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Need some Tube and Class A SS Suggestions

I recently purchased a pair of Spendor D7s and am just loving these speakers. I have them paired with a musical fidelity KW 500 integrated. The combo is super fast, tight, and dynamic. However, the Spendors can be a bit too revealing in the high frequencies given a harsh or bright recording. This has me headed down the rabbit hole of tube amplification and possibly Class A SS. If the lowest bass is not as tightly defined I'm ok with. It actually may be too tight and defined at the moment. Added warmth in the upper bass would be fine as well. And if I'm going to upgrade then maybe it's time for separates too!

Here are the power amps I'm considering:
  • Primaluna EVO 400
  • Pass Labs XA25
  • Line Magnetic 805IA
  • Schiit Aegir Monoblocks - the price is just too good.
And on to the preamps:
  • Rogue Audio RP-5 and RP-7
  • PS Audio BHK Preamp
Ideally I would find at least one of the two Pre/Power used. I can probably get about $2200 for the musical fidelity so budget would be about $6k or so assuming I can somehow get both items used.

I'm curious to hear if any thoughts on what I've picked out already and if there are other units worth looking.

Thanks!
shahram
georgehifi's avatar
georgehifi
10,312 posts
 
shahram OP

for tube amps, given the speaker’s rising impedance in the upper treble region the result of that pairing may be an over-emphasis of the upper treble region, which sounds like the opposite of what you are looking for.
What Almarg said here with many tube amps and the Primaluna could well happen, and be a bit forward/etched in the highs.

I suggest with D7’s 90db and this kind of impedance and -phase angle,
https://www.stereophile.com/images/0415-SD7fig1.jpg
go the XA25 or the XA30.8 and if they are too expensive a Class-A Schiit Aegir https://www.schiit.com/products/aegir
It will give a good 40watts of power into the bass with this loading and have that Class-A sweetness in the highs even though it’s just 20w Class-A into 8ohms.

Cheers George
shahram OP
115 posts
 
Hi @georgehifi 

Thanks for the suggestion here. The impedence of that stereophile graph really doesn't rise until 10khz. A 10khz tone is VERY high pitched. Not much music above 10Khz so that impedence graph doesn't really bother me.

Definitely considering a Primaluna or Rogue Audio preamp with a class A SS power amp. I think if I went class A SS the pass labs XA25 would be my top choice. But part of me really wants to hear what this speaker can do with a Tube power amp...the dilemma continues!
photomax
168 posts
 
I just ordered a Pass Labs XA30.8 to go with my Spendor D9s. Will be selling my Bryston 4BSST-2 amp...
georgehifi's avatar
georgehifi
10,312 posts
 
shahram OP


https://www.stereophile.com/images/1214PLDPIfig01.jpg
Here is a behavior graph of the Prima Luna’s output transformer, as you can see it goes into stability ringing from 10khz up and the harmonics of that can effect even further down the line.
This combined with the high impedance of the speakers in the same area can be put to question.
Because the higher the impedance of the speakers, and if you look the output transformer ringing is worse at high impedance put the two together and you have something nasty going on.

Cheers George
three_easy_payments's avatar
three_easy_payments
2,097 posts
 
@shahram   

But part of me really wants to hear what this speaker can do with a Tube power amp...the dilemma continues!

You likely won't come close to getting the low-end grip (both weight and speed) of SS with a tube amp and you will almost definitely get more noise.  I moved from a tube amp to SS with my D7's and knew the second I turned on my Pass XA30.8 that I had made a transformational improvement even moving to amp with half the watts as my prior tube amp. 
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