Hypex Ncore

[bavmike]

Originally Posted by troystg

Your Monster power bar is a conditioner or does it regulate also? 120 is VERY high for a home circuit, usually 110-115VAC is the norm.

Get (borrow) a Fluke 87 series meter and use the record the max/min voltage function to see if it varies up any..
I had the same issue with a linear power supply on my UcD amps.. My line voltage was 118VAC so I put a cl60 in series and upped the resistors values in my twisted pair power supply PCBs and was able to just squeek under the limit.

I don't know if the Hypex SMPS has an auto adjust funtion to switch between 115 and 230 VAC.

No the monster is just a conditioner, no voltage regulator built in. The readout varies between 118-119v at home where I've never had a problem with the amps. It's stays locked on 120v at the shop and doesn't move. I hooked up the monster bar to my UPS and when I unplugged it from the wall, it switches to the battery supply, both of the amps start working and the readout drops to 109-110v. As soon as I plug it back in one fires up and the other flashes on and off intermittently. Without the monster plugged in both won't work at all. I imagine this is because the monster bar absorbs some of the electricity bringing the voltage down slightly.

[Julf]

Originally Posted by troystg

I don't know if the Hypex SMPS has an auto adjust funtion to switch between 115 and 230 VAC.

It has.

[Julf]

Originally Posted by bavmike

I hooked up the monster bar to my UPS and when I unplugged it from the wall, it switches to the battery supply, both of the amps start working and the readout drops to 109-110v. As soon as I plug it back in one fires up and the other flashes on and off intermittently. Without the monster plugged in both won't work at all. I imagine this is because the monster bar absorbs some of the electricity bringing the voltage down slightly.

It does sound like over-aggressive overvoltage protection in the amps.

[bavmike]

Originally Posted by Julf

It does sound like over-aggressive overvoltage protection in the amps.

Ya seems that way. It would be nice if I could adjust it at home. But on the other hand it might be a good idea to run that voltage regulator anyways. Unless it has any detrimental effects on the sound quality. I read some stories about other audiophiles using the APC regulator with their delicate tube gear with very positive results.

[analog_sa]

Originally Posted by Julf

And do you run the cables in such a way that the speaker cables can induce voltages into the phono input?

Not sure what is the prescribed way to run cables carrying 600mV @450kHz so they don't radiate. Tonearm, which by design has a piece of unscreened, unshielded signal carrying wire is about a meter away.

[Julf]

Originally Posted by analog_sa

Not sure what is the prescribed way to run cables carrying 600mV @450kHz so they don't radiate.

Preferably as twisted pairs.

Tonearm, which by design has a piece of unscreened, unshielded signal carrying wire is about a meter away.

As long as the signal wire doesn't run parallel with the speaker cable, I wouldn't think there would be much interference. How badly does the phono input pick up stray fields from stuff like mobile phones? Can you twist the unshielded signal wires together? And how about putting a small HF capacitor to shunt off HF in parallel with the phono input?

[ChrisPa]

Originally Posted by analog_sa

Not sure what is the prescribed way to run cables carrying 600mV @450kHz so they don't radiate.

Only run them at the speakers
Monoblock amps behind each speaker with xlr leads to the amps

[analog_sa]

Originally Posted by Julf

Preferably as twisted pairs.



As long as the signal wire doesn't run parallel with the speaker cable, I wouldn't think there would be much interference. How badly does the phono input pick up stray fields from stuff like mobile phones? Can you twist the unshielded signal wires together? And how about putting a small HF capacitor to shunt off HF in parallel with the phono input?

Thanks. All good advice but not really applicable. Staying away from anything class D seems the easier option at present.

[Erlend Sæterdal]

Originally Posted by analog_sa

Thanks. All good advice but not really applicable. Staying away from anything class D seems the easier option at present.

[barrows]

Originally Posted by analog_sa

Thanks. All good advice but not really applicable. Staying away from anything class D seems the easier option at present.

Is certainly one option. But, you have also learned something here: your turntable/phono pre set up is sensitive to RF. I would suggest that it is overly sensitive even. It might be a good idea to address this sensitivity, even if you choose not to use a Class D amplifier in your system, as RF pickup from the general background RF levels may be affecting the performance of your vinyl rig in a more subtle way.
Certainly, I would expect tonearm wiring to be twisted. And I would pay special attention to the wires carrying the signal from the 'table to the phono pre as well, making sure that they are high quality, as short as possible, and properly shielded. I do not design phono pre-amps, but considering the high gain needed, would it not be prudent for them to be designed with an RF filter at the input? Perhaps this is one reason why so many who use low output MC cartridges prefer the sound of a step transformer as the first gain stage for vinyl playback, as the transformer itself should be an effective filter against high frequencies. I often wonder why people do not always take full advantage of the fact that phono cartridges output balanced signals; a fully balanced phono pre seems to make perfect sense to me, this approach, coupled with a transformer input, ought to be able to reject any noise pickup at all.