Audio Research reference amplifiers used with RCA IC`s and unbalanced preamplifiers

Yes, you could run it that way. But part of the appeal of most ARC amps and preamps is the fully balanced differential circuitry. You're not getting maximum performance from them if you don't take advantage of that.

You might want to consider the expense of running a tube amplifier. I mention that because you're obviously budget conscious if you're reluctant to buy balanced audio cables for your new amp.

"But part of the appeal...."

But how much of that appeal is really important if you have short runs and no noise issues. I always thought the real benefit of balanced stuff was the connectors and as a solution to noise when used in long runs, i.e. like in a recording studio.

OP, IMHO if you like your present IC’s and pre-amp just use a converter plug. Otherwise you have to go through the painful and expensive process of developing a new and synergistic system, pre-amp & IC’s.

FWIW.

BTW, the first time I had a fully balanced set up I liked my unbalanced cables sonics better than my first set of balanced cables (25ft long!).

I have all ARC stuff. I had high end single ended interconnects when I got my ARC amps. Audio Research recommends using balanced (preamps and amps are internally of balanced design). So I got an identical balanced interconnect and tried it. I could not tell the difference. I did not carefully listen for weeks… so there was probably a small difference… that I would have heard over time. I still swapped them all for balanced. Getting the absolute most out of a system is the sum of small differences… so some of us never let anything go at less than perfect.

So, applying this to your situation. The sonic difference in using converted interconnects is likely to be very small.

The fact that you own three preamps and are conserved with cable costs suggests you like experiencing different sound types as opposed to achieving the ultimate sound quality you can. So, I would go ahead. You are going to get the Audio Research sound from these components. Then if you get hooked on the sound you invest in balanced to get the utmost out of them.

@newbee 

With the 25’ balanced / unbalanced comparison. Where they identical interconnects that were fully broken in?

No, they were different brands. I guess my point was that cable construction was probably more important than whether or not it was balanced or unbalanced unless you had noise problems to deal with. 

cleeds

Thanks. My 2 current amplifiers are both tubes class a/b so I don't think I would incur any extra electric expense.

I understand I may not get maximum performance but as 2 of the 3 preamps are rca only I did not want to spend money on IC's that can only be used with one preamp. 

newbee

Thanks for input. I have no IC'S longer than 2.5 meters in the system.

I was wondering if the output impedance of my preamps makes a difference?

relating to the input impedance of the ARC amps . The ARC amps are both 300k ohm input impedance while my amplifiers are 47kohms and 25 kw input impedance,

ghdprentice

Thanks your suggestion makes sense.If I purchase the ARC amp and really like it I could  sell off several preamps and IC'S and go all ARC with balanced interconnects.

@newbee 

Thanks. I have to agree, quality probably more important than type in this case.

newbee

... how much of that appeal is really important if you have short runs and no noise issues ...

The OP will give up 6 dB of s/n if he uses the single-ended connections. That's why I don't see the wisdom of buying balanced electronics such as ARC and then running them single-ended.

As these amplifiers are fully balanced and don't have an RCA input, can I use RCA interconnects with a conversion plug from RCA to balanced at the amplifier input and will it work in my system?

@nsp I think the answer is no.

IIRC, these two amps, while 'fully differential', have a poor Common Mode Rejection Ratio at their inputs! What this means is that it makes a big difference to them if the balanced input is driven properly. In support of this (again, IIRC), I was told by the front man at ARC (Kalvin, since retired) that the amp will make significantly less power and significantly greater distortion if driven single-ended.

+Atmosphere! Better from the horse's mouth than the horse's ass. :-)

nsp, re impedance issues you referred to. The 300K input impedance should make it a good match, impedance wise, to any SS or tubed preamp, or source directly connected. But, FWIW, I think the other impedances you attribute to ’amplifiers’ refer to the input impedance of your preamps. What is relevant however, as it relates to your amp, is the preamps output impedance.

cleeds

yeah ouch!! Not looking for added service expense/shipping  if possible. I don't repair but am capable of changing tubes, biasing, changing fuses. 

I do have an audio technician who does repairs for me at a reasonable cost  

atmasphere

Thanks thats good information from an insider at ARC. I would try to purchase the ampliifier with a return provision ,if possible . 

I have both a REF150Se and a REF75SE- outstanding amps. I'm pretty sure ARC doesn't want you to use adapters and I def wouldn't entertain having anyone try to convert them to RCA inputs either. There are lots of guys out there who work on tube amps who confidently will tell you they can figure out anything on an ARC and work on it - in my experience they can't without the schematics- and ARC doesn't provide them to non authorized servicers. Also, Kalvin is not retired and is at ARC and is usually the guy who answers the phone. CAll them and ask them directly about the balanced / adapters question. Trust no one else in my experience. 

Both the REF75SE and the REF150 SE are outstanding amps- better than any others I've had and I've had a lot of high end gear. The ARC amps (and their pre amps- I have an LS28Se) are flat out musical, dynamic and detailed- somehow they just get it 'right" for me. Yes, tubes run hot; they use more electricity, they will age and fail and are expensive. Like most other high end toys - like owning a Porsche or similar- they're expensive to maintain at times- but- they're really really good. A tube set from Upscale for the 75SE runs about $700, from ARC $1300. For the 150SE from Upscale about $1600, from ARC $3300. They last about 3k hours. They make wonderful music always.

And, if you get a higher end set of XLR cables you will notice another uptick in performance resolution etc. I run a fully balanced system, Ref 9 CD->LS10-> D240 it’s fabulous musical and an endgame set.
See my set up here.

newbee 

my preamps output impedances are as follows:

200 ohms from the Wavestream Kinetics

150 ohms from the Wyetech Ruby

3500 ohms from the updated /customized Counterpoint SA5000

speedthrills

Thanks. I agree it's a good idea to contact ARC directly and will do so as their answer will be definitive. 

Just curious how much wattage do your 75se and 150se put out in triode mode?

cant seem to find any data on this. 

johnread57

Thanks , Sounds like your fully balanced from source to speakers. Will take a look at your system.

Does anyone have experience with ARC latest iteration , the Reference 80se amplifier at 70 watts/channel as compared to the Reference 75SE soundwise? 

THE REF 80SE has rca inputs on the unit so I guess using RCA IC's would not be a problem? 

Also, Kalvin is not retired and is at ARC and is usually the guy who answers the phone.

@speedthrills I went to Ward's funeral (RIP, Ward) a couple of years ago and saw Kalvin there. He told me he had left ARC a couple of years earlier. If he has since gone back that is news to me.

THE REF 80SE has rca inputs on the unit so I guess using RCA IC's would not be a problem? 

@nsp Of course- no worries!

@nsp - the amps put out 70 rms and 150 rms per channel and are configured one way - not switchable. Both drive Wilson Sasha 2 off of the 8 ohm tap no issue, the 150SE drives them better, bigger and louder if you listen loud. 

@atmasphere - Yup, Kalvin's back, I've talked with him several times in the last month and more often than not he's the person answering the phones when they're open. I need an LED for one of the meters on the REF75SE and just sent the LS28 into him for the LS28SE upgrade earlier this week. 

👍

speedthrills

My bad I was actually referring to an article I read on the new arc reference 80 SE amplifier. It is switchable  from Ultra linear to triode mode but I can't seem to find the power rating for the triode setting.

The 80 SE is 70 watts per Channel in Ultra linear I'm thinking the triode setting might be only half that which might not be enough for my speakers. 150 watts per Channel is probably Overkill for my room and listening habits. My room is 15 by 17 with 8 ft ceiling and I listen from 75 to 85 DB nothing louder

The triode setting would be 35 wpc. I own Ref 160’s.

I run my REF 160’s in triode mode (so 70wpc instead of 140wpc). There seems to be little difference in sound levels… only in the triad mode there is a bit more naturalness to the sound.

I periodically switch back to ultra linear and immediately back to triode. Having come from 350wpc Pass amp… where more power is better… not true in the ARC tube world.

The contemporary ARC Reference amps are incredible. Highly recommended.

ghdprentice

Thanks. That's what I thought 35 Watts or half of 70 Watts.

Well it seems like you're saying that the difference in power/quality switching in your system is not that much different.

Was curious as to what levels your spl's are? Mine or 75 to 85 DB

I typically listen at the 65 to 75 db area. But I occasionally crank it into the 80db area, it sounds great.

If you are listening at an average spl of 85 that is very loud. If you are talking about occasionally peaks touching 85… that is just loud.

I had some kids come over and crank it to…. Loud… I didn’t want to go in to measure the spl, it was too loud. No evidence of running out of power.

I found when I switched over to the ARC amp from a Pass 350 (Wpc). I actually listened at lower volumes because the music was more satisfying at lower volumes.

Wow, 85 db is very loud.  No wonder my wife is always yelling at me.  But going back to cables, if both the preamp and power amps are fully balanced you can use inexpensive balanced cables.  Mogami or something similar for no more than a couple hundred bucks.  For what your investing in the amp seems like a drop in the bucket.  But then again I’m good at spending other people’s money.

Whoops just saw the preamps we not balanced.  Never mind.

ghdprentice

yes just peaks at 85db . If the music goes to continuous spl over 80 db I turn it down to 80db or less. I am aiming for the system to sound best at 70db -80db.

Thats one of the important points about getting better gear. To be able to listen at a lower spl level and achieve maximum enjoyment .  

@ghdprentice ​​​​@nsp I too aim at sub 80 dB sound levels, but my ‘shots’ seem to drift up a bit. It just sounds better with a bit more oomph. Then too, I may be a bit deaf as well. A condition likely exacerbated by the very same SPLs. Good thing that I have only myself to please.

Edit: I turn it down (or up) at 90 dB; that is, if it is playing over 90 dB it is a temporary condition because I want that track to shake walls. And I want my system capable of such performance, if I ask for it. 

I pulled out my sound meter right after my last post. I think the average was 66db  with peaks to 71db. It was at a completely satisfying level. I found the better my system got the less the need was for volume. 

I did the same.  My listening levels average 80 db with peaks in the low 90's.  It's tough getting old.

ghdprentice

I do listen to some music in the 65 to 75 db range and it sounds very good. it's dependent on the recording. Agreed  the better mysystem has beccome the need for less volume.

oldrooney

I too tend to turn up some music slightly as I find there is a "sweet spot" where the music opens up and is dependent upon the track and music. As you say it needs a little"oomph"  to get it to sound good.

marco1

Agreed.Have to watch those high SPL'S as we are getting older.

I have same experience, never use the special care or transformer , doesn't matter it is powered or non power transformer,they won't bring the same quality sound.

The only choice is that you bring the same xlr,or same RCA with both pre and power amplifier.

@atmasphere is right!