Allegro speakers crossover with a sink. Resistor?
Forgive the off-topic.
It made me remember one interesting thing I have seen in a crossover (Allegro speakers, from Suso Ramallo).
KEF Q100 Uni Q bookshelf speakers. 5.25" coaxial with front bass reflex.
What element uses a sink in a crossover? A resistor, in the tweeter filtered?
More pictures: https://www.facebook.com/AllegroByRamallo/photos_stream?ref=page_internal
Forgive the off-topic.
It made me remember one interesting thing I have seen in a crossover (Allegro speakers, from Suso Ramallo).
KEF Q100 Uni Q bookshelf speakers. 5.25" coaxial with front bass reflex.
What element uses a sink in a crossover? A resistor, in the tweeter filtered?
An externally hosted image should be here but it was not working when we last tested it.
More pictures: https://www.facebook.com/AllegroByRamallo/photos_stream?ref=page_internal
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Series resistor to match levels? A zobel network would not dissipate much power.
So I am very intrigued.
By the way, anyone who has heard these speakers say that sounds great.
Suso is a very highly respected person in the profession: Suso Ramallo
ramalloaudio.com Quien somos
By the way, anyone who has heard these speakers say that sounds great.
Suso is a very highly respected person in the profession: Suso Ramallo
ramalloaudio.com Quien somos
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Yes they can get hot. I once put one too close to a cap in a Xover and it melted the outside of the cap.
A series resistor, or one in a zobel network?
We should probably drop this topic, as it has nothing to do with hypex or even class D.
Does someone tried to low the impedance of the Gnd speaker wire between the speaker and the hypex output (by // an other wire for instance to rise the diameter size) : does it change the result at ears ?
Joe, how it performs in relation to a DHT tube amp please ? (let say in the medium and treble range)
PS : and yes, in France some have said the Ncore are sensible to the wires at its output, like the resistive (so the bad) one to be better with some speakers... it seems logical and the sign it can drive anything ! So better to putt bad speaker wires than to buy expensive buffers !
Joe, how it performs in relation to a DHT tube amp please ? (let say in the medium and treble range)
PS : and yes, in France some have said the Ncore are sensible to the wires at its output, like the resistive (so the bad) one to be better with some speakers... it seems logical and the sign it can drive anything ! So better to putt bad speaker wires than to buy expensive buffers !
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Hi Eldam
Not sure if it would be right to answer you re DHT. I do in fact respect that this is an NCore thread.
I don't actually use the resistor, I have already fixed that in the speaker that I design and run. It has a flat 6 Ohm impedance down to 30 Hertz and totally flat, well almost, current phase angle. This has worked great for both solid state and tubes and would also for DHT as it is the speaker that benefits, not the amp.
But this will be covered on another thread and I will PM you then.
I am running NC400 into my Elsinore speakers right now and I am very pleased with the result, it is especially the midrange clarity that I am getting, wow! I don't get it to the same degree when I hook the NC400 with other LR2/LR4 type commercial speakers. The resistor fix in the Elsinore is not a resistor. Uses conjugate networks. This suits all amps.
But again, I hope some of the NC400/500/1200 owners here try that resistor suggestion. There are some here who don't own them. I do.
The NC400 can drive 2 Ohm, makes it a natural to try it - that is the only reason why I mentioned it here - so easy and maybe get some interesting feedback.
The NC500 data sheet's recommended buffer typology uses 47K resistors - not 4.7M. What am I missing? I note that 47K is a very typical resistor value to use in this place in an input board.
If you guys want to dabble with discrete op amps, why not dabble with DIYAudio's finest? DIYAudio member aster has developed a superb discrete op amp... and has all the relevant measurements to boot.
You can read about it in this thread.
Whether it runs in Class A is irrelevant - it's performance is what matters. (It's typology would be classified as Class AB.) I'll let you read up on its current capability.
But note, it's not made available for commercial applications.
Note also that Toni has backed up his work with thorough measurement testing.
BTW Self's Small Signal Audio Design (2nd Ed.) chapter 18 might prove fruitful reading for someone wanting to experiment with improving the input stage recommended in Fig 1 of the NC500 datasheet. Maybe even more fruitful than randomly trying different op amps whose typologies may or may not be suited to drop in replacement in the existing circuit...
Hmmm....
It's worth looking at the THD+N specs of the Sonic Imagery op amps. Not that great.
First, isn't the Sonic Imagery THD+N figure of 0.0003% for a 600R load? And over what bandwidth? At what Vout? The peak output drive current capability statistic is, I believe, for a 75R load. One can't mix those into the same sentence without clarification.
The first chart in the Sonic Imagery data sheet for the 992Enh shows THD+N for 1Vrms output with unity gain. It bounces around 0.0005%. (We can only see the range from 20Hz to 20KHz.) The data sheet for the LM4562 provides a value for 3Vrms output into 600R load with unity gain of 0.00003% (typ). Note the extra zero between the decimal place and the numeral 3.
Second, unless I am mistaken, the application here (the Hypex recommended input buffer typology) is a basic single stage "instrument amplifier" with a gain of 4.4x. I haven't bothered to model Fig 2 from the NC500 data sheet but what drive currents are you expecting are necessary?
If you need to drive greater current or need to operate off relatively high supply voltages then a discrete op amp design has merits. But if you don't, well then....
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Then apparently you are not aware of distortion spectra of by far most class A/B amplifiers, which show decreasing THD with rising signal level up to maximum power.
Typical for class A/B but also for NC400.
Look at the NC400 datasheet and it is clear that THD is significantly lower at 20W than at 2W (2W THD dominated by noise).
I guess you have class A amplifiers in mind but that is not the case here.
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