To choose R5 and R6, I considered that the amplifier had to be useful as a desktop one, due to its limited power. As today it is very common to have a laptop, notebook or desktop PC, I considered it appropriate to operate it from any of them, through the headphone output. This is why the relatively low input impedance should not be a problem, as many outputs are capable of handling 32 ohms with ease (whereas this amplifier has an input impedance of around 350 ohms).
In any case, for those who wish to modify it, they should consider that the frequency response (mainly the high frequency) could be significantly altered. The distortion profile will probably be altered, so it should be checked if it is still useful in how it is altered.
I show you how the frequency response would be altered by taking other values for R5 and R6, maintaining similar gain within the passband.
In any case, for those who wish to modify it, they should consider that the frequency response (mainly the high frequency) could be significantly altered. The distortion profile will probably be altered, so it should be checked if it is still useful in how it is altered.
I show you how the frequency response would be altered by taking other values for R5 and R6, maintaining similar gain within the passband.
Ok, thanks for the explanation on choosing the low input resistance.
For my personal taste I would prefer driving your nice hybrid Zen amp from a normal unbalanced output from example a DAC or similar source, not from the output of an headphone amp unless you know it’s great sounding.
The headphones output jack on regular laptop or similar computer are normally not really Hi-Fi, your amplifier deserves a much better source.
What if R6 is 3Kohm, what would be the upper -3db frequency ?
Thanks
For my personal taste I would prefer driving your nice hybrid Zen amp from a normal unbalanced output from example a DAC or similar source, not from the output of an headphone amp unless you know it’s great sounding.
The headphones output jack on regular laptop or similar computer are normally not really Hi-Fi, your amplifier deserves a much better source.
What if R6 is 3Kohm, what would be the upper -3db frequency ?
Thanks
Last edited:
Thanks Diego
I believe I’ll go with let’s say 3Kohm for R6 and a slightly lower overall gain, maybe 12 dB just to increase slightly the bandwidth. Can I disturb you on more time to see the -3dB with the above? TIA
I believe I’ll go with let’s say 3Kohm for R6 and a slightly lower overall gain, maybe 12 dB just to increase slightly the bandwidth. Can I disturb you on more time to see the -3dB with the above? TIA
With R6 = 3K3 and R5 = 18K => Gain = 12.38 dB aprox.; fcs = 24323 Hz at - 3 dB
With R6 = 3K3 and R5 = 15K => Gain = 11.36 dB aprox.; fcs = 26739 Hz at - 3 dB
Best regards
With R6 = 3K3 and R5 = 15K => Gain = 11.36 dB aprox.; fcs = 26739 Hz at - 3 dB
Best regards
Here is the latest version. I will wait a couple of days for suggested corrections or improvements and then post the Gerbers. I will have my laptop so I can make changes.
I am going to Japan later today for two weeks. It's my first time in Japan and I am hoping to visit a couple of Kissas as well as the electronics shops in Akihabara. And ride a lot of trains and eat plenty of ramen.
ray
I am going to Japan later today for two weeks. It's my first time in Japan and I am hoping to visit a couple of Kissas as well as the electronics shops in Akihabara. And ride a lot of trains and eat plenty of ramen.
ray
Have a fun and safe trip to Japan.
You’ll probably find some very good Output transformers for your tube amplifiers.
You’ll probably find some very good Output transformers for your tube amplifiers.
You are better at this than I am. Still, I am doing better than my original efforts.
Ray
Ray
No need to worry!!! There will always be a worse one, whatever it is. I am a total disaster at designing PCBs. I don't even qualify.
What each of you do is admirable.
What each of you do is admirable.
Very much agree!
I enjoy building stuff, but without guys like yourself and others that take the time to layout pcbs, I could not keep going in this hobby/addiction.
I enjoy building stuff, but without guys like yourself and others that take the time to layout pcbs, I could not keep going in this hobby/addiction.
For resolutions up to 16 bits it will be enough with a simple scheme consisting of transformer, rectifier and capacitor. The rectifier bridge could be the MB1510 (one per channel, if possible). The capacitor could be 6800 uF x 35 V. I suggest one transformer per channel, if possible.
To be aligned with 20-bit resolutions, I recommend interleaving voltage regulators with power ripple rejections of at least 24 dB at the mains frequency.
To be aligned with 24-bit resolutions, I recommend voltage regulators with power ripple rejections of at least 48 dB.
For both the 20-bit and 24-bit options, I am assuming the value of the main filter capacitor is kept at 6800 uF (prior to voltaje regulator).
Best regards
Last edited:
Diego,
I’m not familiar with describing the power supply with “16,20,24-Bit resolution”?
What are you referring to?
I’m not familiar with describing the power supply with “16,20,24-Bit resolution”?
What are you referring to?
^ The bit-depth defines the dynamic range. They're recommending that the PSU be measurably / quantifiably 'quieter' if someone were to want to distinguish a signal from noise at a certain dynamic range. The PSU typically sets the "noise floor".
@Vunce = Jumping in just to see if I actually understand any of this ... I had to look it up. Sorry if I hopped on to your question.
Diego, I'm also curious. Am I close?
@Vunce = Jumping in just to see if I actually understand any of this ... I had to look it up. Sorry if I hopped on to your question.
Diego, I'm also curious. Am I close?