JAT501 simulated using TINA TI and possible improvements

Member
Joined 2011
Paid Member
Removing paralleled output transistors actually makes it JAT501 with added one extra transistor (not counting ccs) and two pole compensation parts.
thd improved to 0.0014%
 

Attachments

  • sch-v2-not-par.PNG
    sch-v2-not-par.PNG
    32.1 KB · Views: 56
  • thd-v2-not par.PNG
    thd-v2-not par.PNG
    12.5 KB · Views: 52
  • jat501-improved-sch-v2-OPS-not paralelled.zip
    128 KB · Views: 40
Member
Joined 2011
Paid Member

Attachments

  • la90d.png
    la90d.png
    39.2 KB · Views: 39
Might be, there is few tricks
Keep the amplifier gain low.
Composite amplifier. Dual Diff , Complementary Cascode Vas
Or yes Power section is basically a follower. So if you can add feedback
/error correction around the output section.
even just Direct coupled or no capacitors in feedback.
Lots of ways to do it.

I can direct couple the simple amp I posted earlier
and set the gain very low. Which does it at 1 kHz
Distortion is -86 dB at that point
at high frequency, probably not, closer to .003%
which puts highest harmonic about -70 dB
Additional feedback / error comp would likely do it.

With preamp and tone filters and highpass for sub.
its rather pointless to care. distortion is meaningless
at that point. with CD playback or bluetooth stream.
blah.. distortion way above even a simple amp.



1686261680999.png
 
  • Like
Reactions: 1 user
Member
Joined 2011
Paid Member
Playing with two pole compensation values here.
Looks like C15 values are best in the range of 15p to 100p
C1 values 220p to 1000p
and resistor > 1k

As it is, 22p and 220p, the ratio of capacitors of 10 gives best distortion performance
 

Attachments

  • sch-v2-compensation.PNG
    sch-v2-compensation.PNG
    5.4 KB · Views: 48
Member
Joined 2011
Paid Member
With preamp and tone filters and highpass for sub.
its rather pointless to care. distortion is meaningless
at that point. with CD playback or bluetooth stream.
blah.. distortion way above even a simple amp.

bunch of DACs are 0.0001
but other than fun yeah, no point...
like having a 600hp car that sits most of the time in the garage, just fun lol ...
probably will not be able to hear the difference, but who knows...
 
Last edited:
Member
Joined 2011
Paid Member
And here is the version that accomplishes lowest THD
0.00073 into 8 ohm
0.00099 into 4 ohm

technically this is 801, with over 200W of power into 4 ohm
 

Attachments

  • sch-v2.PNG
    sch-v2.PNG
    32.3 KB · Views: 68
  • jat501-improved-sch-v2 (2).zip
    162.9 KB · Views: 46
  • thd-tpc-4ohm.PNG
    thd-tpc-4ohm.PNG
    12.2 KB · Views: 68
  • thd-tpc-8ohm.PNG
    thd-tpc-8ohm.PNG
    13.7 KB · Views: 66
  • Like
Reactions: 1 user
Hi. How to add models 2SC4793A, 2SA1837A or 2SD669A, 2SB649A, instead of KSC3503, KSA1318 (BD139, BD140) to this amplifier?
In the pre-output stage, it is necessary to put more powerful transistors so that there is no quasi-saturation.
 

Attachments

  • jat501-improved-sch-v22.zip
    152.6 KB · Views: 29
  • Jat5001.jpg
    Jat5001.jpg
    278.5 KB · Views: 63
  • Like
Reactions: 1 users
Hi. How to add models 2SC4793A, 2SA1837A or 2SD669A, 2SB649A, instead of KSC3503, KSA1318 (BD139, BD140) to this amplifier?

.MODEL 2SD669A NPN (BR=0.0116 CJE=1.5E-10 CJS=0 EG=1.11 FC=0.5 IKF=0.403 IKR=1 IRB=1E-06 IS=6.73F ISC=1E-13 ISE=1.14E-14 ITF=9.99 MJC=0.407 MJE=0.33 NC=2 NE=1.04 NF=0.8 NR=1.03 RB=4 RBM=0.761 RE=0.00255 TR=0 VAF=25.1 VAR=50 VJC=0.3 VJE=0.75 VTF=1E+06 XTB=3.82 XTI=2.5 BF=3.350000E+02 CJC=6.110000E-11 RC=5.550000E-01 TF=9.010000E-10 XTF=4.450000E+01)



.MODEL 2SB649A PNP (IS=293.5F BF=216 NF=1.0 VAF=40 IKF=1.5 ISE=101.1P NE=2.6797 BR=7 NR=1.0 VAR=20 IKR=0.05 ISC=1.345P NC=1.5558 RB=0.46 RBM=0.46 RE=5M RC=1.07 CJE=295.4P VJE=0.6977 MJE=0.5197 TF=0.8569N XTF=53.4 VTF=2.83 ITF=1.22 CJC=113.1P VJC=0.5466 MJC=0.5742 XCJC=0.5 TR=14.65N XTB=1.87 EG=1.11 XTI=3.0 FC=0.5)



.MODEL 2SC4793_E NPN IS=1.8E-09 NF=1.43 BF=146.38 VAF=273 IKF=2.6 NK=0.95 ISE=6.286997E-10 NE=2.223629 BR=4 NR=1 VAR=20 IKR=1.05 RE=0 RB=1.7 RC=1.25 CJE=5.96964E-10 VJE=1.1 MJE=0.5 CJC=5.78E-11 VJC=0.3 MJC=0.3 TF=1.22678E-09 FC=0.5 ITF=10 XTF=99.52253015 TR=983N



.MODEL 2SA1837_E PNP IS=2.39372559E-10 NF=1.304015937 BF=300 VAF=273 IKF=2.087725944 NK=0.94719458 ISE=1.46829699E-11 NE=1.526663542 BR=4 NR=1 VAR=20 IKR=1.05 RE=0 RB=1.8 RC=1.65 CJE=4.7407E-10 VJE=1.1 MJE=0.5 CJC=8.6700E-11 VJC=0.3 MJC=0.3 TF=1.642191E-09 FC=0.5 ITF=1.076260106 XTF=5.868994022 TR=1.38U
 
Member
Joined 2011
Paid Member
Doing a very simple model , and comically tossing in a diode
bias string LOL. This classic topology below will perform same results
or better, with tremendous reduction in parts count.
How did you get such low distortion?
I have put it together, but I can only manage 0.04
 

Attachments

  • sch.PNG
    sch.PNG
    24.4 KB · Views: 54
  • hitachi_amp_v1.zip
    179.4 KB · Views: 34