Okay, but hey.. I'm voting for D3a, E180F, E280F and E810F types = plug and play 🙂
*edit- that quote button is missing, again - please excuse.
*edit- that quote button is missing, again - please excuse.
You simple cant reach this huge psrr with low Riv and high gain tube stage. And this low distortion, and desirable harmonic order
.. hybrid like that because allows tube rectifier when the power transformer does not have a center-tap.
6AK5 is not bad. it is we could say linear for low level signals. Not much difference with load line angle.
ThD is about 0.08 in caces of Ug = -1.5V Ua=125V Ia-16mA G2 (with 100R) and G3 connected to anode.
For higher input signals it is not linear. Linarity decreases and THD increases with input signal...
This 100mV input P-P is for Riv = 25 ohm
.
But Ri and Zout is high, almost forget the output transformer mode... Zout is about 2850 with 12K load. Probably more than 80Hy, needed for good LF response...
And there is a spice model
.
ThD is about 0.08 in caces of Ug = -1.5V Ua=125V Ia-16mA G2 (with 100R) and G3 connected to anode.
For higher input signals it is not linear. Linarity decreases and THD increases with input signal...
This 100mV input P-P is for Riv = 25 ohm
.
But Ri and Zout is high, almost forget the output transformer mode... Zout is about 2850 with 12K load. Probably more than 80Hy, needed for good LF response...
And there is a spice model
.
Code:
**********************************************
* Created on 09/14/2024 11:37 using paint_kit.jar 3.1
* www.dmitrynizh.com/tubeparams_image.htm
* Plate Curves image file: /Users/zoran/Desktop/Model_Paint_Tools/Graph/
* Data source link:
*----------------------------------------------------------------------------------
.SUBCKT TRIODE_ 1 2 3 ; Plate Grid Cathode
+ PARAMS: CCG=4.6P CGP=1P CCP=3.25P RGI=2000
+ MU=31.08 KG1=555 KP=152 KVB=300 VCT=0.2 EX=1.456
* Vp_MAX=300 Ip_MAX=28 Vg_step=1 Vg_start=1 Vg_count=10
* Rp=12000 Vg_ac=0.1 P_max=3.2 Vg_qui=-1.5 Vp_qui=126
* X_MIN=68 Y_MIN=57 X_SIZE=912 Y_SIZE=636 FSZ_X=1757 FSZ_Y=789 XYGrid=true
* showLoadLine=y showIp=y isDHT=n isPP=n isAsymPP=n showDissipLimit=y
* showIg1=n gridLevel2=n isInputSnapped=n
* XYProjections=y harmonicPlot=y dissipPlot=y
*----------------------------------------------------------------------------------
E1 7 0 VALUE={V(1,3)/KP*LOG(1+EXP(KP*(1/MU+(VCT+V(2,3))/SQRT(KVB+V(1,3)*V(1,3)))))}
RE1 7 0 1G ; TO AVOID FLOATING NODES
G1 1 3 VALUE={(PWR(V(7),EX)+PWRS(V(7),EX))/KG1}
RCP 1 3 1G ; TO AVOID FLOATING NODES
C1 2 3 {CCG} ; CATHODE-GRID
C2 2 1 {CGP} ; GRID=PLATE
C3 1 3 {CCP} ; CATHODE-PLATE
D3 5 3 DX ; POSITIVE GRID CURRENT
R1 2 5 {RGI} ; POSITIVE GRID CURRENT
.MODEL DX D(IS=1N RS=1 CJO=10PF TT=1N)
.ENDS
*$
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Why bias at -1.5V? - your gonna need a cathode resistor and a bypass cap if you want to keep Rp under wraps, unless you hybrid mu out .. but why?
-2mADC through I/V resistor at 27 -39 ohm ..
Check out -0.5V bias at 15mA, horizontal load-line.
It's good for the required swing.
-2mADC through I/V resistor at 27 -39 ohm ..
Check out -0.5V bias at 15mA, horizontal load-line.
It's good for the required swing.
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To get the higher Anode voltage as we can. But these 125 Va is still low...
Tube is voltage device not current...
And to have chance to but Battery in cathode (1.5V 1.2V)
Also slightly better hum response it will be with larger I-UgI value...
.
Yup, i described a trick to do it in the 4 layers I showed few pages ago, in order to show to the 2 outputs a correct ref decoupling layer w/o else current crossings or polluted ref plane. But the EMC/EMI thing will be cleaner with 6 layers because no interruptions on some layers to make it feasible with 4 layers.
Whatever the good tubes, at the end the OT or the DC film cap take the the edge on the sound... No economy can be made here, and it is increasing a lot the cost. Maybe the cheapest feasibler could be tin foil film cap from Solen/SCR, IME at least. YMMV as the cost with some others good caps !
Regulation is irrelevant here.
The tube rectifier (if running on the same transformer) damps transformer ringing and switching noise.
One might instead take a bunch of resistors to simulate the resistive loading from the tube rectifier.
So say we use a 50VA (R-Core) transformer to power the whole TDA1541 we can load 20% as resistive load, so say 10VA.
Yes, of course we will burn up 10VA in heat, but the transformer will not unload and become a free-wheeling inductor when we are not having current peaks charging up PSU Capacitor at the peak of the waveform.
Equally, if make a true choke input, we get constant current draw.
double irrelevant?
Thor
This is the biggest snake oil out there. Quality of cap will influence the results, as not every cap is well made to show exemplary linearity with frequency (especially low). You do realise how many caps with opamp for example, your signal goes trough? (And the rest of the chain, and the chain the audio itself was recorded, and many many other discrete stages). Pick a good cap and all is well.
What snake oil ?
Yes i realise it and made and tweaked as much as you if not more. Experienced a lot here, so no lessons to receive from you, sorry. Free world, choose your choices. Let me mines w/o beliving you know it all. Hete incredible alu mid 100 hz to 2100 hz, Chord amp. If i tell you I can hear it not for the best and at the end it impact à lot too much, believe my words 😉 I am not the last here about expectations. And not biased as always checked by musiciens ears.
So guy's, who's gonna be the first to make and show a nice 4 layers pcb made of all those nice schematics given by Thor and Zoran , we had enought of words , now it's time to do , those who diy in the real world are waiting from you 😎
even if the future listening session maybe with some comparisons will be the most interesting
.
even if the future listening session maybe with some comparisons will be the most interesting
.
Thorsten, could you please explain exactly why the regulator is irrelevant?
I am failing to see how the switching noise will reach the audio output if not through the ps lines (because of insufficient ps rejection).
Yup, I have learned nothing, be it here or on the other thread. Ah yes, you like in every circuitries Nichicon KZ... No comment, it is far more complicate than this. At least in my hifi setup.
Let make à pcb, people will décide the BOM. Sorry, nothing against you, just your coments are basic out of the real world and real long expérience.
Okay, à détail, still an important one but à détail. Here, better for you and me, we make just the pcb layout imho. My two cents at least. YmMV but still à détail.
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I don't belive i wrote that i like KZ caps everywhere (i don't belive i mentioned them at all). I have enough knowledge to know what component to choose for the circuit i use or design. My comments are based on datasheets, measurements and real world engineering, not on an ear of an individual. Your ears, your brain, nothing i can say or show that can convince you otherwise. Nothing against you either, just your persistant subjectivism is not good for general consensus.