It sounds wonderful and effortless. It whispers and then kicks like a horse.
Hello Richard,
You ask all the time, How does the amplifier sound?
It sounds wonderful and effortless. It whispers and then kicks like a horse.
I have posted here several times. Thanks to Jack in NJ, I bought his PCB and matched parts kit.
I also have built your amplifier on perf board with my matched parts. Matched with a Keysight Source Measurement Unit, B2902A, with EASYExpert software. The better the parts are matched the better the amplifier measures.
This amplifier easily tests below 0.005% distortion on the APx555. I have built and tested many headphone amplifiers. This one tests better than all the rest.
Thanks DT
Hello Richard,
You ask all the time, How does the amplifier sound?
It sounds wonderful and effortless. It whispers and then kicks like a horse.
I have posted here several times. Thanks to Jack in NJ, I bought his PCB and matched parts kit.
I also have built your amplifier on perf board with my matched parts. Matched with a Keysight Source Measurement Unit, B2902A, with EASYExpert software. The better the parts are matched the better the amplifier measures.
This amplifier easily tests below 0.005% distortion on the APx555. I have built and tested many headphone amplifiers. This one tests better than all the rest.
Thanks DT
And also thank you, DT for the sound review. It makes my day at age 72 a little brighter 🙂
THx-Richard
THx-Richard
The idea was to use the fewest number of transistors possible and at the same time have very, very low distortion driving headphones of various load Z. But, using low - mid mount of FB.
Second, was to be direct-coupled, complimentary push-pull topology operating in current feedback mode; Producing wide open loop BW and have high slew rate. (SR = 145v/usec).
THx-RNMarsh
Second, was to be direct-coupled, complimentary push-pull topology operating in current feedback mode; Producing wide open loop BW and have high slew rate. (SR = 145v/usec).
THx-RNMarsh
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I'm in the process of building one of these fine amps. I'm in a bit of a pickle though. I bought 30 each of the MJE200 and MJE210, but I can't get good matches. The MJE200s all measure between 176 and 202, whereas the MJE210s are between 210 and 300.
Do I need to buy more, or should I just stick with the closest I can get from my current stock?
Do I need to buy more, or should I just stick with the closest I can get from my current stock?
Richard, feel free to jump in here if you like. Especially if I go south.
The MJE200 and MJE210 work together as a Sziklai transistor pair. The current gain for the pair is the product of the individual gains of the MJE200 and the MJE210 that make up the pair.
If you match 2 MJE200’s to each other and also 2 MJE210’s to each other the resulting two MJE200/ MJE210 Sziklia pairs should match each other.
See this link.
https://www.electronics-tutorials.ws/transistor/darlington-transistor.html
Sziklai Darlington Transistor Configuration
This approach to matching is on my list to test. The plan is to test the transistors for likely pairs then test the pairs in a jig to confirm current gain matching Sziklia pairs prior to soldering everything together. I have not tried it yet.
I ended up buying several batches of transistors to get matching pairs.
Thanks DT
The MJE200 and MJE210 work together as a Sziklai transistor pair. The current gain for the pair is the product of the individual gains of the MJE200 and the MJE210 that make up the pair.
If you match 2 MJE200’s to each other and also 2 MJE210’s to each other the resulting two MJE200/ MJE210 Sziklia pairs should match each other.
See this link.
https://www.electronics-tutorials.ws/transistor/darlington-transistor.html
Sziklai Darlington Transistor Configuration
This approach to matching is on my list to test. The plan is to test the transistors for likely pairs then test the pairs in a jig to confirm current gain matching Sziklia pairs prior to soldering everything together. I have not tried it yet.
I ended up buying several batches of transistors to get matching pairs.
Thanks DT
I suppose the gain of a Sziklai pair is the product of the individual transistor gains. So you'd want to match the products. 200 x 210 should match 190 x 220. No?
Edit: DT making the same point.
Jan
Edit: DT making the same point.
Jan
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Jan,
Yes that is what I am saying.
Your example is a very close match if the information in the link above is correct.
DT
I found that even with randomly selected output transistors the THD performance was very, very good.
You guys are doing just fine.
🙂
http://www.tedpavlic.com/teaching/osu/ece327/lab7_proj/lab7_proj_procedure.pdf
-Richard
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Richard, any comments on using this as a line preamp?
Seems like a sound design for preamp duty, too much current output but that's not exactly a downside. Gain seems appropriate.
Seems like a sound design for preamp duty, too much current output but that's not exactly a downside. Gain seems appropriate.
Yes, it is fine for that .. inside CD/DVD players and audio preamps, ADC/DAC I/O etc.
🙂
-Richard
🙂
-Richard
I built this a couple of years ago, tore it down to use some parts and it sat for around 2 years. Rebuilt yesterday and have been letting the caps form. Excellent sound. Very good depth and width, dynamics are superb and very good layering.
This is with a EX9028 dual dac, Focal Utopia, iBasso SR1 and Pioneer SE-Master1 headphones. Right up there with the best amps! And superb transparency.
This is with a EX9028 dual dac, Focal Utopia, iBasso SR1 and Pioneer SE-Master1 headphones. Right up there with the best amps! And superb transparency.
You bet. Do you know what the output impedance is?
On mine I have pretty much made it dual mono as I have separate power supplies and divided the ground except for where they all join.
Let me go back and find the voltage regulator reference, which worked just fine by the way. That conclusion is 52 years behind the times. I believe the actual regulator worked very well with the topology that Richard used. I'll link back to it if able to.
There is an error,
the R2, R3, 5K resistors should go to the +, - rails and not the emitter.