AMB Laboratories DIY Audio

[danbmellow]

Has anyone else had this problem. The e24 switches off when other large loads on the same phase of my electrical panel switch on? If so, how do I remedy this?

[amb]

Turning on the large load caused a power glitch on your AC line, enough to disengage the ε24. There are different ways to deal with this:
1. Move the device with the ε24 or the large load to a different AC circuit.
2. Use some kind of AC line conditioner on the device with ε24.
3. Increase the C1 capacitance on the ε24 and add 0.1uF capacitors across the transformer secondary winding, maybe this would be enough to ride through some power glitches.

[danbmellow]

Thank-you. Especially for the quick response. Number one I am unable to do, but I will try number 3, and I am currently designing a power conditioner. I will post whether these work.
Dan

[zhai]

I have the same problem. I have a pramp/dac and a power amp, both use the epsilon-24. If I turn on the preamp first, most of the time it shuts off when I turn on the power amp. Also, the most annyong thing, both shut off when certain lights are turned on in the apartment, and also seemingly at random. I guess it could be when people in some of the apartments below/above me turn on power intensive devices.

So I'll try out option 3. I've found some possible capacitors, and I hope you could tell me which would be the best to get.

Potential replacements for the C1 cap: (Danish webshop, but it has English text and pictures as well)

680µf / 25VDC:
http://elektronik-lavpris.dk/product_in ... _id=102936

1000µf / 25VDC:
http://elektronik-lavpris.dk/product_in ... s_id=85767

3300µf / 25VDC:
http://elektronik-lavpris.dk/product_in ... _id=122108


Potential 0.1 µF capacitors:

http://elektronik-lavpris.dk/product_in ... _id=115932

http://elektronik-lavpris.dk/product_in ... s_id=85197

http://elektronik-lavpris.dk/product_in ... _id=102691

And just to be sure, when using 0.1 µF capacitors it shouldn't have polarity, so I'll just connect each end to one of the secondaries on the transformer?

Thanks,

Nicklas

[amb]

You'll want to go much higher in capacitance for C1 to make a difference, so I would go with 3300uF, but get a tall, thin one that fits the existing PCB footprint. The 3300uF one you listed is too fat. The 0.1uF cap should be non-polarized, like a film or ceramic type. All the ones in your list are fine, but I would choose the ceramic one because it's the least expensive and there is no need for anything fancy here.

Yes, the 0.1uF should be connected across the transformer secondary.

[zhai]

Ok I tried replacing C1 with a 3300 µF 25V cap, and I put a 0.1 µF cap over the transformer secondaries. This resulted in no difference whatsoever.

Almost every time I turn on my power amp or the bathroom lights, the preamp shuts off. As well as randomly. And it shuts off the exact moment one of those other devices is turned on. Any other ideas? I was researching the AC conditioner option, but it seemed to me that it would be very expensive. And it seems I only have one 230V AC rail in my apartment.

[amb]

Unfortunately, if those remedies make no difference, then your AC mains is just too glitchy for the ε24 to "latch". If cleaning up the AC line is not an option, then there may not be any other solution.

[zhai]

Well since it seems doing something about the AC seems to be the only option, I've been looking into that a bit. Seeing as the epislon-24 shuts off every time I turn on certain electrical equipment, I assume that short AC drops are the cause, so I looked at getting a UPS. From what I could read, there are 3 main types - offline (only activates when AC goes out of acceptable bounds), line interactive (corrects AC up or down if AC error is small, shifts to battery if AC error is large), and online (always using the battery).

The issue is that I don't know if the UPS will correct the voltage drops quickly enough that the epsilon-24 won't shut off. I read something about them taking in the order of 5 milliseconds before activating. The online UPS is noisy and expensive, so I'd rather not get one of those, though they have an activation time of 0 s.

I also thought about whether it would be possible to just connect some kind of battery to the circuit, so that it would always have a reserve, and it would be a bit silly getting a big UPS for the whole pre and power amp system, as it's only the epsilon-24 circuits that are vulnerable. I realize that this will remove the over/undervoltage protection, but at this point I'm exceptionally tired of them shutting off all the time.

[amb]

It's possible to add batteries, but you need something that provides between 13V and 15V, and also need to hack the board to add a couple of "or"ing diodes.