SA2022 - Modular High End Analog Precision Preamp (with headphone amp, digital controlled relay volume, monitor output, IR remote, SE and bal. I/O)

It makes big a difference, if I rotate the 3d stl file 45 degree on z-axis (left) for printing ...
BTW: Have ordered some Aluminium SLM printed buttons - another 2 weeks waiting ...
 

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Today I have tested some universal remote control units. Many of them allow to configure NEC protocol. So buying a universal programmable RC could be an option. As I'm the programmer of the SA2022 controller software I could implement a configurable table for different NEC protocol based RC's. Stay tuned, more to come.

Have fun, Toni

P.S.: I still prefer a custom RC. The costs of the project itself is killing a standard DIY budget. But keeping in mind that e.g. the newest Accuphase Modular Preamp C-3900 is far beyond 25 kEUR you can build the SA2022 preamp and add either the SA2014 or the SA2021-NCH power amplifier several times, buy a CNC machine, let a fab produce you a prototype of your case ... YOU CAN DIY!
 
Just a quick note (black Friday deal): The required 5 transformers are available at Conrad (Germany), likely at the lowest price. However they also have 20EUR off when ordering above 170EUR, which also is coming with free shipping; so that might be a good idea to buy 2 (mini group buy) sets for a really good price.
(I as well received a 25EUR off above 170EUR coupon via email, but that might be unique or attached to my account, so I won't post it. Might be worth to check your emails...)
Honorable mention at Conrad: RTE24012 and PHAP3302B - might be cheaper elsewhere, but not available everywhere.
Note: Get the "B" type RECOMs, they are supposed to be less HF noisy than the "A" type.
 
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Have programmed a newer firmware release which allows you to use nearly every (extended) NEC remote control to be used.
E.g.: this ~ 10 EUR "Hama" universal RC programmed to use "TV - 5481" config works very good.

Help:
Code:
b       : reboot
c       : switch to configuration mode
d       : toggle debug
f       : select power button type (switch=1, push=2, push_save_state=3)
g       : delay power button. number of main loops
j       : temperature sensor type: 1=NTCLE100E3222 (2.2k), 2=NTCLE100E3103 (10k)
k       : set lcd dimmed contrast 0 - 255 (low to high)
l       : set lcd bright contrast 0 - 255 (low to high)
m       : set monitor output to input number e.g. from 1 to max. 8
r       : ir nec 16bit device id, default 43146 (0xA88A, 0-65535)
t,u,v,y : temperature sensor 1 - 4 trip values
                  (0=ignore; 1=use port like digital low for poweroff; 2-99 max. celsius)
n,o,p   : delay (repowering, inrush, mute) 1ms steps
i       : list configuration info
w       : save configuration to eeprom
q,x     : exit
remote commands:
F,N,S   : power off, on, current power status
RI      : get, set input e.g. RI=3
RM      : get, set monitor input RM=4
RV      : get, set volume e.g. RV=99 (range 0-151; -63.5dB to +12dB)
K,L,M   : get current mute status, set mute off, set mute on
T       : get temperatures
Use own NEC infrared ir codes:
        hex code array in this order: IR=[OK,MUTE,BACK,PWR,VOL_UP,VOL_DOWN,0,1,2,3,4,5,6,7,8,9,UP,DOWN,LEFT,RIGHT,MENU,EXIT] (22 hex values))
        e.g.: IR=0a0b0c0d0e0f00010203040506070809101112131415
        use this new ircodes with: IR1; return to default using IR0

Change input related settings - some examples:
IV4=127         : delta volume input 4, 127=0dB, 95=-16dB, 151=+12dB
IN1=AUX6        : rename input 1 to 'AUX6'
IM=8            : maximum active inputs


Using the remotes debug mode ("D4" <ENTER>) helps you to define the hex code array. See screenshot. Don't forget to enter a "w" and reboot with "b".

BR, Toni
 

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BTW: The working hex string for this cheap IR device is: 1888E8F050D090008040C020A060E010A86842C228E8 (hexcode array in this order: IR=[OK,MUTE,BACK,PWR,VOL_UP,VOL_DOWN,0,1,2,3,4,5,6,7,8,9,UP,DOWN,LEFT,RIGHT,MENU,EXIT] (22 hex values))

Code:
preamp controller v2.0.813 2024.12.03 21:51:14, � 2024, astx@astx.at
h=help

ntc type:               j=2
lcd dimmed:             k=0
lcd bright:             l=255
temp sensors t,u,v,y:   0|6|0|0 �C
delay repower:          n=5000 ms
delay inrush:           o=250 ms
delay mute:             p=1500 ms
power button type:      f=3
delay power button:     g=300 main loops
last selected input:    3
power on volume:        50
balance:                127
input1: delta volume=127        name=<MM/MC  >
input2: delta volume=127        name=<CD/DVD >
input3: delta volume=127        name=<USB DAC>
input4: delta volume=127        name=<TAPE   >
input5: delta volume=127        name=<BLURAY >
input6: delta volume=127        name=<TV/AUX >
maximum inputs active:  6
monitor set to input:   m=3     <USB DAC>
ext. NEC rc id  r=24992 (0x61A0)
use alt-ir nec device   r=1
alt-ir nec codes:       1888E8F050D090008040C020A060E010A86842C228E8

The newest help:
Code:
b       : reboot
c       : switch to configuration mode
d       : toggle debug
f       : select power button type (switch=1, push=2, push_save_state=3)
g       : delay power button. number of main loops
j       : temperature sensor type: 1=NTCLE100E3222 (2.2k), 2=NTCLE100E3103 (10k)
k       : set lcd dimmed contrast 0 - 255 (low to high)
l       : set lcd bright contrast 0 - 255 (low to high)
m       : set monitor output to input number e.g. from 1 to max. 8
r       : ext. NEC rc id, default 43146 (0xA88A, 0-65535)
t,u,v,y : temperature sensor 1 - 4 trip values
                  (0=ignore; 1=use port like digital low for poweroff; 2-99 max. celsius)
n,o,p   : delay (repowering, inrush, mute) 1ms steps
i       : list configuration info
w       : save configuration to eeprom
q,x     : exit
remote commands:
F,N,S   : power off, on, current power status
RI      : get, set input e.g. RI=3
RM      : get, set monitor input RM=4
RV      : get, set volume e.g. RV=99 (range 0-151; -63.5dB to +12dB)
K,L,M   : get current mute status, set mute off, set mute on
T       : get temperatures
D{num }: set special debug flags (all=255; lcd=2; ir=4; volume=8; states=16)

alt-infrared ext. NEC codes:
        hexcode array in this order: IR=[OK,MUTE,BACK,PWR,VOL_UP,VOL_DOWN,0,1,2,3,4,5,6,7,8,9,UP,DOWN,LEFT,RIGHT,MENU,EXIT] (22 hex values))
        e.g.: IR=0a0b0c0d0e0f00010203040506070809101112131415
        IR=y   : enable use of alt-NEC codes
        IR=n   : disable use of alt-NEC codes

Change input related settings - some examples:
        IV4=127         : delta volume input 4, 127=0dB, 95=-16dB, 151=+12dB
        IN1=AUX6        : rename input 1 to 'AUX6'
        IM=8            : maximum active inputs
 
Two parts available for a good price:
AXICOM
BCD Drehschalter
The BCD switches from the link are not compatible with the PCB!
SD-1111 from Nidec has the correct pin assignment. Sorry that I have selected such expensive types...
But low resistance and possible higher currents as typical in digital circuits was the criterion to select these types of BCD switches.
The good news is: if you connect modern audio devices the level is typically 2V RMS and you could omit the gain switches. Maybe one or 2 inputs with populated bcd gain switches are enough to connect your beautiful old devices (tape deck or even a older tape machine).

Have fun, Toni
 
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Just seen: the LM4562/LME49720 prices have heavily increased... if you want to build a true analog preamp you should start now ... and not wait another 5 years ...
Have bought LM4562/LME49720 DIP8 a view years ago for about 1.70 € per piece .. now you pay more as 5 € ... crazy ...
Of course one can use DIP adapters and use modern dual smd opamps like opa1642 - should work in SA2022 without any problem.

Glad that I have done a lifetime buy years ago and have hundreds of the LM's on stock...
 
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... looks like the good old DIP8 high end opamp days are gone ... prices have increased by factor 3 ... crazy. 😢
For the very last set of pcb's I have LM4562 DIP8 on stock ...
OPA1612 on DIP8 socket is could be an alternative opamp.