Adding a Dedicated Preamp to a HT/2.2 music system?

Thorton

Alright, I'm boggled on this and wondering if anyone has tried this, knows the answer or currently doing this. I thinking of adding a dedicated tube or nice SS preamp to my current system in my sig. which I currently use for HT and 2.2 music. I really want to experiment. Because of the size, layout and acoustics of the room I want to keep the subs in the mix for music so I'd get a preamp with HT bypass and dual outputs.

Many subs have dual (LFE and 2-channel) hook-up....meaning you can hook up the sub to a pre/pro or avr at the same time as a 2 channel preamp.

1.) So I hook up my 2 LFE outs from my pre/pro to each sub as usual for movies. 2.) I hook up the L/R preouts from the pre/pro to the Cinema bypass on the preamp. 3.) Connect the 1st set of L/R preouts on the preamp to my amplifier for my mains. 4.) Connect the 2nd set of L/R preouts to the other mono input of each sub. Left to the left sub and Right to the right sub.

OK. Using the preamp, I believe, is pretty straight forward. The preamp splits the signal between the mains and the subs so I'd use the in internal crossover on the sub and crossover low.

Here's the confusing part for me. If I'm playing a movie with the pre/pro, the pre/pro sends the signal through the preamp but also to the subs through the LFE connection. The signal that's sent to the preamp is passed through but (I believe) is still split going to my mains amp but also the subs. Won't this send 2 signals to the subs simultaneously?

Am I confused or completely missed something?

tonyb

Couple thoughts....given the way you want to hook it up, one solution when playing movies is to turn the crossover on the subs all the way up to take that aspect out of the equation. My other thought is, depending on the subs, I would think that it would prioritize a signal coming in and use only that one when 2 signals are presented to it. I would think it would be the dedicated one from the receiver.

Check your manual on the subs and see if it refers to this scenario.

Thorton

tonyb wrote: »

Couple thoughts....given the way you want to hook it up, one solution when playing movies is to turn the crossover on the subs all the way up to take that aspect out of the equation. My other thought is, depending on the subs, I would think that it would prioritize a signal coming in and use only that one when 2 signals are presented to it. I would think it would be the dedicated one from the receiver.

Check your manual on the subs and see if it refers to this scenario.

Thanks Tony!

My thoughts kind of agree with you. I believe if you put the crossover on the AVR at say 80 for movies, then below 80 (I know there is a blending process and slightly above 80 can go too) goes to the subs via the LFE. Above 80 is sent to the dedicated preamp, which would pass through the signal, and then the sub (if the crossover is set at say 40 on the sub) crossover would only accept lower than 40 which would essentially be nothing. This is where the prioritizing would take over.

Most manuals I've read are very vague and only describe one connection or the other at a time and not both.

Thorton

DSkip wrote: »

See page 8 of this manual to see how the P5 handles it:

http://parasound.com/pdfs/P5Manual.pdf

Thanks Skip. The P5 is pretty self explanatory (in the manual) and unique in how it's designed. It looks like it was designed for this exact type of scenario (with main and subwoofer inputs with pass-through) plus others. However, I really want to try this with different dedicated preamps which don't have sub inputs to experiment with the sound I'm looking for.

tonyb

Thorton wrote: »

DSkip wrote: »

See page 8 of this manual to see how the P5 handles it:

http://parasound.com/pdfs/P5Manual.pdf

Thanks Skip. The P5 is pretty self explanatory (in the manual) and unique in how it's designed. It looks like it was designed for this exact type of scenario (with main and subwoofer inputs with pass-through) plus others. However, I really want to try this with different dedicated preamps which don't have sub inputs to experiment with the sound I'm looking for.

I was kinda in the same boat, with one system for both. My thoughts were, since movies have become a secondary preference over music, was to lose the sub, or in your case subs. Put that money towards speakers that can produce lower bass with authority. Problem solved....I don't even need a dedicated HT pass thru circuit either. I just connect as you described to one input on my tubed pre so when it's in standby mode, as you would normally keep a tubed pre, it passes that signal anyway from the receiver. Follow ?

There is always going to be a trade off/limitations when trying to do both HT and music in one system. The best way I've come across to achieve a true 2 channel within the same system is to lose the subs and get speakers that can produce lower bass with authority. By authority I mean dynamic and down to the sub 20 hz area, that way your brain won't miss the subs that much. Granted, in your case you have nice subs, 2 yet, so it won't be the same for HT, but it can be close enough.

Thorton

I hear what you're saying. The speakers are fine and dig deep enough. It's more the room (9700 cu.ft), the speaker position and listening position. After auditioning many speakers, I really don't plan to change these anytime soon. I love them for all kinds of music and what they can do.

For me, it's preference over reference. With the subs properly integrated, I just like the overall balance of sound much better. And I prefer a slightly sloping downward frequency response which adds weight and punch to the music which I really haven't heard in other presentations. I'm not a bass hog or like boomy sound, I just enjoy a well balanced and integrated sound across the frequency range. This is very difficult to achieve and until I experienced it, I do not want to go backwards.

So if I can make it work (tubed pre) with the subs intact, great. Then I'll try some different dedicated preamps. If it doesn't, then I'll stick with what I have and look at other upgrade options. I really haven't done cables yet and keep looking for deals.

One last thing, I love 7.2 channel HT (can't wait to go Atmos too) so the subs are here to stay.....actually I'm planning on upgrading them in about a month.

tonyb

Gotcha man, that will limit the amount of pre's you can try out, but hey, we all like what we like. Just have to adjust that crossover on the subs when a tubed pre is in play....if you have the dual inputs still with the new subs. Try it out with the pre you have now to see if it works.

Erik Tracy

I do exactly what the OP states, but with a Musical Fidelity A5 Int Amp.

To NOT have a doubling up of signals when the L/R preouts from the AVR are connected to the preamp you have to confirm that the preamp HT Bypass feature truly bypasses the preamp circuitry so that no signals come out of the preamp preouts.

You could read the manual and hope that this is confirmed someplace.

Or run a test. Disconnect the sub outputs to the LFE inputs on the sub, set the AVR to be fronts=large, play the AVR thru the preamp and listen for anything coming from the subs.

If you don't hear anything, then the preamp preouts are 'bypassed'.

You are G2G for a dual setup.

It works safe and clean for my rig. No swapping cables needed, no switch boxes, no doubling up of signals.

[edit] However, if you do hear something coming from the sub with the above test, then the preamp doesn't have a true HT Bypass and instead has unity gain, and your plan to use both connections won't work unless you put in a switch of some sort in front of the subs.

Thorton

Erik Tracy wrote: »

I do exactly what the OP states, but with a Musical Fidelity A5 Int Amp.

To NOT have a doubling up of signals when the L/R preouts from the AVR are connected to the preamp you have to confirm that the preamp HT Bypass feature truly bypasses the preamp circuitry so that no signals come out of the preamp preouts.

You could read the manual and hope that this is confirmed someplace.

Or run a test. Disconnect the sub outputs to the LFE inputs on the sub, set the AVR to be fronts=large, play the AVR thru the preamp and listen for anything coming from the subs.

If you don't hear anything, then the preamp preouts are 'bypassed'.

You are G2G for a dual setup.

It works safe and clean for my rig. No swapping cables needed, no switch boxes, no doubling up of signals.

[edit] However, if you do hear something coming from the sub with the above test, then the preamp doesn't have a true HT Bypass and instead has unity gain, and your plan to use both connections won't work unless you put in a switch of some sort in front of the subs.

Great. Thanks Eric. I figured someone has tried this before or is using this type of set-up. And thanks for the tip on the test. It makes sense and I will definitely try that first.

I also agree on the safe and clean part. I really don't want to add additional electronics. At least this gives me the opportunity to try it out and see if I like the outcome to what I currently have.

Thanks again.