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
oldpet OP
295 posts
 
Rwwear
It's funny that you have an FPB 600c. In my continuing research on Tube preamps, Tvad, on this thread mentioned the First Sound Presence Deluxe II. So, I contacted Emmanuel Go. He (Emmanuel) LOVES his Presence Deluxe II design with Krell amps. He had personal experience with the 600c and his design and absoluteley RAVED about the combination! So, his designs are safe to use with Krells. I'm looking for one, but I'm trying to wait to see If I can get one used before I would spring for a new one. Here's hoping. :-)
john_tracy
341 posts
 
Oldpet - log on to: www.kandkaudio.com or check out the K&K Audio sponsored forum over on the AudioAsylum. There was also a series of articles published in AudioXpress by Dave Davenport under the title "A Line Stage Odessy". A very complete kit is available for $1799 which is what I purchased and built. The kit has 6 inputs (one XLR, 5 RCAs with one of the RCAs a fixed volume one for HT cinema use), remote volume and mute and two outputs, XLR and RCA. The only change that I made was to substitute Cardas caps for the supplied Kimber parafeed blocking caps.
mmiketmaolcom
2 posts
 
i've been using a cat preamp wiyh my krell fpb 250 mc for the last three years and haven't had any problems. sounds wonderful
oldpet OP
295 posts
 
John/Mike - thanks for the info John. It looks very interesting. Did you need to do any soldering?

Mike - Is the CAT a tube pre?

thanks
paul
ehoehn
169 posts
 
Take a look at the SAS 10A. Steve Sammet has designed it in such a way that DC is not present in the signal path
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