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View Full Version : Using Transporter as a pre amp has me puzzled.



yooper
2007-05-09, 15:49
Unfortunately, my HT (5.1) and two channel listening are done within the same room and I currently run separates.

With that said, I would like to add a 2 channel amp (Moscode 401HR) and connect my Transporter directly to the Moscode. No problem there, connect my mains, run analog from the Transporter to the Moscode.

Now I'm stuck. Since the speakers are now connected to the Moscode, and the Moscodes only two ins are used by the Transporter, how can I listen to HT? Is my only option to disconnect the Transporter, and connect the pre-amp to the Moscode each and every time I listen to one or the other? Is there another option?

Thanks,

Mark

ceejay
2007-05-09, 16:16
Well, unless you have a means of getting the two front channels out of your 5.1 amp and into one the TP inputs, you may be stuck. And I'm not sure I'd call the TP a preamp, really - a multi-input DAC, perhaps.

I have a slightly similar setup, but don't have your problem as my main 2 channel amplifier is an integrated amp with spare inputs - so I can take the preouts from my 5.1 amp and feed them into the 2-ch.

Could you find an alternative (integrated) amp?

Ceejay

discocarp
2007-05-09, 16:45
You aren't going to be able to do this without changing wires when you switch between HT and the transporter. Unfortunately the transporter did not include a home theater bypass, which is what you need.

You CAN do this by just adding a 2 channel preamp into your system. Make sure the preamp has a home theater bypass feature on it. Many do, but not all.

discocarp
2007-05-09, 16:47
Oh home theater bypass is also called unity gain on some preamps. So if you see a preamp with unity gain, that's what you need!

Mark Lanctot
2007-05-09, 17:45
What 5.1 equipment do you have? If it has preouts, could you not attach the 2-channel amp to the mains preouts? When you're listening to the Transporter, use it as another source on the 5.1 but listen in DIRECT or BYPASS mode. (This will essentially turn the 5.1 equipment into a 2-channel preamp.)

You may also consider a speaker switch - one position connects the 5.1 amp, the other the 2-channel amp, but that would be cumbersome. You'd have to keep changing it back and forth.

yooper
2007-05-09, 18:55
Thank you to all.

Mark, I have an Anthem AVM 50 and Anthem MCA 50, I will look into your suggestion, with fingers crossed.

Thanks,

Mark

Skunk
2007-05-09, 19:11
Thank you to all.

Mark, I have an Anthem AVM 50 and Anthem MCA 50, I will look into your suggestion, with fingers crossed.

Thanks,

Mark

Here's the page in the manual for audio connections : http://www.anthemav.com/NewSitev2.0/Downloads/files/OwnersManuals/AVM50_v1_1x_Manual.pdf

As mark says you need to select analog bypass in a menu somewhere, which it says is possible on any input. You could run the transporter balanced output into the anthem, which also has balanced output or RCA. Nice piece of equipment you have there!

Also, you could run a digital output from transporter into the preamp, but set that input to multi-channel. Of course you'd neet DTS material on the server, which I know nothing about.

Skunk
2007-05-09, 19:28
Now I'm stuck. Since the speakers are now connected to the Moscode, and the Moscodes only two ins are used by the Transporter, how can I listen to HT?

Sorry, I think I missed the actual problem.

One solution might be get smaller front mains to leave connected to the anthem, which will have the benefit of a subwoofer and only be used for movies, while the real 2 ch main speakers are connected to the moscode.

Mark Lanctot
2007-05-09, 20:25
Thank you to all.

Mark, I have an Anthem AVM 50 and Anthem MCA 50, I will look into your suggestion, with fingers crossed.

Thanks,

Mark

Hmm, so you actually do have a pre/pro and a multichannel amp - this means those preouts are used already.

Knowing the calibre of Anthem equipment, there may be secondary preouts? Otherwise you'll have to use a Y-adapter on the mains preouts and run interconnects to both amps. This gets messy regarding how and when to turn which amp on. Hmm.

Deaf Cat
2007-05-10, 06:02
I have been reading about modified equipment, now just a thought, would it be possible for one of these specialist companies to put an analogue input on to the transporter, which would run to the existing analogue outputs - switchable from transporter to analogue in?

Allowing pre-outs for example from an AV amp, to output everyting pluged into the av amp, to pass via the transporter to the power amp for the front speakers.

:)

discocarp
2007-05-10, 06:08
That's what a home theater bypass does. It lets one input pass through from the processor to the amp without any volume control applied (so the processor controls the volume on that input). This feature would have been godly on the transporter, its a shame its not there.

You can put the processor in direct mode as someone said above. Doing this you're basically just treating the transporter like any other 2ch input. However, IMO a 2ch preamp with HT bypass is the best solution. Completely skip the processor when listening to 2ch.

Skunk
2007-05-10, 06:18
Completely skip the processor when listening to 2ch.

His preamp can do that. The problem is having speaker wire going to the moscode when he wants to watch movies.

My latest thought was to leave the moscode connected to the mains at all times, and send only the front 2 channels from the pre processor to it even in theater mode, while the other channels go to the theater amp. Not sure if that's an option though.

Mark Lanctot
2007-05-10, 06:24
My latest thought was to leave the moscode connected to the mains at all times, and send only the front 2 channels from the pre processor to it even in theater mode, while the other channels go to the theater amp.

This is really the only way to do it at this point.

discocarp
2007-05-10, 06:28
His preamp can do that. The problem is having speaker wire going to the moscode when he wants to watch movies.

My latest thought was to leave the moscode connected to the mains at all times, and send only the front 2 channels from the pre processor to it even in theater mode, while the other channels go to the theater amp. Not sure if that's an option though.

I must be misunderstanding the problem.

The hookup I was suggesting is along these lines:

HT processor--(preouts)-->2 ch preamp-->2 ch power amp-->speakers

with the transporter also plugged into the 2ch preamp (as a non ht bypass input). How is his setup different that would make this not work?

Mark Lanctot
2007-05-10, 06:34
HT processor--(preouts)-->2 ch preamp-->2 ch power amp-->speakers

All the preouts presently go to the OP's multichannel amp though, unless there was a secondary set, which would then eliminate the need for the 2-channel preamp (just go directly to the 2-channel amp and put the Transporter on one of the pre/pro's inputs.)

discocarp
2007-05-10, 07:05
All the preouts presently go to the OP's multichannel amp though, unless there was a secondary set, which would then eliminate the need for the 2-channel preamp (just go directly to the 2-channel amp and put the Transporter on one of the pre/pro's inputs.)

So the original poster wants to use a different amp in HT from 2ch? Is that the piece of the puzzle I was missing?

And if it were me I'd still rather have a separate 2ch preamp to put the transporter into rather than the ht processor, even in direct mode. But I suppose that is for each person to decide for themselves. :) If the transporter had ht bypass this wouldn't even be a discussion hehe!

Skunk
2007-05-10, 10:29
So the original poster wants to use a different amp in HT from 2ch? Is that the piece of the puzzle I was missing?


Yes, but that would require switching speaker cables.

I did some more looking at the link I posted earlier, and I believe this is what you can do:

The RCA and Balanced output the same thing, but you'll need a way to set the levels properly as one is 6dB louder.

Since the Moscode will be sitting there anyway, you may as well use it for the mains while using surround sound as well:

Transporter balanced out->Pre/Pro Balanced Analog Input...

AVM50 Balanced output to Rear L/R and Center Balanced Input on MCA50>3.1 speakers.
AVM50 Unbalanced output to Moscode amp>Front L/R speakers.

You should then be able to set the balanced analog input to direct bypass, and the HDMI input to 5.1, while using the same front speakers.

The RCA analog output from the Transporter could also be ran directly to the input of the moscode, if you felt like switching the RCA's occasionally for critical listening. You can use the analog attenuation built into the Transporter to match levels there. And then there's the digital output of the Transporter you could send to the AVM50 to compare the sound...

GaryG
2007-05-10, 10:49
As the Transporter is a digital preamp an option would be to take the front L/R channel outputs from the pre into an analogue-to-digital converter and feed the digital signal into the Transporter. For HT you switch to the digital inputs on the Transporter otherwise you use the Transporter as normal. I used to use a M-Audio Flying Cow in this manner but with a DAC rather than the Transporter, on HT the A/D conversion isn't audible.

Regards
Gary

Phil Leigh
2007-05-10, 12:06
If you have a decent AV-capable pre all this hassle can be avoided. If you are going to have a system in one room that can "do it all" then you really need to get to grips with the idea that a you do not need 2 pre-amps. I realise that "decent" means expensive but then - this is the Audiophile forum.
Peronally, I want 2.1 for stereo (from DAC analogue out) and 5.1 for AV (from DVD player DTS/Dolby Digital digital out) from a single Pre-amp with NO switching except from my remote. There are plenty of systems that can do this - Linn, Naim. Meridian etc.
YMMV.