2. amps-preamps
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Switch preamp?

I've been an audiophile for over 5 decades and consequently collected a hodgepodge of equipment that I've mixed and matched with a degree of luck. My current listening room system, and most likely my last, consists of AR's (ss) LS10, Krell's KSA 250S, Martin Logan's 13a -- my latest addition and the reason for my question -- and AS Liveline's chord and speaker wire. I listen to most genres equally in CD, vinyl and Tidal.
It is my understanding that electrostat speakers perform best when utilizing tubes. I am not prepared to switch out my Krell but would consider the Audio Research since it's solid state.... and the clicker has gone missing. Ages ago I owned a Conrad Johnson with another system and have fond memories of its mellow sound.
So, does it make sense to replace the AR with tubes spending in the vicinity of $5k in the used market, or do I have a gem and should leave well enough alone? I am happy with the sound but these are my first electrostats and do not know what they're capable of. The closest audio store is 5 hours away so I count on smarter minds than mine to guide me. Thank you.
128x128notesaddict
willemj
1,036 posts
 
I guess it is just of these audiophile myths. I would stick with solid state, as did Quad's Peter Walker, once he had designed his first solid state amplifier. I drive my Quads with a Quad 606-2, and that is fine, even if I might one day upgrade to the QMP monoblocks for more power (power is king).
notesaddict's avatar
notesaddict OP
63 posts
 
Yes, Erik, outside of the speakers the system is old and maybe it's time to bite the bullet and replace both the amp and preamp.
Vegas, the manual makes no mention of altering the amp to accommodate tubes, although I would call Krell before installing.
The Krell is probably in the 25 year range and I suspect AR LS 10 equally old. The Krell performs flawlessly -- no hum -- and has plenty of power, rated 500 watts per channel into 4 ohm, so the question then becomes will the sound be appreciably richer/ better if I switch out both the amp and preamp when compared to just replacing the preamp. (An audiophile recommended I sell the Krell and go with Prima Luna's Dialogue Premium HP mono blocks.) 

I appreciate my knowledge is notch above a layperson, nevertheless my ears are good and I spend at least 2 hours a day listening. Consequently, because of my age and the amount of time I devote to my passion it is crucial for me to get it right this time around. Your comments are greatly appreciated.
willemj
1,036 posts
 
No reason to expect any sonic improvement from changing the Krell (your electricity bill will be lower with a pair of bridged Benchmark AHB2s, however). Just get it recapped and you are good for ages again.
erik_squires
16,370 posts
 
OP:

When I said the system was "cold" I really was talking about the sound of the gear you purchsed, not so much the age! :)

Best,

E
atmasphere's avatar
atmasphere
11,936 posts
 
 I use to have an older Krell 200 FPB stereo amp.  When I added a tube pre, I had to open the amp up and remove a small jumper(manual switch) connector.  Something about tubes damaging the amp.  The information was in the manual but the location was not so I called Krell and I performed the job with the tech over the phone.
Despite Krell's remonstrations this bit about tubes damaging the amp is a myth. Its based entirely on a single customer's preamp having a failed coupling capacitor; which is the sort of thing that can blow up an amp whether the preamp is tube or solid state!

Regarding the ability of tubes to drive ESLs and Martin Logans in particular:

The issue is that of impedance- Martin Logan makes ESLs (which normally work best with tubes) but to try to get better solid state compatibility (and thus a larger market) they keep their impedances down. The typical Martin Logan is 4 ohms in the bass and 0.7 ohms at 20KHz.

You can correct this with a set of ZEROs (www.zeroimpedance.com) and then a wide variety of tube amps could be used. Of course, many tube amps will work with this speaker if you use the 4 ohm tap even without the ZEROs.
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