Emprit Amplifier

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#22
dedegogo said:
Hi Bimo, could you also share the models?
Click to expand...

.MODEL KSA992 pnp ( IS=5.7544E-14 BF=348.1 NF=1 BR=3.62 NR=0.95 ISE=5.7544f NE=1.5 ISC=1.8378E-14 NC=1 VAF=144 VAR=16.68 IKF=0.298 IKR=0.0525 RB=140 RBM=16.084 IRB=1.4125m RE=0.38 RC=0.47 CJE=2.3093E-11 VJE=0.855 MJE=0.4104 FC=0.5 CJC=8.9251p VJC=0.5 MJC=0.3497 XTB=1.2849 EG=1.1603 XTI=3 XCJC=0.3062 )
.MODEL KSC1845_k npn IS=1.075431E-13 BF=600.7 NF=1 BR=13.565 NR=1 ISE=1.98107E-13 NE=2 ISC=1.8378E-11 NC=1.5 VAF=82.803 VAR=20.6691 IKF=0.596 IKR=0.0190546 RB=157 RBM=12.092 IRB=1.258925E-6 RE=1.5 RC=0 CJE=2.057447E-11 VJE=0.7300286 MJE=0.3619943 FC=0.5 CJC=4.525739E-12 VJC=0.5 MJC=0.3659045 XTB=1.7281 EG=1.1809 XTI=3 TF=3.14E-11 Vceo=120 Icrating=50m mfg=Fairchild
.MODEL BD139_Cordell npn IS=150f BF=260 VAF=99 IKF=1.2 ISE=70f NE=1.2 NF=1.0 RB=5 RC=0.01 RE=0.08 CJE=293p MJE=0.33 VJE=0.67 CJC=49p MJC=0.39 VJC=0.52 FC=0.5 TF=585p XTF=10000 VTF=35 ITF=20 TR=10n BR=78 IKR=0.14 EG=1.21 XTB=1.14 XTI=3 NC=1.45 ISC=19p NR=1.0 VAR=7.5 IRB=0.03 RBM=0.001 XCJC=0.53 mfg=CA041311
.MODEL BD140_Cordell pnp IS=120f BF=113 VAF=140 IKF=1.5 ISE=1000f NE=1.5 NF=1 RB=5 RC=0.01 RE=0.1 CJE=220p MJE=0.35 VJE=0.7 CJC=68p MJC=0.35 VJC=0.6 XCJC=0.5 FC=0.5 TF=320p XTF=10000 VTF=35 ITF=20 TR=100n BR=25 IKR=0.1 EG=1.2 XTB=1.5 XTI=3 NC=1.4 ISC=7p NR=1.0 VAR=8 IRB=0.01 RBM=0.01 mfg=CA041311
.MODEL 2SC5200_k npn IS=300f BF=100 NF=1 BR=8.025 NR=1 ISE=200p IKF=18 NE=2.0 ISC=2.01764E-10 NC=1.5 VAF=400 VAR=100 IKR=1.39087 RB=1.1 RBM=0.00011 IRB=1.51189E-6 RE=0.0032 RC=0.0183 CJE=6.1n VJE=0.711 MJE=0.304 FC=0.5 CJC=380p VJC=0.84 MJC=0.25 TF=5n TR=3.342E-7 XTB=1.72 EG=0.78 XTI=3
.MODEL 2SA1943_k pnp IS=650f BF=100 NF=1 BR=8.805 NR=1 ISE=10p IKF=15 NE=2.0 ISC=2.01764E-10 NC=1.5 VAF=600 VAR=100 IKR=1.39087 RB=1.1 RBM=0.00011 IRB=1.51189n RE=0.0061 RC=0.0103 CJE=5.26n VJE=0.711 MJE=0.304 FC=0.5 CJC=750p VJC=0.84 MJC=0.25 TF=5n TR=3.342E-7 XTB=2.28 EG=0.81 XTI=3

.model 1N4148C D(Is=5n Rs=1.0 N=1.9 Cjo=4p M=.4 tt=20n Iave=200m Vpk=75 mfg=CA112410)
.MODEL LedBLUE D (IS=93.2P RS=42M N=7.47 BV=5 IBV=10U CJO=2.97P VJ=.75 M=.333 TT=4.32U Iave=40m Vpk=5 type=LED)
 
#24
AKSA said:
Hi Rio,

My suggestions were to improve the HF performance by increasing drive and interemitter cap of the drivers. I should have suggesting 2SC4793/2SA1937 Toshiba drivers which I've always found outstanding transistors, but they may be tricky to buy in Indonesia.

Hugh
Click to expand...

Those transistors is quite easy in Solo city (I believe you're familiar with my hometown, Solo), but i found 2SC5171 is cheaper. Rp.15000 vs Rp. 10000.
I'd try to swap with 2SC5171 tomorrow. Thanks Pak Dean.

Salam,
Rio
 
#26
Hello bimo.I tried one of your preamps.i really like it but i have a question.For transistors Q1,Q3,Q5,Q6,Q7 you specify 2SC1845 and 2SA992. I have used 2N5401 and 2N5551 always paying attention to pinout compatibility.I also have access to BC550C and BC560C. which ones do you think sound better?
 

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#27
maouna said:
Hello bimo.I tried one of your preamps.i really like it but i have a question.For transistors Q1,Q3,Q5,Q6,Q7 you specify 2SC1845 and 2SA992. I have used 2N5401 and 2N5551 always paying attention to pinout compatibility.I also have access to BC550C and BC560C. which ones do you think sound better?
Click to expand...

Q1, Q2, Q4, and Q5, i prefer BC550C and BC560C.
Q3, Q6, and Q7, i prefer 2N5551 and 2N5401.
 
#33
Thank you bimo.This is the pcb i made for your preamp.I really enjoy it.

I have also built this retro amp with CFP output from this thread Bigun's TGM8 with Single Supply but i have some concerns about values of capacitors C6,C7 and resistors R16-R17,R21-R22

I have seen in other threads that you can make modifications to designs which result in good sound.Can you suggest any mod to this amp?.I am also attaching the LTSpice file.
 

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#36
Bimo,

Sorry for slow reply.
Yes, you can leave the drivers unsinked, a BD139/140 is fine but generally I find the faster devices, the C4793/A1837 are the best (30MHz). There may be Japanese version which are faster than the 39/140, as the other Indonesian poster mentioned in Solo.
You need a bit more current through the drivers to move charge into and out of the output bases. They are a large die, and high input capacitance, like a mosfet. This improves the top end hugely, as long as the cap is polystyrene with low dielectric.

YTH

Hugh
 
#38
bimo said:
But high frequency is not as good as I tough. A friend choose NJW0281/NJW0302 for output transistors and said the high frequency is slightly better.
Click to expand...
Perceived HF is not well correlated with electrical HF response. For a start I'd make C9 a lot larger, at least 47pF and maybe as high as 100pF to keep the thing stable. Best to use polystyrene.
Grounding arrangements and PSU (not shown in your schematic) will also have a sonic effect.
Lot's of things will effect the sound but these two areas are good places to start.
 
#39
traderbam said:
Perceived HF is not well correlated with electrical HF response. For a start I'd make C9 a lot larger, at least 47pF and maybe as high as 100pF to keep the thing stable. Best to use polystyrene.
Grounding arrangements and PSU (not shown in your schematic) will also have a sonic effect.
Lot's of things will effect the sound but these two areas are good places to start.
Click to expand...

This amplifier is stable. Enough phase margin and gain margin.

I have design an amplifier with much better of high frequency quality than this amplifier. The amplifier using "blameless topology" (according Mr. Douglas Self) with TMC compensation. One of the best sound engineer in my country, compared it with his U$2000 amplifier said my amplifier slightly better 😎 although my amplifier is much cheaper. So, if I said the high frequency quality is not good enough, it compare at least with U$2000 amplifier.
 
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