Which AV processors have an analog pass-thru?

Which AV processors have an analogue pass-thru? I want to use a seperate tube pre-amp when listening to two channel and need a AV processor that has a analogue pass-thru. I believe Simaudio has one but are there others?
I am confused why you would need this... why wouldn't you just plug the source into the preamp directly? I cannot think of an analog source that you would want to share between an AV processor and a preamp.
There are several analogue sources that you may want to keep that way. For instance, a tuner, TT, cassette, etc... would all provide you with analogue signals. No need to convert them to digital and then back to analogue. Hence a pass through would be something to look for. However, RCLad may be better suited to either looking for a two channel tube preamp that has a processor loop or plugging those sources directly into a preamp / processor that has analogue inputs. That is, if he can find a processor that suits his needs and offers good two channel sound. Sean
I added a tubed preamp to my HT system for music and did just what Slartibartfast suggested. My Sony C333 SACD player is connected directly to the tubed preamp. The main L/R channels from the A/V processor, a B&K Components Reference 10, are also connected to the tubed preamp. You can also accomplish this goal by connecting the tape monitor out to the tubed preamp; my understanding is that the signal passes through the A/V preamp virtually untouched.

The Anthem Pre 1L and 2L are both tubed preamps with a processor loop - kinda the opposite of what you asked but they were built with your situation in mind.
I guess my viewpoint is that if you are concerned about audio quality, you shouldn't be wiring your system this way. You should run the 2-channel output of your processor into an input on your preamp or a processor loop if available before running your preamp into an analog pass through input on your processor. This is a bigger pain to deal with because you need to set the position on your volume control for movies but my perspective is that the noticable loss from movies would be much less than from music using an analog passthrough.

The Krell HTS2 has an analog passthrough.
Sunfire's Theater Grand 2 does, and it is, surprisingly good for the price. More tube-like and musical than most <$2k silicone pre-amps I've heard.
I just checked the Casanova manual.

Analog inputs are routed directly to the tape-out i.e. bypasses all else in the pre-processor.

Digital inputs derive the benefit of the Theta DACs and then the output is passed to the tape-outs untouched by any other processing.
The Primare P30 retailing at $4k is an excellent sounding pre/pro that I've been using in my 2-channel system for the last year. Has a 100% analog by-pass mode. A very simple design with no tone controls. In addition to the rca outs, it has xlr outs for the 2 main channels. It appears that the P30 was designed with a music first priority.

I've had a burned-in Ayre k3-x preamp in my home over one weekend performing side-by-side sonic comparisons. The Ayre was a tad sweeter and more musical but the Primare was much more transparent and detailed, as well as more appropriate midrange bloom when compared to a recessed midrange in the Ayre. IMO.

the sony es dolby digital processor from the mid 90's has an analogue pass through. But, I use a DB Audio passive switch box (five rca ins, one out); the parasond psp1500 AV preamp and the McIntosh C22 preamps to into the DB Audio box. The output goes to the Audio Note P2SE amp that drives the front speakers.

NOTE that this little switch box can also be used as a cheap passive preamp IF you have an amplifier that has a gain control. I have done this and it works great.

How do you do that on the BK Ref 30?
Do i connect the tube pre-amp through the line inputs or outputs from the BK.