Salas SSLV1.3 UltraBiB shunt regulator

Thanks Rush. I think Toroidy sells their transformers like this. Could you provide some more detail on the kind of epoxy and bentonite clay and some mix directions? I think I might give it a try.


Begs the question, why do it as opposed to the bolt and top metal plate approach? Have you noticed any difference?

nash
 
I do a fair amount of carbon and epoxy work on my ACAT sail boat. (Built one from scratch)

Just use any laminating epoxy, least expensive you can find for this purpose.
Mix the oil dry/bentonite clay until the mixture is as thick as can get it and still be wet. The bentonite will settle to the bottom, I use a small torch to pop the bubbles on top, after it is poured into the transformer. I just use the torch a couple of passes, don’t really need to as the Forsner bit will cut down through the hardened bubbles on top. Mostly cosmetic.

Then I use a Forsner bit to level the top for the washer, then drill the mounting hole.

I have never compared doing this with the hardware method. I just do it cause I have epoxy and oil dry on hand and higher end toroidal transformers do it.

The bentonite clay came from Cat’s Squirrel’s website about making turn table plynths. Go there and see his testing of every material anyone has ever thought of to make a plynth. https://qualia.webs.com/plinthbuilding.htm

Rush
 
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So the DAC is up running with the triplet boards. All works so good and the harsh sound from boards with lt3045 is gone. Pleased with this solution and thanks again Salas for the great solution and all help :)
 

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I thought of the higher than standard max output voltage capability modifications for Greg :)

1. CRD diodes Semitec E-501 (100V 300mW 0.5mA current regulative diodes) instead of J1 J3. Soldered from drain pad to gate pad replacing those two PF5102. CRD's cathode goes to gate pad is the orientation. R4 & R8 may remain as they will be skipped out of circuit by that action anyway.

2. BC556C BC546C (and B) instead of BC560C BC550C for Q3s

3. 470R instead of 270R for R5 R6. 330R instead of 270R for R7

4. 50K VR1 330K VRR instead of 20K 75K respectively

The above modifications should allow for 5V to 65V adjustable Vout range. Or 5V to 50V if VRR is 100K. Watch the capacitors DCV spec regarding the new higher AC Tx secondaries and new higher Vout range, also remember that the M2 MOSFET will dissipate more as the output voltage goes higher.


To make sure I'm not wrong:)
I want a voltage of + 45V.
It is mentioned that (Q3) BC560C must be replaced with BC556C (B).
What happens to Q1-Q4 BC327 -40, Q2 BC560C, must they be changed as well?
Thank you .
 

PKI

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1N5249B-TR looks fit for the job. Needs little current as this circuit will provide it. You could also try a higher value C2 than used with the trimmer as long as it fits to can filter the lower impedance Zener better. Maybe decide C2 in the end after a comparison when the full preamp board is ready to be installed in its case.
So I finally got a bunch or Zeners to test and with 19.25V one I got exact 24V of pretty stable Vout I need for the b1 korg. Now I am being paranoid about how much I compromised the performance of the regulator by introducing this noisy zener? Should I worry about it, is it that bad? Also I have 3300uf cap that fits into C2 position, should I use it or it is too much?
 
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No its not that bad because filtered. Especially for line level applications which aren't particularly demanding like some zero PSRR MC phonos etc. B1 Korg's rail has additional RC noise filter cells too. 1000uF will do. Don't put too high a C2 unless you have the patience waiting for it to reach the Vout target at start up. Because it just charges through VREF with only 2mA current or so.
Its a soft start also, which can be welcome in many cases, but better don't make it a very long delay up to 24V.
 

PKI

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A bit random question, but would like some of your wisdom. I plan on moving the transformer into a separate chassis with diodes and CRC in there and then umbilical to the main chassis where UBib will be located. I have a push button switch which is rated something like 40V dc and ac, is it better to put it to cut AC in the transformer secondary or in the end to break DC before it goes to the main chassis?
 
I would not switch the secondary or the DC. Why can't you switch the mains voltage going to the transformer?

An alternative is to have a switch in the main chassis that is connected to a relay in the power supply chassis and turns on the transformer. You will require an auxiliary power supply (say 12 or 24V) that is on all the time and another cable.