Another thing I see here are the big toroids people use for the UCD's. I think a waist of money and weight. If you think about it, the class D amps. never use their full spec continiously. They use what they need +10%. So the PSU's are never fully loaded. F.i. I use a 300VA toroid with left/right rectifiers and caps and they can play so loud that's not nice anymore. The toroids have a very low impedance and if you use good caps. like the 0154 series you don't need a 1KVA toroid for a UCD 400 amp. It also makes the amps. like giant blocks cq monsters. Just read that the 0154 series is no more, replaced by the Vishay 102PED and 106PED series. The 106 has better specs.
Initially I run my ice-power amps with a 400 VA traf on each channel but later replaced these with 2 1400VA trafos. It's not about "loud", its about ease, stability,stage and rythm.
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Disabled Account
Joined 2003
Jan Peter,
"Transformer 500VA: 2 x 115 / 2 x 42V / 2 x 16V - EUR 65.00
Suitable for a Stereo UcD400"
I'm confused about this rating. Is that 500VA, 42-0-42V transformer?
What is the 2 x 115 or 2 x 16V?
"Transformer 500VA: 2 x 115 / 2 x 42V / 2 x 16V - EUR 65.00
Suitable for a Stereo UcD400"
I'm confused about this rating. Is that 500VA, 42-0-42V transformer?
What is the 2 x 115 or 2 x 16V?
Maybe that is very speaker dependant. I use Driades D81's, JMLabs profil 3's. I used 2x300VA's but could not hear the difference. For me that's enough to abandon the thought that this could help my sound improve aswhere the cap. change did.
Yeh it's about having the ability to reproduce the signal cleanly at higher power levels, just don't make the transformer the weak link.
Transformer the weaker link??? Its about people using a 2KVA toroid for 2 UCD400 amps instead of 400 or 500VA. How much gain would that give? Not even 3Db! 3Db is a hardly hearable difference.
Try the bridge mode with 2 UCD 400, than the single UCD mode. If you here a difference in tight, dry bass(also mid tones) your PSU is to blame. It should not be different at the same level. A high Z PSU makes a sonic difference. Bad ESR caps. can be compensated(to a certain extend) with a very high VA rating toroid.
Bgt said:
In case the supply is no good, the bridged mode should sound better, is that what you mean? In bridged mode, the supply peak currents would be less so would be less demanding on the supply (at least with the same output power).
Gertjan
Exactly. The internal z of the power supply is not the other leg(or connection pin) of the speaker, now it is the low z of the amp. output.
ghemink said:
Surely the currents must be identical? The difference is in whether the full current is drawn through one winding or two?
If the supply can push it, current output will double.
Usually output current doesn't double, because of current limiting circuitry, some part due to inefficiencies, but if the transformer is the weak link.. it's not going to supply it cleanly ..transformer will overheat.. etc. The point was with a five channel system made up of UCD400's all running off of one 500VA transformer, the transformer is the weak link. It's got nothing to do with gain.
Usually output current doesn't double, because of current limiting circuitry, some part due to inefficiencies, but if the transformer is the weak link.. it's not going to supply it cleanly ..transformer will overheat.. etc. The point was with a five channel system made up of UCD400's all running off of one 500VA transformer, the transformer is the weak link. It's got nothing to do with gain.
You are totally right Chris, but I was just thinking of the one case where bridge vs. single ended of the same power and load impedance.
Hi richie00boy,
Not to worry it was more of a poor reply to a few posts up, something about a 2kVA overkill selection providing gain, I was just too in a hurry and didn't write it very clearly, I also agree with what you're saying about the windings sharing the work load.
Regards
Not to worry it was more of a poor reply to a few posts up, something about a 2kVA overkill selection providing gain, I was just too in a hurry and didn't write it very clearly, I also agree with what you're saying about the windings sharing the work load.
Regards
My UcD400 is singing
Hi,
My UcD 400 based strero power amp is singing finially. As a beginner, it is a hard work to me. Especially when my softstart and fuses was burned couple weeks ago. I rebuilt the softstart and found one of my transformers is short to ground after troubleshot by mt friend Mr. Lin. Now I use one 600VA transformer and 2 X 22,000 UF cap to power two UcD 400s. It will be changed to dual mono PSU when I receive the warranty replacement.
Compare with my AV receiver DENON A1D, A1D as a preamp, the bass is more deep and the separation between different instruments is more claer. But not a quantum jump as I expected. It just runs about 2 hours, therefore, it is too early to descripte the sound. I would say I see the potential.
I would like to say thanks to Mr. Gertjan, Mr. Chrisb03, my friend Mr. Lin and all of you in this forum. I will not complete this project without your help! 😉
Hi,
My UcD 400 based strero power amp is singing finially. As a beginner, it is a hard work to me. Especially when my softstart and fuses was burned couple weeks ago. I rebuilt the softstart and found one of my transformers is short to ground after troubleshot by mt friend Mr. Lin. Now I use one 600VA transformer and 2 X 22,000 UF cap to power two UcD 400s. It will be changed to dual mono PSU when I receive the warranty replacement.
Compare with my AV receiver DENON A1D, A1D as a preamp, the bass is more deep and the separation between different instruments is more claer. But not a quantum jump as I expected. It just runs about 2 hours, therefore, it is too early to descripte the sound. I would say I see the potential.
I would like to say thanks to Mr. Gertjan, Mr. Chrisb03, my friend Mr. Lin and all of you in this forum. I will not complete this project without your help! 😉
Re: My UcD400 is singing
You're welcome, I don't think I was of much help but anyway thanks. Maybe the Denon uses class D amps?? All class D amps I heard so far, although they can sound different, have some sound characteristics in common.
Best regards and happy listening
Gertjan
xman737 said:
You're welcome, I don't think I was of much help but anyway thanks. Maybe the Denon uses class D amps?? All class D amps I heard so far, although they can sound different, have some sound characteristics in common.
Best regards and happy listening
Gertjan
In for a surprise????
I just went to the hypex website www.hypex.nl and was happily surprised. Have a look and you will see why.
Best regards
Gertjan
I just went to the hypex website www.hypex.nl and was happily surprised. Have a look and you will see why.
Best regards
Gertjan
Re: In for a surprise????
Yes indeed
. Congrats to Jan-Peter, Bruno and their colleges. Have fun!
Gerald
ghemink said:
Yes indeed
. Congrats to Jan-Peter, Bruno and their colleges. Have fun!Gerald
Hello,
Yes, we are very proud to have Bruno as our new chief R&D.
Class-D is the Future........😀
Regards,
Jan-Peter
Yes, we are very proud to have Bruno as our new chief R&D.
Class-D is the Future........😀
Regards,
Jan-Peter
