Buying oaps and transistors at ebay aliexpress is risky as said in the thread. Youcan try burson anssparkos discrete...discrete has advantage over oap fori/v
Also amount of h2 is pleasingfor ears..
But transistors must be paired. Have they diamond discrete oaps at burson or sparkos ? In case you have monney opa627 is one of the best choice here cause also its buffer...don t use sockett
Also amount of h2 is pleasingfor ears..
But transistors must be paired. Have they diamond discrete oaps at burson or sparkos ? In case you have monney opa627 is one of the best choice here cause also its buffer...don t use sockett
I’ve been using Burson V6 and V5 discrete opamps. I prefer these to any of the opamps I’ve tried so far. I also took a gamble and tried a pair of the China discrete opamps P03, garbage!! If you go this route, I’d recommend buying from reputable brands like Burson, Sparkos, etc...
Thanks Miro1360.
Could you explain me please, why someone could take in consideration the idea to establish a value for the vrms output different than 2vrms? it is quite a standard (best?) value for feed a power amplifier, it isn't?
Could you explain me please, why someone could take in consideration the idea to establish a value for the vrms output different than 2vrms? it is quite a standard (best?) value for feed a power amplifier, it isn't?
2 V is quite high for most amp and preamp... You can live with less in a normal context : less than 10 meters for instance between the dac and the amp 😀
I found this article. These device have more than 2vrms output. I really don’t understand which value could be the best.
2vrms could be a too low for passive preamp, but ok if we consider to connect an active preamp.
For a class ab power amp what do you suggest? And why?
How can you avoid preamp clipping? - MSB Technology
2vrms could be a too low for passive preamp, but ok if we consider to connect an active preamp.
For a class ab power amp what do you suggest? And why?
How can you avoid preamp clipping? - MSB Technology
It's slighty off topic. You should search for more understanding how to transfer an electric signal between a A point and a B point, google impedance adaptation both in current & voltage. What is interresting you here first is about voltage as you guessed. 1 V or less is ok in your case : just permitt to lower the Z of the I/V conversion... if you can hear the difference. You have to experiment to know. Theory is cool but practice is what you get & need at the end : experiment is your friend.
I settle on wikipedia article:
Line level - Wikipedia
where Vrms for professional audio is 1.228 (3.472 Vpp)... for this DAC the resistor value 1k75 or 1k8 ...
... but there is no limit for you, you can set the Vrms up to ~2 (with 2k7 resistor or even more if you need) ... it all depends on your preferences or equipment 🙂
Line level - Wikipedia
where Vrms for professional audio is 1.228 (3.472 Vpp)... for this DAC the resistor value 1k75 or 1k8 ...
... but there is no limit for you, you can set the Vrms up to ~2 (with 2k7 resistor or even more if you need) ... it all depends on your preferences or equipment 🙂
Thanks. But I didn’t understand how to set the right value in relation with your device. Which factor do you consider to set the output vrms?
If I have to connect this device with a power amp, what I have to check for decide which resistor use?
If I have to connect this device with a power amp, what I have to check for decide which resistor use?
full output current from this DAC is +-1mA
resistor (Rx) in I/V converter is directly related to this output current and forms desired output voltage
Vp = 1 x Rx, thus Vpp = 2 x Rx
Vrms = Vp / 1.414 = Rx / 1.414
==> Rx = Vrms * 1.414 [Rx in kOhm]
if you consider the Vrms to be 1.228, Rx calculation is:
Rx = 1.228 * 1.414 = 1.736[kOhm]
resistor (Rx) in I/V converter is directly related to this output current and forms desired output voltage
Vp = 1 x Rx, thus Vpp = 2 x Rx
Vrms = Vp / 1.414 = Rx / 1.414
==> Rx = Vrms * 1.414 [Rx in kOhm]
if you consider the Vrms to be 1.228, Rx calculation is:
Rx = 1.228 * 1.414 = 1.736[kOhm]
Thanks but I understood how to calculate the resistor for a desiderate VRMS.
The thing that I don't understand is how to decide this value. If a have a passive preamp which factor I have to take in consideration to decide which vrms is needed? And if I feed directly a power amp?...
The thing that I don't understand is how to decide this value. If a have a passive preamp which factor I have to take in consideration to decide which vrms is needed? And if I feed directly a power amp?...
the factor should be input sensitivity in an end device
if you have a passive preamp, go with higher Vrms to cover most end products input sensitivity
if the input sensitivity of an amplifier is 1Vrms (full power) then 1.2Vrms from DAC is enough, but if the amp has 2Vrms input sensitivity, then you need 2Vrms on your passive preamp ...
... 2k7 resistor in I/V should cover almost any device
... what is the input sensitivity of your amplifier or amplifier which will be used with this dac?
if you have a passive preamp, go with higher Vrms to cover most end products input sensitivity
if the input sensitivity of an amplifier is 1Vrms (full power) then 1.2Vrms from DAC is enough, but if the amp has 2Vrms input sensitivity, then you need 2Vrms on your passive preamp ...
... 2k7 resistor in I/V should cover almost any device
... what is the input sensitivity of your amplifier or amplifier which will be used with this dac?
Thank you! I will check it
In case I have a low input sensitivity (let’s say 1vrms) and I feed it with 2vrms, I will have clipping and distortion?
In case I have a low input sensitivity (let’s say 1vrms) and I feed it with 2vrms, I will have clipping and distortion?
see it like this:
your 100W amp has 1Vrms input sensitivity (which is for full power output) ... 1Vrms = 100W ... 1Vrms from passive preamp means a linear potentiometer to be 100% open (you will have the full range of preamp to control the amp (0% - 100% == 0Vrms - 1Vrms))
if DAC is set to 2Vrms, then the linear potentiometer on your passive preamp can be open only 50% at max (preamp will set 1Vrms for amp to get full power, so you will have only half range of preamp to control the amp (0% - 50% == 0Vrms - 1Vrms) ... if you exceed the limit then your amplifier will be pushed to deliver more than its maximum 100W and this is the clipping)
but if the amp has 2Vrms input sensitivity (for 100W max), and your preamp can deliver only 1Vrms, then the output from this amplifier is only 50W
your 100W amp has 1Vrms input sensitivity (which is for full power output) ... 1Vrms = 100W ... 1Vrms from passive preamp means a linear potentiometer to be 100% open (you will have the full range of preamp to control the amp (0% - 100% == 0Vrms - 1Vrms))
if DAC is set to 2Vrms, then the linear potentiometer on your passive preamp can be open only 50% at max (preamp will set 1Vrms for amp to get full power, so you will have only half range of preamp to control the amp (0% - 50% == 0Vrms - 1Vrms) ... if you exceed the limit then your amplifier will be pushed to deliver more than its maximum 100W and this is the clipping)
but if the amp has 2Vrms input sensitivity (for 100W max), and your preamp can deliver only 1Vrms, then the output from this amplifier is only 50W
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