It's ok. When you will power down wait a few minutes for the on board bleeder resistors to drain charge before hooking up to the preamp.
Thank you!
Another thing in general. I need around 10-12V to power up my volume controller and I was wondering what is the best way to get this voltage off DCSTB while powering the preamp at its 17V? I am now using a separate regulator board, but I would like to move to a smaller enclosure remove it. It should drain not more than 100mA I think at 10-12V. I know people use LED, but what would be the best option, maybe tap into DCSTB somewhere?
After you will replace fuses and if they will not be blowing again you will measure DC outputs and we will see
So....fuses finally arrived today.
All I can say is thanks to the design of the board.. nothing else is fried! All led bars are lit and good steady close voltages from all outputs.
Thanks for implementing a fool proof design for idiots like me!
Now to finalise the DCG3 with the Mosfets once I have decided heatsink arrangement...and then test!
All I can say is thanks to the design of the board.. nothing else is fried! All led bars are lit and good steady close voltages from all outputs.
Thanks for implementing a fool proof design for idiots like me!
Now to finalise the DCG3 with the Mosfets once I have decided heatsink arrangement...and then test!
I see Vgeorge didn't answer so if I may take the liberty to add an opinion, I would use an RC filter/current limiter and a 12V Zener when tapping off the main reservoir caps to feed the subsystem. Avoiding association with the stabilizer's DC output to the pre not to mix possible interference etc.
After reading so many good reviews of DCG3 preamp finally decided to pick up the boards from Tea and start the build. I'm planning to use Ultra BiB in dual-mono configuration to power DCG3.
Looking to order pair of JFETs uPA68H. Does anyone know reliable source for it? Found bunch of sellers from China in ebay, but not sure about the quality.. Any other options for the JFETs?
Looking to order pair of JFETs uPA68H. Does anyone know reliable source for it? Found bunch of sellers from China in ebay, but not sure about the quality.. Any other options for the JFETs?
@trancendent
Hmm difficult to guess fakes from listings without sampling them and measuring against reference uUPA68h first. Matched IDSS 2SK170 are also compatible in this design and sound great. There is a verified German source that sells matched quads. Those can serve for two channels when used as two pairs.
2SK170 2SK170GR Toshiba matched Quad | eBay
Hmm difficult to guess fakes from listings without sampling them and measuring against reference uUPA68h first. Matched IDSS 2SK170 are also compatible in this design and sound great. There is a verified German source that sells matched quads. Those can serve for two channels when used as two pairs.
2SK170 2SK170GR Toshiba matched Quad | eBay
Thank you Salas! That question was not for him, for you and anyone else as well. I never done that before, so to clarify. I tap from the big caps and do a Zener first and then RC? Do you think you can maybe just sketch a schematic on a piece of paper if it has not too difficult fur you? Thank you.
I believe sourcing the parts could be part of the fun
Anyways, it's too late to get the kit, already picked up the PCBs only.Awesome, europe based source is what I was looking for. Any modifications needed if I switch to 2SK170?
No, look, its simple. Say you got 25V raw DC source i.e. at the reservoir cap. And you want 12V with say 100mA capability (know your load's max). 25V-12V=13V. 13V/0.1A=130 Ohm. That's your series resistor from the DC source to the Zener. It limits current. But you want some juice left for the Zener to keep working when the load pulls max. 120 Ohm will do because 13V/120 Ohm=0.108A or 108mA. 8mA extra.
Because 13*0.108A=1.4W use a 3-5W resistor. Also a 3-5W Zener for when the load does not pull anything to can shunt all that current at 12V thus dissipating 1.3W without burning up itself. Put a 220uF/25V cap across the Zener to ground for noise filtering. The R to the C filter created will help with the raw DC source's ripple too. Hey, you just made yourself a basic shunt regulator.
Salas DCG3 preamp (line & headphone)
Thank you so much! I do appreciate it a lot
No, look, its simple. Say you got 25V raw DC source i.e. at the reservoir cap. And you want 12V with say 100mA capability (know your load's max). 25V-12V=13V. 13V/0.1A=130 Ohm. That's your series resistor from the DC source to the Zener. It limits current. But you want some juice left for the Zener to keep working when the load pulls max. 120 Ohm will do because 13V/120 Ohm=0.108A or 108mA. 8mA extra.
Because 13*0.108A=1.4W use a 3-5W resistor. Also a 3-5W Zener for when the load does not pull anything to can shunt all that current at 12V thus dissipating 1.3W without burning up itself. Put a 220uF/25V cap across the Zener to ground for noise filtering. The R to the C filter created will help with the raw DC source's ripple too. Hey, you just made yourself a basic shunt regulator.
Thank you so much! I do appreciate it a lot