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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,)
highstream
almarg's avatar
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almarg
9,670 posts
 
Highstream 12-5-2019
... failing improvement there, take a photo of the bottom insides to see if any modification had been made.

It would probably be a good idea to take a look at the underside of the unit in any case, especially to verify that the two output coupling capacitors are the same as the two white objects that are shown closest to the output jacks in this photo, which appears on PL’s website page for the Dialogue Premium preamp as currently produced.

Those objects appear to be 10 uF (ten microfarad) Mundorf capacitors. But it seems possible that in the 5+ years since your unit was produced the output coupling capacitors that are being used have been changed. If those are what is in your unit, though, and assuming the rest of the design of the output stage is the same as in the currently produced version of the Dialogue Premium (with a nominal output impedance of 256 ohms), the output impedance of your unit at the worst case audible frequency (20 Hz) will be about 836 ohms, which means it should be suitable for driving the 10K input impedance of the active speakers.

@newbee, thanks for the mention early in the thread. I just noticed the thread now.

The point @kalali made earlier, that ...

The published 256 ohm output impedance is most probably measured at 1KHz and can be (and most likely is) much higher as the frequency response varies during actual music playback.

... is absolutely correct, especially in the case of many tube-based preamps. With the highest output impedance within the audible range usually being at 20 Hz.

Regards,
-- Al
johnss
569 posts
 
highsream, but being emotionless, am assuming you want more of that CJ warmth from the earlier CJ gear. If so you will need to make two changes.

1. replace the stock coupling caps with jensen or Jupiter copper foil,
2. replace the rectifier tubes with PSVANE 274 high fi grades. the PL pre will come to life then. Its very well made and uses dual mono power supply throughout.

would also suggest you swap out your DAC for a Denafrips. Even the cheapest version will out perform your current dac.

best
techno__dude
511 posts
 
Simple solution. The OP just hasn’t found the good preamp for his tastes.
What he is seeking is ENERGY in the sound, along to go with the euphonia that the PL is giving him. The PL is just not the one.
Preamps with energy I know of:
Naim, Simaudio Moon.


jriggy's avatar
jriggy
562 posts
 
An interesting item of note is TIMING. When I use my DAC>amp pathway in the system, there is a purity, openness and (maybe most importantly) a cohesive-timing aspect that is a big plus... When using my $$$ preamp, all sorts of ‘audiophile’ aspects, like bass, textures, width, depth, separation, in room presence, all get “better.” BUT that simpler signal path of open flowing music all tied together, with seemingly slightly better timing, is way easier to connect to the musical intent of the musician. It might not have all the fullness and tone of the pre but my mind doesn’t care... until I’m ready switch to the pre for a week or two. 
lowrider57's avatar
lowrider57
5,417 posts
 
My take on "emotionless" is different than johnss. 
being emotionless, am assuming you want more of that CJ warmth from the earlier CJ gear.

If you are looking for warmth, then keep the Mullards and use rectifiers that are more lively and provide more clarity. A change in coupling caps could also help.
I assumed you needed a more engaging experience; more dynamic, more transparent and 3 dimensional. It's easy to have these characteristics and maintain some warmth.
 I still maintain it's a mistake to use the same style of tube throughout all the stages. 

Can you provide a more precise description of the sonics you seek from your system?

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