If You Were A Swine Looking To Choose Between 3 Preamps...


Looking to make a choice for a pre to use with an H2O audio 250 Signature amp I recently acquired. The amp sounds lovely running off the tube stage of a Musical Fidelity NuVista integrated. On a lark I boght an Edge SI 1M pre amp to try with it. If this combo doesnt work out, then it gets paired with a First Watt F7 I have.

In that case I need to look at a different pre, and may go tube as the Nuvistor internals on the MF work well with this amp.

Being a pig of limited means I have looked at the used market and came up with 3 interesting choices.

Allnic L3000 MK II

Line Magnetic 512 CA( Japanese voltage)

Triode Corp Trv 4se

Any one of these have to be bought un-auditioned, as two are coming from Canada, one from New York.

Anyone have any insights of the 3 candidates?


neonknight
@neonknight

As far as I can see that review does not address the H2O Audio S250, in either the Signature or non-Signature version.

Here are two sources indicating an 8K input impedance. Note that at the first link the 8K number is stated by Mr. Ho himself, for the Signature version.  (The second link is for the non-Signature version):

https://www.audiogon.com/listings/solid-state-h2o-audio-s250-signature-analog-icepower-amp-2014-06-0...

https://www.gearogs.com/gear/83438-h2o-audio-s250

Regards,
-- Al

@almarg 

Ah yes, I see what you are referencing. And Henrys other amps have nowhere as low input impedance, this one seems to be an outlier. It does indeed look like a SS preamp with low output impedance is in order. That changes things. I guess we will see how this Edge pre amp works when it arrives. It is another odd one, and I cannot find the output impedance on the Si-M1 either. So we will have to see how that works out. 

I’ve dealt with impedance matching for many years now, having the product that I have.

With impedance matching if one stays with the 1:10 or higher ratio you’ll have things covered. This goes for source to pre and from pre to amp/s

All you have to worry about then is if the "1" (source or pre) has an output coupling cap, (if they’re dc coupled no problems) and that cap is large enough to maintain that impedance 1:10 ratio flat from 20hz to 20khz you’ll have no problems

If not and it’s too small you may get a change in that ratio in the bass maybe down to 1:2, if this happens because of that coupling cap being too small then you’ll get a "voltage divider" scenario happening in the bass rolling it off too early, maybe at 50 or 100hz and giving a thinner sound with lack of perceived level in the bass.

Cheers George