I have currently in the stack of amps next to my work bench;
Leach Low TIM, Leach Superamp, P101, Honey Badger, Symasym, TO-3 Peeceebee, PMI VSSA, DX MKIII, DX Super A & SKA GB150. I listen to each of those off and on. Of those, I probably listen to the Peeceebee and the Honey Badger the most but often I am listening to the most recent build as I am soldering up the next. Now-a-days, most of the amps get built attached to an aluminum angle that can be clamped to a heatsink. I have four different power supplies set up all the time. +/-74V, +/-56V, +/-47V and a +/36V SMPS. I also have a variac so I can adjust any of them to different rail voltage if needed. I do have some Slewmaster OPS mounted to large heatsinks for testing the various IPS that Ostripper and Valery are continuously designing. I am retired now and this is what I do for fun and brain exercise.
A while back I started building up my supply of parts so I didn't have to wait for orders to arrive before I could build something. I have most all of the 1/4w metal film resistor values on hand and the commonly used 1/2w, 1w & 2w values. I have a pretty good stock of MLCC caps from 4.6p-680p and a good supply of film caps in the .01n-4.7u. I try to keep the most common values of electrolytics in stock but often have to order some of those as they take up a lot of space so having a large supply of those is not feasible. I guess this is more of an addiction than just a hobby but it's mine.
Blessings, Terry
Leach Low TIM, Leach Superamp, P101, Honey Badger, Symasym, TO-3 Peeceebee, PMI VSSA, DX MKIII, DX Super A & SKA GB150. I listen to each of those off and on. Of those, I probably listen to the Peeceebee and the Honey Badger the most but often I am listening to the most recent build as I am soldering up the next. Now-a-days, most of the amps get built attached to an aluminum angle that can be clamped to a heatsink. I have four different power supplies set up all the time. +/-74V, +/-56V, +/-47V and a +/36V SMPS. I also have a variac so I can adjust any of them to different rail voltage if needed. I do have some Slewmaster OPS mounted to large heatsinks for testing the various IPS that Ostripper and Valery are continuously designing. I am retired now and this is what I do for fun and brain exercise.
A while back I started building up my supply of parts so I didn't have to wait for orders to arrive before I could build something. I have most all of the 1/4w metal film resistor values on hand and the commonly used 1/2w, 1w & 2w values. I have a pretty good stock of MLCC caps from 4.6p-680p and a good supply of film caps in the .01n-4.7u. I try to keep the most common values of electrolytics in stock but often have to order some of those as they take up a lot of space so having a large supply of those is not feasible. I guess this is more of an addiction than just a hobby but it's mine.
Blessings, Terry
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Hi Bimo,
Back to the Micron 50S, I have been playing with the spice file and by changing a few values I seem to have solved the offset issue and now the two outputs are running at similar bias. The THD looks a lot better as well. The harmonic profile looks a little weird. Can you take a look and see if you see something wrong? On home etched boards, they can't take a lot of part swapping before traces start getting damaged.
Thanks, Terry
Back to the Micron 50S, I have been playing with the spice file and by changing a few values I seem to have solved the offset issue and now the two outputs are running at similar bias. The THD looks a lot better as well. The harmonic profile looks a little weird. Can you take a look and see if you see something wrong? On home etched boards, they can't take a lot of part swapping before traces start getting damaged.
Thanks, Terry
I change R4 because Q3 dissipation to high for 2N5551, or you can use TO-126 transistor.
In simulation, I don't see crossover distortion to much. Simulation result:
Phase Margin = 103 degree
Gain Margin = 30 dB
THD at 34W/8Ohm, 1kHz -> 0.014433%
THD at 34W/8Ohm, 20kHz -> 0.140794%
Slew Rate = 5V/uS
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Hi Bimo,
Yes I noticed that Q3 and Q4 were running very hot. Sim showed 16mA on Q3. I have the values in it now from your recent file except that I didn't add D3 and its resistor. It plays fine but the gain is a little low. I think I'll reduce R6 a little farther and see if that helps. It sounds OK but nothing special.
I have the Turtledove almost finished. Just need to install the outputs. I spent too much time on the Micro today. I'll finish it in the morning.
Blessings, Terry
I just knew that "Perkutut" is Turtledove (in English)
Some of my amplifier, I name it with bird name. Although, I don't like bird, but I think their voice are good.
the predicted phase margin and gain margin values are enormous.
Have you asked the simulator the right questions?
may be you have better method than M. Tian with tian probe?
Attachments
I think you don't know about phase margin and gain margin or how to use tian probe or both.
Hi Richie
No I used MJL4381 /4302 for the outputs. Sorry, I know the thread is about 2SC5200 but I have never used those. I have a lot of the onsemi devices. I just thought the circuit looked interesting. Turns out it doesn't work right as published. I'm not sure why. You would think someone must have built it if they went to the trouble of publishing it. I see crossover distortion on the scope and the sound is just so so. Maybe my choice of devices?
you are right about the last comment.
I don't know where to insert the Tian probe.
Do you know?
The results indicate you have asked the wrong question and as a result the model is giving a weird answer that should be investigated before you believe what you see.
I was just reading back through the thread. What happened to andrewlebon? He posted this circuit and said it is 100% tested. I built it per the silkscreen and it has a huge offset. Spice shows the same thing. Bimo has been helping but we are getting farther away from the original circuit. Maybe I missed something when I built the spice file. Maybe someone can check my work. I see in the first post that that circuit has the third diode and parallel resistor that Bimo suggested. I'll try adding those today and see if that will raise the bias enough to get rid of the crossover distortion. There may be a problem with thermal compensation with no diode monitoring the temperature. Still, worth a try I suppose.
Blessings, Terry
Blessings, Terry
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