went over your head faster than a lightening rod. |
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| classd4sure |
| quote: | Originally posted by fokker
bla bla bla...
I asked the question in order to get the poster to think about it a little bit, as the current going through the mostfet is shared by the capacitor in the filter and the load, assuming no cross conduction.
apparently it went over your head faster than a lightening rod. |
No, you posted your non question because you thought you had a clue again, but you didn't sit down fast enough to wait for it to go away.
"is it possible that the current going through the mosfet isn't 1 for 1 going through the load? if so, maybe the instataneous power from those modules is much less?"
You really think they rate the module as per the level of current passing through the mosfet as opposed to the output of the module? :clown: You really think that's even at all related to the actual instantaneous output current... and on a module with a 20A current limitter (at the output... lol)?
You're really trying to pass that off as being some tip out of the grace of your good experience?
Fokker I really think the day you're over my head, I'll be six feed under. Get up earlier if you want to play games like this with me.
PS:
I've never seen a very fast lightning rod, usually they're bolted down fairly solidly, might sway just a little bit in stronger gusts but really, not much velocity or anything.. has anyone ever seen a super fast ligntning rod... |
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| ghemink |
| quote: | Originally posted by beppe61
My sincere congratulations for your amp.
Very well built indeed.
You have personal mail.
Thank you very much for your extremely kind invitation.
Kind regards,
beppe |
Hello Beppe,
Welcome to Class D, great that you can listen to it before you decide. Please let us know here what you think of it. Most people here (including myself) are already in Class D heaven and may not be objective anymore. If you like what you hear, go for it, you will not regret it. I think you will instantly here the difference between Class D and something else. I`m now using UcD modules for more than 2 years in an active speaker system, very pleased with them.
Wish you a good listening session.
Gertjan |
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| fokker |
| quote: | Originally posted by classd4sure
Fokker I really think the day you're over my head, I'll be six feed under. |
and that day was yesterday.
| quote: | Get up earlier if you want to play games like this with me.
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sorry, I don't intend to waste my time. |
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| classd4sure |
| OK, but I'd still like to see a supersonic lightning rod. :dodgy: |
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| JRKO |
Hi guys,
Trying to read up on class D using the UCD modules and learn a bit:confused: but..............
When 6 out of 26 posts (23% ish) on one thread are bickering it really doesn't help. Can we skip it get on with the helpful stuff? I got all the training I need in cussing/dissing/verbal slapping etc at junior school :D
Many thanks for your previous informative posts on the other larger (200+ post) threads, they have been most helpful.:D
JRKO |
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| beppe61 |
| quote: | Originally posted by ghemink
Hello Beppe,
Welcome to Class D, great that you can listen to it before you decide. Please let us know here what you think of it. Most people here (including myself) are already in Class D heaven and may not be objective anymore. If you like what you hear, go for it, you will not regret it. I think you will instantly here the difference between Class D and something else.
I`m now using UcD modules for more than 2 years in an active speaker system, very pleased with them.
Wish you a good listening session.
Gertjan |
Dear Mr. Gertjan,
Actually in the next days I will have the opportunity to listen to an amp sporting UcD modules.
These modules are very interesting.
I have heard of great coherence through the all audio range.
By the final test is to listen for myself.
It would be extremely interesting for me to know which power amps you and other DIYers here have replaced with UcD based power amps.
It would give me a sort of reference to rank the modules.
The UcD 400 looks the more interesting for my needs (a solid bass response, more than the 180 I think).
Thank you very much indeed and kind regards,
beppe |
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| proengin |
| I replaced my Krell 400xi integrated with Bent Audio TAP2 passive preamp and 4 x UcD400AD monoblocks all with SPS80 SMPS. Even this combo costs more but for me this is a heavenly match. |
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| beppe61 |
| quote: | Originally posted by proengin
I replaced my Krell 400xi integrated with Bent Audio TAP2 passive preamp and 4 x UcD400AD monoblocks all with SPS80 SMPS.
Even this combo costs more but for me this is a heavenly match. |
WOW ! What an endorsement.
Not that I have heard the Krell actually but I read great words about it.
Thank you very much indeed.
Kind regards,
beppe
I see you mention a SPS80 SMPS
Could you provide a link for that ?
SMPS good for audio are quite unique out there.
FOUND ! thank you.
Which speakers are you using?
My main doubts mostly concern the low part of the audio range (<50Hz) that I deem of paramount importance for my targets.
Regards,
beppe
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| ssanmor |
You can find more info on SPS80 at:
www.coldamp.com
Using a SPS80 will help a lot in providing very low impedance as its output is VERY stable. That translates in very controlled bass. |
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| Henrik Juhl |
| quote: | Originally posted by Yves Smolders
Download the PDF's from Hypex:
UCD400: Current Limit 20A, stop mode after 40ms
UCD180: 10A stop mode (limit mode available) |
The Danish Hifi magazine 'HighFidelity' ran a test of the UCD400 modules and measured 20.2 Amps into 0.6 ohms - so 20 Amps is a confirmed number (@ ±60V DC rails as far as I remember). |
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| beppe61 |
| quote: | Originally posted by ssanmor
You can find more info on SPS80 at:
www.coldamp.com
Using a SPS80 will help a lot in providing very low impedance as its output is VERY stable.
That translates in very controlled bass. |
I did not know that power supply can influence the output impedance of an amp.
Thank you for the valuable info.
regards,
beppe |
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| beppe61 |
| quote: | Originally posted by Henrik Juhl
The Danish Hifi magazine 'HighFidelity' ran a test of the UCD400 modules and measured 20.2 Amps into 0.6 ohms -
so 20 Amps is a confirmed number (@ ±60V DC rails as far as I remember). |
Thanks a lot.
Then there should be no problem with bass response.
Kind regards,
beppe |
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| fokker |
| quote: | Originally posted by Henrik Juhl
The Danish Hifi magazine 'HighFidelity' ran a test of the UCD400 modules and measured 20.2 Amps into 0.6 ohms - so 20 Amps is a confirmed number (@ ?0V DC rails as far as I remember). |
I don't doubt for a second that's true.
my point, which went over someone's head fairly quickly, is that the current going through the mosfet isn't 1:10 going through the load, because of the "shunt" capacitor in the filter.
so if the OC protection scheme is similar to that in the Phillips design, you can have very high (pulsing) current going through the mosfet, yet very little current going through the load, even if there is no shoot-through.
and it looks lik ethe phillips OC protection is instanenous, and triggers at 0.67v/0.05ohm=12amp or so. so if the UcD is designed to trigger at 20amp, it would have surprised if the measurement is otherwise. |
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| beppe61 |
| quote: | Originally posted by fokker
I don't doubt for a second that's true.
my point, which went over someone's head fairly quickly, is that the current going through the mosfet isn't 1:10 going through the load, because of the "shunt" capacitor in the filter.
so if the OC protection scheme is similar to that in the Phillips design, you can have very high (pulsing) current going through the mosfet, yet very little current going through the load, even if there is no shoot-through.
and it looks lik ethe phillips OC protection is instanenous, and triggers at 0.67v/0.05ohm=12amp or so. so if the UcD is designed to trigger at 20amp, it would have surprised if the measurement is otherwise. |
I confess honestly my almost complete ignorance in electronics.
Would you mean that the actual current through the load will be very low?
please could you elaborate more?
Thanks and regards,
beppe |
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| KeithC |
| quote: | Originally posted by beppe61
The UcD 400 looks the more interesting for my needs (a solid bass response, more than the 180 I think).
beppe |
No difference. |
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| beppe61 |
| quote: | Originally posted by KeithC
No difference. |
Please excuse me: both good or not ?
I am in search of a solid bass (maybe not Krell like but in that direction).
What is your opinion?
thanks and regards,
beppe |
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| BWRX |
He means they sound the same, but the UcD400 just has more power capability.
What is the sensitivity of your speakers? Obviously you could go with the 400 modules and have more than enough power for almost anything, but you will have to pay more for both the modules and the power supplies. |
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| ghemink |
| quote: | Originally posted by beppe61
Dear Mr. Gertjan,
Actually in the next days I will have the opportunity to listen to an amp sporting UcD modules.
These modules are very interesting.
I have heard of great coherence through the all audio range.
By the final test is to listen for myself.
It would be extremely interesting for me to know which power amps you and other DIYers here have replaced with UcD based power amps.
It would give me a sort of reference to rank the modules.
The UcD 400 looks the more interesting for my needs (a solid bass response, more than the 180 I think).
Thank you very much indeed and kind regards,
beppe |
They beat my Accuphase E407 which is still in use though with the passive B&W CDM9NT speakers (the kids use it sometimes when they watch DVDs). The active speakers are home-made and all UcD driven. I have tried Tripath based Marantz (class D) sounded not so bad but had too high noise level for an active system. Also tried ZAPpulse 2.3SE (or was it 2.2), also too much noise and other issues. Finally I arrived at UcD, no noise (extremely silent) and no issues. I have made some modifications to the modules though (as many have done here).
Best regards
Gertjan |
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| beppe61 |
| quote: | Originally posted by BWRX
He means they sound the same, but the UcD400 just has more power capability.
What is the sensitivity of your speakers?
Obviously you could go with the 400 modules and have more than enough power for almost anything, but you will have to pay more for both the modules and the power supplies. |
They are 86dB 4 ohm Dynaudio.
They like high current amps quite a lot.
Actually it is the only way to get them "singing" and not just "making noise".
Maybe a test is the only way to point out the right choice.
Thank you very much indeed.
Kind regards,
beppe |
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| beppe61 |
| quote: | Originally posted by Pierre
I think that my Coldamp modules have a limit of around 25A or so. With the SPS80 PSU they have absolutely incredible bass. You will find opinions in this forums that endorse this opinion...
http://www.diyaudio.com/forums/show...0412#post970412 |
Thank you. Very interesting.
Nevertheless I would like to use a more conventional linear power supply as my first try with UcD modules.
I already have some caps around that I could use and the whole wiring should be possible even for me.
Regards,
bg
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| classd4sure |
| quote: | | my point, which went over someone's head fairly quickly, |
Still babbling about supersonic lightning rods, fokker? You've only got one point man, it's keeping your hat on.
Beppe, go for the 400 over the 180, they sound very much alike but the 400 will have a better low end response, the whole board is made for higher current.. translates to lower ESR.
How did Coldamp ever come into this discussion anyway? |
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| beppe61 |
| quote: | Originally posted by classd4sure
... Beppe, go for the 400 over the 180
they sound very much alike but the 400 will have a better low end response, the whole board is made for higher current.. translates to lower ESR.
... |
That is what I wanted to hear.
Thanks a lot and kind regards,
beppe |
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| BWRX |
| quote: | Originally posted by beppe61
They are 86dB 4 ohm Dynaudio.
They like high current amps quite a lot.
Actually it is the only way to get them "singing" and not just "making noise".
Maybe a test is the only way to point out the right choice. |
Trying out both would definitely be the best thing to do. The 180s would most likely be adequate for your speakers and listening room (unless it's really large), but the 400s would give you quite a bit more headroom. |
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| classd4sure |
You're welcome.
The other thing is they're more tweaker friendly with DC offset adjustments, single op amp footprints, very tweakable.
I'm using the 400's still with just a 180 power supply, great results.
STill if money is an issue or whatever there's really nothing wrong with the 180's either :) |
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| eleson |
| quote: | Originally posted by classd4sure
How did Coldamp ever come into this discussion anyway? |
As someone pointed out, this thread is indeed two parallell threads;
- And it showed up in the other one, quite naturally and not feeling misplaced to me.
/Erland |
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| classd4sure |
| quote: | Originally posted by eleson
As someone pointed out, this thread is indeed two parallell threads;
- And it showed up in the other one, quite naturally and not feeling misplaced to me.
/Erland |
Thanks, I just saw a question about the power supply for it. |
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| fokker |
| quote: | Originally posted by beppe61
I confess honestly my almost complete ignorance in electronics.
Would you mean that the actual current through the load will be very low?
please could you elaborate more?
Thanks and regards,
beppe |
it is actually quite simple. class d amps work by alternatively connecting the filter / load network to the positive rail and the negative rail. When the filter / load network is connected to the positive rail, the inductor limits the flow of the current through the network, and the capacitor limits the change of voltage over the load - remember the voltage across a capacitor cannot change suddenly.
so the load is essentially shorted (zero current through the load) and the bulk of the (instanenous) current flows through the capacitor at the beginning of the switching.
The current going through the inductor will gradually charge up the capacitor, which causes the voltage drop over the load to increase, thus the current through the load to increase, until the next switching cycle.
as you can see, there is a divergence between the current through the switches and the current through the load in a class d amp. and the over-current protection in the phillips (and likely the ucd) is done on the mosfets. |
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| KeithC |
| quote: | Originally posted by beppe61
Please excuse me: both good or not ?
I am in search of a solid bass (maybe not Krell like but in that direction).
What is your opinion?
thanks and regards,
beppe |
Apologies for the terse response - had my cryptic hat on.
Both UcD180 and UcD400 have equally acceptable bass response.
If you are in search of solid bass, Coldamp has fuller bass than UcD, but higher ambient noise level which would probably not be noticeable with your inneficient speakers.
Coldamp psus have built-in soft start, but Hypex psus have speaker voltage protection. UcD400 & Coldamp can interchange psus.
You really need to audition all combinations to see which suits you best.
Regards,
Keith |
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| beppe61 |
| quote: | Originally posted by KeithC
Apologies for the terse response - had my cryptic hat on.
Both UcD180 and UcD400 have equally acceptable bass response.
If you are in search of solid bass, Coldamp has fuller bass than UcD, but higher ambient noise level which would probably not be noticeable with your inneficient speakers.
Coldamp psus have built-in soft start, but Hypex psus have speaker voltage protection. UcD400 & Coldamp can interchange psus.
You really need to audition all combinations to see which suits you best.
Regards,
Keith |
Thank you very much Mr. Keith.
I think I have got very valuable info, more than enough to start with some tests.
Kind regards,
beppe |
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| ghemink |
| quote: | Originally posted by beppe61
Thank you very much Mr. Keith.
I think I have got very valuable info, more than enough to start with some tests.
Kind regards,
beppe |
Hello Beppe,
What do you mean with "solid bass"?
I like "solid bass" too. However what I mean with solid bass is that it is accurate and fast. That is why I use dipole woofers (less likely to cause room resonances and also not resonating by themselves, unlike bassreflex boxes). In that respect, UcD performs very well, fast and accurate bass if you ask me.
Anyway, as you have a chance to listen for yourself, you can decide yourself whether you like it or not.
Best regards
Gertjan |
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| beppe61 |
| quote: | Originally posted by ghemink
Hello Beppe, What do you mean with "solid bass"?
I like "solid bass" too.
However what I mean with solid bass is that it is accurate and fast.
That is why I use dipole woofers (less likely to cause room resonances and also not resonating by themselves, unlike bassreflex boxes).
In that respect, UcD performs very well, fast and accurate bass if you ask me.
Anyway, as you have a chance to listen for yourself, you can decide yourself whether you like it or not.
Best regards
Gertjan |
Dear Mr. Gertjan,
I try to explain but I am not that good at using English.
A "solid" bass is a bass that is deep, powerful, fast and without "tails".
Some amps can shake the walls while keeping a very strong grip on the woofers (of course with the right speakers).
I think it can be related in some way to the current flowing through the woofers coils and damping factor.
I heard this kind of bass from a Krell KSA100 driving a B&W 801 for instance.
Of course my speakers response extend only to about 50Hz flat.
Nevertheless not all the amps I tried are able to give back a good response down to 50Hz.
I think a UcD400 will not have any problem though.
Thank you very much indeed.
Kind regards,
beppe |
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| ghemink |
| quote: | Originally posted by beppe61
Dear Mr. Gertjan,
I try to explain but I am not that good at using English.
A "solid" bass is a bass that is deep, powerful, fast and without "tails".
Some amps can shake the walls while keeping a very strong grip on the woofers (of course with the right speakers).
I think it can be related in some way to the current flowing through the woofers coils and damping factor.
I heard this kind of bass from a Krell KSA100 driving a B&W 801 for instance.
Of course my speakers response extend only to about 50Hz flat.
Nevertheless not all the amps I tried are able to give back a good response down to 50Hz.
I think a UcD400 will not have any problem though.
Thank you very much indeed.
Kind regards,
beppe |
Hello Beppe,
No need for an excuse, many of us are non-native english speakers or writers (like myself). So it looks like our definition of solid bass is the same, happy to hear that. In that case, I think you will like the UcD. One you have listened to them, let us know what you think of them.
Would also be interesting to know if the amps you are listening to are modified. Many people do some modifications. The most obvious one is the coupling capacitors that are electrolytic types, some people replace them with film capacitors, high grade electrolytic caps (like black gate), or remove them completely (short them). In the latter case you have to be really sure that the preamp does not have any DC on the output. Another spot for modification is the filter cap in the output LC filter, there is a 680nF cap (small one near the coil). I have replaced it with 2x330nF WIMA MKP2 caps (one on the top of the PCB and one on the bottom) I find it sounding better, others here have done similar replacements. Also some people change the 470uF caps on the power rails, however, I think there is not a single clear recommendatiion what it should be, some people do not like to have Panasonic FC at that spot. I do not know what the best option is for that cap, I still use the standard caps at that spot. Also many people report that the power supply caps (not on the UcD board) are important. I think in general there is consencus that 4-pole caps like Jensen (expensive) and T-network caps are very good (Classd4sure I think likes the Jensens). I have never tried the Jensens so can not comment.
Anyway, have fun and I would be interested to hear from you what you think of the modules sound.
Best regards
Gertjan |
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| classd4sure |
Hi Gertjan,
I'll be going with the BC136 for the 470uF caps.
Jensen's are OK, they were locally available, which is why I went with them, preferably I'd have the BHC T-networks though, as they include slit foil technology. They're very similar though.
The stock filter caps on the 400 (red panasonic) aren't half bad. Much better than those white ones.
The input stage bypass caps and resistors are worth looking into as well.
Really though, the main thing is to do something about the electrolytic coupling caps. You can live with that result very easily.
Cheers,
Chris |
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| beppe61 |
| quote: | Originally posted by ghemink
Hello Beppe,
No need for an excuse, many of us are non-native english speakers or writers (like myself).
So it looks like our definition of solid bass is the same, happy to hear that. In that case, I think you will like the UcD.
One you have listened to them, let us know what you think of them.
Would also be interesting to know if the amps you are listening to are modified. Many people do some modifications. The most obvious one is ....
Anyway, have fun and I would be interested to hear from you what you think of the modules sound.
Best regards
Gertjan |
Thanks a lot again Mr. Gertjan.
I will report my opinion of course.
Very interesting to know that some mods can be carry out easily enough.
Kind regards,
beppe |
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| beppe61 |
| quote: | Originally posted by classd4sure
Hi Gertjan,
...
Really though, the main thing is to do something about the electrolytic coupling caps.
You can live with that result very easily.
Cheers,
Chris |
Dear Mr. Chris,
could you give a description about improvement on sound after removing the coupling caps?
I assume you mean the input coupling cap in series with signal.
I have already heard about the bad effect of electrolytic caps when used to block DC.
Anyway my preamp have an output coupling cap (4,7uF red Wima). So there should be no DC at the output.
Thank you very much again.
Kind regards,
beppe |
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| classd4sure |
| quote: | Originally posted by beppe61
Dear Mr. Chris,
could you give a description about improvement on sound after removing the coupling caps?
I assume you mean the input coupling cap in series with signal.
I have already heard about the bad effect of electrolytic caps when used to block DC.
Anyway my preamp have an output coupling cap (4,7uF red Wima). So there should be no DC at the output.
Thank you very much again.
Kind regards,
beppe |
Yes Sir,
The problem here is that there's just not much DC to hold them together. They'll sound ok with them in place, kind of, but alot of the micro detail will be getting smeared/blurred /lost.
By upgrading with a better film cap you can improve on the smearing /blurryness, but you'll get whatever signature the film cap has.
If you're able to jump out the electrolytics as it sounds like you can do since you have a DC free input, the audio will gain far greater coherency /precision, and all in the micro detail where the module is truly _very_ capable. So it's easy to consider that as a "must" for step 1, and is very worthwhile, especially with the AD version that has constant current source biasing of the input stage.
Try it with them first though, for a few days, then you can see the difference it makes for yourself when you jump them out, which is always better than taking someone elses word, and feel free to report here :)
Cheers,
Chris |
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| beppe61 |
| quote: | Originally posted by classd4sure
Yes Sir,
The problem here is that there's just not much DC to hold them together.
They'll sound ok with them in place, kind of, but alot of the micro detail will be getting smeared/blurred /lost.
By upgrading with a better film cap you can improve on the smearing /blurryness, but you'll get whatever signature the film cap has.
If you're able to jump out the electrolytics as it sounds like you can do since you have a DC free input, the audio will gain far greater coherency /precision, and all in the micro detail where the module is truly _very_ capable.
So it's easy to consider that as a "must" for step 1, and is very worthwhile, especially with the AD version that has constant current source biasing of the input stage.
Try it with them first though, for a few days, then you can see the difference it makes for yourself when you jump them out, which is always better than taking someone elses word, and feel free to report here :)
Cheers,
Chris |
Thank you very much again Mr Chris.
Very valuable advice.
I understand caps degrade in some way the waveform of signals, and electrolytic more than film types.
Sometimes are just unavoidable (when single power supplies are used, for instance).
I am sure that just a little piece of silver wire is so much better than any cap on the planet.
Thank you very much again.
My best wishes,
beppe |
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| beppe61 |
Is the schematic of the UcD 400 available somewhere?
I understand that most of the components used to built it are very standard off-the-shelf parts.
Input coupling caps are cheap elkos.
I understand there is just a pair of standard mosfets in the output stage (do not know the model though).
I wonder what this technology could reach with the best parts available on the market (like Sanken output devices for instance. I understand they are by far the best output deivces).
I am quite astonished after my first listening session.
In the next future I will test it on my recalcitrant Dynaudios.
By now I am extremely impressed by what I have listened.
Thank you very much to anyone.
Kind regards,
beppe |
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| classd4sure |
| quote: | | I wonder what this technology could reach with the best parts available on the market (like Sanken output devices for instance. I understand they are by far the best output deivces). |
Greetings Sir Beppe,
Do they make decent mosfets for power switching? Requirements are probably a little different than what's best for linear amplification.
The modules have some decent mosfets for switching already. I wouldn't bother swapping them around at all.
You can play around with things like caps though.
There is no schematic available.
Good stuff though, huh? It only gets better.
Best,
Chris |
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| beppe61 |
| quote: | Originally posted by classd4sure
Greetings Sir Beppe,
Do they make decent mosfets for power switching?
Requirements are probably a little different than what's best for linear amplification.
The modules have some decent mosfets for switching already.
I wouldn't bother swapping them around at all.
You can play around with things like caps though.
There is no schematic available.
Good stuff though, huh? It only gets better.
Best,
Chris |
The modules have some decent mosfets for switching already.
Thank you Mr Chris for the kind advice.
As usual I am quite superficial.
You can play around with things like caps though.
I have seen the pcbs. Actually the tiny input caps look poor enough to swap them for something better performing.
I would try to place some PP caps there.
As I understand the input impedance is 100 Kohm, a 0,47-1uF film caps should be fine. Am I wrong?
I feel a little uncomfortable about direct coupling, even if this is the best solution by far.
I think this technology is a tremendous achievement.
Very very remarkable.
I read some listening impressions and power amps based on UcD embarassed well known high-end amps.
High-end for the masses ?
thank you very much again.
Kind regards,
beppe |
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| classd4sure |
Hello,
Didn't you say your preamp has coupling caps on the output? That would do fine alone.
2.2uF before the op amp would be fine. Currently they're after it, valued at 22uF.
A film cap or straight wire would be a good improvement.
Regards,
Chris |
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| beppe61 |
| quote: | Originally posted by classd4sure
Hello,
1) Didn't you say your preamp has coupling caps on the output? That would do fine alone. 2.2uF before the op amp would be fine. Currently they're after it, valued at 22uF.
A film cap or straight wire would be a good improvement.
Regards,
Chris |
Yes Mr Chris. My Bryston has a 4,7uF output cap.
So the caps are after the input op-amp.
I think I would not touch anything, at first.
The amp I listened had modules 400 in stock form and performed just wonderfully.
Expecially considering where I come from (Adcom GFA 545).
Thanks a lot and regards,
beppe |
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| deafandumb |
Forgive me for posting here....but I need some advice on my UcD 400. The amp was built for me (since I know nothing about electronics) but it kept on blowing fuses (4 A) after a few starts when the power was turned on. There must be hundreds of reasons but what would be the most likely one? Is it normal because of power surge and what can I do to solve it?
Most grateful for any answer, and once again sorry to interrupt. |
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| classd4sure |
Who built your amp, Ric Shultz?
Where's the fuse, power rails or mains? I guess mains? Try a 10 amp. Usually a soft start circuit is used to limit inrush current, without it you'll need a beefier fuse. |
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| deafandumb |
| Thanks for replying classd4ever. The unit was built locally with some upgrade parts and included a soft start! That is why I am concerned why this is still occurring? Would a 10 A fuse be too much for some parts to take? Thanks again. |
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| deafandumb |
| Sorry, it should be classd4sure! BTW, mine is a dual-mono but there is only 1 soft start, maybe that is not enough? |
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| classd4sure |
OK, bad advice then. Since it includes a soft start and is blowing the fuse I'd be a hell of alot more paranoid.
If you don't know electronics at all, is there a possibility you can bring it back to whoever built it and have them look it over?
Otherwise it might be time to invest in a multimeter and get familiar with it, check for shorts to the case. |
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| deafandumb |
I followed your advice and called the tech. He suggested that I try an 8A fuse first and that it might be the caps (Jensen's) are still new and suck up too much current. He definitely will check the unit if it blew up again. Does it make sense?
I am going to follow your other advice and take up some electronics primer soon. I have not touch a soldering iron for over 20 years :).
Thanks again. |
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| bremen nacht |
| quote: | Originally posted by deafandumb
I followed your advice and called the tech. He suggested that I try an 8A fuse first and that it might be the caps (Jensen's) are still new and suck up too much current. He definitely will check the unit if it blew up again. Does it make sense?
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First I've heard of new caps 'sucking up more current' (and what does this mean exactly? Higher leakage current? Enough to pop fuses?) than old ones. Right enough, electrolytics age badly but a brand-new cap should surely be the same as a middle-aged one? |
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| lucpes |
| quote: | Originally posted by bremen nacht
First I've heard of new caps 'sucking up more current' (and what does this mean exactly? Higher leakage current? Enough to pop fuses?) than old ones. Right enough, electrolytics age badly but a brand-new cap should surely be the same as a middle-aged one? |
Maybe it is referred to the fact that brand-new elkos have bigger leakage current than in the datasheet, and it will settle to the spec'ed values in some time when you have a DC voltage across them. |
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| beppe61 |
| quote: | Originally posted by lucpes
Maybe it is referred to the fact that brand-new elkos have bigger leakage current than in the datasheet, and it will settle to the spec'ed values in some time when you have a DC voltage across them. |
I wonder if this behaviour could be related in someway to what is called "break-in" of brand new equipment.
This is a real effect, IMHO of course.
I experienced a vast change in sound after some hours of continuous use. And for the better of course.
Nevertheless I would like to know your point of view on the so-called break-in.
Thanks and regards,
beppe |
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| m.parigi |
Sorry to switch back to the much-debated issue of the input caps, but I really need some sort of comfort before I start tampering with my modules.
By putting together the various pieces of wisdom I've been able to gather across several threads, it looks like [limited to the input caps issue!!!]:
A) There's seems to be wide consensus about the absolute sonic best being attained without any caps on the input signal, i.e. shorting or - even better - completely removing the stock electrolytic caps. Drawback: DC vulnerability of the setup.
B) If unsure about the presence of DC at the input, the second choice in sonic terms would be to remove the stock caps and to put 6 uF (approx.) high-quality caps (Auricap, Mundorf, etc.) between the input XLR/RCA and the input of the module.
C) The last option, in sonic terms, would be to replace the stock caps with higher quality ones, like Black Gates.
Did I get it right? Suggestions?
Now the tough questions:
I am thinking about setting up a temporary rig whereby I could switch in real time between option A) and B).
This could be implemented via a four-way switch (for balanced operation), that would alternatively place a cap or a jumper in the signal path.
The possibility of real time comparing two different setups really attracts me.
Do you think this is a worthwhile effort? How much sonic degradation do you reckon the switch will introduce?
Last questions: does anybody know whether the Pass Labs X-1 has an output cap? I wouldn't like the pre to fry my speakers when I DC couple the UCD... |
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| classd4sure |
| quote: | Originally posted by deafandumb
I followed your advice and called the tech. He suggested that I try an 8A fuse first and that it might be the caps (Jensen's) are still new and suck up too much current. He definitely will check the unit if it blew up again. Does it make sense?
I am going to follow your other advice and take up some electronics primer soon. I have not touch a soldering iron for over 20 years :).
Thanks again. |
Yeah leakage is higher in new caps, but quite frankly, I think that's a load of ****. The little bit of extra leakage is just not going to fry a fuse.
Are you _sure_ there's a soft start circuit, and if so, what does it consist of? Thanks to these nice little modules there's far too many people who think they can build amps but hardly have a clue what they're doing. It sounds like what you got wasn't even plugged in for a first test..... scary **** man.
If you ask me a 4A mains fuse is just way too small anyway, and I would go for something closer to 8 or even 10. But I'd make damn sure nothing is wrong with it first... if it does have a soft start that actually works, there's no reason in the world for the fuse to blow when powering it up!
Buyer beware eh? |
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| pinkmouse |
| quote: | Originally posted by classd4sure
If you ask me a 4A mains fuse is just way too small anyway, and I would go for something closer to 8 or even 10. |
Depending on your mains voltage of course. ;) |
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| classd4sure |
| quote: | Originally posted by m.parigi
Sorry to switch back to the much-debated issue of the input caps, but I really need some sort of comfort before I start tampering with my modules.
By putting together the various pieces of wisdom I've been able to gather across several threads, it looks like [limited to the input caps issue!!!]:
A) There's seems to be wide consensus about the absolute sonic best being attained without any caps on the input signal, i.e. shorting or - even better - completely removing the stock electrolytic caps. Drawback: DC vulnerability of the setup.
B) If unsure about the presence of DC at the input, the second choice in sonic terms would be to remove the stock caps and to put 6 uF (approx.) high-quality caps (Auricap, Mundorf, etc.) between the input XLR/RCA and the input of the module.
C) The last option, in sonic terms, would be to replace the stock caps with higher quality ones, like Black Gates.
Did I get it right? Suggestions?
Now the tough questions:
I am thinking about setting up a temporary rig whereby I could switch in real time between option A) and B).
This could be implemented via a four-way switch (for balanced operation), that would alternatively place a cap or a jumper in the signal path.
The possibility of real time comparing two different setups really attracts me.
Do you think this is a worthwhile effort? How much sonic degradation do you reckon the switch will introduce?
Last questions: does anybody know whether the Pass Labs X-1 has an output cap? I wouldn't like the pre to fry my speakers when I DC couple the UCD... |
You can go with a boutique film type cap if you want but... probably any will do and be an improvement over the electrolytics. It's up you.
Also up to you is wanting to play around with some sort of A/B test setup, personally I don't need it. If the caps are close enough that you need an A/B test of anything more than swapping balance from right/left, you can probably consider it a safe bet that they're the same.
Personally I just change one module at a time and keep the other as a baseline, makes it nice and fast to tell what sort of difference there is. Of course, now the argument about the need for blind testing and all that will start, but that's all I have to say on the matter. |
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| classd4sure |
| quote: | Originally posted by pinkmouse
Depending on your mains voltage of course. ;) |
Oh yeah... I think in terms of 120, so a 4A fuse could be about just right for 240. Thanks for pointing that out. |
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| lucpes |
| quote: | Originally posted by m.parigi
If unsure about the presence of DC at the input, the second choice in sonic terms would be to remove the stock caps and to put 6 uF (approx.) high-quality caps (Auricap, Mundorf, etc.) between the input XLR/RCA and the input of the module.
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You can get away with as little as 1.6 uf for a highpass corner frequency of 1Hz on the input caps at the module. 6uf would be 0.3Hz and I don't see the point of going that low... (the series capacitor and the 100K input resistor to ground form a highpass filter) :p I have 1uf coupling caps at the preamp end and it works just fine... |
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| deafandumb |
| quote: | | Yeah leakage is higher in new caps, but quite frankly, I think that's a load of ****. The little bit of extra leakage is just not going to fry a fuse. |
I am now using a 6.3A fuse (yes, our outlet is 230W), and it seems to work fine. But I definitely will have the amp. checked out when I have the time.
Thanks for the advise! |
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| patriz |
| quote: | Originally posted by lucpes
You can get away with as little as 1.6 uf for a highpass corner frequency of 1Hz on the input caps at the module. 6uf would be 0.3Hz and I don't see the point of going that low... (the series capacitor and the 100K input resistor to ground form a highpass filter) :p I have 1uf coupling caps at the preamp end and it works just fine... |
Are you sure you can use such low capacitor? |
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