Versatile and comfortable passive pre-amp

[meanman1964]

Rudi,
i've two NTC CL70 measurering 25,4 R OK to use for the soft start?

 

[Rudi_Ratlos]

Patrick, the name "Lightspeed" is copyrighted by George Stantscheff.
Please do not use this name, when you are talking about my VCPre (which is using LDRs for attenuation as well).
The NTCs are o.k.

Best regards - Rudi_Ratlos

 

[meanman1964]

Sorry, for that Rudi

 

[meanman1964]

Rudi,
You used for the soft start the BC548B which relplacement can I use there?

 

[meanman1964]

Also forget to order the 5V LEDS

 

[meanman1964]

Rudi,
You used for the soft start the BC548B which relplacement can I use there?

Rudi???

 

[Rudi_Ratlos]

Patrick, take any NPN that you have at hand: BC546, 2N5551, ...
The transistor is used to switch on the relay's coil.

Best regards - Rudi

 

[meanman1964]

What about the 5 V LED?Can you tell me which resistor value is used?

 

[Rudi_Ratlos]

This is a simple calculation Patrick:

The forward voltage drop across a any (?) LED is about 2V. So 3V remain to drop across the resistor. Take a 3 KOhm resistor and 10mA will be flowing (the LED will then shine very bright!), take a 6.8 KOhm resistor and some 5mA will be flowing (still very bright) - so I advise you take a 10 KOhm resistor.

Best regards - Rudi

 

[meanman1964]

Thanks Rudi,
Gonna read the manuell for the last time and after that finishing the boards and adjust and testing.

 

[yyzz]

Hi, Rudi
Sorry to bother you, the shopping cart of Rev. 1 VCPre on #154
seems no longer there. Does anyone has a copy?
thanks a lot

 

[meanman1964]

Do you mean the one from Reichelt?

 

[yyzz]

yes, i remembered it's there weeks ago

 

[meanman1964]

I maybe can make mine public

 

[yyzz]

its nice, meanman1964

 

[meanman1964]

Rudi,
Is it possible to do the remote control learning fase without the LDR's installed

 

[wineds]

Yes it is Patrick.

 

[meanman1964]

I've a cd player(Kenwood KA880SG) of 1988,I hope the remote control of this unit will do the job.

 

[meanman1964]

Did try at least 7 remote controls none of them work So please help me find one

 

[meanman1964]

If I can't find a remote i've to sell the kit🙁