Bent Passive TVC TAP and Home Theater

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drcruz

Bent Passive TVC TAP and Home Theater
« on: 1 Dec 2006, 05:01 am »
John,

Am I interpreting your website correctly in that, can a six channel (5.1) source be control by a six input TAP?

"Any Input(s) can be programmed as HT Input via back panel button press"

What does "HT Bypass" do?

Thanks in advance :)

John Chapman

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Re: Bent Passive TVC TAP and Home Theater
« Reply #1 on: 1 Dec 2006, 10:36 pm »
Hello!

We need to spearate 'inputs' from 'channels'.

Inputs are the number of sources you can connect to your system - ie. cd player, dvd, phono stage, etc....

Channels are the number of - well - channels you can control the volume of - ie. Front left, Front right, Center, Sub, etc....

The standard TAP unit has '1 or 6 INPUTS' and '2 CHANNELS'. For a typical music system or for systems combining music and an HT processor (as described below) this is just fine.

1- The TAP can be expanded to as many channels as you'd like by adding additional 2 channel expansion units. Each exapansion unit can have 1 or 6 inputs.  For expansion channels you could use TVC based units for all channels but the less expensive units make more sense for surround channels - an all TVC 6 channel system would really add up cost wise!

2- The HT Bypass feature is a convienience to allow you to program any input connected to an HT processor / pre-amp to 'lock' it's volume when that input is selected. Usually this input volume would lock at unity gain but the volume can be set so it jumps and locks to any level. There is a small push button on the back that you press to toggle between normal and HT mode for each input - setting to HT programs it to jump to the volume it was on when the button is pressed. You know if an iput is in HT mode - it's led indicator turns red in HT mode rather than green (for normal mode). The way it works is the volume jumps to the programmed volume level as the HT input is selected and then the volume returns to the prev volume setting (likely much lower) when a new input is selected. It saves you from manually turning the TAP to a particular level each time you use that input and more importanly from remembering to turn the volume down after it is switched to a 'normal' input. 

The two questions you had point to 2 alternate ways of setting up an HT in a TAP system so I'll expand on that a bit for clarity.

1- If you will use the TAP in a high quality system with decent speakers all around and intend on using SACD surround or DVD-A suround as a source then going with a 6 channel TAP system might make sense. Then you'd likely use the built in processing in your player and have no 'HT processor' in the system.

2- If you just need to patch an HT into your 2 channel system for use for movies, etc then very likely the best setup will be to add an HT processor (or a reciever with preamp outputs) to the system. Then for 2 channel music you have a really clean high quality signal path for music listenning and when you want to watch a movie in the system you:

1- Turn on the HT reciever (or processor)
2- Select the TAP input that the processor is connected to - that TAP input will jump to unity gain and stay there.
3- Now during the movie you simply use the processor to adjust the volume in the system - all channels stay level matched.
4- As you select a new input on the TAP the volume returns to the level it was at before jumping into HT bypass mode.


Hope that is the info you needed!

Thanks!

John


drcruz

Re: Bent Passive TVC TAP and Home Theater
« Reply #2 on: 2 Dec 2006, 07:08 pm »
Quote
1- The TAP can be expanded to as many channels as you'd like by adding additional 2 channel expansion units. Each exapansion unit can have 1 or 6 inputs.  For expansion channels you could use TVC based units for all channels...
Quote
1- If you will use the TAP in a high quality system with decent speakers all around and intend on using SACD surround or DVD-A suround as a source then going with a 6 channel TAP system might make sense. Then you'd likely use the built in processing in your player and have no 'HT processor' in the system.
Thanks for the reply...my mouth waters just thinking about it :wink:

When ever I tweaked my (humble) system, the best sound always came from the tweaks that mangled the signal the least. So currently I use the analog outs from my DVD player (w/ the players audio set to LARGE) and run my HT receiver in full bypass, then I run my video straight to the monitor.

With this in mind, I eventually want to by an audiophile quality DVD player (Underwood or Expemplar) and a TVC that could handle 6 "channels"  :thumb:

LAST QUESTION:
Does the TAP also act as a "Y" spliter, meaning each channel intp gets split into two channels out?

Thanks again for the good info  :)

John Chapman

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Re: Bent Passive TVC TAP and Home Theater
« Reply #3 on: 2 Dec 2006, 07:44 pm »
Hello!

I have an Exemplar here myself - very nice player!

The audio outputs of all TAP TVC pre-amps have dual RCA and dual XLR outputs for each channel. It is really doing the same thing as a splitter outside the unit would but it's much less 'messy' and cleaner from a signal path point of view. I don't understand why all pre-amps don't double up on output connectors - it really does not add much cost or work and it is handy to have around when you need to bi-amp or run an output to a  subwoofer.


Many Thanks!

John

drcruz

Re: Bent Passive TVC TAP and Home Theater
« Reply #4 on: 2 Dec 2006, 10:00 pm »
Quote
The audio outputs of all TAP TVC pre-amps have dual RCA and dual XLR outputs for each channel...it's much less 'messy' and cleaner from a signal path point of view.
Great!
Quote
[The dual outputs are] handy to have around when you need to...run an output to a subwoofer.
My goal exactly!

Thanks again  :)
« Last Edit: 3 Dec 2006, 04:41 am by drcruz »

dnd

Re: Bent Passive TVC TAP and Home Theater
« Reply #5 on: 8 Jan 2007, 04:02 pm »
John,

I am really keen on trying a passive pre and just recently came across yours now.  Like drcruz, my installation is also used for HT and occasionally multi-channel [albeit rare].

Along the lines of drcruz’s questioning, I use stereo subs driven by the extra single ended outputs of my pre/pro, while my main amp is driven by the balanced outputs.

Now my questions…does the TAP output via the single ended AND the balanced outputs simultaneously?  What I read implies it doesn’t unless it is especially spec’d  to do so.  If not, can a simple XLR-RCA adapter be used on the extra XLR outputs without any problems? 

Thanks,

Dave
« Last Edit: 9 Jan 2007, 02:30 am by dnd »

John Chapman

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Re: Bent Passive TVC TAP and Home Theater
« Reply #6 on: 11 Jan 2007, 02:53 pm »
Hello!

Sorry for the delayed reply - just back from CES and catching up now.....

The TAP has both dual RCA and Dual XLR outputs but as you not if you want to use both RCA and XLR at the same time we need to be mindful of a few things.

To run XLR to your main amps and RCA to a sub woofer I use a small box with LO410 transformers inside in the path to the subwoofer. These are very good Line Output transformers (really better than a sub would demand!) and they effectively isolate the ground connection to the subwoofer - so that the XLR output stays as a true XLR output. Without these in-line the system will function fine BUT you will have effectively turned the XLR ballanced output into a single ended output when you plug in the sub's rca cable. Technically what happens is that you ground pin3 of the xlr output when you plug in the sub's rca cable.

A 'simple' XLR to RCA converter used on one of the TAP's XLR outputs would do the same thing as above (affecting the other XLR output). Either it would ground pin3 or it would just scoop pin2 and ground from the rca connection and feed it to the rca cable. This kinda throws the 'balance' of the XLR connection off since it is now seeing more of a load on pin2 than pin 3 so again it is not an ideal solution.

To run RCA to your main amp and then an XLR to the sub's I do not worry about the isolation box unless the sub for some reason is really requiring an XLR connection. If the sub amp is XLR (likely a pro audio amp at that point) then running it via a single ended conection would in most cases still function great for sub duties.

Bottom line if you use an XLR to your main amp is to use the isolation box and that way you keep the critical main amp XLR path correct. Hope that was the info you were wanting.

Thansk!

John

denjo

Re: Bent Passive TVC TAP and Home Theater
« Reply #7 on: 17 Jan 2007, 01:15 am »
Hi John
Greetings for a great 2007!

I have a question from your last post and hope you can elaborate:
Quote
[The TAP has both dual RCA and Dual XLR outputs but as you not if you want to use both RCA and XLR at the same time we need to be mindful of a few things.

To run XLR to your main amps and RCA to a sub woofer I use a small box with LO410 transformers inside in the path to the subwoofer. These are very good Line Output transformers (really better than a sub would demand!) and they effectively isolate the ground connection to the subwoofer - so that the XLR output stays as a true XLR output. Without these in-line the system will function fine BUT you will have effectively turned the XLR ballanced output into a single ended output when you plug in the sub's rca cable. Technically what happens is that you ground pin3 of the xlr output when you plug in the sub's rca cable.
/quote]
Quote


This is exactly what I am doing - XLR to amps and RCA to Sub at the same time. Does this mean that the sonics are compromised? I am already very pleased with the Bent TAP in this cable configuration. Does this mean that if I were to add a LO410 transformer between the TAP's RCA and the Sub the sonics would improve since I would now be running the TAP in true XLR balanced output?

Sorry but I am not technically minded ...

Best Regards
Dennis

John Chapman

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Re: Bent Passive TVC TAP and Home Theater
« Reply #8 on: 17 Jan 2007, 11:29 pm »
Hello!

Well - I would not go as far as saying the sonics would be 'compromised' now. It would maybe be worth a try with the LO410 isolation units. Alternately an easy test (if your speakers are full range or almost full range) would be to remove the sub rca cable and listen for a time then plug it in (with the sub turned off) and listen again - see if you can hear a difference. If your amp is much happier running ballanced mode then the isolation transformer might improve sonics a bit.

BTW - It is possible that the sub has an isolation transformer built into it's input stage - so it is isolated now. That is the way I would do it if I designed a sub amp but I suspect for cost reasons that most would not be that way.....

Thanks!

John

denjo

Re: Bent Passive TVC TAP and Home Theater
« Reply #9 on: 18 Jan 2007, 12:35 am »
Thanks John. how much would the Lo410 isolation transformer cost assembled and ready to go!
Best Regards
Dennis

John Chapman

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Re: Bent Passive TVC TAP and Home Theater
« Reply #10 on: 18 Jan 2007, 03:03 pm »
Hello!

It would be $350 for a finished box. I would do the listenning test to make sure it will improve things before ordering one. I would be happy to send it on a trial bassis but the ship costs to you would be a few $ I'd guess.....

Thansk!

John