Its true I don't know about circuits. Just basic stuff. I am diying simple things, I put them to the listen, and if I feel they work good I show them. But I don't know if they are safe for all scalings or if they inhibit some flaws, beyond what I made for a particular working application. So its there for others to explore further if they fancy. No claims.
Hi Salas !
You can hepl me plesea!
Now i make pre tube 6c45 pi, I need the Salas shunt for my Pre!
You can sent for me the origenal cricuit for my Pre:
In put: 300V and out put : 230-250V, 40mA for two chanel!
Thank you very much!
I Waiting to you , because Now Im doing it, tomorow I have to finish!
You can hepl me plesea!
Now i make pre tube 6c45 pi, I need the Salas shunt for my Pre!
You can sent for me the origenal cricuit for my Pre:
In put: 300V and out put : 230-250V, 40mA for two chanel!
Thank you very much!
I Waiting to you , because Now Im doing it, tomorow I have to finish!
OK! I m finish my pre whith Salas shunt,
The sound is very good, but there is a litle noise * is eeee*, i dont know why?
I think my pre is not good, I have to check it now!
thank Salas!
pm I use Filter 220uf- 900R- 220uf/450V . After I connect to Salas shunt!
290V. and out put 230V.
Can be anything anywhere. Needs some luck now. Not having the smoke out is quite something.
6C45pi is notorious for oscillation, there's some info on applying cathodestoppers (!) at diyaudio.
Last edited:
Hey quang, do you have one shunt regulator feeding both pre channels? How much current does each preamp channel draws?
I think you setup your shunt reg current limit too low. This could explain the voltage so low on the output.
From your measurements it shows that the total current through R1 is 47mA = 2.21V / 47R. Seems a bit low.
I think you setup your shunt reg current limit too low. This could explain the voltage so low on the output.
From your measurements it shows that the total current through R1 is 47mA = 2.21V / 47R. Seems a bit low.
Hi ikoflexer! help me!
do you have one shunt regulator feeding both pre channels? = yes one shunt for two chanel my pre!
How much current does each preamp channel draws?
17ma one chanel!
I think you setup your shunt reg current limit too low. This could explain the voltage so low on the output.
What Do i can?? for mya pre? and Shunt?
QuangHao
do you have one shunt regulator feeding both pre channels? = yes one shunt for two chanel my pre!
How much current does each preamp channel draws?
17ma one chanel!
I think you setup your shunt reg current limit too low. This could explain the voltage so low on the output.
What Do i can?? for mya pre? and Shunt?
QuangHao
OK, let's see. You got 47mA total going through. If you are 100% sure that each channel takes 17mA, then 47 - 17 - 17 = 13mA. That is the total current that is left for biasing and shunt mosfet. I think that's too small. Make R1 just a little smaller value and measure everything again. Do you have a resistor around 40 ohm for R1? You could use two 75R in parallel.
Also, insert a 1R or a 0R1 resistor between the source of Q3 and ground, and measure the voltage across it, with the circuit powered.
You're working with high voltage, be careful! I see you don't have a bleeder resistor in your PSU filter. Your caps retain high voltage, so make sure they are discharged when you work on the circuit.
Also, insert a 1R or a 0R1 resistor between the source of Q3 and ground, and measure the voltage across it, with the circuit powered.
You're working with high voltage, be careful! I see you don't have a bleeder resistor in your PSU filter. Your caps retain high voltage, so make sure they are discharged when you work on the circuit.
What takes you so long?
Just kidding, take your time and above all, do it safely!
ok! i change r= paralle 75 R R1 =35R. V= 2.16 v!
An R 1 r = 226V!
ok or no??
Looks a bit better now. I also asked you to insert a 1 ohm or a 0.1 ohm resistor between the source of Q3 and ground, and measure the voltage across it, with the circuit powered. Have you done that?[/QUOTE]
Yes, I do that!
My pre is stil ees ..esss ! * not change*
I do sample you show!
1 ohm or a 0.1 ohm resistor between the source of Q3 and ground,
I use 1R between Q3 to ground and V= 220V.
i think my pre use tube 6c45, Is is noise!
I check my pre!
Thank
Yes, I do that!
My pre is stil ees ..esss ! * not change*
I do sample you show!
1 ohm or a 0.1 ohm resistor between the source of Q3 and ground,
I use 1R between Q3 to ground and V= 220V.
i think my pre use tube 6c45, Is is noise!
I check my pre!
Thank