back to www.audiodesignguide.com |
To get more information contact me at: webmaster@audiodesignguide.com |
![]() ![]() |
High Power Hi-End Hybrid
Amplifier End 2023
started on November 20 st , 2022
so we need to keep this value very low to eliminate strange peak on audio low frequency band.where
Tube | configuration | Va (V) | Rk (ohm) | Ia (mA) | Ck (uF) | Vin (Vrms) | Vout (Vrms) | Load (ohm) | Thd (%) | Frequency (Hz) |
6Z51P | LL1667/15mA in parallel | 140 | 68 | 15 | 470 | 0.53 | 42 | 100K | 0.64 | 5 - 500K |
6Z51P | LL1667/15mA in parallel | 140 | 68 | 15 | 470 | 0.53 | 41 | 50k | 0.78 | 5 - 500K |
6Z51P | LL1667/15mA in parallel | 140 | 68 | 15 | 470 | 0.53 | 39 | 25k | 1.04 | 7 - 449K |
6Z51P | Ra=11.75K IRF820 Rs=6.75K Id=20mA | 320 | 68 | 15 | 470 | 0.60 | 40 | 100K | 1.60 | 0 - 2.4M |
6Z51P | Ra=11.75K IRF820 Rs=6.75K Id=20mA | 320 | 68 | 15 | 470 | 0.60 | 40 | 50K | 1.60 | 0 - 2.4M |
6Z51P | Ra=11.75K IRF820 Rs=6.75K Id=20mA | 320 | 68 | 15 | 470 | 0.60 | 40 | 25K | 1.60 | 0 - 2.4M |
6Z51P | Ra=11.75K IRF820 Rs=6.75K Id=20mA | 320 | 68 | 15 | 470 | 0.60 | 40 | 10K | 1.60 | 0 - 2.4M |
● the bias current in the driver limits the current supplied to the load
It is evident that there are many benefits, but to overcome the problem of the current supplied to the load you need to study well the working points of the driver and final.
R1,R25
47Kohm 1/4W 1% Vishay Dale RN55
R2,R14
10ohm 2W 1% Vishay PR02
R3,R36
280ohm
1/4W 1%
R26,R27
2700ohm
2W 5% Vishay PR02
R34,R35
15ohm
2W 5%
Vishay PR02
R23,R33
270ohm
1W 1%
R24,R28
5600ohm
2W 5% Vishay PR02
R5,R6,R7,R8,R17,R18,R19,R20 0.47ohm
5W 5% Vishay AC03
R15,R16
220K
1/4W 1%
R55,R56 2200ohm 1/4W 1% Vishay Dale RN55
R51,R52,R53,R54
220ohm 1/4W 1%
Vishay Dale RN55
R4,R13
6800ohm
2W 5% Vishay PR02
R29,R30,R21,R22
10Kohm 1/4W 1%
R9,R11,R10,R12 0ohm
(jump)
C6,C8,C9,C14
0,47uF 63V Wima MKS
C1,C2,C10,C11
100uF 25V UFW
C3
empty
C5
0.1uF 100V Vishay MKP1837
C7,C17,C4,C24,C18,C20
2700uF 63V
Nichicon KG type 30x35mm
C15,C16
1000uF 63V Nichicon
D1,D2
Zener 15V 1W
D3,D4
UF4007
D5,D14
1N4007
D8,D12,D11,D10,D6,D7
1N4148
F1,F2
FUSE 5A FAST (with fuse holder)
U$1
2N5550 o 2N5551
U$3
2N5401
Q1,Q3,Q16,Q18
MJE15033 (PNP)
Q2,Q4,Q14,Q17
MJE15032 (NPN)
Q9,Q5,Q6,Q7,Q13
NJW0281G (NPN)
Q12,Q11,Q8,Q10,Q15
NJW0302G (PNP)
IC1
OPA134, OPA602 (you can use many others single op-amp
like the TL071)
The connections are 63862-1 (CUT STRIP) by TE Connectivity / AMP (cod. Mouser 571-63862-1-CT, cod. RS 718-7987)
VOLTAGE AMPLIFIER
R1,R2,R18,R19
220K 1/4W
Vishay Dale RN55
R3,R4,R20,R21 1K 1/4W
Vishay Dale RN55
R7,R24 68ohm
1/4W
Vishay Dale RN55
R14,R29 47K(conf.1)
or 150K(conf.2) 3W
Vishay PR03
R13,R28 22K(conf.1)
or 10K(conf.2) 2W
Vishay PR02
R11,R34 4700ohm 1/4W
R12,R30
470K 1/4W
R45
68K 1/4W
R46
220ohm 1/4W
R48
1K 1/4W
R27,R39
47ohm 1/2W
Vishay Dale RN60
R47
100ohm multi-turn trimmer
R5,R6,R8,R9 empty
RF
1ohm 5W (in series to the secondary filament to reduce the
LM317 dissipation)
C1,C3 470uF 6.3V
Nichicon UFG
C2,C4
33uF 400V
C6
100uF 400V
C7 4700uF 16V
C10,C11,C8 220uF 16V
C5,C9,C12,C13 empty
CY5,6,7,8 0.01uF 440VAC
U$4,U$5
50uF 500V
Vishay MKP
1848H
D1,D2,D3,D4 UF5407
D5,D10
zener 10V 1W
B1
diode bridge 100V 2A 2KBP01
U$19,U$16
1N4007
T3
2N2904
U$6,U$3 IRF840
U$15
LM317
6Z51P + tube
socket
The connections are 63862-1 (CUT STRIP) by TE Connectivity / AMP
KK2 Heatsink type SK104
or EA-T220-38E compatible L=38mm
Thermal resistance
= 7.5K/W
VOLTAGE AMPLIFIER (SECOND CONFIGURATION)
R1,R2,R3,R4,R9,R10,R11,R12,
R21,R22,R24,R23,R29,R30
82Kohm
2W
Vishay PR02
R5,R6,R7,R8,R13,R14,R15,R16,
R25,R26,R28,R27,R33,R34
47Kohm 2W
Vishay PR02
R17,R18,R19,R20
2Kohm 1/4W
Vishay Dale RN55
U$1,U$2
IRF820
KK1,KK2
Heatsink
The
connections are 63862-1 (CUT STRIP) by
TE Connectivity / AMP
(cod. Mouser 571-63862-1-CT, cod. RS 718-7987)
KK1,KK2 Heatsink type SK129 or
FA-T220-51E compatible
L=50mm Thermal
resistance = 3.4K/W
If you will use the configuration with anode choke use a transformer like this:
R-CORE model R26-90 with primaries 2 x 115v and the secondaries 0-165v(0.2A) and 2 x 0-9v (1.1A)
available on Ebay or Alixpress shop
If you will use the configuration with IRF820 use a transformer like this:
R80-55 0-9 X2 (3A), 0-250(200mA) 11.5(L)x9(W)x5(H)
Primary voltage: 0-115V-230V
available in the
analogmetric.com,
Ebay or Alixpress
shop.
I have add a 100ohm 25W in series to the primary to reduce a
10% on filament and anodic voltage.
In my last version I have used a custom made by Italtras with these parameters:
primary |
secondary |
current |
VA |
260 |
8 |
3 |
24 |
|
271 |
0,25 |
68 |
|
|
|
92 |
to use with 230VAC in order to keep the flux very low.
PCB
All the pcb will
be available at low cost on Ebay shop or you can download the Eagle files to
produce these in your local area.
●
Current Amplifier pcb
●
Voltage Amplifier for both
configurations pcb
●
Voltage Amplifer for
IRF820 configuration pcb
●
Soft start module pcb
●
Protection module pcb
●
Diode bridge
See Ebay shop
to buy pcbs
Here the link to buy the
complete pcb set
I don't get money from this Ebay shop.
VACUUM TUBE
For this design is necessary a tube with high amplification factor > 60x and low internal resistance < 3000ohm.
In the driver section you can decide to use the Siemens
D3a (expensive
pentode to use in triode connection) or the Russian
6Z51P / 6Ж51П (cheap
pentode tested on
Bartola® article).
I
have used these russian pentode also in the my last
Power Folllower,
in the Inpol/Mofo
and in my last
Amplifier End.
These vacuum tubes sounded more transparent than the NOS Mullard and Siemens.
The socket pins are not the same for both the tubes,
the pcb is for 6Z51 so it need a little modification to be used with D3a.
I suggest to buy a large stock of 6Z51P to make a selection on voltage gain.
SIMULATIONS
Here all the files to simulate this circuit with LTSpice software.
Download
triode.asy from
Ducan's Amp Pages.
Add these following ines in the file
C:\Program
Files\LTC\lib\cmp\standard.bjt or in
C:\Users\[Windows
user]\Documents\LTspiceXVII\lib\cmp\standard.bjt
to have the transistors models:
.MODEL Qnjw0302g pnp IS=5.16751e-16 BF=114.657
NF=0.895716 VAF=50.2189 IKF=6.409 ISE=3.9641e-15 NE=4 BR=1.47167 NR=0.923324
VAR=255.567 IKR=6.34299 ISC=3.96408e-15 NC=2.82194 RB=2.66347 IRB=0.1 RBM=2.0828
RE=0.0001 RC=0.0652395 XTB=1.45322 XTI=1.08126 EG=1.05 CJE=2.14504e-09 VJE=0.4
MJE=0.376227 TF=2.16864e-09 XTF=1000 VTF=843.737 ITF=501.348 CJC=5e-10 VJC=0.95
MJC=0.251547 XCJC=1 FC=0.8 CJS=0 VJS=0.75 MJS=0.5 TR=1e-07 PTF=0 KF=0 AF=1
.MODEL Qnjw0281g npn IS=4.36849e-12 BF=98.1488 NF=1.01332 VAF=37.9046 IKF=9.71849
ISE=1e-16 NE=1.8326 BR=0.79921 NR=1.09994 VAR=339.743 IKR=5.77305 ISC=1e-16
NC=2.71592 RB=2.74892 IRB=0.33289 RBM=2.74892 RE=0.000344671 RC=0.03203 XTB=1.7742
XTI=1.12262 EG=1.20598 CJE=3.66793e-09 VJE=0.74806 MJE=0.85 TF=2.27115e-09 XTF=1000
VTF=912.955 ITF=296.602 CJC=5e-10 VJC=0.95 MJC=0.270858 XCJC=0.98254 FC=0.8
CJS=0 VJS=0.75 MJS=0.5 TR=1e-07 PTF=0 KF=0 AF=1
.MODEL Qmje15032 npn IS=3.7344e-10 BF=86.8313 NF=1.23974 VAF=31.5491 IKF=9.1678
ISE=9.2499e-12 NE=3.28127 BR=5.59346 NR=1.33161 VAR=2.1791 IKR=5.15023 ISC=4e-13
NC=4 RB=9.54492 IRB=0.1 RBM=0.1 RE=0.000568481 RC=0.0931741 XTB=0.737036 XTI=1.04983
EG=1.206 CJE=3.05969e-09 VJE=0.648491 MJE=0.352663 TF=4.94819e-09 XTF=1.50001
VTF=1.0001 ITF=0.999982 CJC=3.00108e-10 VJC=0.600021 MJC=0.40991 XCJC=0.8
FC=0.534651 CJS=0 VJS=0.75 MJS=0.5 TR=1e-07 PTF=0 KF=0 AF=1
.MODEL Qmje15033 pnp IS=7.51228e-10 BF=134.35 NF=1.25737 VAF=12.5778 IKF=1.88497
ISE=7.74267e-12 NE=3.34528 BR=5.14173 NR=1.47488 VAR=1.4505 IKR=7.47186 ISC=3.25e-13
NC=4 RB=4.37743 IRB=0.1 RBM=0.1 RE=0.000332989 RC=0.381218 XTB=0.223027 XTI=1 EG=1.05
CJE=3.06005e-09 VJE=0.64838 MJE=0.352991 TF=4.78203e-09 XTF=1.50001 VTF=1.00006
ITF=0.999988 CJC=3.00101e-10 VJC=0.600019 MJC=0.409916 XCJC=0.8 FC=0.534975
CJS=0 VJS=0.75 MJS=0.5 TR=1e-07 PTF=0 KF=0 AF=1
POWER SUPPLY FOR THE CURRENT AMPLIFIER
The following is an example of normal power supply, there are 2 toroidal
transformers with about 300VA.
You can use min 4 x10000uF and max 4 x
22000uF.
Following the experince of my last amplifiers I have used Schottky Fast Soft recovery diodes in the power supply but you can use normal 36A diode bridge.
To create a fast diode bridge with these TO220 I have created a simple pcb.
It is possible use
switching
power supply modules, one per channel to to avoid ground loops.
There is
a little difference in
sound by hot switching between conventional power supply made of transformer,
diode bridge, capacitors and these switching power supplies.
These
modules are availbale at low cost on
Alixpress
shop.
Input voltage: AC200-240V
Output: ;
Main voltage
+-55V/6.5A;
Independent 12V/0.5A;
Auxiliary +-12V/0.5A (with the main voltage for ground)
Voltage regulation
accuracy: main no-load ±3%, with load ±3%; (when AC220V input)
Continuous
power: 350W (can work continuously for long-term 350W work at 25°C ambient
temperature, fan cooling is required)
Rated power: 700W (can work
continuously for about 5 minutes at 25°C ambient temperature)
Instantaneous
power: 900W (power generated during dynamic signal impact, less than 100
milliseconds)
Conversion efficiency: Max 98%
Dimensions: length, width
and height = 96*96*38mm
Weight: 310g
It is possible use also
a pair of
MEAN WELL LRS-150-36 connected in series
to obtain a dual voltage.
It is a 150W Single Output Switching Power
Supply with a variable DC output in the range 32.4 ~ 39.6V.
There are
integrated protections for short circuit, overload, over volatge, over
temperature.
This model has been choised because it is cooling by free
air convection and give until 4.3A.
There are also more expensive models
with PFC like the UHP series.
SOFT START - PROTECTION
B1 diode bridge 100V 2A 2KBP01
IC1 4013 or HCF40138
IC2 7805 in TO220 case
IC3 NE555
T1,T3 BC337
C1 100uF 16V
C3 100uF 16V
C4
470uF 16V
C5 1uF 63V MKT
R2
22Kohm 1/4W
R1,R3,R6,R8 1Kohm 1/4W
R13
8200OHM 1/4w
R5,R18
4700ohm 1/4W
R4,R7,R9
4.7ohm 5W
U1,U2 Relay
Fider mod.
41.61 12V
and use the following module to add an extra dc protection to switch off th amplifier in case of problems
R17,R14
empty (not used)
R16,R15
10Kohm 1/4W
This is the 1NO1NC switch available in 2 configuration Momentary
or Latching and you can buy from
Alixpress.
The panel cut out is 22mm, the same of noval socket, so this is the ideal
choice for the 10mm front panel.
Use
Momentary model if you think to use the Soft start from
Alixpress
otherwise if you use my Soft start use the
Latching type.
CABINET
In order to dissipate all the
heat generated by this amplifier in my case I chose this container by
HiFi 2000.
I suggest to use the CUSTOMIZATION service by HiFi 2000 for the M3 threading
on the heatsinks.
●
File dxf to use
If you will use the
switching power supply for the current amplifier use this model:
Dissipante 04/300B 4U 10mm
SILVER or
BLACK
Product Code: 1NPD04300B or 1NPD04300N
temperature coefficient 0,31 C°/W per each side
Internal height 165mm
If you will use the
normal power supply for the current amplifier probably you should use this
model:
Dissipante 05/300B 5U 10mm
SILVER or
BLACK
Product Code: 1NPD04300B or 1NPD04300N
temperature coefficient 0,18 C°/W per each side
Internal height 210mm
Inner baseplate for
Dissipante 300mm
Product Code: 1BASEPD300
Add an internal aluminium panel 3mm size 20 x 29cm
INTERSTAGE CAPACITOR
This is a very hi-end amplifier with a incredible sonic performances but
reach this level it is necessary use a very good interstage capacitor.
I
suggest these models:
See some test results on Humble Homemade Hifi .
MEASUREMENTS
Here a first measurement with 2 x 37VAC r-core transformer.
Here the final measurements with 2 x 55VDC switching power supply.
BIAS
This project does not have a bias adjustment so you have to use the same
transistors I used.
In my version with 2 x 36VAC 400VA toroidal
transformers I have this bias.
2 x 22000uF 63V on each channel
2 x 46.5VDC on amplifier input
2 x 42VDC after regulators
from 65mV to 69mV on 0.47ohm output resistors so 0.147A for each output
transistor
about 800-900mV on the 10ohm resistor so 2 x 90mA on driver
stage
4 x 0.147A = 0.59A
2 x 90mA = 0.18A
= 0.76A => 2 x 46.5VDC x 0.76A = 71W on each channel
Using a 2 x 55VDC on amplifier input you will arrive to about 95W
PHOTOS & CONSTRUCTION DETAILS
1) set the variac to about + 2v and -2V dc to check that the heatsink is not
connected to these tensions
2) control the voltage after the regulators these
should rise slowly in a few seconds
3) set the variac to + 15V and -15V to
verify that the output voltage goes to zero volts dc
4) set the variac and
-20V to + 20c to verify that the voltage across the resistance from 0.47ohm is
almost equal among all the transistors (0.05V - 0,06V)
5) set the variac at
the final voltage
Here a test environment with a single high power r-core for both channels.
Here the version of a my friend with separated power supply using 2 x 42VAC 420VA toroidal transformers and 4 x 19000V 75VDC capacitors
124W on 8ohm with a perfect decay 1.54% thd
150W on 8ohm with about
2.54%
1 x HiFi2000 Dissipante 04/300N 4U 10mm BLACK
1 x HiFi2000
Pesante 02PN 2U 10mm BLACK
Here the final version in a 5 unit chassie.
TOTAL COST
Configuration with
IRF820 and switching power supply
description | unit price | quantity | total (euro) |
HI-Fi2000 chassie with machining (about) | 300 | 1 | 300 |
80VA transfomer for volatge amplifier | 70 | 1 | 70 |
Swicthing modules | 35 | 2 | 70 |
LKG capacitors | 7 | 12 | 84 |
Various components | 150 | 1 | 150 |
6Z51P (10 items to make a selection) | 4 | 10 | 40 |
output transistor | 4 | 20 | 80 |
Interstage capacitor | 40 | 2 | 80 |
rca, iec, output terminal | 50 | 1 | 50 |
total | 924 |
Configuration with IRF820 and normal power supply
description | unit price | quantity | total (euro) |
HI-Fi2000 chassie with machining (about) | 300 | 1 | 300 |
80VA transfomer for volatge amplifier | 70 | 1 | 70 |
Toroidal transformer 300VA | 70 | 2 | 140 |
LKG capacitors 15000uF 63V | 25 | 4 | 100 |
LKG capacitors | 7 | 12 | 84 |
Various components | 150 | 1 | 150 |
6Z51P (10 items to make a selection) | 4 | 10 | 40 |
output transistor | 4 | 20 | 80 |
Interstagr capacitor | 40 | 2 | 80 |
rca, iec, output terminal | 50 | 1 | 50 |
total | 1100 |