Valve pre and/or power amps for Proac D38?

[malcesine]

Looking for amplification advice for my newly acquired Proac D38 floorstanders.

Current class A hybrid amp bought for Quad 63’s is really amazing all round in that combo but despite the superb bass control the hybrid brings to the Proac it is ever so slightly zingy/bright top end.

I am now leaning toward tubes to bring a wee bit more warmth to the tweeter.

Happy to biamp to avoid losing all important grip on the bass so hopefully that can open up options on low power tubes, even SET.

The other option could be an all tube preamp and keep the hybrid in place driving both woofers and tweeters.

The Proacs (surprisingly) are fairly sensitive at 91db and an easy load.

Any thoughts or advice? cheers

 

[Psilonaught]

Krell, Plinius or Pass, you want a good class A amp IMO. Or Sugden. Mate to a decent valve preamp and you're in business. Not a "zing" in sight. In my experience this is a great mix.

 

[uzzy]

If it is just a touch zingy with the hybrid - the first thing I would try is to add a 1ohm or a 0.75 ohm 15 watt resistor in series with the tweeter.   It will reduce its output just a tad - what it will prove is if the zing goes then it was the tweeter but if it doesn't then it is the mids causing the problem and a valve amp or a good class A is the way to go.  If it does cure the problem then no need to change the amp.

You can do the same with the mids but you will may need a higher wattage resistor.

Simple experiments like that can save a lot of money in determining what the problem is.   Also the purists will tell you this will alter the frequency response (I guess you can call it voicing the loudspeaker) 

 

[pmcuk]

If it's going to be valves, you would need push-pull for the power unless you have a small room and listen at low volumes. As I posted in another thread, you can find World Audio tube amps for around £500 on eBay and these should be good value. I don't personally find valve preamps very interesting - I don't use one and go straight from my Dac into my 300b amp. Unnecessary gain usually, and just casts a veil over the sound. I'm not a fan of 12A*7 kind of tubes outside of stage amps. 

Or a class A solid state amp. Single ended solid state amps are unusual and get quite hot, but can sound great. The PASS SIT amps are wonderful, but expensive and US products. 

 

[hifinutt]

And rare !!!

 

[Nopiano]

...Proac it is ever so slightly zingy/bright top end

I agree based on auditioning the D28 when choosing (ultimately) my ATCs, and also hearing the D38s at another Wammer’s home  It makes them shine on jazz and live sounding recordings.  
You mention Quad 63 and your profile lists Martin Logan, both of which I’d say give a slightly dull, rounded sound in many British rooms.  It’s either very low distortion due to lack of traditional dome tweeter, or an artefact of dipoles in other than highly reflective rooms.  (One look at ML adverts and they’re all glass and hard floors, and loft apartments etc).  
Before spending on another amp, have you exhausted the possibilities of toe-in, especially straight ahead, and maybe even speakers cables to get greater smoothness?  Not forgetting @uzzy’s suggestions above. 

 

[malcesine]

Thanks for all the great suggestions.

I had previously moved the D38’s around extensively, including to exactly where my previous big Proacs had been (floor marks still there - I know!), tried all sorts of position and toe in combos from straight to crossed over in front of listening position - so had basically ruled position out.

But I gave positioning one last attempt last night and after 3+ hours, voila! everything came beautifully together by moving both speakers further into the room than I had ever tried before (a mere 4” further!) and precisely setting both speakers the same distance from side/rear wall and matching slight toe in within a near equilateral triangle.

I‘ll check again it wasn’t just my ears getting accustomed after 3 hours (or my desperation to hear an improvement!)  rather than the actual position change but feeling very confident as change for the better was so immediately obvious.

Thats not to say I won’t also splurge on tubes at some future point!

 

[Nopiano]

Wow, that’s great news, and hopefully has saved you a few quid too!  Until that tube hankering returns, anyway. 

 

[Psilonaught]

Well done. Spending hours moving speakers around is tedious but so important. I need to do the same with my 20.1s but at 60kg each I keep putting it off!

I'd recommend REW measuring at the same time as you change placement. You can literally see the changes to response as the position changes. 

 

[Tarzan]

Lovely sounding speakers the D38- heard them at a show a few years ago, however cannot recall the amp make or model being used, other than they were indeed valve amps- stupid getting old. >