2. amps-preamps
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Krell amps and Tube Preamps - enemies?

Wow! I never realized how difficult it would be to add tubes with a KRELL amp. I'm no engineer, and, I don't pretend to be into the "technical" side of the audio world. So I'll try to explain.

It seems that tube Preamps create DC. I've been told that DC will dammage my Krell amp (FPB400cx), and possibly my speakers(Tyler Acoustics Linbrook Sig, System 1 piece). UNLESS, I open the amp up and do something to the "jumpers on the digital board" . This puts some protection into the signal path. The Bad thing is, I'm told, - it also colors or degrades the audible signal coming thru the speakers. So, if I want to use my SS set up, say for SACD or DVD-V/DVD-A, I would have to open the amp up again and reverse the proceedure. This would remove the "blockage" in the signal path. :-( This of course, would have to be re-done when I want to go back to the tube setup. WHAT A PAIN!

Needless to say, this has thrown the proverbial 'wet blanket' on my tube enthusiasm. Is this problem common to ALL SS amps? Or is it just a KRELL thing?

Any thoughts would be helpful.
(This is part of a thread i started on the speaker threads, but i thought i might have more luck here on the "amp' Threads)
Thanks
oldpet
rwwear
2,867 posts
 
How can you say such a thing Newbee? If one can hear the difference between cables, one should surely be able to hear a capacitor in line with his equipment. After all, they make a difference in speakers. And if someone did make an amplifier that sounded like tubes, who would admit it that it did? I like tubes and use them but they don't always sound better.
newbee
4,767 posts
 
Rwwear, What would you expect from a newbee who still listens to a 20 year old pre-amp and 10 year old amps? :-)

My point was only that while you might be able to hear the capacitor it might not really make any substantive difference sonically speaking, different perhaps but not better or worse, and if it allows an upstream improvement it would be worthwhile.

sidssp
1,077 posts
 
Solid state preamp can leak DC also. It is not unique to tube.
oldpet OP
295 posts
 
Will the manufacturers say if their products "leak" DC? It doesn't seem to be something a company would want to admit.
rwwear
2,867 posts
 
Well Newbee you got me on that one. But just because equipment is old doesn't mean it can't sound good. By the way, BAT has probably fixed the DC leakage problem that they had in their earlier preamps. I guess an SS preamp can leak DC but it is not as likely. You can easily measure for leakage with a voltmeter to the outputs of the preamp. I am pretty sure that Krell amps will only shut down when DC is present at the inputs. Once the problem is removed the amp will come back on without damage.
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