Found it. The Nak's input impedance is 50kohm. |
This say to me that the PH1 maybe capacitor coupled and could be rolling of the bass into the 10k of the Redgum but not the 50k of the Nakka.
If so this is an easy fix, just make the output coupling cap of the PH1 4 x larger. eg: If 1uf make it 4uf.
Cheers George |
Nak's output voltage/impedance is 1v/2.2kohm. Plays real good. |
According to John Atkinson's measurements in Stereophile the PH-1 has an output impedance of "220 ohms at all frequencies." The review also indicates that the circuit " appears to be based on Burr-Brown OPA2134 op-amp chips." A quick look at the OPA2134 datasheet indicates that it can drive much lower impedances than 10K, albeit with a slight sacrifice in how much output voltage it can swing. So the 10K minimum load recommendation appears to be conservative, and the Redgum's 10K input impedance is unlikely to be an issue.
...
how would you explain the fact that when running the phono thru the
deck I don't have such a problem, I only got slight drop in resolution
and soundstage.
It's hard to say, in part because the capacitance of the phono cable is unknown. And it's quite possible that the excess load capacitance being applied to the cartridge is not a significant contributor to the issue. On the other hand, though, perhaps the tape deck is a bit rolled off in the treble region, which might compensate for the frequency response peak that the excess capacitance is likely to be causing somewhere in the treble region.
What seems safe to say, though, is that the excess capacitance is causing the cartridge to perform at less than its full potential. The degree to which that may be true, however, is anyone's guess.
Regards,
-- Al
|
Well, from what I can get there doesn't appear to be any components and cables mismatch, I think it comes down to the fact that passive preamp is no way to go if you want full-bodied sound, and this was confirmed by many here who tried it both ways. Most though not all prefer active preamp.
I don't think I will ask the designer to increase the amp's gain, it may throw the amp off the balance with little or no benefit, it would be a gamble, I guess. The resolution and soundstage decrease when running the phono thru the deck is slight, excellent Purist cables help a lot. I'll just wait till I am ready for a major upgrade. |
