Seriously considering tube preamp…opinions?

@tvad , all: I went back and read the last few pages of this long thread and really appreciate all the advice. I do regret that in some ways, my posts occasionally ran people in circles — reiterating good advice to me that had already been given, with sufficient clarity! My apologies.

* I now have a very, very short list of tube amps to drive inefficient speakers.
* I now have a very, very short list of solid state amps to drive inefficient speakers.
* I have some very powerful advice to reconsider buying inefficient speakers.

Since I am not fiscally committed yet, I can keep this in mind as I audition the Salks vs. Dynaudios.

Given the above lesson that "tube speakers love efficient speakers," the only question I'm left with as I keep the inquiry into more efficient speakers is a simple question:

At what *starting* level of db sensitivity does the choice of quality all-tube amplification open up? 88db? 92 db? more? (I suppose I'm not thinking of the tiny-watt tube systems, but things that are up to 35-40 wpc)
[Context for the question are the earlier parameters: listening at modest volume (85db), room (450sq ft), genres (classical/jazz/rock), digital sources, comfortable headroom]

Regarding the PrimaLuna EVO 400, I don’t know about that specific model but Stereophile’s measurements of several other PrimaLuna amps reveal them to have very high output impedances, even for tube amps. That stands a good chance of resulting in tonal imbalances when paired with many small two-way speakers. As well as with some larger speakers, depending on how their impedance varies as a function of frequency, and especially if the speaker was designed with the expectation that it would be driven with solid state amplification.

Regarding VTL, over the years a number of members have reported in threads here that they had customer service experiences with VTL that were, shall we say, less than ideal.

To add to Tvad’s comments about VAC amplifiers, with which as a former VAC owner I entirely agree, a nice thing about them is that they usually include a 2 ohm (or "1-2 ohm") output tap, in addition to the usual 4 and 8 ohm taps. The lower the impedance designation of a given output tap the lower the corresponding output impedance will be, and that additional tap adds significantly to the amp’s versatility with respect to speaker matching. The VAC models that were mentioned above include that third tap.

Regarding ...

At what *starting* level of db sensitivity does the choice of quality all-tube amplification open up? 88db? 92 db? more? (I suppose I’m not thinking of the tiny-watt tube systems, but things that are up to 35-40 wpc)

... Answers to that question will vary considerably among different listeners. And IMO a major reason for the variability is that it depends on the dynamic range of the kinds of recordings that are listened to (i.e., the **difference** in volume between the loudest notes and the softest notes). As I think I mentioned earlier in one of your threads there are some classical symphonic recordings in my collection that have been engineered with minimal or no dynamic compression which can reach brief dynamic peaks of 100 to 105 db at my 12 foot listening distance, while being listened to at average levels in the 70s, and with the softest notes being in the low 50s. And lest that amazing 50+ db dynamic range be questioned I’ll add that I have verified those dynamic ranges on a few such recordings by examining their waveforms on a computer, using a professional audio editing program.

Tvad’s suggestion of 90 db or more as the answer to your question is certainly reasonable. Beyond that the only things I can suggest are to try plugging various numbers into the SPL calculator I linked to earlier, and preferably to obtain an SPL meter which provides fast response time and "c-weighting." I use an older Radio Shack model 33-2055 digital SPL meter, which may be findable at eBay.

Finally, as a Daedalus owner I certainly agree with Tvad’s comments regarding them. However all of their models are floorstanding, and their prices may be discouraging. There is a used Daedalus Athena for sale here presently for $6K; with the possible exception of some particularly old models I doubt that other models are likely to appear for sale for much less than that.

Best regards,
-- Al

At the beginning of your quest, based on 3 threads many here have contributed on, you have increase your system budget from $5-6K to $10-11K. The room size the system  will be placed in has increased from 150sq.ft. to 450sq. ft.  This is not an unusual outcome for someone entering this hobby, the extra funds and room size provide greater flexibility for, and enjoyment from the end result. Al the better for you.

I would reconsider the speaker budget to around $3000. This would allow for a stand mount speaker that could provide deeper bass response at greater sensitivity.

Your budget of $5-$6K for amplification opens up many possibilities. At that level the use of separates become more feasible. However I am not saying that the end result would be better over the right integrated. You started out your quest not sure you wanted to enter the 'tube' world to the extent of using tubes for the output stage. There are many who also think this way. I myself have saved that as the last consideration. There is no right or wrong between SS and tube based amplification.

This leaves you with $2K-$3K for source components. Since you already have a transport you would will be looking for a DAC. You also mentioned wanting a streamer.

I suggest you visit the several dealers in your area, be on the lookout for any used equipment that fits into your goal I have saved several dollars going this route.

I have my grand sons home with me (3-4 years) and they just got up. Have to sign off. Will get back

Take your time and enjoy your quest. 

@tvad Thanks. I did consider that perhaps since my Salk order is standard veneer and not delivered yet, I might just change my order with Jim and go with a more sensitive speaker. Not sure if he’d allow that but IF the speaker I ordered was of higher quality and price, I’d still come out the same in overall costs and Jim would sell a more expensive product. (I don’t want to make assumptions about what he considers reasonable, so I’m ready to be rebuffed if he balks at such a proposal.)

The key issue is that the other models I might now consider that are more sensitive than the 84 db speakers I order are: 87db, 88db, or 90db. The 90db speakers are more than double the Wow1’s ($3800 vs. $1500). QUESTION: a jump of 3 or 4 db in sensitivity doesn't really buy me enough, does it? It should be 6db? 

@almarg Thanks for reminding me of the dynamic jumps. That’s key part of music realism in the genres I enjoy. Good to have 90db as a starting point. That may rule out some makes of speaker if I try to broaden out my amp choices. Daedalus is nice, perhaps a bit much for me right now. I’ll keep an eye open.

@mesch Part of it was increase, part was just thinking out the wider parameters. "I wandered into a bar, looking for love," kind of captures my state of mind at the start.
I will reconsider the speaker budget. Part of that might come from a higher sensitivity speaker choice. The output stage (tubes or not) is still open. I have heard both sides. But I also am aware that matching tubes/ss is a dangerous game, and I’m a bit shy on this front. That leads back either to integrated tube/ss, all tubes, or all ss.
I will check for used and visit dealers.
Thanks for posting and enjoy your family time!