PREAMP technology shift? - Class A/ balanced/ dual-mono/ zero feedback vs. op-amp preamps

Woops, you are right Johnny, I should have given the context of my repeated comparisons.

I had both Rowland Capri and Ref 3 in my system using the following amplifiers:

Rowland M312: 40K Ohms inpput impedance.

Rowland M625: 10K Ohms

Rowland M725: 40K Ohms

Rowland M925: 40K Ohms.

I have never used Ref3 on lower impedance amps.

The source was the Esoteric X-01 Limited CD/SACD player in all cases.

My results were consistent for all linestage / amp combinations. I much prefered the original Rowland Capri over Ref3 in all cases.

Saluti, Guido

One more clarification.... Both Ref 3 and Capri were fully broken in.... REF 3 had a few thousand hours on it, and had fresh but broken in tubes for the SET Winged 6550 in the power supply and the 6H30s... Particularly important in the 6550... It takes this tube about 500 hours to reach full performance, and by 1000 total hours, it starts to sag.

Capri takes about 800 hours to reach maturity... Fresh out of the box, Capri is somewhat flat and blanched, and is easily outperformed by a well broken in Ref3.

After a quick initial comparison with Capri fresh out of the box, in which Ref3 was clearly superior, I did not apply Ref 3 again until completion of Capri break-in, so not to wear tubes down.

G.

anyone who is running a tube PRE amp into a low input impedance amp should be alert that they won’t achieve bliss.

For you to claim op amp Pre amps
out perform a ref tube unit without stating the conditions is misleading
and wanted to point this out.

The tube route is always possible, but I like the idea of a no-fuss, very clean ss, valuing sound stage and detail over warmth,

My apologies Johnny, your automotive metaphores are quite impenetrable.

Per the following page:

http://www.aragonav.com/8008-bb-mondial

The Aragon 8008BB has a balanced input impedance of 44KOhms, which is commensurate with the 40KOhms of three of my amps. It does not appear to have the 100KOhms input impedance that you asserted.

Interestingly, the input/output impedance ratio of my 40KOhms amps vs Ref 3 -- as well as versus ARC LS28 -- is

40,000Ohms / 600Ohms = 66.66 (periodic),

which exceeds the minimum safe threshold of 20 by a factor greater than 3. This strongly suggests that my Rowland amps are comfortably compatible with REF3. Similarly, the corresponding ratio on the Aragon 8008BB is

44,000Ohms / 600Ohms = 73.33 (periodic),

which is not staggeringly different.

The hybrid ARC LS28 is doubtless a lovely linestage. I have heard it at RMAF, and liked it. From my admittedly non-tuboholic point of view, with its SS power supply, it has the advantage over the REF series of limiting retubing to every couple of thousand hours or more for the 6H30s, as there is no fast-burner 6550 in the power supply which in old REF3 required a replacement every 1K hours or so.

It is worth pointing out that at $7500 new, LS28 is almost twice as expensive as the Rowland Capri S2 at $3995. From sheer memory, and not having heard the two linestages in the same system, it was not apparent to me if LS28 yielded any audible advantage over Capri S2. On the other hand, a side by side comparison of a well broken in pair in the same system might shed some light about any relative audible advantages of one over the other. However, preferability is hardly an absolute: personal musical taste and sonic priorities of the end user play a major role in every evaluation.

Saluti, G.