Any thoughts about this?

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xXBrunoXx

Member
Joined 2016
#1
Hello everyone, if you have a little bit of time come take a look at this amp I recently build ( only in simulation so far ) and maybe tell me your toughts, improvements , what you think.

Also attached the .asc, if someone wants to simulate it, also for THD , im not sure I did it correctly.
BD135-136 are gonna be 140/139 in reality.
 

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#2
Did some THD simulations , not sure they are 100% accurate ( I did change the simulation speed based on the signal freq , used the spice directives found here somewhere on the forum, Im sorry can't remember exactly where.)



4v output



############ 1khz - 4ohm ############



N-Period=1

Fourier components of V(output)

DC component:-0.00274391



Harmonic Frequency Fourier Normalized Phase Normalized

Number [Hz] Component Component [degree] Phase [deg]

1 1.000e+03 4.193e+00 1.000e+00 -0.23° 0.00°

2 2.000e+03 1.533e-05 3.657e-06 -179.59° -179.36°

3 3.000e+03 4.166e-05 9.936e-06 -97.16° -96.93°

4 4.000e+03 3.746e-06 8.934e-07 -179.07° -178.84°

5 5.000e+03 1.974e-05 4.708e-06 -98.97° -98.74°

6 6.000e+03 1.835e-06 4.376e-07 -176.14° -175.91°

7 7.000e+03 9.697e-06 2.313e-06 -102.57° -102.34°

8 8.000e+03 1.058e-06 2.524e-07 -172.54° -172.31°

9 9.000e+03 4.962e-06 1.184e-06 -107.67° -107.44°

Total Harmonic Distortion: 0.001192%(0.011659%)





N-Period=1

Fourier components of V(input)

DC component:2.62125e-009



Harmonic Frequency Fourier Normalized Phase Normalized

Number [Hz] Component Component [degree] Phase [deg]

1 1.000e+03 1.999e-01 1.000e+00 0.00° 0.00°

2 2.000e+03 5.825e-09 2.913e-08 63.63° 63.63°

3 3.000e+03 6.124e-09 3.063e-08 58.75° 58.75°

4 4.000e+03 6.742e-09 3.372e-08 54.13° 54.13°

5 5.000e+03 7.030e-09 3.516e-08 44.70° 44.70°

6 6.000e+03 7.595e-09 3.799e-08 39.66° 39.66°

7 7.000e+03 9.667e-09 4.835e-08 32.47° 32.47°

8 8.000e+03 1.058e-08 5.293e-08 24.35° 24.35°

9 9.000e+03 1.066e-08 5.334e-08 29.00° 29.00°

Total Harmonic Distortion: 0.000012%(0.011598%)



########################

############ 1khz - 8ohm ############



N-Period=1

Fourier components of V(output)

DC component:-0.00274452



Harmonic Frequency Fourier Normalized Phase Normalized

Number [Hz] Component Component [degree] Phase [deg]

1 1.000e+03 4.193e+00 1.000e+00 -0.13° 0.00°

2 2.000e+03 1.038e-05 2.474e-06 -175.71° -175.58°

3 3.000e+03 1.628e-05 3.882e-06 -106.63° -106.50°

4 4.000e+03 2.947e-06 7.028e-07 -166.88° -166.75°

5 5.000e+03 5.372e-06 1.281e-06 -120.95° -120.82°

6 6.000e+03 2.034e-06 4.850e-07 -161.13° -160.99°

7 7.000e+03 2.594e-06 6.185e-07 -137.79° -137.65°

8 8.000e+03 1.623e-06 3.870e-07 -157.01° -156.87°

9 9.000e+03 1.696e-06 4.045e-07 -147.98° -147.85°

Total Harmonic Distortion: 0.000492%(0.014389%)





N-Period=1

Fourier components of V(input)

DC component:-3.01809e-009



Harmonic Frequency Fourier Normalized Phase Normalized

Number [Hz] Component Component [degree] Phase [deg]

1 1.000e+03 1.999e-01 1.000e+00 -0.00° 0.00°

2 2.000e+03 5.248e-09 2.625e-08 -99.79° -99.79°

3 3.000e+03 5.266e-09 2.634e-08 -94.93° -94.93°

4 4.000e+03 5.335e-09 2.669e-08 -103.14° -103.14°

5 5.000e+03 5.481e-09 2.741e-08 -111.35° -111.35°

6 6.000e+03 4.546e-09 2.274e-08 -110.80° -110.80°

7 7.000e+03 3.674e-09 1.838e-08 -114.38° -114.38°

8 8.000e+03 4.061e-09 2.031e-08 -118.69° -118.69°

9 9.000e+03 3.795e-09 1.898e-08 -128.41° -128.41°

Total Harmonic Distortion: 0.000007%(0.014380%)



#####################################

############# 10khz - 4ohm ############



N-Period=1

Fourier components of V(output)

DC component:0.00268343



Harmonic Frequency Fourier Normalized Phase Normalized

Number [Hz] Component Component [degree] Phase [deg]

1 1.000e+04 4.193e+00 1.000e+00 -3.16° 0.00°

2 2.000e+04 8.094e-05 1.930e-05 164.35° 167.50°

3 3.000e+04 4.170e-04 9.944e-05 -98.55° -95.40°

4 4.000e+04 8.811e-06 2.101e-06 84.34° 87.50°

5 5.000e+04 1.978e-04 4.717e-05 -104.19° -101.03°

6 6.000e+04 8.203e-06 1.956e-06 20.68° 23.83°

7 7.000e+04 9.654e-05 2.302e-05 -109.35° -106.19°

8 8.000e+04 7.618e-06 1.817e-06 -4.83° -1.67°

9 9.000e+04 4.839e-05 1.154e-05 -114.06° -110.90°

Total Harmonic Distortion: 0.011472%(0.016810%)





N-Period=1

Fourier components of V(input)

DC component:7.76781e-010



Harmonic Frequency Fourier Normalized Phase Normalized

Number [Hz] Component Component [degree] Phase [deg]

1 1.000e+04 1.999e-01 1.000e+00 0.00° 0.00°

2 2.000e+04 2.097e-09 1.049e-08 35.83° 35.83°

3 3.000e+04 3.830e-09 1.916e-08 12.89° 12.89°

4 4.000e+04 3.826e-09 1.913e-08 11.57° 11.57°

5 5.000e+04 4.110e-09 2.056e-08 24.15° 24.15°

6 6.000e+04 6.128e-09 3.065e-08 14.75° 14.75°

7 7.000e+04 7.099e-09 3.550e-08 10.28° 10.28°

8 8.000e+04 6.598e-09 3.300e-08 8.78° 8.78°

9 9.000e+04 7.913e-09 3.958e-08 11.38° 11.38°

Total Harmonic Distortion: 0.000008%(0.012247%)





#######################################

################ 10khz - 8ohm ###########



N-Period=1

Fourier components of V(output)

DC component:0.00268448



Harmonic Frequency Fourier Normalized Phase Normalized

Number [Hz] Component Component [degree] Phase [deg]

1 1.000e+04 4.196e+00 1.000e+00 -2.23° 0.00°

2 2.000e+04 3.238e-05 7.719e-06 162.74° 164.97°

3 3.000e+04 1.532e-04 3.651e-05 -87.35° -85.11°

4 4.000e+04 7.436e-06 1.772e-06 19.88° 22.11°

5 5.000e+04 4.222e-05 1.006e-05 -85.35° -83.12°

6 6.000e+04 4.469e-06 1.065e-06 0.97° 3.20°

7 7.000e+04 1.259e-05 3.001e-06 -82.45° -80.22°

8 8.000e+04 2.348e-06 5.596e-07 -23.18° -20.95°

9 9.000e+04 4.610e-06 1.099e-06 -79.71° -77.48°

Total Harmonic Distortion: 0.003884%(0.013722%)





N-Period=1

Fourier components of V(input)

DC component:3.40916e-009



Harmonic Frequency Fourier Normalized Phase Normalized

Number [Hz] Component Component [degree] Phase [deg]

1 1.000e+04 1.999e-01 1.000e+00 0.00° 0.00°

2 2.000e+04 5.319e-09 2.660e-08 80.51° 80.51°

3 3.000e+04 5.994e-09 2.998e-08 82.36° 82.36°

4 4.000e+04 6.716e-09 3.359e-08 72.72° 72.72°

5 5.000e+04 7.378e-09 3.690e-08 74.26° 74.26°

6 6.000e+04 6.346e-09 3.174e-08 81.75° 81.75°

7 7.000e+04 5.828e-09 2.915e-08 68.53° 68.53°

8 8.000e+04 6.717e-09 3.359e-08 63.00° 63.00°

9 9.000e+04 6.182e-09 3.092e-08 67.57° 67.57°

Total Harmonic Distortion: 0.000009%(0.013156%)



######################################
 
#7
3rd party models here: ( standard.bjt )

.MODEL BD135P NPN(IS=4.815E-14 ISE=1.389E-14 ISC=1.295E-13 XTI=3 BF=124.2 BR=13.26 IKF=1.6 IKR=0.29 XTB=1.5 VAF=222 VAR=81.4 VJE=0.7313 VJC=0.5642 RE=0.165 RC=0.096 RB=0.5 RBM=0.5 IRB=1E-06 CJE=1.243E-10 CJC=3.04E-11 XCJC=0.15 FC=0.9359 NF=0.9897 NR=0.9895 NE=1.6 NC=1.183 MJE=0.3476 MJC=0.4371 TF=6.478E-10 TR=1m2 ITF=3.35 VTF=2.648 XTF=29 EG=1.11 VCEO=45 ICRATING=1.5 MFG=PHILIPS)
.MODEL BD136P PNP(IS=7.401E-14 ISE=4.104E-16 ISC=1.290E-14 XTI=3 BF=336.5 BR=13.91 IKF=0.1689 IKR=9.888E-2 XTB=1.5 VAF=224.7 VAR=30.00 VJE=0.6900 VJC=0.6431 RE=0.208 RC=5.526E-02 RB=0.500 RBM=0.500 IRB=1E-06 CJE=1.066E-10 CJC=5.234E-11 XCJC=0.440 FC=0.990 NF=0.9938 NR=0.9913 NE=1.054 NC=1.100 MJE=0.3676 MJC=0.4436 TF=2.578E-10 TR=1E-25 ITF=1.3040 VTF=2.366 XTF=13.56 EG=1.11 VCEO=45 ICRATING=1.5 MFG=PHILIPS)
.model BC546B NPN(IS=2.39E-14 NF=1.008 ISE=3.55E-15 NE=1.541 BF=294.3 IKF=0.1357 VAF=63.2 NR=1.004 ISC=6.27E-14 NC=1.243 BR=7.946 IKR=0.1144 VAR=25.9 RB=1 IRB=1.00E-06 RBM=1 RE=0.4683 RC=0.85 XTB=0 EG=1.11 XTI=3 CJE=1.36E-11 VJE=0.65 MJE=0.3279 TF=4.39E-10 XTF=120 VTF=2.643 ITF=0.7495 PTF=0 CJC=3.73E-12 VJC=0.3997 MJC=0.2955 XCJC=0.6193 TR=1.00E-32 CJS=0 VJS=0.75 MJS=0.333 FC=0.9579 Vceo=65 Icrating=100m mfg=NXP)
.model BC556B PNP(IS=3.83E-14 NF=1.008 ISE=1.22E-14 NE=1.528 BF=344.4 IKF=0.08039 VAF=21.11 NR=1.005 ISC=2.85E-13 NC=1.28 BR=14.84 IKR=0.047 VAR=32.02 RB=1 IRB=1.00E-06 RBM=1 RE=0.6202 RC=0.5713 XTB=0 EG=1.11 XTI=3 CJE=1.23E-11 VJE=0.6106 MJE=0.378 TF=5.60E-10 XTF=3.414 VTF=5.23 ITF=0.1483 PTF=0 CJC=1.08E-11 VJC=0.1022 MJC=0.3563 XCJC=0.6288 TR=1.00E-32 CJS=0 VJS=0.75 MJS=0.333 FC=0.8027 Vceo=65 Icrating=100m mfg=NXP)
.MODEL mjL4281a npn IS=9.94641e-11 BF=191.836 NF=1.11524 VAF=24.7449 IKF=5.75399 ISE=6.4507p NE=3.39407 BR=4.35182 NR=1.1764 VAR=4.25175 IKR=6.61715 ISC=3.89999e-13 NC=3.99 RB=4.37715 IRB=0.00966879 RBM=1f RE=0.00608852 RC=0.0434329 XTB=0.661303 XTI=1.00355 EG=1.05 CJE=9.04931n VJE=0.99 MJE=0.844324 TF=1.6665n XTF=1000 VTF=17023.9 ITF=152.472 CJC=8.80163e-10 VJC=0.942802 MJC=0.23183 FC=0.8 TR=1e-07 Vceo=350 Icrating=15 mfg=ON_Semi
.MODEL mjL4302a pnp IS=8.52181e-11 BF=505.26 NF=1.14612 VAF=15.6851 IKF=2.86699 ISE=3.82966n NE=2.09196 BR=50.526 NR=1.18655 VAR=1.41005 IKR=9.95655 ISC=4.51392e-11 NC=1.28018 RB=98.7069 IRB=4.30971e-06 RBM=0.110355 RE=0.00577433 RC=0.0288716 XTB=0.00344757 XTI=0.00948369 EG=1.05 CJE=1.42406e-08 VJE=0.99 MJE=0.23 TF=2.22092e-09 XTF=15.6824 VTF=100000 ITF=63.5289 CJC=5.00002e-10 VJC=0.893622 MJC=2.3e-21 FC=0.1 TR=1e-07 Vceo=350 Icrating=15 mfg=ON_Semi
 
#10
Kay Pirinha said:
What exactly do resistors R23 and R26 do? What does the simulation say if you'd omit them?

Best regards!
Click to expand...
It is a EF output stage, darlington configuration, and base emitter resistors would " make the darlington nicer" !?.
Im not sure maybe it also makes a close loop gain in the output stage, im not sure. I " inspired " myself from this Pioneer amplifier output stage.
Pioneera702r.JPG
Initially I used a CFP output stage that oscillated at 10 mhz or so ( I couldnt fix it , even with dom capacitors ranging from 50-200p, output transistors base collector caps 10-30p nothing. , and I switched to darlington. no oscillations now.
 
#11
Mooly said:
You need to provide a simulation that will click and run and that means including the 3rd party models you have used.
Click to expand...
Im not sure how could I share them, maybe like this ?.
3rd party models here: ( standard.bjt )

.MODEL BD135P NPN(IS=4.815E-14 ISE=1.389E-14 ISC=1.295E-13 XTI=3 BF=124.2 BR=13.26 IKF=1.6 IKR=0.29 XTB=1.5 VAF=222 VAR=81.4 VJE=0.7313 VJC=0.5642 RE=0.165 RC=0.096 RB=0.5 RBM=0.5 IRB=1E-06 CJE=1.243E-10 CJC=3.04E-11 XCJC=0.15 FC=0.9359 NF=0.9897 NR=0.9895 NE=1.6 NC=1.183 MJE=0.3476 MJC=0.4371 TF=6.478E-10 TR=1m2 ITF=3.35 VTF=2.648 XTF=29 EG=1.11 VCEO=45 ICRATING=1.5 MFG=PHILIPS)
.MODEL BD136P PNP(IS=7.401E-14 ISE=4.104E-16 ISC=1.290E-14 XTI=3 BF=336.5 BR=13.91 IKF=0.1689 IKR=9.888E-2 XTB=1.5 VAF=224.7 VAR=30.00 VJE=0.6900 VJC=0.6431 RE=0.208 RC=5.526E-02 RB=0.500 RBM=0.500 IRB=1E-06 CJE=1.066E-10 CJC=5.234E-11 XCJC=0.440 FC=0.990 NF=0.9938 NR=0.9913 NE=1.054 NC=1.100 MJE=0.3676 MJC=0.4436 TF=2.578E-10 TR=1E-25 ITF=1.3040 VTF=2.366 XTF=13.56 EG=1.11 VCEO=45 ICRATING=1.5 MFG=PHILIPS)
.model BC546B NPN(IS=2.39E-14 NF=1.008 ISE=3.55E-15 NE=1.541 BF=294.3 IKF=0.1357 VAF=63.2 NR=1.004 ISC=6.27E-14 NC=1.243 BR=7.946 IKR=0.1144 VAR=25.9 RB=1 IRB=1.00E-06 RBM=1 RE=0.4683 RC=0.85 XTB=0 EG=1.11 XTI=3 CJE=1.36E-11 VJE=0.65 MJE=0.3279 TF=4.39E-10 XTF=120 VTF=2.643 ITF=0.7495 PTF=0 CJC=3.73E-12 VJC=0.3997 MJC=0.2955 XCJC=0.6193 TR=1.00E-32 CJS=0 VJS=0.75 MJS=0.333 FC=0.9579 Vceo=65 Icrating=100m mfg=NXP)
.model BC556B PNP(IS=3.83E-14 NF=1.008 ISE=1.22E-14 NE=1.528 BF=344.4 IKF=0.08039 VAF=21.11 NR=1.005 ISC=2.85E-13 NC=1.28 BR=14.84 IKR=0.047 VAR=32.02 RB=1 IRB=1.00E-06 RBM=1 RE=0.6202 RC=0.5713 XTB=0 EG=1.11 XTI=3 CJE=1.23E-11 VJE=0.6106 MJE=0.378 TF=5.60E-10 XTF=3.414 VTF=5.23 ITF=0.1483 PTF=0 CJC=1.08E-11 VJC=0.1022 MJC=0.3563 XCJC=0.6288 TR=1.00E-32 CJS=0 VJS=0.75 MJS=0.333 FC=0.8027 Vceo=65 Icrating=100m mfg=NXP)
.MODEL mjL4281a npn IS=9.94641e-11 BF=191.836 NF=1.11524 VAF=24.7449 IKF=5.75399 ISE=6.4507p NE=3.39407 BR=4.35182 NR=1.1764 VAR=4.25175 IKR=6.61715 ISC=3.89999e-13 NC=3.99 RB=4.37715 IRB=0.00966879 RBM=1f RE=0.00608852 RC=0.0434329 XTB=0.661303 XTI=1.00355 EG=1.05 CJE=9.04931n VJE=0.99 MJE=0.844324 TF=1.6665n XTF=1000 VTF=17023.9 ITF=152.472 CJC=8.80163e-10 VJC=0.942802 MJC=0.23183 FC=0.8 TR=1e-07 Vceo=350 Icrating=15 mfg=ON_Semi
.MODEL mjL4302a pnp IS=8.52181e-11 BF=505.26 NF=1.14612 VAF=15.6851 IKF=2.86699 ISE=3.82966n NE=2.09196 BR=50.526 NR=1.18655 VAR=1.41005 IKR=9.95655 ISC=4.51392e-11 NC=1.28018 RB=98.7069 IRB=4.30971e-06 RBM=0.110355 RE=0.00577433 RC=0.0288716 XTB=0.00344757 XTI=0.00948369 EG=1.05 CJE=1.42406e-08 VJE=0.99 MJE=0.23 TF=2.22092e-09 XTF=15.6824 VTF=100000 ITF=63.5289 CJC=5.00002e-10 VJC=0.893622 MJC=2.3e-21 FC=0.1 TR=1e-07 Vceo=350 Icrating=15 mfg=ON_Semi
 
#12
TNT said:
Yes, one don't put a full stop efter a questionmark 🙂

//
Click to expand...
Im not really sure what you mean sir. but if it is because I asked for help and did not provide the models of transistors I used, I'm sorry , I did not think not everyone has BC546-556, BD139-140 in their LTSpice, and that even if , they would not mean they are the same models I used. 😊
 
#13
You should include the models with the .asc in a zip file, or place the models on the schematic, that is best.
Posting it here doesn´t make it run.
So this is not your design, you used something from someone else and changed it?
If you tell what you changed people may be more willing to reply.
What about R24 and R25 in your latest schem? Why two resistors is series, why not one R?

Jan
 
#14
That was just a reply to Kay Pirinha, tried without the r23 r26.
Yes makes no sense using two resistors , in the schematic you pointed out.

Except for the output stage shown from Pioneer a702r's I used ( emitter follower darlington output stage , nothing special, just with that weird resistors used , hoped someone would tell me why they used it like that . ) apart from that, the "design is mine ".

Started out with the LTP with constant current, current mirror, added EF VAS with constant current, cascode for the LTP , not really sure thats the best way you do it. made an CFP output stage that I didn't like , it oscillated . ended up using the darlington configuration , from Pioneer's amp. if that is copyright in some way , I'll delete it and the post no problem. I did not copy and modify its schematic, just copied its output stage to say so.

"You should include the models with the .asc in a zip file, or place the models on the schematic, that is best." Im not really sure how to do that.
 
#15
I would check the response to a small current step of the loop Q7-Q9 to see if it rings. If it does, a small capacitor from the base of Q7 to the negative rail, with or without a small series resistor, could fix that.

A decoupling capacitor across the VBE-multiplier could ensure it doesn't affect the stability of the overall loop.

A small change in the output filter could change it into a first-order series filter, as recommended by A. N. Thiele to reduce the sensitivity to RF signals picked up by the cable to the loudspeaker.
R31 = 8.2 ohm
R32 = 0 (short)
C13 = 33 nF

If you haven't done so yet, check start up, what happens during clipping and during recovery from clipping.

The current through Q13 will probably increase enormously during clipping to the negative rail. You could connect a resistor between its collector and ground with a small decoupling capacitor to the negative rail to keep it from going up in smoke.
 
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