You typically want no less than 5V DCinput-DCoutput difference on a UBiB. DCinput is the rectified DC on it. More drop can allow less parasitic capacitance for its M1 input CCS MOSFET. But with each extra dropping Volt you pay back quickly in escalating dissipation. Especially in CCSed shunt regs. Many transformers produce more than nominal secondary voltage output due to higher than nominal mains and a small portion of their rated current drawn.
Both UBiB and DCSTB can work with less than 5V difference across them but I believe they tend to sound best with no less than so.
Both UBiB and DCSTB can work with less than 5V difference across them but I believe they tend to sound best with no less than so.
I better buy the 20v 60VA r-cores then, there will be 7 ubibs in 1 case.
Just a shame i cant use the selectronic 120va ones, i will need to find another project for those.😀
regards,
John
Each UBiB wants its own secondary. Anticipate about AC x1.3 = raw DC after losses. Don't use too high secondaries if you have choices. 22-23V raw DC would be the more thermally efficient target for 17V DC output rails.
Hello Salas -
I bought a pair of DCG3 preamp kits from Tea-Bag to make a Balanced version. Tea-Bag was kind enough to match the 2 kits for me, I have a pair of R core transformers and just finished the relay control for the XLR inputs. The relay control uses two double relays per channel, so that both phases of each channel are switched.
I have three main inputs, two have Balanced XLR outputs and one, my FSP has single ended RCA's.
What would be the best way to wire the FSP to a Balanced DCG3 preamp? I have RCA to XLR adapters, yet I would like to have a pair of RCA's hardwired to the preamp inputs.
I bought a pair of DCG3 preamp kits from Tea-Bag to make a Balanced version. Tea-Bag was kind enough to match the 2 kits for me, I have a pair of R core transformers and just finished the relay control for the XLR inputs. The relay control uses two double relays per channel, so that both phases of each channel are switched.
I have three main inputs, two have Balanced XLR outputs and one, my FSP has single ended RCA's.
What would be the best way to wire the FSP to a Balanced DCG3 preamp? I have RCA to XLR adapters, yet I would like to have a pair of RCA's hardwired to the preamp inputs.
OK.
My subwoofer (REL) used either HL or LowL to drive the plate amp. When I use a Balanced preamp into a Balanced amp (ALEPH J) I have to use the RCA Low Level input to avoid a hum. Would I wire an RCA output for the subwoofer the same way?
My subwoofer (REL) used either HL or LowL to drive the plate amp. When I use a Balanced preamp into a Balanced amp (ALEPH J) I have to use the RCA Low Level input to avoid a hum. Would I wire an RCA output for the subwoofer the same way?
You can wire from XLR out pin 2 to RCA out hot & from pin 1 to RCA out cold. You may also put a 100 Ohm buffering resistor between pin 2 and RCA hot for better outputs separation.
Perfect. Thank you. One last question, I'm using a separate chassis for the power supply and will use an umbilical to the preamp. Should I use the metal sheath around the wires with power supply side grounded and the preamp side open like the FSP and UFSP?
This is how I wired mine. It works like a charm for any kind of source/load. For SE connections circuit gnd needs to be engaged. Same thing for balanced input. However for balanced output, it works better when pin1 is attached to the chassis. And my built has completely floating gnd i.e. those SLBs are omitted. Not sure how it works but it does. My amp is tuby with true differential input for that matter...
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Yes that's good anti EMI practice, i.e. to one way drain the umbilical cable's shield.
Do you mean the SLB's shown in your pic are omitted?
I have found that without SLB's I always see a large 60hz spike when I do my FFT; almost completely gone with it installed.
Thanks. nash
Yes no SLB's at all. Circuit gnd floating for DCG3 and DAC, and since XLR pin1 of DCG3/power amps is attached to their chassis that leaves only the amps' gnd earthed. Seems to work very nice. An FFT of DCG3 alone is posted in post #5370.
@elwood625,
Could you show a pic of your DCG3 separate PS box. Just starting on mine.
Thanks,
Don
Could you show a pic of your DCG3 separate PS box. Just starting on mine.
Thanks,
Don
I'm using the DCSTB for the preamp and a 12vdc regulated supply for the relay input section and the Balanced Muse volume control (both of with are in progress.
I only have the preamp section chassis, I'll select the power supply chassis after I finish the 12vdc regulated supply.
Here is a pic of how far along I am.
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Spike at 60hz is indeed small as shown in #5370. Is that FFT for DCG3 in SE mode or balanced?
Thanks. nash