Battery for a dynavector p75 mkII

[StanleyB]

I have an inexpensive phono preamp listed on my site that can be used with batteries or with a mains adapter. The differences are startling. The Battery powered configuration gives far better mids and tops.

The Technics battery/mains powered phono preamp that I used to have also produced far better sound with batteries.

So I would expect the Dynavector to produce the same results. A cheap 12V Li-ion battery pack should be sufficient enough to at least offer a starting point.

[ossy]

I have an inexpensive phono preamp listed on my site that can be used with batteries or with a mains adapter. The differences are startling. The Battery powered configuration gives far better mids and tops.

The Technics battery/mains powered phono preamp that I used to have also produced far better sound with batteries.

So I would expect the Dynavector to produce the same results. A cheap 12V Li-ion battery pack should be sufficient enough to at least offer a starting point.

Is this advice, or an advert?

[StanleyB]

Is this advice, or an advert?

I advertise here all the time and many AoS members own several pieces of kits from me . But I also offer my own technical input using kits I have actually tried out. So stick to the information provided instead of trying to be cheeky.

[sq225917]

Is this advice, or an advert?

I was going to ask you the same thing?




While the P75 might be immune to its own noise, chances are the rest of your hifi does not have sufficient high frequency filtering on it if it is more than 5 years old. It's only quite recently that all gear started coming with IEC inlets filtered for HF grunge coming from smps's. Older linear power supplies built into hifi gear tend to be poor at very high frequencies compared to within the audioband.

[StanleyB]

I was going to ask you the same thing?

Feel free to ask. It won't harm my sales .

[ossy]

Feel free to ask. It won't harm my sales .

Must have been an advert then (cheeky, moi?).




Btw - I have a beresford dac (maybe I'll try it with one of those wind up torches).

[awkwardbydesign]

Dynavector claim it makes no difference because of the design of the internal power supply. Now one would assume they tried this out before making such claims. Worth tryng a better power adaptor or filters to see if interference from that supplied is having an effect though.

And manufacturers are well known for never making unproven claims.

[6L6]

Mike g - The best thing to do is try it. Assuming you don't mis-wire it, you are not going to hurt anything, and you will know for yourself. If you do mis-wire it, you will likely be buying a new phonostage...

Anyway, there are a few good bits of information in this thread before it started getting, well, opinionated...

The P-75 mkII power supply runs at over 1/4MHz. It takes the low grade single voltage DC supply from the ac adapter and converts it to the dual high voltages required for true professional quality audio reproduction. The operating frequency is over 12 times higher than the top of the audio band and it incorporates super low noise wideband regulators in its output stage to give ultra low noise supply rails. The internal P-75 mkII power supply is totally self contained and stores many times the maximum possible energy requirements for the phono amplifiers. This means that the quality or size of the external ac adaptor is irrelevant. Increasing the capacity of the external supply will make no difference to the quality of the sound.

This was obviously taken from the manual. (which is good) From this we can determine the following;

The PSU is a switch-mode power supply (SMPS), not a linear supply.

It has a switch frequency of ~250,000Hz, well above the audio range, and not even near any close multiples of something audible.

They also mention that the reservoir capacitors hold much more than the circuit ever fluctuates.

I.E., this is a SMPS that is designed for an audio component. Is this good? Is this bad? That question will quickly devolve into a religious argument, but it is a well-designed supply.

Also, there is one other thing nobody has mentioned, that the inexpensive wall-wart power converter is going to filter quite a bit of the grunge off the AC mains, as it's using an EI transformer that isn't going to couple the HF noise from the mains very well. (that's good) As odd as it seems, the cheap wall-wart is helping.

I have an inexpensive phono preamp listed on my site that can be used with batteries or with a mains adapter. The differences are startling. The Battery powered configuration gives far better mids and tops.

There is no doubt that the battery supply would greatly help an 'inexpensive phono preamp' as it will undoubtedly have a poorly-designed and likely undersized linear PSU. Batteries will be simply be quieter in that situation.

So, what is my suggestion? Try the batteries. You will then know if there is a benefit or even a difference. In this particular situation I don't think there will be a change. There are many different situations where I would unashamedly cheer for the construction of a battery supply.

[sq225917]

Stanley I was referring to Ossy's DV advert, not your post.

[Mike A]

Looks like all my arguements have been covered, thank you everybody, saves me typing