Many questions about HT pass-through options

I'm trying to consolidate/simplify equipment in my dual purpose (2 channel and home theater) media room. The net is I want to use the same amplifiers and front speakers for both systems without recabling each time I switch.

I'm completely satisfied with my preamp (Musical Fidelity Nu-Vista) and prefer not to swap it out, but want to easily switch 5.1 (via my pre-pro) to 2 channel and back.

I'm considering a new preamp with home theater passthru, or equivalent alternatives not requiring a new pre.

My questions:

1) Exactly how is HT passthrough implemented in audiophile preamps? Is it simply a high quality switch, or is there something more to it?
2) I read in one post that the standard tape loop can be used for bypass. Is this true? Has anyone done it? Isn't there a risk to the internal circuitry of my preamp?
3) In lieu of a new preamp, is there high quality selector switch that doesn't cost a small fortune? Has anyone made one DIY, and if so, can you recommend good switch parts?

Finally - any recommndations for a good quality preamp, preferably Tube, with a really good phone section, passtrhu, and remote controllable. Budget is in the $1500 range used.

any and all advice or opinion is welcome, and appreciated
Why don't you just run the preamp L+R outputs from your prepro into an unused input on your Musical Fidelity?...I've used this method in the past and it works very well.

You set your Musical Fidelity volume control at twelve O'clock to do a one time channel balance setup with the prepro...after that, you just set it there every time you watch a movie...very simple.

Many people use this type of can do a search to confirm this.

The above will work but you do have two volume controls in line and will degrade the sound. It is better to have an HT pass-thru.
"The above will work but you do have two volume controls in line and will degrade the sound. It is better to have an HT pass-thru"

Yep, you'll have non-audiophile hometheater sound... Of course if watch the movie you'll never know.

take a look to Primare stereo preamp,has HT pass thru,remote and you have just to push one buton on remote,that's all you have to do.Simple.Nice sounding too.Check the website for more info
I totally agree with Dave. His suggested setup works just fine and you don't have to buy anything.

Since you are affectively not touching your 2-channel setup at all (except connecting an additional input to it), it does not affect your 2-channel enjoy at all. There is a potential for a slight degradation to your multi-channel setup, but as Dave said (paraphrase) "it's a movie, who cares". Also, it will only affect the L&R fronts anyway, so not a big deal since most of the important stuff comes out of the center channel for movies.

As long as you can tolerate the "hassle" of setting the volume control on your pre-amp to a pre-determined spot (like 12 o'clock), then you are good to go.


The sound may not matter when watching a movie but may when watching a concert DVD.
thanks for the responses so far . . .

Let me add a little qualification to my set-up. My listening in this room is probably 85% 2 channel, but virtually all of the 5.1 listening is Music/Concert video. We watch movies in the living room, and I frankly am much less critical of the sound for movies as you all point out.

I still like the idea of trying the pre-input first since it's free and easy. I guess that's where I'll start, and if I find noticable degradation due to the preamp circuitry, I'll try something else.

Anticipating that - any other advice on a switch, or a Tube pre with HT bypass?

thanks again, Brad G.
check this thread:

There are other as well under the pre-amp/Amp forum.
A BAT VK3i (and I assume other BAT pre-amps) have a volume setting called Unity Gain, which is essentially a HT throughput. The volume control is effectively removed from the circuit.

As a two channel audio only pre-amp, the BAT line is excellent and the VK-3i can be had at truly bargain prices on a'gon.
I had my "stereo guy" tackle this issue for me a few years ago. I have a switchbox that I click in when I want 5.1 and I click out for two channel. I just added a Audio Research SP16 pre that has a processor mode and a nice phono stage. My dealer gave me a great deal in February by selling it to me for $2000 new. I think it lists for $2500 and the price may have gone up. You might be able to find one used at a fair price.
I agree with Dave's method on a standard preamp, with no "bypass"/"direct" input. The auxilary or whatever works fine.
Degrade sound? Not usually a problem really. Just because there's two volume controls in line, doesn't mean degradation IME. Infact, if you're 2 channel pre's sound was pure from that input to begin with, you should have no problem with the same kind of pure sound you'd otherwise get just using the AV pre'pro for the L/R!
Yep, 12 oclock, or you can tinker.
I've, yes also, used this setup many times, and it works great.
I just happened to see this thread after posting on your other one. I didn't realize you had the MF pre so some of my comments regarding the virtues of a 2 ch. pre vs. a pre/pro are irrelevant. I just picked up an ARC SP16 which has the HT pass through. I can’t comment on the phono section, I don’t do vinyl, but the pass through definitely improves the surround sound listening experience over using a pre without the pass through, setting the volume at 12 o’clock, etc. I still say that for music though you’ll eventually come back to 2 channel so it may be an exercise in futility.
Assuming you integrate a pre-amp with a pass through function, does the pre-amp in the pass through mode pass on any of the sonic benefits associated with it when you are listening to it in the 2 channel configuration. Is there a sonic benefit to going through the pre-amp pass through as opposed to taking the surround sound processor straight to the amplifier? Having a pre-amp incorporated into the system certainly is a benefit for CD listening, but I'd like to hear perspectives if the pre-amp pass through also provides any benefit to HT listening, specifically HT concert DVD's.
The volume control on your preamp is probably much better than what is on your pre-processor, so any degradation resulting from going through both volume controls would likely be virtually unnoticeable. I have tried it both ways and IME the HT pass-thru feature is simply more convenient but no better sounding.
thanks to all of the posters, and I appreciate the additional comments re: the virtues/tradeoffs of using my MF Pre especially.

Last night I did it. I removed the extra speakers and amp, and connected my front channel outs into "aux 2" on the MF. I indeed set the MF volume at 12 o'clock, which is easy to remember and set whenever I switch to HT, and didn't require much adjustment in the pre-pro (ie from 0 db) in order to balance speaker volume levels.

I didn't do an A-B to see if there was any degradation, but really didn't notice anything from the little bit I played last night. It sounded great, except I have a little ground loop problem I need to resolve. Since my existing HT has been a true "bottom feeder" assembly and the sound wasn't really audiophile quality in the first place, so this will be at least as good. More importantly, it gives me the opportunity improve it and approach audiophile. I save $ from one amp, one set of speakers, not to mention removing equipment clutter from the room (yes, I actually had 2 sets of speakers in the fronts - one set for each system).

At some point I'll get the bug to buy a new preamp (yea, just because it's what we do) with HT passthru, but this for now is great, and much easier than I even hoped for to implement.

Next up is to swap speakers. I just picked up a Von Schweikert LCR-15 for my center. I currently have Mani-2s set up in this room and will move them into my dedicated 2 channel room, bring my VSA VR4-IIIs from that room to run as mains, and will have VSA VR3's running in the rear. This will be the first time I've had all channels in the HT running the same brand, closely matched speakers, so I'm really looking forward to the result.

thanks again, Brad G.

Glad it all worked out for you (so far). Enjoy the new combo system!