The true experimental tweak thread

[Kritpoon]

1 hour ago, lmitche said:

http://www.bristolwatch.com/ele/basic_ac_rectification.htm

Thank you.

[Cornan]

7 hours ago, lmitche said:

Cornan, Alexey is right to point out you may smoke your boards with a 15 volt ac transformer. The voltage of the rectifiers are likely to be over the maximum input thresholds of the lt3045s.

 

I would actually be extremely surprised if 15VAC would smoke the HC-HPULNS since they are still suitable for 20V plus capable to endure a higher voltage drop and current than other LT3045s. However, just in case I have sent Michael a e-mail to make 100% sure that I will be fine. I will let you know his answer.

My intension will be like this: 15VAC - 20VDC>15VDC - 15DVC>12VDC - Brooklyn DAC (plus possibly additional aluminium polymer cap inbetween the HC-HPULN)

 

[mozes]

Cornan,

Why do you think it is superior to feed your boards 15VAC rather than 15VDC?

[lmitche]

5 hours ago, Cornan said:

 

I would actually be extremely surprised if 15VAC would smoke the HC-HPULNS since they are still suitable for 20V plus capable to endure a higher voltage drop and current than other LT3045s. However, just in case I have sent Michael a e-mail to make 100% sure that I will be fine. I will let you know his answer.

My intension will be like this: 15VAC - 20VDC>15VDC - 15DVC>12VDC - Brooklyn DAC (plus possibly additional aluminium polymer cap inbetween the HC-HPULN)

 

Happy to hear you are reaching out to Michael. He will steer you the right way.  He did the same for me.

[Cornan]

1 minute ago, mozes said:

Cornan,

Why do you think it is superior to feed your boards 15VAC rather than 15VDC?

 

I don´t actually know until I have tried. There are several advantages with the AC-AC PS as a feeder supply compared to the Gophert. Things like balanced transformers, EMI input filter, torodial transformer, bigger transformer, no pre-regulation (=possibly less noise) etc are things that I consider an advantage to the Gophert. Both are floating. Gophert have an advantage of optimal pre-regulation (= possibly less heat). Other have said (over and over again) that the SMPS design is Gophert´s culpit...but I do not agree that it is true in my perticular setup!  

Anyway, the reason I bought the AC-AC PS is to find out if it could concur my Gophert? I really do think it could, but mainly due to the things I mensioned above and not due to the actual SMPS design. The balanced & floating design is the most important apect IMO.

[lmitche]

4 minutes ago, Cornan said:

 

I don´t actually know until I have tried. There are several advantages with the AC-AC PS as a feeder supply compared to the Gophert. Things like balanced transformers, EMI input filter, torodial transformer, bigger transformer, no pre-regulation (=possibly less noise) etc are things that I consider an advantage to the Gophert. Both are floating. Gophert have an advantage of optimal pre-regulation (= possibly less heat). Other have said (over and over again) that the SMPS design is Gophert´s culpit...but I do not agree that it is true in my perticular setup!  

Anyway, the reason I bought the AC-AC PS is to find out if it could concur my Gophert? I really do think it could, but mainly due to the things I mensioned above and not due to the actual SMPS design. The balanced & floating design is the most important apect IMO.

You could add a $35 12 volt Sigma 11 discrete regulator board between the AC transformer box and the lt3045s and have a kick ass 12 volt solution. That's what I did here with Michaels 3 amp lt3045 board.

[Cornan]

7 minutes ago, lmitche said:

Happy to hear you are reaching out to Michael. He will steer you the right way.  He did the same for me.

 

I know he will. Still no answer though, but I will let you know what he said. Meanwhile I have been looking into my options to use a pre regulation of some kind. The LT1084 5A seems to be a likely candidate, but since it requires the AC input voltage to be minimum 2v MORE than the DC output voltage that would mean that I could just use a single HC-HPULN with 1v drop-down (15VAC>13VDC>12VDC) for this combo. Not optimal. Do you know of any other 5A pre regulators that might suits the purpose of getting the 15VAC down to 16VDC?

[Cornan]

3 minutes ago, lmitche said:

You could add a $35 12 volt Sigma 11 discrete regulator board between the AC transformer box and the lt3045s and have a kick ass 12 volt solution. That's what I did here with Michaels 3 amp lt3045 board.

 

Interesting! Do you have a link to that Sigma 11 discrete regulator board?

[mozes]

13 minutes ago, Cornan said:

 

I don´t actually know until I have tried. There are several advantages with the AC-AC PS as a feeder supply compared to the Gophert. Things like balanced transformers, EMI input filter, torodial transformer, bigger transformer, no pre-regulation (=possibly less noise) etc are things that I consider an advantage to the Gophert. Both are floating. Gophert have an advantage of optimal pre-regulation (= possibly less heat). Other have said (over and over again) that the SMPS design is Gophert´s culpit...but I do not agree that it is true in my perticular setup!  

Anyway, the reason I bought the AC-AC PS is to find out if it could concur my Gophert? I really do think it could, but mainly due to the things I mensioned above and not due to the actual SMPS design. The balanced & floating design is the most important apect IMO.

As you said, will know for sure once you tried it.

[lmitche]

4 minutes ago, Cornan said:

 

Interesting! Do you have a link to that Sigma 11 discrete regulator board?

Here you go!

 

https://www.ebay.com/itm/S12-Super-regulated-linear-power-supply-board-5-30V-LPS-10000uF-50V-Versio-PSU/132048787951?hash=item1ebeb899ef:g:odUAAOSwbopZPMnE

 

But on second thought, a 15 volt transformer may not be enough. You may need 18 volts AC into a chinese Sigma 11 to get 12 volts out.

 

Another approach is to find an lt1083/1084 board with enough current for your application. Here is one:

 

https://www.ebay.com/itm/LT1083-7A-Adjustable-Linear-Voltage-Regulated-Power-Supply-Board-Self-Recovery/282892603399?epid=2130705681&hash=item41ddb69007:g:3ucAAOSwutNasRD0

[Cornan]

24 minutes ago, lmitche said:

Here you go!

 

https://www.ebay.com/itm/S12-Super-regulated-linear-power-supply-board-5-30V-LPS-10000uF-50V-Versio-PSU/132048787951?hash=item1ebeb899ef:g:odUAAOSwbopZPMnE

 

But on second thought, a 15 volt transformer may not be enough. You may need 18 volts AC into a chinese Sigma 11 to get 12 volts out.

 

Another approach is to find an lt1083/1084 board with enough current for your application. Here is one:

 

https://www.ebay.com/itm/LT1083-7A-Adjustable-Linear-Voltage-Regulated-Power-Supply-Board-Self-Recovery/282892603399?epid=2130705681&hash=item41ddb69007:g:3ucAAOSwutNasRD0

 

Thanks a lot Larry!  

I will surely take this into consideration if needed. Another one that I have been looking into is the Sjostrom SSR-01 http://sjostromaudio.net/shop/super-regulators/17-ssr01-sjostrom-super-regulator-built.html

 

I´m sure you´ve heard about it. Since this is a locally made regulator it would mean quicker delivery, but is it a better or worse option to your ones do you think?

 

EDIT! Bummer! I thought this one was capable of more than 1A. Apparently not!  

[Cornan]

30 minutes ago, mozes said:

As you said, will know for sure once you tried it.

 

Yes, it beats interpret data sheets any day!  

 

Another important thing that I forgot to say is that due to the AC-AC PSs balanced & floating design I am actually quite comfortable to try it out connected directly to the AC mains wall outlet (maybe via a DC blocker trap filter though) instead of via the balanced & floating IT. That could have a bunch of positive effects to SQ as well if that holds true.

[Cornan]

5 hours ago, lmitche said:

Happy to hear you are reaching out to Michael. He will steer you the right way.  He did the same for me.

 

I just got a reply from Michael. Not the answer I was hoping for unfortunately so it looks like I’ll need to find a solution to either drop down 15VAC to 14VAC or find a pre-regulator that doesn’t need a 2v drop from AC to DC. Otherwise the series HC-HPULNs is out of the equation. A real challenge it seems! ?

Not a feel-good feeling at all right now to be honest! ?

 

Use following formula for calculating DC:

 

DC = AC x 1,414 - Diode Vf

15VAC x 1,414 - 0,4V = 20,81VDC

 

The LT's SOA is 20V, so you drive it with 0,81V above his good-feel-area.

 

A transformer with 14VAC would deliver the maximum voltage. 

 

 

[mozes]

36 minutes ago, Cornan said:

 

I just got a reply from Michael. Not the answer I was hoping for unfortunately so it looks like I’ll need to find a solution to either drop down 15VAC to 14VAC or find a pre-regulator that doesn’t need a 2v drop from AC to DC. Otherwise the series HC-HPULNs is out of the equation. A real challenge it seems! ?

Not a feel-good feeling at all right now to be honest! ?

 

Use following formula for calculating DC:

 

DC = AC x 1,414 - Diode Vf

15VAC x 1,414 - 0,4V = 20,81VDC

 

The LT's SOA is 20V, so you drive it with 0,81V above his good-feel-area.

 

A transformer with 14VAC would deliver the maximum voltage. 

 

 

Oops that’s a bummer, but you will find a solution!

[Cornan]

1 minute ago, mozes said:

Oops that’s a bummer, but you will find a solution!

 

Yeah, a real bummer! Not sure yet there is any good solutions either. I thought there would be AC-AC regulators around, but that straw seems very slim. The only luck I see right now is that my Brooklyn DAC really doesn’t need more than 1,5A. That will greatly improve the search results for suitable AC-DC reg boards, but it is still not optimal.

[look&listen]

54 minutes ago, Cornan said:

I’ll need to find a solution to either drop down 15VAC to 14VAC or find a pre-regulator that doesn’t need a 2v drop from AC to DC

Perhaps something to drop wall AC down a little so input to your balanced AC box is less and then output is less too.

[Cornan]

2 minutes ago, look&listen said:

Perhaps something to drop wall AC down a little so input to your balanced AC box is less and then output is less too.

 

Maybe, but I am not confident how that works IRL though? You mean reducing 230VAC to 220VAC for example?

[Cornan]

I’ll guess these are the sorts of challenges an EE would face on a daily basis. I’ll bet they’ll laugh their heads off reading this challenge! ?

 

@Speedskater & @marce where are you? I could use a little support here! ?

[look&listen]

6 hours ago, lmitche said:

Here you go!

 

https://www.ebay.com/itm/S12-Super-regulated-linear-power-supply-board-5-30V-LPS-10000uF-50V-Versio-PSU/132048787951?hash=item1ebeb899ef:g:odUAAOSwbopZPMnE

Thx for link!

Already fan of AMB s11 & clone & variant LPSUs. This standout because board layout seem special to me.

AC come in bottom left, rectified on left side, regulated on top side, DC out top right. Clean path for major current along outside edges of PCB. Center of board full of energy storage (caps). sensitive control circuitry on bottom right away from current path. Perhaps @JohnSwenson has thoughts too, if not too large for him?

Very good data on circuit and components. Like may other things too, like only $40. But circuit layout is best I see in long time (of those i understand). Impressed on top of proven fine circuit design, 24A capacity, and call out to designer. Would buy one if need more hi-current LPSU!

 

https://i.ebayimg.com/images/g/qNcAAOSwOMdZPMm9/s-l1600.jpg

[look&listen]

18 minutes ago, Cornan said:

 

Maybe, but I am not confident how that works IRL though? You mean reducing 230VAC to 220VAC for example?

Exactly. Like some volt regulator transformers, or auto-transformer, maybe more. Path to search?

[Cornan]

1 minute ago, look&listen said:

Exactly. Like some volt regulator transformers, or auto-transformer, maybe more. Path to search?

 

For sure! Would you know how to calculate how much high voltage VAC I’ll need to drop before reaching a 0.81 VAC output drop-down by any chance? ?

[look&listen]

2 minutes ago, Cornan said:

Would you know how to calculate how much high voltage VAC I’ll need to drop before reaching a 0.81 VAC output drop-down by any chance?

Not sure. Not big math guy. But think percentages. What is percentage of voltage reduction in box? Then apply that to reduction needed. Probably go a bit more away from danger zone too.

[Cornan]

1 minute ago, look&listen said:

Not sure. Not big math guy. But think percentages. What is percentage of voltage reduction in box? Then apply that to reduction needed. Probably go a bit more away from danger zone too.

 

That’s a bit too average to be inside the comfort zone for me personally. Since I am very close to what the LT3045 can handle I’ll need both belts and braces to be relaxed about it! ?

[mfin]

Maybe you can build something for an item that doesn't need 12V dc?

 

Aries mini you have takes a higher range https://support.auralic.com/hc/en-us/articles/205863008-What-is-the-Specificaion-of-ARIES-MINI-Power-Input

[Cornan]

13 minutes ago, mfin said:

Maybe you can build something for an item that doesn't need 12V dc?

 

Aries mini you have takes a higher range https://support.auralic.com/hc/en-us/articles/205863008-What-is-the-Specificaion-of-ARIES-MINI-Power-Input

 

You must be reading my mind! ? The Aries Mini is already my escape route out of this misery! ?

However, that does’nt change the fact that LT3045 needs <20VDC though.