Moving from a stereo amp to a dual mono set up

I notice your ARC-Ref 3 preamp has remote balance, that will be wonderful, especially when using two amps.

OP

I am impressed with your ability to make it all happen simultaneously. Those are some impressive amps, congrats on finding a rare 2nd unit. I just glanced at this:

Stereophile Review of Plinius SA

Sometimes I recommend the idea of potential bridging, i.e. start with an amp that can be bridged, exactly what you did. I think of it more for tube power, hope one affordable/less heat less heavy Stereo Amp is enough power. If not, get a second one (phased spending can be a reason), OR, IF you change to less efficient speakers, NEED more, get a 2nd one. I suspect you are doing it out of ’now or maybe lost opportunity’ more than need.

I recently noticed impedance taps become limited on McIntosh models when bridged, and reading testpilot’s comments, I looked, Plinius only lists 8 ohms when bridged:

"testpilot

You really haven’t experienced the full benefit of “true” dual mono amplifier set up as you are using 2 stereo amplifiers “bridged” where amplifier phase of one channel has been inverted - that is why you are now using the positive L and R terminals for a single speaker. Bridging typically halves the minimum impedance the amplifier can safely handle, lowers the damping factor, and increases THD and noise. Bridged amplifiers are typical limited to speakers with a nominal 8 ohm impedance with no significant dips below 6 ohms. "

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I found this review of Canton Model 3.2 (You mentioned model 3)

Stereophile Review of Canton Reference 3.2

"My estimate of the Canton’s voltage sensitivity was a high 91dB/2.83V/m; this loudspeaker will play loudly with just a few watts. However, its impedance plot (fig.1) indicates that the partnering amplifier needs to be comfortable driving a low impedance. The magnitude remains below 4 ohms for almost the entire bass and midrange regions, with a minimum value of 3 ohms at 360Hz and a current-demanding combination of 4.6 ohms and –45° electrical phase angle at 88Hz, a frequency where music can have high energy levels."

I presume you told Plinius which speakers you have.

When replacing my speaker’s 16 ohm L Pads, I asked here and learned about very slight frequency shifts if I used 8 ohm taps on my Cayin instead of it’s 16 ohm taps, and that some guitarists choose which tap to use to purposely get slightly different sounds out of their tube amps playing live.

Your Canton’s 91 sensitivity helps (assuming 3.2 and 3 are the same), you shouldn’t need to push them hard, and bi-wire using different cable type for lows is still an interesting option, your speaker’s readily provide for that.

Your amp offers class a (whole lotta heat) and class ab (a timed 10 minute switch?), are you able to easily or always hear differences, or do you use class a only for special content, short periods, all winter?

Ok I am all done.  Costs for the electrician was $960. He ran 2 circuits from the box to my wall. Large wire. 20 amps available. 

I patched the holes and painted the wall from snaking wires down. 

I bought a second amp stand. Then there is the amp and rebuild. About $4000 total for that. 

Altered speaker cables $160. Also they sold me 2 new power cables for the amp. $1225 total from the power cables.

The guy that sold me the used SA 102 amp said it was in perfect condition.  Ralph told me that it looked like it had water damage internal. That caused problems.

But now all this is behind me. 

The system is really good. 

I have (2) Plinius SA 102 amps running mono producing about 250 upcoming ea

Audio Research Ref 3 pre amp

Canton Ref 3 speakers

Wyred4sound 10th anniversary DAC

Aurender N10 streamer

Teac VTS transport cd

Dr Feickert Volare turntable 

Unami blue cart mc

Stogi unipiviot arm.

All the hi zoot wires I need.

PS power filter

Myrna Loy Chooses Her Paint Scheme

The "Mr, Blandings" film always reminds of the famous scene above which always suggests to me the discontents and headaches of audiophilia.

No need to reinvent the wheel my friend. Everything that you’re wanting to do has already been done many times before.

You really haven’t experienced the full benefit of “true” dual mono amplifier set up as you are using 2 stereo amplifiers “bridged”  where amplifier phase of one channel has been inverted - that is why you are now using the positive L and R terminals for a single speaker.  Bridging typically halves the minimum impedance the amplifier can safely handle, lowers the damping factor, and increases THD and noise.  Bridged amplifiers are typical limited to speakers with a nominal 8 ohm impedance with no significant dips below 6 ohms.  

Any home that one considers to buy ought to have it's wiring checked for aluminum wiring prior to a signature on the documents.  It can function fine if kept within it's limits.  Lights and lighting are typically fine, but any circuit posed with a varying amp load ought to be replaced; however, if one circuit is being swapped out, it's better to bite the bullet and change everything and ignore the 'grandfathering' option.

We had a house that was all knob and tube next to live gas lines, the latter got disconnected and vented.  A latter one has one continuous ground for all the circuits, making 'short circuit searches' a real bug chase....

Know ahead of what you want to upgrade....copper and alum wiring together in one installation is considered a real hazard...

"Know thyself....Then, know everything else in close proximity to you and ;oved ones....." ;)

i wondered if you could use each of the amps within the stereo amp to biamp one of the speakers and do the same thing on the other side.  Not adding two more dual amplifiers.  Although that might be kind of fun.

I do not know. All I do know is the main Plinius man here in the USA told me how to do it. And I have all i can do to hook up 2 amps and not 4 of these beasts.

So why are they connecting positive and positive from speaker wires supposed to be connected to positive and negative? Why would they internally wire it this way when it’s to be used for mono after being bridged over from a stereo amplifier?

Why not use the four individual amps in a biamp configuration?

No, 2 separate amps. I per speaker. 

The wiring of the speaker to the back of the amplifier is kind of weird. So I guess it's not doing bi amp

Regarding setting on the Plinius.

The amp is a designed with a switch on the rear of the unit to run in Stereo, or Mono and which inputs I am using. I am using the XLR inputs. SO I move the switch to the Mono position with XLR Inputs.   So my connection is to connect to the right channel input. The speaker connection is  Positive speaker wire to the Positive Right channel, Negative speaker wire to the POSITIVE left channel.   There is a distance of 9" to those 2 binding posts on the back of the amp.  That is why I sent my cables to be altered, the speaker wire leads could not stretch that far apart. 

Shipped them on Thursday. Straight Wire will be getting them tomorrow. They should be back in UPS by Friday. I might have them by the 19th of this month. 

Bu then I hope the electrician is done. I should only take about 4 hours max for them.  And I am sure I will have to move my system off the back wall to give them some room to work. So, I can then reposition everything so things reach. 

Good thing I have a second system in the same room to use for my birthday and the holiday weekends we have coming up. 

@61falcon  yes you are correct thar makes  big difference  more than just ground  loops. I would also suggest  12 3 wire not just 14 3 wire. As long as it is being  rewired heavy wire is a good thing. Make the wires in the wall identical  length  as well. . I changed the feed wire to my house from aluminum  to copper. That was a good improvement  acr9ss the board. Went to a 200 amp service  and when I needed the wire going to the house to be heavier I paid the extra for copper. It was well worth it. Also you might want to have better receptacles put in as well. Furutech  I have been very happy with. Lol power is a slippery  slope. As the improvement is hard to believe.  But much cheaper  than most other items 

@emergingsoul 

I probably should have said to keep them on the same busbar in the panel e.g. if you're on the L1 bus, ensure both breakers are on the L1 bus. I had a ground loop issue until I put both circuits on the same bus.

I'm certain there are a lot of other possibilities for ground loops though.

@61falcon 

I thought you're supposed to keep all the circuits in the same phase for your system.

As long as you don't have components Sharing different circuits ground loops should go away. 

get listening to some dynamic stuff now, with instant peak needs, so you can hear the difference, if any, when you double your power for peaks.

or, I guess you need to wait till when the speaker wires come back, listen to the single stereo unit before you go dual mono

Every facet of change always meets with frustration. I don't understand the connections you're making on the back of the Mono.  Is this A biamp exercise? Kind of confusing to my tiny mind.

Congratulations plinius are very good.I own SA100 for more than 25 yrs now. The cost of electrician doing your project depends on how mow much work and he will spend to install it and how greedy he is?This hobby when you add gear or cables it change the sound.With mono beside they are heavy you need extra space to accommodate them? And maybe longer cables. Lots of work needed .At the end of you do it right , you will be happy enjoying music.

If you are running two separate electrical circuits for each amp, you may want to tell your electrician to take them off the same phase. I've had issues with ground loops when I went off opposite phases.

@bill_peloquin 

Before you drop some big money on redo’s, etc., why not try DSP to correct some of the shortcomings your’e experiencing. Until recently I was totally against it, feeling I was cheating or something, but it came down to weather I wanted great sound or not so I gave it a try… It may not be morally right for everybody, but I gotta tell ya… Fixed the issues I was experiencing allowing me to enjoy my set up and room again. Just a recommendation.   

Funny thing - I actually started this hobby years ago with dual mono blocks. After years of moving around the country and setting up the system, I finally decided to go stereo. Haven’t looked back! 

Thanks for sharing your experience.  We’ve probably all been there.  It’s why this hobby is a journey and not a destination.  Enjoy the journey.  If not it’s like taking the kids on a long car ride on vacation with shouts of, Are we there yet?  Are we there yet?  Please keep us updated on your progress and as Hans says, enjoy the music! 

sometimes I ask my wife: do you want some music or silence is fine and more often than not she says silence is fine. Imagine the costs and setup needs of that options.

I feel your pain.

I would suggest you watch the original 1948 version of the movie, "Mr. Blandings Builds His Dream House", starring Cary Grant and Myra Loy.

Suffice to say, you will know exactly how Cary feels about how simple projects can turn into a nightmare of complications.

Bill,  you forgot a step.  Walking into the backyard at 2 in the morning, staring at the stars, and cursing the stereo gods for tempting you into this hobby!

I feel your pain.  I recently moved into a new house and was psyched that I could finally setup a dedicated listening room in a spare bedroom!  A year later, I'm to the point of starting over.  The room is too small, the seating position is too close, too many windows, the equipment rack is too big, I can't get the bass issues under control, and the electrical circuit is undersized and unstable.

So, now I'm going to build a dedicated listening room in the basement. (more $$$)  Damn those gods on Mount Audiophile!

Keep us appraised on how things go.  

- Jeff

I hate it when something that appears to be simple spirals into a major project. I’ll be interested to hear what you think of the sound differences when complete. 
 

You are reminding me of wanting to get my component stack moved from between the speakers to off to the side. It used to be that way, and it improved imaging; but the stack has much more stuff than it used to.

Space or the lack thereof can be the most ticklish part of home music playback.