Help Tannoy XT6F with Primaluna

Hello all.
Just got a pair of Tannoy Revolution XT6F speakers. They are supposed to replace KEF LS50s. I'm driving them with a Primaluna Prologue Premium power amp. The new Tannoys sound awful with the Primaluna. Very peaky upper midrange and not much bass. Pretty unlistenable. Tried them with my old Rotel RB990 solid state power amp and they sound much much better. Tried the 4 and 8 ohm taps. Tried the stock Primaluna tubes and some KT 150s. No good. The Primaluna sounds great with the KEFs. Any ideas? Thanks in advance.

The Tannoys have a 90db sensitivity rating so the Primaluna should drive them fine. Have they had time to break in? I would play them for at least 50 to 100 hours before critically listening. Also, cables make a big difference, what are you using? Some speakers just don't like tube power. I would never use tubes in the power amp section to drive my Dynaudio speakers. They do not like tube power. So I use tubes (10 of them ) in the pre amp section to inject that tube quality I love.




P.S. I would do what ever, to get those Tannoy's sounding right, great choice!

Give them a month to break in. Hopefully, they will sound much better. Mine did -- not the same model, though.
I had used a Japanese Triode integrated 300B amplifier with a pair of Tannoy DC 8's and that sounded really really good.
I had used a Japanese Triode integrated 300B amplifier with a pair of Tannoy DC 8's and that sounded really really good.
Ben, I agree with the earlier poster that additional breakin may very well help. However, although most Tannoy speakers that I am familiar with have tube friendly impedance characteristics, unfortunately I suspect that the root cause of the problem in this case is that yours do not.

I suspect that the impedance curve of your XT6F speakers is similar to the one shown for the XT8F in the graph at the very end of this review. As you'll see, the impedance of that speaker, despite its 8 ohm nominal rating, is around 3 ohms in much of the bass region, rising to around 10 ohms in the mid-range, followed by a sharp rise to more than 40 ohms at about 4 kHz, followed by a decrease to around 10 ohms in the upper treble.

As a zero feedback tube power amp, your PrimaLuna undoubtedly has a fairly high output impedance, corresponding to a very low damping factor, although neither parameter appears to be specified. The interaction of a high amplifier output impedance with the speaker impedance characteristic shown in the graph will result in EXACTLY what you have described -- weak bass and an over-emphasized upper mid-range.

If the sound continues to be unsatisfactory following additional breakin, I suspect that among tube amplifiers a much better choice for use with the XT6F would be a medium powered Audio Research model, if you can find one used at a suitable price point. ARC designs tend to have significantly lower output impedances/higher damping factors than many other tube amps, in part due to the use of moderate amounts of feedback. Also, they tend to have robust power supplies, which may also be helpful with respect to the low impedance of the speakers in the bass region.

Good luck. Regards,
-- Al
 Well I have been trying everything I know to try. I have let the speakers play for hours on end. I have tried Cables, room position, Toe in tow out tilting forward tilting back. I still can't seem to tame that harshness. Things that sound good sound really really good but the things sound bad sound horrible. The kefs seem to be able to make everything sound pretty good. I even tried hanging paper towels in front of the upper driver. It did tame the sound but then the things that sounded good now sounded dull. I'm going to try a McCormack power amp this weekend.  I'm hoping for something good. If not I guess I have to sell the speakers. 

By the way none of this has been with the prima Luna. It's all been with the Rotel solid-state power amp. The primaluna will absolutely not work with these speakers.

Honashagen - what speaker cables have you tried?

Which sounded the best?


Morrow audio and Kimber. Morrow sounds better.

Question for Al - I think you have probably nailed the issue in your second-to -last paragraph.

The question I have is - would it be possible to match the amp to the speakers via some type of custom built "matching transformer"?

I did have an issue with an amp many many years ago and had a matching transformer custom built by a very knowledgeable guy that built transformers for a living

Just trying to think of a solution for the OP - other than replacing the amp :-)


Hi Steve (Williewonka),

That’s a logical question, but I doubt that it would be a good solution in this case.  While raising the load impedance seen by the amp with, for example, a set of Zeros, would ameliorate the effect I referred to, it would mean that the output tap of the amp would not be working into the load impedance it was designed for.  Which I suspect would have adverse effects on both the distortion characteristics of the amp and on its output power capability. 

Also, the cost of the Zeros ($540 without enclosures or $1140 with enclosures) is perhaps a bit unreasonable in relation to the cost of the amplifier ($2199).  And, finally, I note that subsequent to my post the OP reported that he is not even getting acceptable results with a solid state amp.  So it seems clear that other issues are contributing to the problem, in addition to the effect I cited.

Best regards,
-- Al
More info: Tried a set of Kimber 8tc speaker cables with amazing results. Silky top end and the upper mid peak is greatly improved. Truly amazing. Going to try bi wire and shot gunning to see what happens. 

Was that with the SS or the tube amp?
Solid state Rotel amp. I don't think there is any hope for the Primaluna with these Tannoys.
Rotel SS amp: Bi wire brought the peak back out some. Shot gun made no change I could hear.
honashagen, i guess the only other  thing I can suggest is to try the KLEI gzero6 speaker cables. They really are excellent.

When I heard them ffor the first time the depth and control of the bass left me speechless and their smoothness in the top end is superb. Their biggeset asset being their clarity, imaging and dynamics

I first tried the gzero2, their lower end model, which are now on my A/V system. Also a very good performer.

They may also perform miracles with the Primaluna.

 Well I have about 60 to 70 hours on the speakers I believe. Morrow Audio says it will probably take at least 200 hours. I have them set up out-of-the-way facing each other as close as I could get them with a mono signal and wired out of phase.  I'm going to play them 24 hours a day for five days and see what happens.  That should get me close to 200 hours total.

The Klei cables appear awesome.  It scares me though to spend $800 on new cables.

I knew the reason once but I forgot it, but cables break in better if you give them about an 8 hr " rest"  every other day .

Honashagen - I agree - they are a lot of money :-)

I had the advantage of trying them first.

When I received the gZero2’s for review I could not believe how skinny they were.

I had tried some "skinny cables" before and found they lacked bass performance compared to my Van den Hul D352’s, so I installed the gZero2’s with A LOT of doubt.

It only took the first track to realize these were something really special. Then the album surfing began and my doubts vanished!

I had no such doubts when the gZero6’s arrived and found they provided even deeper and a more controlled bass performance.

Their performance in the rest of the frequency range is excellent also - the most articulate cables I have ever tried :-)

Unfortunately I’m unable to guarantee they will work, especially with the Premaluna, which I’m sure would be your preference.

Unless.... you live in the Toronto region? :-)


I got another 125 hours of burn in on the Tannoys for a total of about 200. Sounding better. Another 200 should do it. 

If your morrows are also brand new, then that's a major cause of sound oddities.  The Morrow cables absolutely REQUIRE around 400 hours of break in.  

The Morrow site explains this in great detail, they are not like most other brands since they have mainly solid core copper plated with silver.   I've got 3 pairs of Morrow RCA's and experienced this myself.  I decided against buying Morrow speaker cables for this reason.  I had left my system alone for about a month, and the Morrow cables needed an hour to get back to normal.  
Sold the Tannoys and the Primaluna. Tried the XT8Fs. Awesome speaker. If have since moved on to a pair of Dynaudio Contour 3.4s.

 The Prima Luna Dialogue HP
will drive anything. 6 signal tubes  and 8 power tubes 4 a channel you even put in KT150's.  

Musical and built with no apologies.