Re: Re: Re: Re: Give me a call...
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
beppe61 said:
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
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?
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
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
beppe61 said:
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.
beppe61 said:
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
beppe61 said:
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
ghemink said:
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
beppe61 said:
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
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
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
classd4sure said:
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
beppe61 said:
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
classd4sure said: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
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.