The future of preamps

@ Atmasphere, Thankyou for your reply,I will try to give you a phone call after new years to find out the closest place for me to hear your preamps and if you have documentation saying that your preamp will not emit Dc into a amplifier. Happy new year!

Audiolabyrinth, no preamp manufacturer would get very far if their preamp had DC at its output! Any preamp manufacturer has to deal with the fact that their preamp will be used with a transistor amp that is direct-coupled from input to output.

A DC level at the output can cause all sorts of problems, and not just for transistors. If a tube amplifier has a direct-coupled input (our amps do and many others do as well), a DC level at the input would cause the input circuit to make distortion and could adversely affect gain.

So it is simply something that preamps don't do! That is why I said earlier that Krell was promoting a myth.

Preamps, *all preamps*, do not have DC at their output. It does not matter tube or transistor.

So the Krell person you spoke to who is looking for 'documentation' need look no further than this post. No manufacturer in their right mind would make a preamp that puts out DC. It is literally that simple.

If you have it in writting in your manual or other wise that your preamp will not emit Dc at all, its all good to protect my investment!

Audiolabyrinth, I suggest hiring a team of lawyers to review the manual and getting it in writing. LOL!

I've used tube pre with ss amps for years and never had a problem. These are not your grandfather's tube pre. LOL!

@ Atmasphere, Hi, I agree with you 100%, However, Do you have in writting that DC will not enter my amp under no circumstances of what problems that may occur with useage over a number of years?, I can attest that most tube preamps will put out DC when their is a major failure of some sort, LOL!, some brands damage other componets with-in a preamplifier when only the tubes run amock!, not saying your products do that, I have read numerous horror stories of this, right here on audiogon!, Keep in mind, I have, and will still be using particular tube products, To elaborate on this matter further, I have personally have had a respected tube product before, that in no way was suppose to emit DC, IT DID!, I used a volt meter, there it was, my amp was shutting off into stand-by all the time!, I believe your products may not do this, its out there thou!, I also wanted to ask you what a audio signal would be on a volt meter, I'm thinking, VOLts!, not DC?, thanks Ralph, Happy new year!

You have rights to be cautious Audiolabyrinth about protecting your expensive poweramps, I agree get it in writing.

A tube pre if it's output is capacitor or transformer coupled gives some safeguard to precious large power dc coupled poweramps.

But if a tube pre is direct coupled and you get a bad tube or something goes haywire then your dc coupled power amps are in grave danger, even if the pre has output relays which can switch too late.

If something goes wrong, the dc offset in a direct coupled tube preamp premap can be up to 100 x larger that a transistor pre. Your poweramp may survive a dc coupled transitor pre going bad, but not a dc coupled tube pre.

Cheers George