Bernhard said:
I am afraid, this will not work, it would mean more power on 8 ohm less power on 4 ohm.
Somethings wrong...
I put your schematic on the sim but like you say, it doesn't work.
I have no idee how to make it work, so this is a question for
'our smart thinkers' 😉
/Hugo - Is very smart, but not thinking
Could you guys please make faster ? I wanna built that amp.
Ok, just 😉 😉 😉
This makes me nervous, may be I gonna look for the right transformer and try different setups.
Ok, just 😉 😉 😉
This makes me nervous, may be I gonna look for the right transformer and try different setups.
Bernhard said:
Ok, found one big mistake: I connected the collectors of both transistor pairs together. This means I shorted the outputs.
I have 2 30V/3A lab power supply's. No need for a trafo right now.
/Hugo - Looking for isolators now (as fast as he can)
Progress 5
Now the Monolithic SuperSymmetry amp is fully ready for the experiment. 🙂
I have one dummy load of 8-ohm 80W (10-ohm||40-ohm), one oscillator (sine and square curves) and one oscilloscope. Honestly, however, I have never used these tools before. Therefore, your help or advice would much appreciate. First of all, what should I check...? (I am reading Pass articles, The 40W Power Amplifier and The MOSFET Citation 12, to get some ideas.)
JH
PS. I do not recommend you to make the amp open to unprotected space as shown in the photo. It could be a dangerous lethal weapon.
Now the Monolithic SuperSymmetry amp is fully ready for the experiment. 🙂
I have one dummy load of 8-ohm 80W (10-ohm||40-ohm), one oscillator (sine and square curves) and one oscilloscope. Honestly, however, I have never used these tools before. Therefore, your help or advice would much appreciate. First of all, what should I check...? (I am reading Pass articles, The 40W Power Amplifier and The MOSFET Citation 12, to get some ideas.)
JH
PS. I do not recommend you to make the amp open to unprotected space as shown in the photo. It could be a dangerous lethal weapon.
Attachments
As i know, the 741 is the oldest op-amp used in audio (I think it dates from 70's).There are many newer op-amps that are better. If you can, try to order some samples from Burr-Brown (Texas Instruments) or Analog Devices (I don't know if the sample program works in Korea ).
jh6you said:
Nice, nice🙂
I try the setup with no load at the outputs, no sine wave at the inputs. I slowly increase the voltage with a variac. (don’t know if you have one) Then I look if no smoke or flares comes out and try to measure the voltages. If all is well, I connect the sine generator,
(1Khz 0.5V will do) and check if I can trace the signal throughout the circuit with the scope.
Then I connect the load and go on with the measurements.
/Hugo - also drinks a lot of coffee - or is it a cup of tea on the picture?
Measurement 1
PSU works fine. Both channels are measured. Transformer is EI type of 300VA with 2x12V 50/60Hz. I hear no transformer noise--surprisingly good quality compared with its price of about USD 25. Bridge diodes are of 25A 400V. Between the transformer secondary output and the bridge diodes, I arranged 0.3R 5W resistors. Four PSU electrolytic capacitors are of 22,000uF 35V 85degC.
JH
PS. Thanks for the info, Rookie. Since the 741 is already soldered into, I will see what happens from it. Later, I might have chance to replace it with others.
PSU works fine. Both channels are measured. Transformer is EI type of 300VA with 2x12V 50/60Hz. I hear no transformer noise--surprisingly good quality compared with its price of about USD 25. Bridge diodes are of 25A 400V. Between the transformer secondary output and the bridge diodes, I arranged 0.3R 5W resistors. Four PSU electrolytic capacitors are of 22,000uF 35V 85degC.
JH
PS. Thanks for the info, Rookie. Since the 741 is already soldered into, I will see what happens from it. Later, I might have chance to replace it with others.
Attachments
I think you should go on with the 741.
Just to see what happens with the circuit.
Mine seems to work now, but not good at all.
Anyway, the input square wave is visible on the output with very low distortion, but almost no gain. And a lot of heat!!😉
/Hugo - wonders why those Pass circuits always produce so much heat.
Just to see what happens with the circuit.
Mine seems to work now, but not good at all.
Anyway, the input square wave is visible on the output with very low distortion, but almost no gain. And a lot of heat!!😉
/Hugo - wonders why those Pass circuits always produce so much heat.
Netlist said:
I will.
By the way, since LM6181 has high supply current (typical 7.5mA, max 10mA) and output current, I would try the reduced R5, R6, R7 and R8 from 2K to about 100. I presume this would reduce the idling current across the power transistors and accordingly reduce the heat.
JH
jh6you said:
IT WORKS!!!!!
I will let you know how the (semi final) setup is done in a moment.
If you succeed we will have 2 different new amps born in 1 day.
/Hugo - very happy now! Donald Fagen playing on a Mono Monolithic SuperSymmetry( tm) amp with Current Feedback (MMSCF)
So, here's what I’ve done:
Replaced R5, R6, R7, R8 with trimpots.
All are set between 120-150ohm. (Thanks JH)
R13, R14, R15, R16 are now 0.94ohm (2 x 0.47 in series)
Connected the negative input to ground, as well as 1 speaker terminal. (R10 & C2 are out of duty now)
Without the speaker terminal connected to ground the gain is very low.
(don't know if we still have the originally intended amp here?)
Removed the 2 100ohm resistors to ground at the outputs.
Still got 0.4V DC over the output terminals (with or without resistors).That's the lowest value I can get for the moment.
For 2VAC sinewave in I get 9,2VAC Out at 8ohm before clipping.
The total current draw is about 1.8A.
The first impression when listening is good, but not as good as the ZenV4. The ZenV4 really spits out the music. A feeling I haven't with this amp. Still very detailed, but with less deep bass then ZenV4.
All feedback highly appreciated.
Thanks everyone, and of course, once again, Mr. Pass.
/Hugo - still listening to Mr. Donald 🙂
Replaced R5, R6, R7, R8 with trimpots.
All are set between 120-150ohm. (Thanks JH)
R13, R14, R15, R16 are now 0.94ohm (2 x 0.47 in series)
Connected the negative input to ground, as well as 1 speaker terminal. (R10 & C2 are out of duty now)
Without the speaker terminal connected to ground the gain is very low.
(don't know if we still have the originally intended amp here?)Removed the 2 100ohm resistors to ground at the outputs.
Still got 0.4V DC over the output terminals (with or without resistors).That's the lowest value I can get for the moment.
For 2VAC sinewave in I get 9,2VAC Out at 8ohm before clipping.
The total current draw is about 1.8A.
The first impression when listening is good, but not as good as the ZenV4. The ZenV4 really spits out the music. A feeling I haven't with this amp. Still very detailed, but with less deep bass then ZenV4.
All feedback highly appreciated.
Thanks everyone, and of course, once again, Mr. Pass.
/Hugo - still listening to Mr. Donald 🙂
Attachments
Very cool, congratulations!
I would try some Darlingtons or Mosfets next, to get the
current up.
I would try some Darlingtons or Mosfets next, to get the
current up.
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