Home theater bypass


Hi I am am new member I need some help with routing for my home theatre. I have a Onkyo 7.2 receiver and a mac275 amp with a cj pre amp. My speakers are Maggie's which I use for both systems I'm plugging and unplugging every time I want to use one or the other. How can I wire up a permanent setup to avoid this. Any suggestions would be great!
audiomaze
Does the CJ have home theater bypass?

If yes... run front R&L outputs (rca) to input on CJ

Actually, you can use any input... the CJ sees the FR&FL from your processor as an analog input. You will then need to level match the CJ volume for those speakers manually.
Hey thanks for your suggestions but most of it is Greek to me. It looks like the safest way is to continue to plug and unplug as needed. Maybe my next preamp or amp will have a factory bypass. Again thanks 
What model CJ preamp do you have?  I thought they've been including HT bypass on their preamps for years.  Let's just start there. 
It's a pv-1 the first preamp cj made in the 70's. I have a Onkyo 805 7 channel with preouts but I don't know if you can run two preamps in series to the amp which is a Mac 275mkvi. 
If you want to use the Mac 275 for both stereo and HT duty, there will be two ways for connections:
1. Use a line level source selector connect to Mac 275 input to select the output from cj preamp or Onkyo 805.

2. Connect the Onkyo 805 front R/L preout to cj pv1 one of the line level input (not the phono) and set the cj volume control to unity gain position during HT playback.

To find the cj volume control at unity gain position:
connect the cj preamp main output to Onkyo 805 one of the analog input (i.e. CD input),
connect the cj preamp monitor or tape out to Onkyo 805 another analog input (i.e. AUX1 input),
connect a cd player to the cj preamp to play some test tone,
switch between the two input on Onkyo 805 and adjust the volume control on the cj preamp until both input getting same loudness/SPL.
Mark that volume control position on the cj preamp front panel, it’s the unity gain position.
With that type setup which preamp controls the sound to the amp?
It depends.  When you're doing surround the AVR controls the volume, but for 2-channel not only does the stereo pre control the volume, the AVR is COMPLETELY out of the playback chain.  This is the real benefit of this setup.  Instead of swapping cables to switch between stereo and multichannel you just change the stereo pre to the input that takes the L/R preouts from the AVR and set the CJ's volume control to the proper reference volume level and you're done. 

BTW, while the method by @imhififan is maybe the more accurate way to go, another and perhaps easier method from a practical standpoint is to use the 12:00 position on your CJ as the reference point for the input from the AVR and then use the AVR to set the correct volume levels for each channel.  This method doesn't find unity gain for the CJ, but it avoids having to mark the proper volume level on the faceplate of your stereo preamp.  Hope this helps, and enjoy your new setup!  I did this for years before I got a dedicated listening room and it was awesome. 
If connect the Onkyo 805 front R/L preout to one of the line level input on cj pv1 and set the cj volume control to a fixed position during HT playback, the cj preamp act as a pass-through and the Onkyo 805 do all the control (i.e. select input source, surround mode, volume ...)

http://daveayers.com/Audio_Diagrams.htm
perhaps easier method from a practical standpoint is to use the 12:00 position on your CJ as the reference point for the input from the AVR and then use the AVR to set the correct volume levels for each channel.  This method doesn't find unity gain for the CJ, but it avoids having to mark the proper volume level on the faceplate of your stereo preamp
+1 soix
I like the schematic but I have a question. The passive pre is the cj the amp is the Mac receiver than what is the CDP where does it connect on the cj. Please excuse all the questions but I am still learning and I don't want to blow anything up. Many thanks 
You connect the CDP to any line level (non-phono, let's say the "tuner") input on the CJ and the L/R preouts from the Onkyo to another line level (let's say the "ancillary") input also on the CJ.  When you want to listen to 2-channel you choose the "Tuner" input on the CJ and when you want to do surround through the Onkyo you switch the CJ input to "Ancillary" and adjust the volume on the CJ to the reference level that keeps the L/R speakers balanced with the center/surround speakers.  That's basically it.  Just to be clear, only the preouts from the CJ go to the Mac 275. 
https://www.computeraudiophile.com/uploads/monthly_2013_09/58cd96b7e0681_HomeTheaterBypass.JPG.02904...
In the schematic, CDP is a compact disc player (CD player), passive pre is the cj and amp is Mac 275 and receiver is Onkyo 805.

Maybe this schematic give you a better idea:
http://daveayers.com/Audio_Diagrams.htm
To operate ether system all units must be on ?
I tried it and the protection circuit tripped on the Mac 275 twice ?
Please tell us exactly how you have this whole thing hooked up.  Something's wrong somewhere. 
Ok the DVD player is connected to the receiver with a hdmi and connected via the audio outs to the preamp inputs. The receiver preouts are connected to the preamps tuner inputs. The preamp is connected to the Mac then the speakers Maggie 1.7. 
To operate either system all units must be on ?
For stereo playback, only the source (CD player, turntable or tuner), cj preamp and Mac power amp need to be on, the Onkyo receiver can be off.
Before any playback using Onkyo receiver at the first time, you need to set the cj preamp volume to 12 o’clock and re-calibrate the speakers level setting via automatic speaker setup or adjust the front R/L speakers manually (see page 55-59 of Onkyo TX-SR805 Owner’s manual).
Ok guys, here is a HT bypass question for whoever can answer. I asked it months ago on the Asylum when I was thinking of getting a Oppo 205, but nobody could answer.
I have a Mac C48 preamp that only goes into bypass mode by a 12v trigger from a processor. I have been working around this as my Oppo 105 that I use as a processor has no 12v trigger. 
So now I am about to set up my new 205 which has a trigger to put the C48 in bypass,  but what if I just want to play a CD and not HT,  how do i control that, if every time I turn on the 205, the C48 goes into bypass.

I searched the Oppo manual and it was no help.
A couple of ideas here.  If you are using a separate amp for center/surrounds, then you could use the 12V trigger output from that amp to trigger the C48 into bypass mode. 

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Another idea would be to get one of those 12V wall wart DC power adapters, chop the end and solder it into a 1/8" male mono plug.  Use that as the 12V trigger for C48 and then just plug it in when you want to trigger the C48 into bypass mode.
I have a Mac C48 preamp that only goes into bypass mode by a 12v trigger from a processor. I have been working around this as my Oppo 105 that I use as a processor has no 12v trigger.

Another idea would be to get one of those 12V wall wart DC power adapters, chop the end and solder it into a 1/8" male mono plug. Use that as the 12V trigger for C48 and then just plug it in when you want to trigger the C48 into bypass mode.
Same idea with some refinement :
Use a 12V wall wart DC power adapters with inline on/off switch and a 3.5mm Male to 5.5x2.1mm Female DC Adapter.
https://www.amazon.com/Gxilee-100-240V-Converter-Household-Electronics/dp/B01FXF6AEQ
https://www.ebay.com/itm/3-5mm-Male-to-5-5x2-1mm-Female-DC-Adapter-Converter-Jack-Power-Plug-CCTV-DV...
Turn on the inline switch if you want bypass.
So now I am about to set up my new 205 which has a trigger to put the C48 in bypass, but what if I just want to play a CD and not HT, how do i control that, if every time I turn on the 205, the C48 goes into bypass.
https://www.amazon.com/RDL-ST-ACR2-Line-Level-Audio-Controlled/dp/B01D96JVFG
Connect the RDL input to center channel or LFE output of 205, connect the RDL relay switch between 205 trigger output and C48 trigger input.
The HT bypass will be done automatically.
Thanks guys, good ideas, I will check them out.
@audiomaze -- what input on the CJ are the audio outs from the DVD player connected to?
the DVD player is connected to the receiver with a hdmi and connected via the audio outs to the preamp inputs. The receiver preouts are connected to the preamps tuner inputs. The preamp is connected to the Mac then the speakers Maggie 1.7.
@audiomaze -- what input on the CJ are the audio outs from the DVD player connected to?
The tuner.
How many tuner input on the cj preamp?
Ok, so the Tuner input is your HT input.  Do you have a dedicated 2-channel source or is the DVD player used for both stereo and movies?
I have a Panasonic bluray player that does both and is connected via hdmi to the Onkyo for the video. The Onkyo preouts were connected to the tuner on the cj. The Panasonic is also connected to the cj aux input. Thanks for the reply 
Got it.  If you unhook the RCAs from the tuner input and just run the Panasonic in stereo through the aux input does the CJ still trip its protection circuit?  If not, unhook that from the CJ and hook the preouts from the Onkyo to the aux input and see if it still trips.
It stil trips it but now it trip when I play it without any connection to the Onkyo. Not the phono just the auxiliary. I am afraid it damaged the cj. Another trip to the shop.