It is a board from China where I replace apot with the Alps pot.
Next step is to move the Muses volume control from the other preamp I have.
One more question pls.
I am considering to put 2-3 regulators into a dedicated chassis.
The cable length between regulators and the preamp & volume control will be around 1 meter + internal cabling around 30 cm. So, in total 1.3m = 4 feet.
Would you advise any extra compensation at the preamp board (some capacitance) for such lengthy wires?
I am considering to put 2-3 regulators into a dedicated chassis.
The cable length between regulators and the preamp & volume control will be around 1 meter + internal cabling around 30 cm. So, in total 1.3m = 4 feet.
Would you advise any extra compensation at the preamp board (some capacitance) for such lengthy wires?
Such lengthy wires are going to add output resistance. Depending on the nature of the loads they might degrade the perceived performance vs having the regs installed in the same box. Steady bias circuits might be less affected. But big current swings modulate voltage drop across cable resistance. Use thickest cables practical.
As for instability compensation I don't think it is going to be needed. I had tried one meter test leads as output wires during the Ubib's development and it remained stable. You could add 10uF tantalum locally at the receiving ends for decoupling from the long incoming wires inductance. In case you will get stability problems in your installation let us know specifically so we will think of possible measures.
As for instability compensation I don't think it is going to be needed. I had tried one meter test leads as output wires during the Ubib's development and it remained stable. You could add 10uF tantalum locally at the receiving ends for decoupling from the long incoming wires inductance. In case you will get stability problems in your installation let us know specifically so we will think of possible measures.
May I ask if anyone did this mod and uses the ultrabib at 3.3v ? Which parts did you use in the end ?
By the way, the Vrr resistor's value which runs across VR1 can set a tighter bracket to the adjustment region if you intend the reg for low voltages only. Say 3.3V to 12V. Small Vrr forces VR1 to smaller too. So you get less bottom to top span but more within range resolution on the trimmer too.
Hello i have a problem with salas 1.3bib, sory i have an problem with four salasys
transformer have 10ac. So i have 14.7vdc on first capacitor. But all salasys have 14,7v out. Trimer dont change anythink. Leds dont work. If my pf5102 jfets works i have ids near 6 or 8mA. Where i should find a problem ? Mayby 270resistors are to smal for that ids? Bye.
transformer have 10ac. So i have 14.7vdc on first capacitor. But all salasys have 14,7v out. Trimer dont change anythink. Leds dont work. If my pf5102 jfets works i have ids near 6 or 8mA. Where i should find a problem ? Mayby 270resistors are to smal for that ids? Bye.
Did you turn the trimmers in both directions? Clockwise & anticlockwise?
Are they official boards so we can exclude routing mistakes? One thing to keep, its a systematic error. Can't be performing same way wrong in four sections just because of bad luck. So lets look for that mistake or failure.
Maybe its about M1 or Q2. More probable. First a thorough visual inspection. Make sure they are the proper types. Then make sure no other component is populated systematically wrong either for type or orientation. A photo would also help.
Correct Vgs for the IRF Mosfets is 3-4V (voltage between legs 1 & 3). For FQP type 4-5V. Correct Vbe for BC transistors is 0.55-0.65V (legs 2,3). Good voltage over 270 Ohm resistors is 270mV-540mV leg to leg. If you see no voltage drop on such a resistor, means the associated JFET does not conduct. Do check all those voltages.
Are they official boards so we can exclude routing mistakes? One thing to keep, its a systematic error. Can't be performing same way wrong in four sections just because of bad luck. So lets look for that mistake or failure.
Maybe its about M1 or Q2. More probable. First a thorough visual inspection. Make sure they are the proper types. Then make sure no other component is populated systematically wrong either for type or orientation. A photo would also help.
Correct Vgs for the IRF Mosfets is 3-4V (voltage between legs 1 & 3). For FQP type 4-5V. Correct Vbe for BC transistors is 0.55-0.65V (legs 2,3). Good voltage over 270 Ohm resistors is 270mV-540mV leg to leg. If you see no voltage drop on such a resistor, means the associated JFET does not conduct. Do check all those voltages.