Re: Hpr12/hnr12
The regulator's performance was measured with an input voltage of 18V but the regulators are specified to have a max dropout voltage of 3V (assuming that's with a load current of 100mA but that is not specified). With an output voltage of 12V, 15V is the minimum input voltage you should use.
Two specs I wanted to see that are missing are the line and load regulation. Not sure why those weren't included as they are important to know since these are voltage regulators.
DSP_Geek said:
The regulator's performance was measured with an input voltage of 18V but the regulators are specified to have a max dropout voltage of 3V (assuming that's with a load current of 100mA but that is not specified). With an output voltage of 12V, 15V is the minimum input voltage you should use.
Two specs I wanted to see that are missing are the line and load regulation. Not sure why those weren't included as they are important to know since these are voltage regulators.
Re: Re: Hpr12/hnr12
Aren't those spec there (in an indirect form)?
There is a graph for ripple rejection versus frequency, stating 110dB rejection for a wide frequency range, I would say that is equivalent to line regulation in a sense.
There is also a graph for output impedance versus frequency, showing about 50mOhm over a wide frequency range.
Isn't that saying enough?
Gertjan
BWRX said:
Aren't those spec there (in an indirect form)?
There is a graph for ripple rejection versus frequency, stating 110dB rejection for a wide frequency range, I would say that is equivalent to line regulation in a sense.
There is also a graph for output impedance versus frequency, showing about 50mOhm over a wide frequency range.
Isn't that saying enough?
Gertjan
Line regulation corresponds to ripple rejection at DC, expressed in %. Load regulation corresponds to output impedance at DC multiplied by load current divided by output voltage. Clearly ripple rejection and output impedance vs frequency plots tell quite a bit more. It's not very useful to have a fantastic load regulation figure (i.e. DC output impedance) if you can't have the same value at audio frequencies.
Hello.
Im just finishing my UCD400 amps and i have some questions.
1. I didnt twist the wires from power supply to the amps. They are about 15cm long. Is this bad?
2.Do i need to bypass bridge diodes with caps? What if i dont?
3. Any simple mods for better sound (not on the modules)?
4. I use transformer with 2x 40v sec. and dual bridge with ground in the middle of the caps. Is this ok?
5. Is anything wrong if the AC cable goes near to the modules?
thank you for help.
Im just finishing my UCD400 amps and i have some questions.
1. I didnt twist the wires from power supply to the amps. They are about 15cm long. Is this bad?
2.Do i need to bypass bridge diodes with caps? What if i dont?
3. Any simple mods for better sound (not on the modules)?
4. I use transformer with 2x 40v sec. and dual bridge with ground in the middle of the caps. Is this ok?
5. Is anything wrong if the AC cable goes near to the modules?
thank you for help.
a007udio said:
1) Best to twist those to minimize radiation.
2) You'll get different responses from different folks on this.
I wouldn't bypass the bridge diodes.
The bridge also matters. i.e. FRED's better than standard.
If you want to do something, you put a series RC on the leg of the output secondaries (before the bridge.)
You may search around. I don't recall the values and I did once actually measure a transformer. It is transformer dependent, but something on the order of 100n, 47ohms is a very dusty guess.
Bottom line. You need not do anything. It will be fine, but there is always room for improvement. IMO snubbers best done with a scope to optimize, or measure the transformer properties. i.e. A lab more than most DYIers don't have.
3) #4 for sure. Good clean wiring. Good PS caps. FRED bridges. I'll stop there for others to add.
4) That's good.
5) That depends on how close, but bottom line is that's not great, but the UCD is less dependant on EMI than most amps I think.
You might make sure you have a tight twist in the wires, and also shield them. I'd worry most about keeping them away from the input wires I think. Make sure your inputs are shielded for sure though!
Good luck and good listening!
Portland Mike
my knowledge is limited but im trying to understand the use of differential signal or more rather what I stand to gain, from what I can gather i might be wrong is that a differential amplifier will "push and pull" where a single ended amplifies whole + and half - signal ???? so would there be an ultimate reason to bridge ucd modules and what in terms of loudspeaker control this may gain (or not)
i understand that the use of differential signal rejects common mode noise in the signal but what im pondering on is having the difference stage working all the way to the loudspeaker (bridging two ucd modules)
so if the ucd modules have a damping facter which controls the emf of the speaker would that be a different scenario for a full-bridge configuration?
these questions have probably been answered on another forum but like so many others looking for a needle in a haystack isnt my first choice!
please help my limited knowledge and others! any help greatly appreciated thanks...
i understand that the use of differential signal rejects common mode noise in the signal but what im pondering on is having the difference stage working all the way to the loudspeaker (bridging two ucd modules)
so if the ucd modules have a damping facter which controls the emf of the speaker would that be a different scenario for a full-bridge configuration?
these questions have probably been answered on another forum but like so many others looking for a needle in a haystack isnt my first choice!
please help my limited knowledge and others! any help greatly appreciated thanks...
tawn10 said:
The input of the UCD is differential. That means that it amplifies the difference. You can ground one side if that makes life easier, say from a single ended preamp. The advantage of differential input is that you get some benifit in CMR, which for the UCD isn't bad, but not stellar. I believe its 45dB, but its likely better than that over most of the audio band.
Bridging two UCD's would be most benifitial if you wanted more power. That would be the main, and perhaps the only reason if you were using hypex UCD's.
The damping factor would be half, as in any bridge, but likely would not be an issue.
The more talked about issue is pumping. That is when a ucd is sourcing current to the speaker, it actually is sucking current from the negative rail, i.e. making it more negative. This really isn't an issue though, even with minimalistic supply caps, and I think is only an issue is Lab amp applicatoins where one might actually wish to drive something at 5Hz -10 Hz at high power.
The less talked about issue is that when you bridge, the noise or ripple induced by the load becomes primarly 2nd harmonic. When single ended, the induced ripple from the load is a mirror of the fundimental times the impedance of the supply caps.
One theory is this is preferred. The PSSR of the UCD's, like hte CMR, is not stellar, unless one considers its flat over the audio band, which is very good. Thus given the DS spec for PSSR of 45dB (i think i recall) one could conclude that single ended may be better.
Bottom line though, if you need more power, maybe do it, or just up the ucd to the next bigger one.
Best Regards,
Portlandmike
Thanks Mike for help.
Ok, the amp is ready for use. Its dead quiet.
I have some more questions.
I cant ground chasis and XLR conector. Anything wrom with this?
When the amp is playing and i swich on solder station it makes pops in speaker. Way?
When i put amp off after 2, 3 seconds meke some kind of sweep in twetter????
Thats all.
Thanks.
Ok, the amp is ready for use. Its dead quiet.
I have some more questions.
I cant ground chasis and XLR conector. Anything wrom with this?
When the amp is playing and i swich on solder station it makes pops in speaker. Way?
When i put amp off after 2, 3 seconds meke some kind of sweep in twetter????
Thats all.
Thanks.
a007udio said:
Solder station on off getting into your amp may be getting into preamp. Not ideal either way, but not the end of the world either.
Grounding the XLR to the chassis is ideal from a shielding point, but if you can't.... can you at least tie it to the UCD board ground?
If you are talking about not having a 3 terminal power cord with a ground... This is different. Again, its ideal, but not having it is not so bad as not having a UCD. Be careful with how you wire so you don't shock yourself or others though.
As for the tweeter 3 second after off, you just told me you didn't use lots of PS cap ;>). That is actually normal. I personally live with that.
I just don't shut my amps off. And if I need them kind of off, I use a switch on the ..... forget what they call it, but there is a line you pull on to turn them on and off into low power mode. Make them low power or standby before off and the noise goes away.
If you must rid the noise for your sanity, then go to it. Find a way to make the "standby, or "on" line go off before the rails drop past say 35V and there will be no noise.
Also, never solder when your amp is on ;>)
Best Regards,
Mike
Yes i dont have 3 terminal power cord. But is grounding the chasis an XLR only becouse of safety and hum problem or it sounds better with ground?
I use 40000uF for stereo amp baypased with MKP.
The sound from speaker at swich off the amp doesent bother me i just dont want to damage the speakers. Is this bed for speakers?
And i put my solder station in the corner so no risc of soldering.
Thanks again Mike.
I use 40000uF for stereo amp baypased with MKP.
The sound from speaker at swich off the amp doesent bother me i just dont want to damage the speakers. Is this bed for speakers?
And i put my solder station in the corner so no risc of soldering.
Thanks again Mike.
IVX said:
thank you portlandmike for the response, I am guessing that the figures being quoted here as good but not stellar (or are they stellar!) are responsible for the deathly blackness being reported in so many casses? (besides quality caps and great workmanship ofcourse!)
so appart from either signal noise or output level can we conclude that these are the only reasons needed for the use of differential signal or bridging?? any takers??
like would signal noise be the only affected notable here?
I only say this because my current setup uses single ended input and output and I hear only silence in the blackspots, the question is really would unaudiable cm noise affect the audio signal? (ie distortion) ???
I'm sure that this question has been already answered but I didn't find the exact answer I was looking for.
My question is about XLR grounding.
1) Should I just let the amplifier module handle the termination duties and not do anything at the XLR connector? Avoiding multiple ground paths.
2) Just attach the XLR connector body lug to the shield pin 1.
3) Attach the XLR connector body lug to the chassis.
4) Attach the pin 1 shield, connector body and chassis all together.
My question is about XLR grounding.
1) Should I just let the amplifier module handle the termination duties and not do anything at the XLR connector? Avoiding multiple ground paths.
2) Just attach the XLR connector body lug to the shield pin 1.
3) Attach the XLR connector body lug to the chassis.
4) Attach the pin 1 shield, connector body and chassis all together.
as far as my experience building amplifiers go I can only offer general advice and say try it and see, personally if It was me I would keep the output and power grounds as far from the signal grounds as possible, certainly avoid the signal sharing the same pathway, simply adding an ground strap from power ground to power ground and signal ground to signal ground will help avoid any unplesentries : ) hope this helps
Chassis not connected to safety earth?
hmmm.. the recommended grounding scheme is to link the RCA ground to the chassis and the chassis is not supposed to be linked to the safety earth. Isn't that dangerous? What if there's a live wire touching the chassis?
hope to get your advice on this.
hmmm.. the recommended grounding scheme is to link the RCA ground to the chassis and the chassis is not supposed to be linked to the safety earth. Isn't that dangerous? What if there's a live wire touching the chassis?
hope to get your advice on this.
The grounding scheme for use with RCA connectors as recommended by Hypex is what is used in the vast majority of HiFi equipment. There are some exceptions, like some gear with XLR, some german amplifiers and some other stuff.
As pointed out by ghemink, double isolation is the crucial point here. The mains transformer must be explicitely specified and tested for double isolation. The transformers sold by Hypex are. Some from other suppliers are also, some are not, so be careful.
I have gone the double isolation way with my UcDs; clear sound and absolutely no trace of hum or noise.
As pointed out by ghemink, double isolation is the crucial point here. The mains transformer must be explicitely specified and tested for double isolation. The transformers sold by Hypex are. Some from other suppliers are also, some are not, so be careful.
I have gone the double isolation way with my UcDs; clear sound and absolutely no trace of hum or noise.