The true experimental tweak thread

[Abtr]

10 hours ago, Cornan said:

...

I have also asked ALT Hi-Fi how much he wants for a 200VA balanced AND floating isolation transformer. I have already asked him for the same one unbalanced and floating, but after reading the great posts by @Abtr how much he prefer his floating IT to be balanced wired I descided to give it a try for the fun of it. Still not intirely sure where I will put it yet though, but my primary choises in order for the moment are between these spots: post DC blocker trap filter and pre Voltcraft 1134>main router, post Ultra IT and pre active speakers in B setup, pre Gophert PSU>Thinkpad X201 or maybe a dedicated line for the Gophert PSU>Aqvox switch-8 in my A setup. We´ll see where it ends up!? 

 

 

Interesting.. Make sure that the balanced IT doesn't have a ground/Earth connection to the (secondary) center tap and/or the equipment chassis.

[Abtr]

3 hours ago, Cornan said:

... Actually, the best thing when using a isolation transformer with floating secondary is to connect all the devices to it. ...

 

Well, IME with my (balanced) IT with floating secondary, it seems best to connect the power supplies of all gear that has an analogue audio output function and/or a digital audio clocking function to the isolation transformer (i.e., DAC, pre-amp, power-amp). All other (audio related) equipment (computer, streamer, etc.) should be isolated from the analogue gear as much as possible, maybe even with their own IT.

 

I'm currently experimenting with an Uptone iso Regen and its LPS-1 power supply. The combo sounds better when the Meanwell SMPS of the LPS-1 is *not* connected to the isolation transformer. So there may be a grey area of devices with which you'll have to experiment..

 

BTW, I didn't try the Gophert yet, but I intent to use it as a power supply for the LPS-1 or my laptop.  

[Abtr]

4 minutes ago, octaviars said:

So one IT to my CD/DAC/pre-amp (one box) and poweramplifier and one IT to the streamer.

 

Do you have any info on the IT you make that you can share @Abtr ?

 

I currently use an Amplimo ZN1902S: https://www.toroidal-transformer.com/shop/high-end-audio/audio-safety-transformer/709/audio-scheidingstrafo-900va.html I have an Airlink BPS1502 coming: https://airlinktransformers.com/product/standard-balanced-power-supply-bps1502 

[Abtr]

16 hours ago, octaviars said:

 

There are no coils so the filter wont affect the impedance.

 

As per definition any AC filter increases AC impedance for specific frequencies.

[Abtr]

13 minutes ago, octaviars said:

Yes but does XY-capacitors and varistors that only are in parallell to the signal also affect the impedance at 50Hz? I cant measure any difference in impedance before and after the filter with my Fluke installation tester.

 

It's not about 50Hz impedance. The impedance for high frequency noise from noisy power supplies in your system will increase. See e.g. this thread:

 

[Abtr]

19 minutes ago, octaviars said:

Yes I get that but are you just refering to a transformer that have higher impedance for higher frequenzy? I talk about capacitors and varistors not a transformer.

 

 

The impedance for high frequency noise from noisy power supplies *within* your audio system will increase. According to John Swenson (and I concur), that causes audible degradation of sound. It's better to have common mode AC noise loops with low impedance than high impedance ones. 

[Abtr]

1 hour ago, Cornan said:

After work I got right to my B setup. Got everything hooked up and spend a couple of hours messing with settings and driver's. It reminded me why I left PC based music in the first place! ? Anyway, I'm back atleast to give it another go.

PC are loaded with JplayStreamer, AO, Fidelizer Pro & Process Lasso and are heavily tweaked for years. Control point with BubbleDS Next playing Tidal only.

 

 

I added the ATL balanced IT with switch on the outside of the case that can float or ground the center tap. It is a bit tight with space, but here is some pictures inside the cubborn.

 

 

My Monkey Banana Turbo 5 speakers are connected to my Ultra IT only. Thinkpad X201 laptop is powered by a Gophert csp-3205II and another Gophert is powering the D-Link switch. Both Gopherts with grounded DC negative outputs to Aucharm box. Gopherts and D-Link wireless adapter is connected to the balanced IT which is the center of attention on this post.

 

I wanted to try the center tap lift. Started with grounded center tap and it sounded just great with a lot of body and weight and transparent sound. Then center tap lift. Holy cow! Amazing transformation with space deep sound stage and a tight and yet firm and deep bass performance never heard before in my B setup. Awesome mid-range. The sound is truly glowing with a floating balanced IT. @Abtr was right. It sounds really really good!

 

Remember that this setup is only in its initial phase, but it already sounds glorious thanks to the balanced IT and my beloved Gopherts! ?

 

 

 

That's very nice. You may also want to try powering your DAC, pre-amp and power-amp(s) with a dedicated floating balanced mains IT (+ DC blocker).

[Abtr]

40 minutes ago, Cornan said:

 

My Gustard DAC-X10 is already powered with the balanced IT (I just forgot to mention it. Also the balanced IT is connected to a BlueWalker PowerWalker 1200VA voltage regulator). I have no preamp or Poweramp in this setup. The DAC have built-in volume vontrol is connected to my active speakers via balanced XLRs.

The active speakers are connected to a Ultra IT that can be transformed into a balanced IT. I will probably do that later on since I doubt my 200VA balanced floating IT is sufficient for both the speakers and the rest of the setup. However, since the ATL balanced IT is dead silent and the Ultra IT hums quite a bit I might just order a second one from ATL and sell if the Ultra IT. After hearing it there is absolutely no doubt in my mind that it will improve things further. I have also the possibility to ground the center tap from the outside of the case if I want to or need it in the future.

 

BTW. How do you protect the output of your balanced floating IT? As I understand a 2-pole GFCI is needed. I have not found a portable 2-pole GFCI so far.

 

I use this 2-pole 16A 230V Eaton 236948 RCD/GFCI (not exactly portable):

 

 

And, IME a truly dedicated balanced IT just for your DAC and amps (or active speakers) sounds best..

[Abtr]

59 minutes ago, John769 said:

@Abtr Have you somehow modified your Airlink BPS 1502 to make it floating, or use another brand?

 

I currently run everything- PC, DAC with PRE, active speakers through a Peaktech 2240 floating PSU. Total system draw is 150 to 200 watts (max) with a watt meter.  Sounds pretty good but I am planning to get an Airlink 1500va, or perhaps 2000va, because the speakers might be better fed by a balanced IT.

 

I was thinking maybe to run the speakers only through the Airlink (once purchased) and the rest of the gear with the Peaktech.  Or alternately to plug both the speakers and peaktech (with other gear) into separate sockets of the Airlink.   There's also the option of selling the Peaktech and starting afresh, but only after making comparisons 

 

Anyhow just wondering what you might advise, seeing as you own the Airlink model I was planning on getting?  Thanks!

 

Well, if you have multiple (floating) balanced ITs then you can experiment with different configurations. My personal experience with the Airlink is that it's best to power only DAC, pre-amp and power-amps by the Airlink. All other (digital) audio gear is powered separetly (and is galvanically isolated from the DAC).

 

Regarding the Airlink BPS1502, I disconnected (floated) the secondary ground from mains Earth where it was bolted to the chassis:

 

 

And I installed a simple DC-blocker (no soldering required) : 

 

  

[Abtr]

17 hours ago, mikicasellas said:

Hi,

 

Where do yuo connect this device, before or after the transformer which is connected to the wall? any pictures?

 

A 2 pole RCD must be connected in series with the AC *output* of a floating balanced mains isolation transformer, because any potentially lethal short to the equipment chassis won't trip your regular leakage current detector (centrally positioned before the IT). An RCD at the floating balanced output will trip and disconnect both AC output poles when a current difference of about 30mA is detected between the poles, which takes care of the problem. (Note that  the equipment chassis is connected to balanced ground/null at the secondary center tap of the IT).

[Abtr]

1 hour ago, John769 said:

Hi @Abtr. When your model BPS1502EU is used in standard form (ie without your floating modification), does it need an RCD on the output at all (which would be for my speakers)?

The standard form with secondary center tap connected to mains Earth will trip your regular central AC leakage current detector in case of a (balanced) short to chassis, so it doesn't need the output RCD.

 

Quote

How about if I plugged my Peaktech floating IT into one of the sockets, which already has a portable RCD on it:

 

https://www.amazon.co.uk/gp/product/B007K50PS0/ref=ox_sc_sfl_title_4?ie=UTF8&psc=1&smid=A3P5ROKL5A1OLE

I guess that might be safe if it's a 2-pole RCD/GFCI..

[Abtr]

24 minutes ago, Cornan said:

...

In the end it is all just an hide-and-seek-game between power, isolation and grounding. The winner is the one that can balance them all! ?

 

An AC mains isolation transformer with (floating) balanced output?

[Abtr]

13 minutes ago, Cornan said:

 

Yes, that provides a great balance indeed! ? I am extremely happy with that perticular choise. Thanks for opening the door! ?

Do you use a balanced mains isolation transformer for your (analog) gear? (That is a 230VAC to 230VAC transformer..)

[Abtr]

15 minutes ago, Cornan said:

Yes, for the moment I do connect my turntable (my one and only analogue gear in A setup) to the balanced & floating IT.

...

 

First try powering *all* analog gear with a single dedicated balanced IT. Note that for a decent power amp alone you'll need at least 500VA.. 

[Abtr]

22 minutes ago, Cornan said:

 

Well, that's the problem. My ATL is just 250VA and my Peaktech 2240 is 500VA. The ATL is sufficient for the active speakers and perhaps the Brooklyn DAC as well. The remaining things needs to be connected to the Peaktech 2240 until I get a bigger balanced & floating IT. Anyway, I will experiment with any possible combo when I merge the two setups into one. Right now I am all focused on where the coming voltage regulators, Luckit BluWave PCB and shunt regulators with starquad Kelvin cables and DC plugs will end up.

 

So you need a high power mains IT to feed balanced AC to your DAC (pre-amp) and power-amps. I currently use an Airlink BPS 1502EU (1500VA)..

[Abtr]

13 minutes ago, Cornan said:

... Did you rewire the Airlink BPS 1502EU into a floating one? If so, could you share how you did that? 

 

I shared that here:

 

[Abtr]

22 hours ago, drjimwillie said:

Hi - I just received a MGE (Topaz clone) Ultra Isolation Transformer 91097-31T it is 750 VA.

I live in the USA and want to use it 120V in - 120V out.  It came wired 120V in - 240V out.

I posted images and questions over on the AC mains isolation transformer thread.

I received some schematics and the most detailed wiring diagram, from the back of a transformer access door, that I have seen yet.

One of the CA senior contributors (an angel), helped me get it wired correctly, but I still have questions.

I have it wired: Primary (input)

120V Hot (black) ->H1

jumper H2 + H3

120V Neutral (white) -> H4

Ground from the wall ->G

 

Secondary (output)

Output 1 Hot (black)

jumper X2 + X3 & X3 + G

Output 2 Hot (white) ->X4

G-> output grounds

 

He also advised "wire in a green cable & join the Primary and Secondary terminals".  I did not do this because I ASSUMED that it is part of the factory wiring & because I got continuity from the input to the output ground.

 

My Angel feels strongly that the Secondary be grounded as you can see from above, and from all of his posts.  I would like the secondary to be floating because I understand that J.S. says it is safer that way, it looks like from the schematic it is designed that way & I understand that it sounds better.  Please correct me if I am wrong on any of these points, please.

 

Wired with the jumper X3 + G, I measure:

X1 - X2 = 62.7V

X4 - X2 = 62.7V

X1 - X4 = 126V

X1 - G   = 62.7V

X4 - G   = 62.7V

 

With the jumper removed from X3 + G, I measure:

X1 - X2 = 62.7V

X4 - X2 = 62.7V

X1 - X4 = 126V

X1 - G   = 32.3V (is this weird that these do not match)

X4 - G   = 86.0V (is this weird that these do not match)

 

I thought from the @JohnSwenson example that I would measure 0V from the ground because it is floating??

What is strange is that when I look at the access door schematic, that this transformer is wired 220V in - 220V out.

 

My questions are:

1. With the jumper removed from X3 + G is this a floating Secondary?

        a. Is it wired correctly for a floating secondary?

        b.  Do I want it wired for a floating secondary?

2.  Is this wired Balanced?

        a.  How do I wire it for balanced?

        b. Do I want it wired balanced?

I am so excited - thank you very much for your help! (then I did a little dance)  (any comments are appreciated)

Will

 

 

Basically a low capacitance IT (like a Topaz or your MGE) with unbalanced secondary isolates/filters high frequency noise from the mains power. In addition a balanced secondary (largely) eliminates (common mode) noise thrown back into the mains by the load, which might otherwise end up as distortion in the analogue audio signal. Below are the possible balanced/unbalanced/floating/non-floating connection schemes for your IT as far as I can tell:

*Always* connect mains 120V hot (black) to H1, mains 120V neutral (white) to H4 and mains earth to  G at the input. Note that input G is (should be) internally connected to primary neutral (H4), the electrostatic shield and the chassis of the transformer.

For 120V ->120V unbalanced non-floating output, jump H1 (H1A) and H3, jump H2 and H4, jump X1 and X3, jump  X2 and X4, jump X4 and G and connect both the green-yellow wire and the solid green wire at the output to X4. This is safe because your gear's chassis is now connected to mains earth and a short to chassis will trip your central GFCI and/or blow a mains fuse.

For 120V -> 120V unbalanced *floating* output, disconnect the green-yellow wire and the solid green wire from G at the output. Note that this is *unsafe* because now your gear's chassis is not connected to mains earth and a short to chassis will not trip your central GFCI or blow a mains fuse!

For 120V -> 120V balanced non-floating output, jump H2 and H3 (and remove the jumpers between H1A and H3 and between H2 and H4), jump X2 and X3 and remove the jumper at the top between G and X4 at the output, connect both the green-yellow wire and the solid green wire to G at the output and jump G to X2/X3 (which is now the secondary center tap). This is safe because your gear's chassis is connected to mains earth and a short to chassis will trip your central GFCI and/or blow a mains fuse.

Now, for 120V -> 120V balanced *floating* output, connect everything as was described above for a 120V -> 120V balanced non-floating output, and simply disconnect the yellow-green earth wire from G at the output but keep the solid green wire connected to G. This is *unsafe* because your gear's chassis is not connected to mains earth and a short to chassis will therefore not trip your central GFCI or blow a mains fuse! However, you can make this safe by installing a 2 pole RCD/GFCI at the output of the IT. Your gear’s chassis is connected to the zero voltage center tap (X2/X3) of the balanced secondary and a short to chassis will trip the 2 pole GFCI at the output of the IT.

 

Note that you should experimentally determine whether in your case a floating secondary sounds better than a non-floating secondary. In theory if you have no DC offset in your AC mains power and ground, then a *non-floating* balanced secondary should be best for CM noise reduction/cancellation..

[Abtr]

 

On ‎15‎-‎5‎-‎2018 at 4:33 PM, drjimwillie said:

@Abtr thank you so much for the extensive reply. 

 When you say wiring the transformer balanced eliminates common mode noise, is that because it does not get created in the first place or because it gets dumped into the ground,  or someplace else?

Reactive common mode noise from powersupplies will still be generated but with balanced power the noise in both legs of the PS is in opposite phase and cancels itself. This is called common mode noise rejection and it is comparable to the noise cancelation with balanced XLR connections.

 

Quote

I just posted two pictures of my transformer.   At the input there is a green wire going into the chassis.  On the output there are two gray wires coming out of the chassis.   No green wire.   How do I deal with this, please. 

At the input there are 2 green wires going from G into the chassis (yellow-green = savety ground, black-green = grounding to shield). At the output there is a yellow-green savety ground wire connected to G (ground) and to X4 (neutral) with a jumper. 

 

Quote

 If I plan to experiment with floating the secondary, balanced then I need to purchase and use the two pole GFI before I can experiment, correct? 

Yes.

 

Quote

 I plan to hardwire an Alt hifi DC blocker before the IT.  So then  I will only be susceptible to DC coming in over the ground. 

Correct. You can use a capacitor in the input savety ground wire (solid green) to block DC from ground (I use a 600V 18uF MKP type capacitor for that).

 

Quote

  One of the reasons I got into all of this is because I had a Hum coming over my speakers.   I have a dedicated circuit for my amp and a separate dedicated circuit for the rest of my system.   I did and experiment where I turned off every breaker in my house except for the one connected to the amp.   Only the amp was connected to the speakers,  no interconnect.  When I plugged it in I had a hum.   When I put a cheater plug on it and lifted the ground, the hum went away. To my limited knowledge this led me to think I have TC coming in over the ground.  To my limited knowledge this led me to think I have DC coming in over the ground.   The manufacture of my CJ solid-state amp said that this was an invalid experiment.   However, I have lifted the ground in my amp.  I did that week where I added  (2) 2/0  cables from the chassis of my preamp and amp to the ground on my preamp. When I touch the cables from  The chassis of my amp to my preamp I get a loud hum.  I am in Denver in to clean everything up to see if I can fix this arm without the ground left and so I am able to connect the chassis. I am in deep. 

 

 

 

On ‎15‎-‎5‎-‎2018 at 5:27 PM, drjimwillie said:

The last lines above should read:

 I am endeavoring to clean up everything to see if I can fix this hum,  without the ground lift,  so I can connect The cables from the chassis of the amp to the preamp.  The cables from the chassis of the amp to the preamp 

Sorry for the typo. 

DC offset in your AC power may saturate the transformer of your amp which might cause it to hum, but this is not the cause of hum through your speakers. Try the experiment with the input connections of the amp grounded (i.e., ground the outer connectors of the RCA inputs). Balanced power may reduce/elimininate hum from ground loops.

[Abtr]

25 minutes ago, drjimwillie said:

I have an ultra isolation transformer, and I'm going to wire it balanced,  which means essentially, as far as I understand it, that the hot and the neutral wire are both live. I have the ground lifted on my amp and my preamp. I thought it was probably a good idea to reattach the grounds before I attach a balanced power supply  to these pieces of equipment. Because I am thinking that with two live wires then the ground is going to be required as a return for the current. Is that correct? 

No.

 

25 minutes ago, drjimwillie said:

Does it affect anything that here in the USA the ground and the neutral are both bonded together at the panel? 

No.

 

25 minutes ago, drjimwillie said:

I have two dedicated circuits. One has my amp the other has everything else.  I am building a  Power strip where  each type of wire is terminated in a star type configuration.  I am waiting for a part for each of the transformer and the power strip so I was thinking in the meantime I would try and experiment. I am thinking to reduce ground loops, because both of my circuits, although they are in separate boxes are on opposite sides of a stud so right next to each other. I was thinking to abandon the ground in the amp  amp circuit and extend a ground from the other circuit over to my amp receptacle.  This way both circuits share one ground so less chance of a ground loop.   What do you think? 

Try it.

 

25 minutes ago, drjimwillie said:

And then I thought well, I could bond the grounds of  both circuits together?  And use that now common, double, ground to feed my receptacles.  I was thinking this would increase the capacity of the grounds, but I don't know if it's a good idea?

Again, try it.