Since there are C1 C2 1000uF on each BA3pre channel I wonder if there is some condition created during start up. How long are the rail cables from PSU to BA3pre board, and is there any length difference between pos & neg in your build?
Lengths are about the same, 3 inches max (7cm).
Turn on s have been normal the last few days.
Lengths are about the same, 3 inches max (7cm).
Turn on s have been normal the last few days.
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Salas, I was looking at the UltraBIB type 1.3S you designed for higher voltage with the phono pre. I am planning to use regular 1.3 ultrabibs likely at 28v or 38v to power an output stage (100ma-180ma output most likely).
Is there anything I should keep in mind running them at higher voltage?
Is there anything I should keep in mind running them at higher voltage?
There is increased time of Vout settling in the higher range. Only that. If Vout drift is not crucial to your application there is nothing to worry about. For the specific phono the Vout drift was moving along its input stage JFETs drift and that was annoying for setting its test point faster. That is why I specialized its reg version. I shortened its Vo range to the upper part only.
I had to desolder a C1 cap to use elsewhere and in the process took up part of the copper tracing on the inside of the right-most cap pin. As long as the new cap pin is fully soldered to the bottom of the board should this be fine?
An externally hosted image should be here but it was not working when we last tested it.
Hi! Have ordered a Salas Ultrabib triplet to source a Soekris DAM 1921. (same as DAM1941 but with 2 ladders)
It needs +-5V 45mA Max for ladders and +5V 350mA Max for digital. Have also ordered minikits for triplet. Then I need transformers. I have read the general info. Seems 9volt AC is suitable but what VA or current ratings for ladders and Digital?
Will also need some resistors for suitable CC coupling. Advise?
Is there other components I need for replace current PS? Caps?
It needs +-5V 45mA Max for ladders and +5V 350mA Max for digital. Have also ordered minikits for triplet. Then I need transformers. I have read the general info. Seems 9volt AC is suitable but what VA or current ratings for ladders and Digital?
Will also need some resistors for suitable CC coupling. Advise?
Is there other components I need for replace current PS? Caps?
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@ForsbackaKalle
Rectification bridge drops the AC rated secondary current spec of a transformer by times 0.707. Considering its best to have three times the current ability on tap for the transformers to run cool enough, don't use lower than 200mA per secondary spec for ladders and no lower than 1.5A for digital regarding Soekris DAM 1921.
Rectification bridge drops the AC rated secondary current spec of a transformer by times 0.707. Considering its best to have three times the current ability on tap for the transformers to run cool enough, don't use lower than 200mA per secondary spec for ladders and no lower than 1.5A for digital regarding Soekris DAM 1921.
9Volt AC is fine. For CC use 3.9R R1 per polarity for the ladders. And 1.2R for the digital. The Ultrabib 1.3 has rectification bridge and reservoir filter cap for each one section already on its PCB. You only need a dedicated transformer secondary for each section. No other external parts. Dedicated secondary means four wire type transformer for dual polarity not three wire type with center tap.
No.
45mA typical, 85mA maximum for +/- analogue part -practically choose 100mA as maximum-;
350mA maximum for digital part -practically choose 400mA-.
If you use at least 100mA for shunt, the CCS currents are:
200mA for analogue parts;
500mA for digital part;
R=0.6/I
so resistors are 3R and 1R2.
I use -for 1941, which needed higher current for four ladders- 1R8 and 1R2.
I use 2x9V 40VA transformer for analogue (+/-) parts and 9V 40VA for digital part.
Each transformer are lukewarm, so 40VA is a minimum.
I'm running my 1941 with the exact value Salas suggested R3.9 for analog +- and R1.2 Digital inclusive of the display (I use a Reflektor-D Mini for Digital), in this post Soren wrote:
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Don't know if 1941's or 1921's stated power spec is average or max, that's important to be clear because we apply a constant current sourced psu here, but if you have never seen the Ubib LEDs fading a bit or even blinking its a visual indication that the load did not go beyond current limiting and had not starved the shunt part of the reg. In hard limiting the Vout would drop way lower than 5V anyway and it should have had strong effect on the DAC also. The CCS limit behaves exactly as the CC safety mode of bench supplies. Limits and protects. But if set short its simply like an auto break set to cut in at the wrong speed.
I use Ohmite 5W AG series, like this:
ohmite ag - Searched phrase | Electronic components. Distributor, online shop – Transfer Multisort Elektronik
ohmite ag - Searched phrase | Electronic components. Distributor, online shop – Transfer Multisort Elektronik
I used Mills MRA5 5w and in another built Vishay Dale RS 3W. In the Build Guide Salas suggest for minimum 2w or for CC >1A R1 4-5W.
Consider good sinking for the digital UltraBiB.
Would like to ask Salas, given the same resistance in R1 is heat generated conparable between a UltraBiB and a Reflektor Mini?
Consider good sinking for the digital UltraBiB.
Would like to ask Salas, given the same resistance in R1 is heat generated conparable between a UltraBiB and a Reflektor Mini?
