Questions & Answers

Eris Sub 8 power unit improvements

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asked Feb 21, 2023 in Sceptre, Eris, R-Series by tamaskamocsai (180 points)
I have some suggestions or recommendation for future builds of Eris Sub 8 and it's series.

First of all, I noticed that the main transformer causing a relatively big burmming noise. This noise can be detected when everything is quiet, but it was loud enough to be annoying even if my main computer is running. I disassembled the sub and noticed that the screws of transformer were loose. I don't know if it was caused by handling issue during transportation or manufacturing issue, but gluing the screws could fix / prevent this issue easily and cost effectively. I don't know if this was a unique situation or others experienced with the same issue, but I gently tighten the screws and the brumming noise gone.

The second problem I found is a switch on/off transient issue. This could be easily fixed by applying a small, 4.7 - 22nF / 600V capacitor + 500KOhm resistor in parallel of the main switch (between the two contacts). This used in many high-end systems to avoid switch-on/off transients.

The same must be added to ERIS studio monitors as well!

Future improvement could be a slow-switching on (so-called cold-start) circuit which could help reduce the stress to transformer and the whole power line. Some times, my UPS detecting that I'm switching it on...

Last recommendation to add a power outlet to Eris Sub and only switching on the SUB (of course it could be selectable) if the power outlet having a power consumer. Couple of Euros device can do this, but would be awesome to have this feature. Especially when users having Eris 3.5, 4, 5 monitors...

2 Answers

0 votes
answered Feb 21, 2023 by mattbennett1 (4,080 points)
Regarding the second problem, my Eris E8 do not make any sort of noise when switching on or off, so it must be specific to your model or something is actually malfunctioning, maybe even related to your first issue.
0 votes
answered Feb 24, 2023 by tamaskamocsai (180 points)

Thank you foryour answer mattbennett1, But, all of my respect, I have to say, no. The switching on/off noise will be there anyway. Just you haven't noticed it yet. This is a standard problem caused by inductive loads: Transformer core is magnetically natural and in the first start, it acts nearly as an ohmic load. When you switch it on slowly or you switch it on during sine-wave peak, you can easily generate a huge peak. For the same reason, many devices having specific noise filters and switch-on/off filters. Most probably, you haven't connected your sub in the same way and / or not closely checked when switching it on and off. This switch on noise is not big, just noticeable. But, when I switch on my Eris speakers on my desktop prior I'm switching on the sub, I have this small "pop" noise. The fact is that this unit has no noise-filter on it's power inlet line which could help to avoid these like transient caused problems. It is not a big deal to implement it in the future releases. I'm planning to add it to my sub after I already tested the issue  just as I'm added the required filters so many amplifiers I built.

After I written this down all, I realized that you probably speaking about your Eris E8XT instead of Eris Sub8, which causing the problem. E8 XT having a different amplifier inside therefore it will be totally different from the E3.5 and Sub 8.

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