2. amps-preamps
  3. 131040-1601

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

Hi all,

Even ten years ago, it seemed that the gold standard for solid-state pre's was some combination of the following: Class A/ balanced/ dual-mono/ zero feedback or local feedback. Recently, I'm seeing a range of well-reviewed preamps, from Schiit to Rowland, that use new, high-quality op-amps in their circuitry, to the extent that I wonder if op-amp technology, and chip manufacture in general, has gotten so good that some of the tried and true markers of quality (MOSFETs, Class A circuits) are not in the market except at the highest end, and even then, see also Jeff Rowland. Or is it that manufacturers are looking to less power hungry designs (I know that Rowland was concerned with meeting EU efficiency requirements in its latest designs) and so avoid Class A, for example? Does balanced/ dual mono seem less popular because separates are now less popular than integrateds? Have we reached a tipping point with op amps?

Here's a more focused question. I have invested in a 90s era Aragon 8008BB dual mono balanced amp, but i have an early 90s B&K PRO10-MC that I want to upgrade. Is a Schiit Freya a significant step up, or should I save my pennies for a used, more recent example of the old school: Classe CP500, Pass Labs Aleph or X2.5, or a good example of a newer approach, the Rowland Capri. Speakers are Vandersteen 2CE Sigs. Input impedance of the Aragon is 44 kOhms. 

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, which makes me think I'd be wasting my time with the Freya (any shoutouts for its JFET stage?)

Thanks for letting me wonder aloud!

Paul


paulburnett
audioconnection
1,270 posts
 
Guido
Let's  get real
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.

Best
JohnnyR




guidocorona
4,298 posts
 

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


guidocorona
4,298 posts
 

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.


audioconnection
1,270 posts
 
Guido
 Like I said using a Ferrari as a tow truck =
  Denile trial..........
 Let it breathe into a 100 k load as intended
 
 A  modern ARC LS 28 would be great into the OPs Amp
      Best
       JohnnyR 
 
atmasphere's avatar
atmasphere
11,676 posts
 
@audioconnection

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

Just a FWIW, we make two balanced tube preamps and both can drive 10K no worries. They have a direct-coupled output so no loss of bass driving lower impedances.

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.

I agree- I have yet to see an opamp based preamp that can keep up.


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,
If you like soundstaging abilities, so far I've yet to see a solid state preamp that can keep up with a good tube preamp in that regard. It always seems that low level detail suffers on the solid state preamps.
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