Say seriously. I also don't like single-ended amplifier.
I prefer the operational amplifier. But there are a lot of people, but they don't like the operational amplifier.
I just provide a solution to these people. But in fact I recommend HA - PRO2 more
It is better than 47 headphone amplifier performance a lot. Almost no better solution.
The birth of another HA - PRO2 time. Earlier than HA - PRO.
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In fact personally, I prefer the operational amplifier. Production of headphone amplifier.
HA - PRO2 is my design, high performance amplifier, low distortion is composed of eight single op-amp.
It's very small distortion and noise. At least 10 times better than 47 headphone amplifier performance. This is my test results.
But in fact. There are still many people do not like the operational amplifier. I have a friend, he used a lot of amplifier, finally still like HA - PRO single-ended amplifier. Is TIP41C version.
The single-ended amplifier has many shortcomings, but his voice is very special. Some people don't like it. Because it has no low distortion and noise. But there are many people like the sound of it.
If someone need to other test data can email me. I really very slow landing site.
Three minutes maybe can open web pages.
Here I send a HA - PRO2 test data of low distortion amplifier.
Audio Precision 2
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I didn't use LM7824 in about five years ago. But the LM317
Of course. The original photos that long PCB.
Less. The latter is a kind of double sided PCB. Can reduce the noise.
Well it is a couple of years too late. However I have the original long board and a simple solution is to power it from regulated +34V. I use +/- 17V from a low noise LM317/LM337 board.
So I use the + and - outputs to get the +34V regulated (low noise) which is connected to the screw terminals for the AC24-28. The polarity must be correct or it will not turn on the diodes and the bridge.
I left the IRF640/TL431 regulator in circuit. No modifications to the old long board. So if you have the old original long board and you don't like the hum you could try this. The attached supply is only $6 on AliExpress and is very useful and low noise.
So I use the + and - outputs to get the +34V regulated (low noise) which is connected to the screw terminals for the AC24-28. The polarity must be correct or it will not turn on the diodes and the bridge.
I left the IRF640/TL431 regulator in circuit. No modifications to the old long board. So if you have the old original long board and you don't like the hum you could try this. The attached supply is only $6 on AliExpress and is very useful and low noise.
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Not strange at all!
34 = 24*1.414
That is the same voltage the filter capacitors charge up to when you hook up 24VAC which is what LJM specifies for the design.
The only difference is that the diodes are not switching and there is no (or almost no) ripple anymore. Quick and easy fix resulting in a very clean supply.
34 = 24*1.414
That is the same voltage the filter capacitors charge up to when you hook up 24VAC which is what LJM specifies for the design.
The only difference is that the diodes are not switching and there is no (or almost no) ripple anymore. Quick and easy fix resulting in a very clean supply.
LJM,
I have the HA-PRO with mosfet output stage. Can replace the IRF610 Q3 with TIP41C to listen to the latest improvements? Are there other changes to bring it to latest performance level?
The "Noir" headphone amp PCB and project kit in the diyAudio Store, is a single ended amplifier using an N-channel MOSFET output stage. The MOSFET operates in class A, at 150 milliamps of bias current. The chassis contains a total of four transistors: two for the left channel, and two more for the right channel. No vacuum tubes, no ICs, no daughter cards. AC mains power never enters the chassis; instead, Noir uses a 24VDC, 500mA wall wart. Yes really.