[L0rdGwyn]

@oneguy did you build the chassis for the 2.4kVA Topaz in your classifieds listing?

https://www.head-fi.org/threads/fs-topaz-91002-32-in-aluminum-enclosure.921004/

It's very sleek, I have thought of doing something similar for the unit I ordered. Having a bare naked 60lbs anvil on the floor isn't going to sit well with the Mrs.

 

[Zenvota]

Any guidelines on what size unit does one need? My setup consists of:
- Music server PC which is NUC based (so very low power)
- Lampizator Amber DAC
- GOTL headphone amp
- Another headphone amp being built by Glenn
- Couple other headphone amps, but they're not all powered at the same time...

Also, can anyone confirm (or dispute) the claim that being under-loaded is bad (and therefore bigger is not always better)?
I mean is it possible that the 1kva that @Zenvota used initially was just faulty?

I think a general guideline is keep your load between 10% to 60% of the rated value of the unit. I still use that 1kv unit on my multichannel system and it works wonders. It doesnt appear to be faulty, Ive checked unloaded and loaded voltage, power draw, etc. Currently have on it:
Denon x4200w
Audiosource amp100vs
2x bic v1220s
and a dayton sa70

Typically load during dialog is 140w, and max spl is 700w for the whole system.

If the transformer is underloaded power transfers between the windings differently I forget the word ><

 

[oneguy]

@L0rdGwyn the cases can be found on eBay. It’s hard to find them now because all of the sellers on “away” which pulls their listings from the search engine. Here is the listing for a case the same size as the one I sold.

https://rover.ebay.com/rover/0/0/0?mpre=https://www.ebay.com/ulk/itm/302660809662

While that case worked for my -32 2.4kVa I had to shoe horn it in by cutting transformer narrower and shorter. You have the 2.5kVa -31 which is 0.9 longer and won’t work with the above listing without extreme cutting. Maybe not event then.




When the sellers come back from what I suspect Chinese New Year holiday try searching for “300 311 aluminum.” It should yield some results of cases like the one below. That may just barely work for your increased length without cutting. These cases measure 300mmx300mmx311mm. Expect to pay about $160-170 shipped. I turned my transformer sideways to make it fit. You may or may not be able to do that. The listing will have the internal dimensions posted.




Here is the first case next to a the same jug for comparison



The next larger cases can be found by searching for “356 aluminum enclosure” these are 356mm long and will definitely fit your transformer. These cases measure 300mmx300mmx356mm. I believe they are about $25 or $30 more than the 300x311 case. Your transformer will fit with no cutting running lengthwise.

 

[L0rdGwyn]

@oneguy thank you sir, that is extremely helpful. I'll most likely seek out the 356mm chassis when those eBay sellers return, think that would be the easiest route and I'd like to avoid trimming the transformer. That big chassis could make for a nice footrest since the cost will be pushing $200, I suppose another option would be to have a custom chassis cut, but the cost would be a bit higher, probably around $250-300 through Landfall Systems, they are doing a chassis for me now for another project. Something to think about, thanks again.

 

[Zachik]

Typically load during dialog is 140w, and max spl is 700w for the whole system.

How do you measure? Using one of those "Kill A Watt"?

 

[Zenvota]

How do you measure? Using one of those "Kill A Watt"?

Yup, I use those cyberpower ups units (surge + autoformer + sinewave ups) that have a readout.

I think it makes for a nice power system, wall > ups > isolation transformer, im in florida so anytime theres a surge or brown out or black out(which is daily) the transformers would lose power and then in rush current and i dont think thats great for components.

Reducing all the surges, maintaining stable voltage, and reducing line noise is probably good for the lifespan of electrical components as well, especially alot of the budget ht audio gear and projectors(not so budget projectors) with switching supplies.

 

[oneguy]

How do you measure? Using one of those "Kill A Watt"?

I’m almost positive the Kill A Watt has a VA setting. That’s the one that should be used for these measurements since it accounts for reactive power and real power which is what these units are rated in (VA).



I couldn’t find my Kill A watt so I need to do more searching to verify what my system is using but with a 5kVA in balanced or a 2.4kVA in conventional and powering the following components (speakers/pre-amp and headphone amp not at the same time) I haven’t heard any negative effects from low loading.

KG Grounded Grid
Spire KTE
LH Labs Pulse Blue
LH Labs 20G
Emotive XPS-1

Schiit Freya
Emotiva last Stealth 8

 

[L0rdGwyn]

Can anyone share what design considerations must be made before wiring for balanced power? For example, does equipment connected to a balanced transformer require DPDT switches since both poles are hot relative to ground?

I specifically went for the -31 model for the option of wiring in balanced, but want to be sure the implementation is safe before I move forward. Diving into this topic this weekend.

 

[oneguy]

@L0rdGwyn
1. Consult the manufacturer to make sure you’re equipment accepts balanced power. That being said, the CTO of Emotiva told me my Stealth 8’s wouldn’t cut on with balanced power. That was incorrect. So the company may not have correct info for you either.

2. Wire your transformer for 240 in and out. (Jumper x2/X3 and h2/h3)

3. Ground x2 or x3 on the output side (doesn’t matter which one)

then:

Correct, I always check the finished wiring with a multimeter to make sure it’s wired properly.

1. H1 and H4 to the case HAS TO read as an open circuit.

2. X1 to X4 should read something really low. Probably less than an ohm

3. H1 to H4 should read something really low. Probably less than an ohm

4. X3 to the ground should be low, close to 0 ohms or reading 0 ohms depending on your multimeter.

5. Re-check all the screws to make sure they are all tight then...

AFTER you have done the steps above (the first one is the most important) then plug it in and check the output voltage. On my non-balanced transformer setup I typically see 2-3v higher on the output side than the input side. I haven’t personally done a balanced setup and tested the voltage output but I imagine it should be about the same 2-3v above input voltage.

Now your transformer is wired for balanced power. All my switches are stock.

 

[L0rdGwyn]

Well thank you again @oneguy , I'll do my due diligence and be sure everything that could potentially be connected will function properly. I'll post here once I have taken the plunge, will give the transformer a go non-balanced first. Should hopefully have it early next week.

 

[oneguy]

I’m almost positive the Kill A Watt has a VA setting. That’s the one that should be used for these measurements since it accounts for reactive power and real power which is what these units are rated in (VA).



I couldn’t find my Kill A watt so I need to do more searching to verify what my system is using but with a 5kVA in balanced or a 2.4kVA in conventional and powering the following components (speakers/pre-amp and headphone amp not at the same time) I haven’t heard any negative effects from low loading.

KG Grounded Grid
Spire KTE
LH Labs Pulse Blue
LH Labs 20G
Emotive XPS-1

Schiit Freya
Emotiva last Stealth 8

At idle in headphone listing configuration my system sits at 192W and 234VA

At idle in speakers configuration I sit at 133W and 157VA

At idle with both headphone and speaker related components at idle I sit at 262W and 313VA

Due to the Kill A Watt covering the top plug I can’t test it during a listening session because I need the top plug in the wall to power my other transformer (has LPS-1.2 powering SU-1 and iBOX-V1000 on it)

 

[Zenvota]

I haven’t heard any negative effects from low loading.

Oh, good! I have some low power(5-10w) hdmi extenders/switchers on the transformers as well and was worried that they may be affected.

 

[L0rdGwyn]

My 91002-31T arrived today. Holy cow this thing is a BEAST. Not sure I am comfortable carrying this more than a foot off the ground, pretty sure if I dropped it it would go straight through the original floor of my 1920s home

Here is a pic:



Interestingly, it is wired for 120V on the primary, 240V on the secondary and has a Schuko connector on the secondary side. Must have been used with some European equipment in its life.



Primary wiring:



Secondary wiring:



Going to have to do some rewiring before I can even test it, either go full balanced right away since I'm partway there or revert to 120V in and out. Might have a connector lying around somewhere to replace the Schuko, or I could order an adapter to test just in case there is a problem, seller was very flexible about returning if there is an issue. I did test for primary to secondary shorts at least, no issues there.

My girlfriend's first words upon seeing it: "Wow, that IS ugly."

 

[Zenvota]

Nice lookin' unit!

My girlfriend's first words upon seeing it: "Wow, that IS ugly."

Kind of anecotal but interesting I think. Before adding these to my multi-channel system, my gf always kept the volume very low when watching things on youtube, even with range compression, as the audio just didnt sound good. Say videos of people walking around urban areas, all the background sounds smeared into a convoluted mess. After adding the topaz though and doing some additional isolating she keeps the volume much higher, and commented several times about how much more natural everything sounds.

 

[L0rdGwyn]

Nice lookin' unit!


Kind of anecotal but interesting I think. Before adding these to my multi-channel system, my gf always kept the volume very low when watching things on youtube, even with range compression, as the audio just didnt sound good. Say videos of people walking around urban areas, all the background sounds smeared into a convoluted mess. After adding the topaz though and doing some additional isolating she keeps the volume much higher, and commented several times about how much more natural everything sounds.

That is interesting, hopefully the power of hifi audio will warm my girflriend's cold heart. I actually don't find it very ugly, just bulky. I'll get it into an attractive enclosure at some point.