it is extremely exactly! What about class D for 4-6 years further? 😕
PS: My feeling is that this planet will not be needing for more then 10 such designers (super stars) never..
because "audio is only a fringe activity "and class D just a part (bigger part in close future) of it forever.
2 subwo1: However all electronics just a part of the entertainment, also the entertainment only a part of the modern human life.
2 all: So, where our class D forum, if this is definitely part of our life?
edited: Sheriff, Congratulations!!
Kids is a power source of the pleasure for me (and noise too).😉
So, why and under what circumstances would it be beneficial to short the pin 1 and 3 on the xlr at the source side?😕
/Roland
/Roland
Hello!
I am very enthused by the UCD technology.
I am new to DIY to DIY so please bear with me.
I have a couple questions about the OPamp in the circuit:
1. What is the model# of the opamp?
2. What is the voltage going to the opamp? Is it the same as going to the module? If not, how is the volatge stepped down?
3. Would it be beneficial/possible to have seperate power leads on the module for the opamp so that the opamp could have its own regulated power supply (or use a lower voltage for some AD opamps that have lower voltage limits)?
4. How does changing the opamp change the input impedence of the module? the gain of the module?
Thanks!
I am very enthused by the UCD technology.
I am new to DIY to DIY so please bear with me.
I have a couple questions about the OPamp in the circuit:
1. What is the model# of the opamp?
2. What is the voltage going to the opamp? Is it the same as going to the module? If not, how is the volatge stepped down?
3. Would it be beneficial/possible to have seperate power leads on the module for the opamp so that the opamp could have its own regulated power supply (or use a lower voltage for some AD opamps that have lower voltage limits)?
4. How does changing the opamp change the input impedence of the module? the gain of the module?
Thanks!
IVX said:2 subwo1: However all electronics just a part of the entertainment, also the entertainment only a part of the modern human life.
2 all: So, where our class D forum, if this is definitely part of our life?
Recreation is important for human functionality. 🙂
I'd just drop in a few replies to the most recent posts:
Jan-Peter: The UcD gets its sound quality from the minimalist control circuit, the smooth load-independent frequency response and frequency-independent THD. The result is that most of my time and effort tweaking the sound of UcD goes into the buffer op amp input stage! I reckon this is a sign of transparency...
As for comparison with other amps, are you asking me to blow my own horn?!
All I'd say is that I'm quite proud of the little beast.😀
Loudandclear: The op amp is only a buffer stage. It is not part of the actual "UcD" circuit, but is added to obtain better gain, impedance and DC stability. It has no impact whatsoever on the "specs" such as output impedance.
The op amp on JP's module (5532) is powered by regulators coming off the main rails. There is quite some sonic progress to be made using different power schemes.
JP is aware of this fact, but going all the way to super-high-end construction would seriously detract from the module's universality, so there had to be a number of compromises made for practicality's sake.
Paradigm: There's never a good reason for shorting pin 3 to ground at the source. If the source has an XLR output and the destination has an XLR input, connect normally.
In cases where the source has a balanced, floating output and the destination has only an unbalanced input (NOT the UcD module!), you'd tie the cold (-) line to ground at the destination end.
IVX ("Kids is a power source of the pleasure for me"): So true.
Jan-Peter: The UcD gets its sound quality from the minimalist control circuit, the smooth load-independent frequency response and frequency-independent THD. The result is that most of my time and effort tweaking the sound of UcD goes into the buffer op amp input stage! I reckon this is a sign of transparency...
As for comparison with other amps, are you asking me to blow my own horn?!
All I'd say is that I'm quite proud of the little beast.😀 Loudandclear: The op amp is only a buffer stage. It is not part of the actual "UcD" circuit, but is added to obtain better gain, impedance and DC stability. It has no impact whatsoever on the "specs" such as output impedance.
The op amp on JP's module (5532) is powered by regulators coming off the main rails. There is quite some sonic progress to be made using different power schemes.
JP is aware of this fact, but going all the way to super-high-end construction would seriously detract from the module's universality, so there had to be a number of compromises made for practicality's sake.
Paradigm: There's never a good reason for shorting pin 3 to ground at the source. If the source has an XLR output and the destination has an XLR input, connect normally.
In cases where the source has a balanced, floating output and the destination has only an unbalanced input (NOT the UcD module!), you'd tie the cold (-) line to ground at the destination end.
IVX ("Kids is a power source of the pleasure for me"): So true.
paradigm said:
Never as far as I can tell as it actually shorts the output of the pre and may actually destroy it. I think you base that question on earlier misunderstandings. The issue here is that the signal is better if minus of the balanced input on AMP side is grounded on the SOURCE side (rather than amp side) in case driven by an UNBALANCED source (i.e. RCA). So in cases where you are running a balanced source that is simply what you are doing which means no shorting of any pins at all but running a balanced cable as you would with anything else.
So this means for optimum results as per Jan-Peter and Bruno:
Source side balanced =>
Connect with your preferred balanced cable.
Source side unbalanced =>
Connect with your CUSTOM cable where you have soldered minus (cold) conductor to ground in the RCA connector that plugs into the source output. Amp side of the cable is XLR connected the usual way.
Thanks!
That makes sense to me. It also sounds familiar.
Now we just have to find a balanced multi-channel attenuator some how, with at least 7 or 8 channels and which doesn't degenerate the sound too much.
/Roland
That makes sense to me. It also sounds familiar.
Now we just have to find a balanced multi-channel attenuator some how, with at least 7 or 8 channels and which doesn't degenerate the sound too much.
/Roland
Yep, I'm after a 6-7 channel balanced attenuator as well... I think the Dact might be a partial fit, but I think at this level you need to look at the various chip options. Something like the PGA2310?
http://www.diyaudio.com/forums/showthread.php?s=&threadid=35660&highlight=
Wiring up a half dozen of these (or even the four channel versions) is beyond me, but there is at least one kit out there. Probably your best option right now.
Ed
http://www.diyaudio.com/forums/showthread.php?s=&threadid=35660&highlight=
Wiring up a half dozen of these (or even the four channel versions) is beyond me, but there is at least one kit out there. Probably your best option right now.
Ed
I would also need help in designing/programming the attenuator.
I think there are many out there with similar hindering shortcomings. 🙁
Programming just gives me a terrible allergic itch. 😉
I've mailed Hennesey, but haven't yet received an answer.
I'll pass on the info here, if and when I get a response.
/Roland
I think there are many out there with similar hindering shortcomings. 🙁
Programming just gives me a terrible allergic itch. 😉
I've mailed Hennesey, but haven't yet received an answer.
I'll pass on the info here, if and when I get a response.
/Roland
Roland,
The Dutch Hobby Electronic magazine Elektor (Elektuur) wrote an articel to build a digital volume control. Perhaps this is something for you?
http://www.elektor-electronics.co.uk/
http://www.elektor-electronics.co.uk/ln/details/e0404u.htm
Regards,
Jan-Peter
www.hypex.nl
The Dutch Hobby Electronic magazine Elektor (Elektuur) wrote an articel to build a digital volume control. Perhaps this is something for you?
http://www.elektor-electronics.co.uk/
http://www.elektor-electronics.co.uk/ln/details/e0404u.htm
Regards,
Jan-Peter
www.hypex.nl
I went there, but couldn't find out if the design allows balanced in- and outputs, nor could I se if the design is purely for digital two-channel (stereo) attenuation (AES/EBU S/PDIF in pre UltraDrive configuration), or if it allows any number of analog balanced channel daisychaining (post UltraDrive configuration) attenuation. Or for that matter, what that would cost in each case.
Do you have any knowledge on these questions?
Otherwise it looks very interesting.🙂
/Roland
Do you have any knowledge on these questions?
Otherwise it looks very interesting.🙂
/Roland
Roland,
As far as I know the input and output of this preamp is unbalanced. It wil not be so difficult to add a symmetrical input and output on this design. There some INA*** IC who converts asymmetrical to symmetrical and vice versa. I don't know how they sound, but the specs looks ok. I can't either write software, but if you only want an extra volume control I guess you can simple add an extra IC if you like to have 2 channels more.
If you look with google there are more hobby project going on with the PGA2311. Perhaps a good idee to start a new topic to keep this topic on the subject 😉
Regards,
Jan-Peter
www.hypex.nl
As far as I know the input and output of this preamp is unbalanced. It wil not be so difficult to add a symmetrical input and output on this design. There some INA*** IC who converts asymmetrical to symmetrical and vice versa. I don't know how they sound, but the specs looks ok. I can't either write software, but if you only want an extra volume control I guess you can simple add an extra IC if you like to have 2 channels more.
If you look with google there are more hobby project going on with the PGA2311. Perhaps a good idee to start a new topic to keep this topic on the subject 😉
Regards,
Jan-Peter
www.hypex.nl
Yes of course, this thread is about the UcD modules.
So, I have just posted a new thread in the "chip amp" section on the PGA2311 and the four channel version PGA4311 IC's.
/Roland
So, I have just posted a new thread in the "chip amp" section on the PGA2311 and the four channel version PGA4311 IC's.
/Roland
Try looking into the transformer based volume control units available from S&B via Bent Audio. Others are making them now too I believe. They have gotten rave reviews all over the place....
-kuribo
Thanks for the tip. It sure is an interesting alternative, as long as only the sonic's are in focus, but I'm afraid it falls under the category of unobtainable dreams, simply because I cannot afford it.
I need a balanced 2*4 channel attennuator and if I make a rough estimate, it will take far too many transformer, along with all the other stuff that's needed, to even begin adding all the costs.
To bad though, I wouldn't have minded having one of those kits.
/Roland
Thanks for the tip. It sure is an interesting alternative, as long as only the sonic's are in focus, but I'm afraid it falls under the category of unobtainable dreams, simply because I cannot afford it.
I need a balanced 2*4 channel attennuator and if I make a rough estimate, it will take far too many transformer, along with all the other stuff that's needed, to even begin adding all the costs.
To bad though, I wouldn't have minded having one of those kits.
/Roland
Balanced is not the be all and end all. You can of course place the transformer physically near the source component, then add a transformer stage afterwards to split phase and create a balanced output again. This way you control the volume, but recreate the balanced signal for transmission after the preamp phase.
Not ideal, but much cheaper.
Not ideal, but much cheaper.
You should have a look around www.jensentransformers.com . Bill Whitlock provides a good exposé on what balanced means.
The crux of the story is: you don't need a symmetrical output signal. The "requirement" for a symmetrical output signal is one of the longer standing myths of audio.
You need to have identical impedances on the hot and cold wires, and a good differential input. It means you can make a fine balanced output on an unbalanced pre-amp by simply tying the cold wire to ground through an impedance which is identical to the impedance of the (unbalanced!) output buffer that drives the hot wire. The differential input does the work.
The crux of the story is: you don't need a symmetrical output signal. The "requirement" for a symmetrical output signal is one of the longer standing myths of audio.
You need to have identical impedances on the hot and cold wires, and a good differential input. It means you can make a fine balanced output on an unbalanced pre-amp by simply tying the cold wire to ground through an impedance which is identical to the impedance of the (unbalanced!) output buffer that drives the hot wire. The differential input does the work.
It's not that I absolutely need to have everything balanced, but since I've already have quite a few gadgets with xlr connectors from the pro sector (Behringer UltraCurve and UltraDrive and soon will have a UltraMatch), which as you know, shouldn't be hooked up to a ungrounded outlet, I decided to go "all the way". Besides, the only thing I need now to become Balanced is the attenuator, since the CD-player can be connected optically, so there is no potential problem with ground-loopes there.
I still got the impression it would be much more expensive to use transformers to do the balancing act, or am I wrong there!?
/Roland
I still got the impression it would be much more expensive to use transformers to do the balancing act, or am I wrong there!?
/Roland
I can not see any solution with quality transformers that would end up cheaper than a solid-state solution. And in my opinion this would both be absurd overkill AFA balancing goes and would probably create more distortion than a good IC-based solution. You don't have hundreds of feet of mic cable running all over the place and next to a 100 kW light rig but rather a few feet of interconnect cable at line level in a not too "hostile" environment.
And the THAT 1200-series differential receivers mentioned in another thread (designed by Bill Whitlock) achieve near-transformer performance. Actually, the circuit topology he has adapted is well known and widely used in medical (ECG, EEG, EMG) amplifiers and is commonly referred to as "active ground driven" or "right leg drive" (for ECG amps) and achieves excellent performance for signals in the uV range superimposed on common-mode voltages (including 50/60 Hz line noise) of several volts. All at the cost of a dollar...
/M
And the THAT 1200-series differential receivers mentioned in another thread (designed by Bill Whitlock) achieve near-transformer performance. Actually, the circuit topology he has adapted is well known and widely used in medical (ECG, EEG, EMG) amplifiers and is commonly referred to as "active ground driven" or "right leg drive" (for ECG amps) and achieves excellent performance for signals in the uV range superimposed on common-mode voltages (including 50/60 Hz line noise) of several volts. All at the cost of a dollar...
/M