Hotrodding the UCD modules

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#462
stef1777 said:


I suggest you to ask Hypex on the right placement rules. I asked Hypex and got the right answer.

I personally built a 5 channels UcD180 amps. Each module are close to each other (2cm). NO PROBLEM AT ALL. You should be careful only with temp. Your box should have vent holes above (and preferred under too) the modules.

P8023311.jpg
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Ofcourse they work next to eachother but what about the interference?
Try to measure 2 channels next to eachother, 1 with closed input and the other with a sweeping signal from 1kc-20kc with full output on 8 ohms loads. Put a probe on the amp. with closed input and watch what you'll see. The placement of the amps the way you have it is the best if you have a small housing.
I prefer to place only 2 amps in a small housing (GX383=33x23x8cm) and have 2 housings rather than having 5 in 1.
For me separation/crosstalk=depth in sound is far more important than to compromise on sound.

PS and the UCD180 is a bit easier to work with than a UCD400 in placement.
 
#463
Ofcourse they work next to eachother but what about the interference?
Try to measure 2 channels next to eachother, 1 with closed input and the other with a sweeping signal from 1kc-20kc with full output on 8 ohms loads. Put a probe on the amp. with closed input and watch what you'll see. The placement of the amps the way you have it is the best if you have a small housing.
I prefer to place only 2 amps in a small housing (GX383=33x23x8cm) and have 2 housings rather than having 5 in 1.
For me separation/crosstalk=depth in sound is far more important than to compromise on sound.
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What do you like to prove in this way? That by a very high outputpower you have cross talks.....

We have mount the amps very close to each other without any problems with heterodyne tones (in a 5-channel setup). So you can save mount the amps as close as you like, for heat transfer you better mount the amps vertical.

The best would be OF COURSE to build a true monoblok, no risk of cross talks......😉

Jan-Peter
 
#468
thats also why I don't like active preamps/poweramps with a combined left/right amp. stage. There will always be crosstalk/interference with the left/right channels. Look at the Elektor2000 DAC, it uses 2 DAC's separated by a shield so you have the utmost clarity/depth/separation. Any chip power/preamp has compromises(in the stereo image sense) which, for me, are sometimes unacceptable. If you use a bridge for each channel..that's different.
 
#470
Bgt said:
thats also why I don't like active preamps/poweramps with a combined left/right amp. stage. There will always be crosstalk/interference with the left/right channels. Look at the Elektor2000 DAC, it uses 2 DAC's separated by a shield so you have the utmost clarity/depth/separation. Any chip power/preamp has compromises(in the stereo image sense) which, for me, are sometimes unacceptable. If you use a bridge for each channel..that's different.
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Burt,
This has always been a fundamental issue with me, the sharing of grounds between channels. There is no separation of signal return currents and they will be equally present from both channels, on both channels. This is a direct degradation of channel separation. This also allows large ground loop currents to flow due to low impedance in the ground connections. Not much we can do for our front end pieces but effort should be made to separate the grounds from there on. If not, at least twist the interconnect cables together a few turns per foot. This will at least help the line freq. pick up. I use all dual mono or straight monoblocks for this reason. Makes things more expensive and complex but if you want the best….
Roger
Ps. Kilocycles? Been in this business a while?
 
#471
Originally posted by BGT:why do you think Tripath has different osc. freq.'s on their stereo chips? Just to avoid all this garbage/crosstalk interference. They have a 40kc difference in osc. freq.'s.
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Because they have problems with whistling, so they have to do this.......😀

Originally posted by Classd4shure:
Because they need to, as you can see from all their posts around here about them whistling. I ask you again, do you hear whistling?
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So....again...again....do you have problems with whistling????

Jan-Peter
 
#472
stef1777 said:


I suggest you to ask Hypex on the right placement rules. I asked Hypex and got the right answer.

I personally built a 5 channels UcD180 amps. Each module are close to each other (2cm). NO PROBLEM AT ALL. You should be careful only with temp. Your box should have vent holes above (and preferred under too) the modules.

P8023311.jpg
Click to expand...

I just had to say "an incredible piece of work". Lots of nice touches like the Speakon’s.
I do see wires that should be twisted though.
Roger
 
#473
HOw have yo mounted the transformers

Steff1777, your amp looks great I hope its sounds as good as it looks.

How have you mounted the transformers to the case? It looks as though they are bolted to a pice of Aluminium but how is that connected to the case?

Could you post a picture of the underside of tha case or alternativeley email pictures to me?
 
#474
Re: HOw have yo mounted the transformers

wytco0 said:
Steff1777, your amp looks great I hope its sounds as good as it looks.

How have you mounted the transformers to the case? It looks as though they are bolted to a pice of Aluminium but how is that connected to the case?

Could you post a picture of the underside of tha case or alternativeley email pictures to me?
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Here it goes.

P8023304.jpg


entrees_montees.jpg


P8023327.jpg


The DC protection circuit is not represented on this drawing.

wiring.jpg
 
#476
This has always been a fundamental issue with me, the sharing of grounds between channels. There is no separation of signal return currents and they will be equally present from both channels, on both channels. This is a direct degradation of channel separation. This also allows large ground loop currents to flow due to low impedance in the ground connections. Not much we can do for our front end pieces but effort should be made to separate the grounds from there on. If not, at least twist the interconnect cables together a few turns per foot. This will at least help the line freq. pick up. I use all dual mono or straight monoblocks for this reason. Makes things more expensive and complex but if you want the best….
Click to expand...

I guess the question I'd ask is at what point is it audible? I've made some A/B comparisons between listening with two different amps and one stereo amp and I've not been able to decern a difference. Perhaps with a more careful setup and listening session I'd be able to tell some differences but if they are there they are subtle in my set-up.

Passive bi-amping does seem to make an audible difference in my system. I'm not sure if it's just due to more power or if the theoretical virtues of bi-amping are the cause. I'm looking into it further though because bi-amping with four UCD180s isn't much different in price from using a pair of UCD400s.
 
#477
sx881663 said:




Burt,
This has always been a fundamental issue with me, the sharing of grounds between channels. There is no separation of signal return currents and they will be equally present from both channels, on both channels. This is a direct degradation of channel separation. This also allows large ground loop currents to flow due to low impedance in the ground connections. Not much we can do for our front end pieces but effort should be made to separate the grounds from there on. If not, at least twist the interconnect cables together a few turns per foot. This will at least help the line freq. pick up. I use all dual mono or straight monoblocks for this reason. Makes things more expensive and complex but if you want the best….
Roger
Ps. Kilocycles? Been in this business a while?
Click to expand...



SX, I only use 1 hard ground point, its the 0v of the cap. pcb where the +and- of the power supply is. I really don't have any problems with earth loops/crosstalk. My total separation of power and pre is at least 100Db at 15kc. For testing it I made an AB switching box so you can test Amp. A and Amp. B while playing the same music on both amps.
The DAC's output is 100ohms so no problem. Now switch from a standard pre/power amp, in my case either a high end Rotel or NAD, to my passive pre with UCD 180 or 400's,and listen to the difference. What you hear is depth. Its like making the sound stage wider. The ssss are also nicer. Now you maybe say.....ahhh...the UCD's sound better so I take my Elektor Crescendo(completely symmetrical positioning of the audio and psu pcb's) and the same applies. It makes a difference how you position your parts. It also makes the sound very clean.
And JP, I don't want to prove anything just share the experience.
And kc, well we use this in RF like mc.

PS Steff...........truly beautiful😀
 
#478
Kevin Haskins said:


I guess the question I'd ask is at what point is it audible? I've made some A/B comparisons between listening with two different amps and one stereo amp and I've not been able to decern a difference. Perhaps with a more careful setup and listening session I'd be able to tell some differences but if they are there they are subtle in my set-up.
Click to expand...

Kevin, you need a source with excellent stereo image(high quality DAC). If I do the same test with my CD players DAC(sony)......hardly any difference.
 
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