The true experimental tweak thread

[BigGuy]

1 hour ago, Cornan said:

I am sitting in my comfy coach listening to my new sound. A bit star-strucked! ✨ I wish I could just let it be like this. No more changes. The latest change in my second LPSU made me appreciate importance of parallel LT3045 even more. I wish I had the funds to change out all my remaining 6 LT3045s to HC-HPULNs, my three HPULNs to HC-HPULNs and my remaning three Gopherts to balanced & isolated toriodal transformers in one go and be done with it. Happy forever! ?

I know I know. It won’t happen, but it was a really nice day-dream for a couple of seconds! ?

Forever is a long, long time! 

Being happy for that amount of time is NOT an audiophile trait, as least among those I know and, assuredly, not those posting on CA!

Glad you ARE enjoying the music!

[BigGuy]

1 hour ago, Cornan said:

 

If you want to power both FMC input and output with best results with a valuable option I would recommend that you buy this two-way independant LPSU https://www.ebay.com/itm/50VA-50VA-HIFI-Linear-power-supply-2Way-LPS-50W-50W-DC-5V-9V-12V-15V-18V-19V-24V/132431179122?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m1438.l2649

 

 

You can also step it up a little by choosing 5v on the upstream FMC (close to the router) ad 9v on the downstream FMC (close to the audio setup) and add LT3045s (1A), MS-HPULNs (3A) or  LS-HPULs (5A) i series with 2 Vf (voltage forward drop).

 

Ps. Note that you can adjust the output voltage yourself with the blue voltage adjusters inside the case if you want to change it later on. Ds.

Nice find!

Few questions...

Site says "ultra low noise" but do not see any spec.   Is this known?

From pics, does not appear to be much heat sinking.  Is this a potential problem?

I have read that it is not advisable to have multiple PSs in same box.  Is this an issue?

[BigGuy]

9 minutes ago, Cornan said:

 

Thanks! ?

This LPSU have two Sigma 11 (S12) type discrete voltage regs which is both very low noice and not perticulary sensitive to heat (requires a higher voltage drop than LT3045). It also have separate toroidal transformers for each S12 type which will ensure less transformer artifacts compared to a single transformer. Toroidal transformers do not get as hot as for example an R-core.

I was going to build an LPS from this S12 module...

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

which seems to have more heat sinking than the dual supply you found.  I would prefer not having to worry about heat or its side effects or need to modify the LPS to deal with this issue.

IF neither heat nor "artifacts" will be an issue, this will take care of my reqs for [email protected] and [email protected] plus eliminate a box.

Currently I am using no LT3045 regulators.

[BigGuy]

12 hours ago, lmitche said:

Hi Frank,

 

Nice catch! Yes you want the sigma 11 boards with the four heatsinks on the rectifiers and two big black 10,000 uf caps. 

 

I have made five lpsus here with these boards, three single, and one dual box. They are excellent lpsus for our use here but be careful, the mosfets fail when shorted. I have learned to unplug them, make all Dc connections, and lastly connect the AC power.

 

These things power multiple lt3045 chains here so I usually buy them in odd voltages like 7, 9 and 15 to have room for 1 volt of vdrop in each of the lt3045 boards.

 

You have to change one of resistors to make a major voltage output change as the blue pot has only about 1 to 1.5 volts plus and minus. You may also need to change out the transformer.

 

Make sure the mosfets are truly insulated on the heatsink or case floor as otherwise weirdness happens.

 

You can find these in nice cases already pre-made with one, two or three transfos and regulator boards inside. These cost roughly $100, $200 and $300 respectively plus shipping. I have one of these as well and it is very nicely done.

 

Larry

Appreciate the watch-out on hooking up the LPS!  No need to let smoke out of box.  ?

 

Can you provide more detail on what to look for re mosfet insulation?

 

I will have to look for LPSs based on S11...maybe one with double output, e.g., [email protected] and [email protected].

[BigGuy]

On 5/13/2018 at 12:32 PM, Cornan said:

 

Thanks John! ?

Yes, it is two boards. The first board have a Kemet at the input and the last board have a Kemet at the output. No Kemet inbetween the boards (under the Entreq mini wrap cover).

I read  this thread but a poster just suggested the use of the Kemet cap(s) in a DIY LPS I am building around the S12 module.

Is this a recommended addition?  If so, where would it/they be installed?

[BigGuy]

29 minutes ago, Cornan said:

 

The Kemet A750 (25v/560uF) is an awesome upgrade IME. I use them on the voltage reg DC output (all LT3045) on all of my LPSUs. Quite often they also improve on the LT3045 input, but that needs to be tested in your setup. ?

 

I am not (yet) using LT3045 so would it still be good to add the Kemets?

Given my lack of circuit knowledge, would need more "Betty Crocker" on where to install.

[BigGuy]

5 minutes ago, Cornan said:

 

Well, I am not at all pro using dual output PSUs for FMCs, but since a dual LPSU was what I understood original question was all about I suggested this one as a good solution for a dual output LPSU since it have separate transformers for each voltage reg. 

For a better solution the downstream FMC should have the best possible LPSU while the upstream FMC (close to the router) is not as important. Separate LPSUs will always beat multiple output LPSUs with the identical specs IMO.

Cornan understood correctly and I thought the dual LPS was a good suggestion.  The 9V and 5V that need to be supplied are 2 separate devices.  The FMC receiver takes the [email protected] and the FMC transmitter plug-in card is powered by the PC.  The only connection the PC (with internal FMC) and FMC share in common is at the master panel. 

Makes for extra luggage but perhaps why I have also read that separate supplies are better.

[BigGuy]

We have recommendations for various treatments of DC cables, e.g., JSSG(360), JSGT, quadcore, Kemet caps, muMetal, etc. which are literally "outside of the box". 

 

What about the PS internal wiring?  Should it be shielded, e.g., JSSG?

 

What about the transformer?  Should it be boxed or canned to mitigate magnetic field interference?

 

I have read that r-core may be better, noisewise, than toroidal but worse with regard to generating fields.

 

Was thinking about going with r-core replacement of toroidal in a planned DIY LPS but now wonder if some sort of Faraday cage, etc., needs to be considered?

 

This has become, in my case, one where a little knowledge is a dangerous thing!

[BigGuy]

20 minutes ago, jabbr said:

If you are using an isolation transformer and you have increased hum “buzz” coming from your speakers then the transformer is not helping, rather hurting. It may be defective or else you may have another issue. 

Maybe already reported but does the system/speakers buzz if IT is removed?