I apologize if I sound like an idiot. It's not hard for me to do. I just don't know how to do the calculation for frequency response if the output and input impedance is known. I know there's more involved like capacitance.
I guess my real question is if the volume is on the input of the Luminara and headphones had an impedance of 600 ohms what would the frequency response be?
I guess my real question is if the volume is on the input of the Luminara and headphones had an impedance of 600 ohms what would the frequency response be?
Thinking about it a bit more ideally if you plan to use it as only as a headphone amp then the design parameters are not ideal.
The major impediment is the output impedance which is rather high and will only work well with high impedance phones. If i am not mistaken the high output impedance may interact with the impedance curve of the phones if it is not a "benign" one. So to have a more versatile head amp using the luminaria design you would have to lower the output impedance to something like 20ohm and then it could take on most phones on the market. Since you do not want a high voltage swing or high amplification factor you can sacrifice some voltage and go to higher current. In a way more like the L'Amp. Off the top of my head something like a 55V supply, 20ohm drain resistor and about 500ma needing a 20w per channel heatsink.
I am far from being a an audiodiy guru so anybody else is welcome to criticize.
The major impediment is the output impedance which is rather high and will only work well with high impedance phones. If i am not mistaken the high output impedance may interact with the impedance curve of the phones if it is not a "benign" one. So to have a more versatile head amp using the luminaria design you would have to lower the output impedance to something like 20ohm and then it could take on most phones on the market. Since you do not want a high voltage swing or high amplification factor you can sacrifice some voltage and go to higher current. In a way more like the L'Amp. Off the top of my head something like a 55V supply, 20ohm drain resistor and about 500ma needing a 20w per channel heatsink.
I am far from being a an audiodiy guru so anybody else is welcome to criticize.
the buffer is in front of Luminaria, so the buffer is not connected to the output impedance of Luminaria….
as far as I see it….
@protos: indeed the curves and transconductance of the SK82 vary a great deal , so I am not astonished about your lower gain values.
So I think only people with a good fund of SK82 can build this pre and choose the right pair………. :-(
as far as I see it….
@protos: indeed the curves and transconductance of the SK82 vary a great deal , so I am not astonished about your lower gain values.
So I think only people with a good fund of SK82 can build this pre and choose the right pair………. :-(
I also think that a gain of 4x is sufficient in most cases for a pre….
so good luck!
I had sent my Luminaria to late permaneder and he was really enthusiastic about the sound. He missed a bit bass, so I sent him also the parts for the buffer in front. Michael also uses it mostly, as he wrote to me…..
but helas this buffer was never build…… :-(
So I have to build a new Luminaria, sometime.
Permaneder was the only one I knew who owned as well the First Watt line as well as many amps from Pass Labs (XP20, XA30.5, XA200.5). So he had a broad experience how Nelsons amps sound.
so good luck!
I had sent my Luminaria to late permaneder and he was really enthusiastic about the sound. He missed a bit bass, so I sent him also the parts for the buffer in front. Michael also uses it mostly, as he wrote to me…..
but helas this buffer was never build…… :-(
So I have to build a new Luminaria, sometime.
Permaneder was the only one I knew who owned as well the First Watt line as well as many amps from Pass Labs (XP20, XA30.5, XA200.5). So he had a broad experience how Nelsons amps sound.
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I only have 4 pieces of SK82 and the curves for best match among them is attached. Would they be OK for a Luminaria ?
Attachments
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Yes I think that is good enough. The problem is more If the measurement and the reality will fit....
To get the gain whatever it is more equal I suggest to augment the source resistor a bit with the SK showing higher gain until the gain is equal.
But I did not do it myself and I do not know if there is any drawback.
Good luck!
To get the gain whatever it is more equal I suggest to augment the source resistor a bit with the SK showing higher gain until the gain is equal.
But I did not do it myself and I do not know if there is any drawback.
Good luck!
First class sound....at last
My LuminAria at last
And what a revelation it is: The sound is so much more dynamic and gives much more presence and involvment with whats on the CD or streamed media. Compared to the very good passive Pass-B1(and the LuminaAria is the oppsite of passive – it digs to the bone and lifts my SIT mono to new heights)....so it is more lifelike and gives a fuller sound. But it is also twice as powerful in output – so I have more headroom with my Alpair12P. With the B1 it was no problem running it with the vol-pot full throttle, but with the LuminA it can be earblowing. And that is when both is driving my monoblocks SITs (the resistor version of Làmp – Michael Rothacher nice build) on about 7-8watt.
I have only one pair of the 2SK82 and they where somwhat different in caracter – so I had to try (and burn) some drainresistor before I got a fairly even result. Not quite perfect – but you will not hear any difference between the channels! Thats a FACT! And my experience of the newest investment is: everything got bigger and more involving – so you are sitting close to an ensemble and enjoying live music. So touching the music got!
Here are the measurement:
Right Channel: Id=52,5mA
Drain/Source=89,4Volt
Source/Earth=23,8Volt
Gate/Earth=5,6Volt
Gate/Source=18,1Volt
Rdrain Right after some adjustment: 635 ohm/15watt – 3 serie/parallel CarbonComp each 5watt
Left Channel: Id=52,5mA
Drain/Source=90,5Volt
Source/Earth=23,4Volt
Gate/Earth=7,7Volt
Gate/Source=15,6Volt
Rdrain Right after some adjustment: 565 ohm/15watt – 3 serie/parallel CarbonComp each 5watt
Tried with (metal film)2 x 1200ohm/2watt = 600 ohm/4watt + 1 42ohm/1watt = 642 on each channel – but the resistor started to smoke and it was difficult to get the right voltage/current on the left channel!
The case got somewhat stuffed – I did not have the time to order a bigger case. And I was in a hurry to get it up and running before NewYear Eve. And I made it. PERFECT. And I have to let it be for awhile – take some action to my health/family. But when I`m back from hospital I will have something that not only is a small new preamp – but feels like I have got new bigger speaker and two more powerful SIT-moblocs.
THAT is something: 2 simple transistor = SIT`s to drive my Alpairs to new highs!!
Thanks again Michael!! For once again giving wings to my music!!!
The reason for the delay of my building-prosess is somewhat because 29 july 2014 I had 20 centimeter removed of my bowel(polypus/cancer). That was 2 months drawback – but I ordered some part to my building. Then the rest of my stuff arrived late november – and I started the installation. Then I came home from plattform in the NorthSea 15 desember and when checking my health got the news that a little part of the liver is infected – so i have to be hospitalized once more. The good news is that probably it is has good potensial to be healed(the liver is the only organ that can build itself up nearly full)
So in time I will relocate the inside of this magnificent build to enclosure where it is easier to change component and measure things. I have ordered some thinfilm resistor to try in the signal chain. So I have some project when recuperating after operation! Or should I maybe do like ZEN MOD says: stop fiddling!
I will give more photos later when my new case is arrived - it is so stuffed now!
Best to all
Olav
My LuminAria at last
And what a revelation it is: The sound is so much more dynamic and gives much more presence and involvment with whats on the CD or streamed media. Compared to the very good passive Pass-B1(and the LuminaAria is the oppsite of passive – it digs to the bone and lifts my SIT mono to new heights)....so it is more lifelike and gives a fuller sound. But it is also twice as powerful in output – so I have more headroom with my Alpair12P. With the B1 it was no problem running it with the vol-pot full throttle, but with the LuminA it can be earblowing. And that is when both is driving my monoblocks SITs (the resistor version of Làmp – Michael Rothacher nice build) on about 7-8watt.
I have only one pair of the 2SK82 and they where somwhat different in caracter – so I had to try (and burn) some drainresistor before I got a fairly even result. Not quite perfect – but you will not hear any difference between the channels! Thats a FACT! And my experience of the newest investment is: everything got bigger and more involving – so you are sitting close to an ensemble and enjoying live music. So touching the music got!
Here are the measurement:
Right Channel: Id=52,5mA
Drain/Source=89,4Volt
Source/Earth=23,8Volt
Gate/Earth=5,6Volt
Gate/Source=18,1Volt
Rdrain Right after some adjustment: 635 ohm/15watt – 3 serie/parallel CarbonComp each 5watt
Left Channel: Id=52,5mA
Drain/Source=90,5Volt
Source/Earth=23,4Volt
Gate/Earth=7,7Volt
Gate/Source=15,6Volt
Rdrain Right after some adjustment: 565 ohm/15watt – 3 serie/parallel CarbonComp each 5watt
Tried with (metal film)2 x 1200ohm/2watt = 600 ohm/4watt + 1 42ohm/1watt = 642 on each channel – but the resistor started to smoke and it was difficult to get the right voltage/current on the left channel!
The case got somewhat stuffed – I did not have the time to order a bigger case. And I was in a hurry to get it up and running before NewYear Eve. And I made it. PERFECT. And I have to let it be for awhile – take some action to my health/family. But when I`m back from hospital I will have something that not only is a small new preamp – but feels like I have got new bigger speaker and two more powerful SIT-moblocs.
THAT is something: 2 simple transistor = SIT`s to drive my Alpairs to new highs!!
Thanks again Michael!! For once again giving wings to my music!!!
The reason for the delay of my building-prosess is somewhat because 29 july 2014 I had 20 centimeter removed of my bowel(polypus/cancer). That was 2 months drawback – but I ordered some part to my building. Then the rest of my stuff arrived late november – and I started the installation. Then I came home from plattform in the NorthSea 15 desember and when checking my health got the news that a little part of the liver is infected – so i have to be hospitalized once more. The good news is that probably it is has good potensial to be healed(the liver is the only organ that can build itself up nearly full)
So in time I will relocate the inside of this magnificent build to enclosure where it is easier to change component and measure things. I have ordered some thinfilm resistor to try in the signal chain. So I have some project when recuperating after operation! Or should I maybe do like ZEN MOD says: stop fiddling!
I will give more photos later when my new case is arrived - it is so stuffed now!
Best to all
Olav
