2. amps-preamps
  3. 152875-3731

PrimaLuna Dialogue Preamp = emotionless?

After years of running a PS Audio Direcstream dac directly into ATC active floorstanders, I decided to take everyone’s advice and add a preamp into the mix. I picked up a used PrimaLuna Dialogue with highly regarded Mullard CV4003’s and Phillips 5R4GYS’s, the tubes purchased by the original owner five years ago from Upscale Audio, a terrific source. My correspondents were correct about adding a good preamp: it transforms everything in a very big way. That’s the good news -- and bad. The latter is the reason for posting.

Before the preamp, this was a modestly warm system, for which the Directstream is known. It was one in which it was not hard to find myself drawn into the music and performance. Since adding the PrimaLuna however, I find myself watching -- or listening to -- emotion but not feeling a thing. That is, beyond marveling at the other characteristics of the presentation. After that, I’m left perfectly cold - 100%. This is not at all what I expected -- or desire.

So what to do... Is there anything I should look at with the preamp? What about other preamps, preferably tube ones? The skinny these days is that tube gear developers are trying to imitate the "neutrality" of solid state, the so-called modern tube sound some call it. With the PrimaLuna, I was expecting to find a point in between the classic tube sound and the common solid state one, but what I’m hearing is more than a little distant from that.

(Other than adding the PrimaLuna and not having Ultimate beeswax fuses in the DS and PL currently for other reasons, nothing else in my system has changed: modified Oppo 203 w/ digital output only, PS Audio P15 Regenerator and AC-12 power cords, and MG Audio Design AG2 ICs,)
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mulveling's avatar
mulveling
1,887 posts
 
Wow I didn’t realize the PrimaLuna preamp uses such a large heap of 12AU7. I’ve had 3 or 4 amps & preamps that use these tubes, and every time the 12AU7 has ended up seeming like the major bottleneck in system performance. I tried some of the NOS 12AU7 and 5814 to solve the problem, but only got so far - still sounded like the "12AU7 bottleneck". Then I used the 12BH7 sub whenever there was enough heater current overhead available to supply them (they are a drop-in sub otherwise) - and the result was always a much more dynamic, engaging, "alive" sound. 13D5 has been pitched as an excellent sub too, and (I think) has the huge advantage (versus 12BH7) of not drawing extra heater current (which you’ll probably need for your application) though I’ve not personally tried them.

I’d recommend not burning more money chasing NOS 12AU7, and try some of these sub types which are simply superior sounding to 12AU7.

The E80CC recommended above also look cool, and don’t draw extra heater current either. I think anyone who’s spent time looking for 12AU7 alternatives has realized how much the 12AU7 actually sucks.
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aolmrd1241
1,039 posts
 
mulveling  said..." I think anyone who’s spent time looking for 12AU7 alternatives has realized how much the 12AU7 actually sucks.’

Your blanket statement of 12au7’s sucking is just that...a personal opinion at best. We all listen differently and what I like,may not be..what you like. Which is completely fine. As they say..horses for courses.
avanti1960
1,471 posts
 
PS audio’s voicing tends to be on the warm side and was a good complement to the ATCs "surgical" sound.
Introducing a tube preamp does not necessarily mean that it will sound warm but rather sound more transparent with midrange bloom / forwardness, depending on the tube and the voicing of the preamp.
In other words a miss-match with your speakers.

Does the preamp add other value that you didn’t have before- example better dynamics and drive? If so, there are things you can do. If not then you are barking up the wrong tree.

If there is added value in other areas you can alter the sound to make it more warm,
The RCA 5963 variant of the 12AU7 will definitely sound warm and smooth.
Cabling could be another area- definitely ditch any cables with silver plating for example. I assume that your preamp does not have balanced connections and that your speakers do, so you must be using some adaptors.
While not necessarily bad, the situation is less than ideal.
Chord interconnects have a warm signature and could be a benefit.
A preamp with balanced outputs could be an option to consider if all else fails.
Also a preamp that is warm and rich out of the box is another direction.  Various  older Conrad Johnson and Cary Audio preamps are known for their rich warm sound that can be too much of a good thing in some systems but would likely be a good match with your ATC speakers.  
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