HT Bypass for AVA preamplifiers?

avahifi · « **on:** 5 Jul 2010, 05:30 pm »

I have had several requests for an AVA preamp with a HT bypass recently.

As I understand it, what you want is a switchable unity gain output set on the preamp that bypasses the controls and preamp line stage, so that in the HT mode, the mother HT processor is a simple feed through the preamp driving the main left and right amplifier and speakers.

If I am reading this correctly, then yes it can be done - - - three ways.

First the inexpensive way. This would require only the installation of a simple DPDT toggle switch on the back panel of the preamp. One position would connect the line outs to the audio output jacks as normal. The other position would would connect the tape outputs to the line output jacks. The tape outputs provide the "bypass everything including the line section" qualification. This would cost about $50 extra for the hardware and extra assembly time.

The second and preferred way would be to combine the above with our standard very high quality unity gain buffered tape output circuits, a $199 option. The buffer circuit would be switched in automatically when the back panel toggle switch was in the HT mode. This would provide very high drive current to the power amplifier and unload the normally pretty anemic HT unit active line circuits. We would expect higher sonic quality in almost all cases with this option.

The third option would be all of the above, but first retooling the preamp chassis and faceplate to support another front panel switch and its necessary hardware and wiring. This would result in a price increase for everyone, whether or not the HT bypass option was ordered. My suggestion, reach behind the preamp and flip the switch when needed.

I would appreciate your responses.

Best regards,

Frank Van Alstine

Toka · « **Reply #1 on:** 5 Jul 2010, 06:06 pm »

Not sure if the demand is there to warrant option #3, so in that case option #2 seems like the best bet.

Listens2tubes · « **Reply #2 on:** 5 Jul 2010, 06:12 pm »

I too think option 2 is just right where option 3 is overkill. Reading this leads me to a question about the tape outs on my T8+. Are they buffered?

avahifi · « **Reply #3 on:** 5 Jul 2010, 06:23 pm »

If your tape outputs are buffered, that option should show up on your back panel ID label.

Regards,

Frank Van Alstine

coke · « **Reply #4 on:** 5 Jul 2010, 06:25 pm »

I'm working on moving from a 2.0 setup to a 5.1.

My plan was to run a digital signal to a receiver. Then, I'd take the outputs from a receiver and run them to one of the inputs of my Ultra preamp. When I wanted to activate this, i'd simply choose that input on the preamp.

The other outputs from the receiver would be sent to a 3 channel amp for my center and surrounds. (ultra preamp not in this part of the system).

I'd adjust the preamp level so that the 2 channel amp and 3 channel amps were the same. I'd also use the receiver to control the volume of the entire system once levels were matched.

Are the options you listed above superior to this?

WGH · « **Reply #5 on:** 5 Jul 2010, 06:25 pm »

How about a remote DPDT switch instead of the toggle? A quick search found a switch that works on radio frequencies instead of IR for $39.99.
http://www.clickerstar.com/

Luckily I don't need HT bypass for my Insight EC preamp (yet).

Wayne

gjs_cds · « **Reply #6 on:** 5 Jul 2010, 07:20 pm »

I, for one, have no desire for an ht passthrough. I believe in separate systems...

adydula · « **Reply #7 on:** 5 Jul 2010, 09:49 pm »

Frank,

Thank for replying, I was one of those guys that was asking if a HT bypass similar to what is found on a Parasound 2100 was possible in a Insight SL+ preamp.

I would like to have the L/R preamp outs from the AVR to simply pass thru the AVA Preamp without having to power on the AVA Preamp, simple in and out....

Then when you do want to listen to high quality analog, flip the switch and the AVR is OFF, only the AVA Preamp and Ultravalve are on.

If this is what your describing for Option 1 with the DPDT switch I am ok with this.

The 2 ch analog is not in any way impacted soncially.

The AVR HT L/R preamp outs that go to the Ultravalve amp may not be up to AVA's standards in not being a high current source, but for movies I am ok with this as well.

I will call you on tuesday to dscuss.

Thanks
Alex

Rocket · « **Reply #8 on:** 6 Jul 2010, 07:56 am »

Hi,

I use separate systems for my HT and music. I wonder whether the HT guys would be able to reach behind the amplifier if iit is in a bookshelf etc...

Just offering my 2 cents.

Regards

Rod

Mr_Superstar · « **Reply #9 on:** 6 Jul 2010, 12:48 pm »

I don't own any AVA products, yet, but I've been considering them (to go with my SongTower's). One feature I would like is HT-bypass, but that isn't quite enough. I would also like a Subwoofer "pass through", if you will. The issue is that my subwoofer only has one set of inputs, currently, I have my receiver connected to it. If I added a pre-amp to the mix, I could use the second set of outputs for my subwoofer, but then I have no LFE from my receiver.. I could switch cables around, but this would be a pain (and not wife approved).

I don't know how big of a "demand" this will be, so perhaps it would just be a better idea for me to build an RCA selector switch to switch between the second set of outputs on a pre-amp and the LFE channel of my receiver.

Just a thought.

adydula · « **Reply #10 on:** 6 Jul 2010, 01:00 pm »

Here is a picture of a Parasound 2100 back panel. You can see the HT inputs from an AVR and outs to the amp.

This has the desired inputs for the L/R Mains from an AVR and for 2 subs.
The HT is selectable from the remote as well on this unit.

Alex

coke · « **Reply #11 on:** 6 Jul 2010, 01:28 pm »

Quote from: Mr_Superstar on 6 Jul 2010, 12:48 pm

I don't own any AVA products, yet, but I've been considering them (to go with my SongTower's). One feature I would like is HT-bypass, but that isn't quite enough. I would also like a Subwoofer "pass through", if you will. The issue is that my subwoofer only has one set of inputs, currently, I have my receiver connected to it. If I added a pre-amp to the mix, I could use the second set of outputs for my subwoofer, but then I have no LFE from my receiver.. I could switch cables around, but this would be a pain (and not wife approved).

I don't know how big of a "demand" this will be, so perhaps it would just be a better idea for me to build an RCA selector switch to switch between the second set of outputs on a pre-amp and the LFE channel of my receiver.

Just a thought.

That's something I overlooked. I usually don't use a sub for music, but it would nice to have the option.

A feature I'd love to have on my preamp would be a defeatable high pass crossover.

This would be cool, and maybe even possible since the preamps already have 2 outputs (not much experience with using preamps in a home theater setup, so maybe there's a more effecient way?):

The 2 ouputs on the preamps would be designated "speaker out" and "sub out".

Switch in position 1 - sub output and speaker output full range. High pass crossover completely out of the circuit. (or maybe have the sub output off on this setting)

Switch in position 2 - sub output active and high pass crossover active for speaker output. (most subs have a low pass crossover, so i don't see the need for one on the preamp)

switch in position 3 - Bypass mode for both outputs. Preamp would allow the signals to pass through without having to be turned on.

avahifi · « **Reply #12 on:** 6 Jul 2010, 09:23 pm »

OK, we are building an Insight+ SL preamp for adydula with the lowest cost HT option, a simple back panel mounted switch described above.

We will be interested in his reports herein as to how well that works for him.

Best regards,

Frank Van Alstine

adydula · « **Reply #13 on:** 7 Jul 2010, 03:16 pm »

I dont use a sub in my 2 ch listening, I have used it but always go back to just the SongTowers...

So this is not a real requirement for me, but I can understand those wanting this feature...

2ch listening is 80% of my time, movies 20% at best...so the switch to me is not problematic...having it on the back makes me think of where i put the preamp so i can easily access it.

Looking forward to playing with the new toys, going to wire up some new speaker cables as well to try as well, the 12 gauge home depot type!! (lol)...

Now my problem is trying to fit all this stuff on my stands, and have to get some 110VAC outlets!

Such problems!
Alex

Mr_Superstar · « **Reply #14 on:** 7 Jul 2010, 04:05 pm »

Quote from: adydula on 7 Jul 2010, 03:16 pm

I dont use a sub in my 2 ch listening, I have used it but always go back to just the SongTowers...

Funny story.. so I have been listening to music using my "Pure Direct" mode on my Marantz for a while and have been very satisfied with the sound. After a number of storms here over the course of the week (Kansas City weather has been crazy this year...) I decided to make sure the amplifier on my subwoofer didn't explode or anything. So while I was listening, I noticed the LED on my subwoofer was still red. I was very concerned for about 10 minutes, until I remembered that in "Pure Direct" mode, the front speakers are set to Large and the subwoofer is disabled.

So I've been listening to music for a few weeks with no subwoofer, all while thinking it was on

.

I'm not saying the SongTower's NEED a subwoofer, as mentioned above, there is plenty of bass already. However, there is plenty of time where the extra bass is welcome (I listen to a lot of metal and I want to "feel" the song).

adydula · « **Reply #15 on:** 7 Jul 2010, 05:02 pm »

Mr_Superstar!

Funny indeed...my Onkyo when in the Pure Audio mode also turns off the Sub. I have it there in Multi-channel (from the Oppo multi out , all 7 cables) and in the HT DSP modes...

Most of the time its not needed and at times when its there its fine and other selections its too much or detracts from the tonality...

Alex

OkRon · « **Reply #16 on:** 7 Jul 2010, 08:29 pm »

Quote from: Rocket on 6 Jul 2010, 07:56 am

Hi,

I use separate systems for my HT and music. I wonder whether the HT guys would be able to reach behind the amplifier if iit is in a bookshelf etc...

Just offering my 2 cents.

Regards

Rod

Reaching behind would be an issue for my cramped rack ....would a side switch be an alternative? I'd go with option #2 over #1

avahifi · « **Reply #17 on:** 7 Jul 2010, 08:42 pm »

Sorry, there is no room on the chassis sides for mounting a switch. It would have to be mounted to the side of the cover and that would be a wiring layout mess.

Maybe that little remote switch mentioned above would work. We would need to have a true DPDT action. Line ins coming into a top set, tape ins into the bottom set, and output to line jacks out the middle so that one set or the other is connected.

Regards,

Frank Van Alstine

adydula · « **Reply #18 on:** 8 Jul 2010, 05:40 pm »

The switch for me on the back is not a real issue. Depending on what side its on may make me put it on one side or the other in my setup.

Alex

sarge_in · « **Reply #19 on:** 9 Jul 2010, 10:28 pm »

While my current situation has made me postpone my audio component purchases, HT bypass was one of the key features I was looking for during my search as the system was going to share in HT and music duties. Of course, the easier it is to integreate the better, esp for WAF. In any case, a physical switch at the back would be quite inconvenient as the component would have been in a cabinet. Hopefully an elegant solution would be available by the time I am ready to buy again. Best of luck!