Audio Research

[AnotherJohnson]

FWIW, the REF 250 SEs slightly lighter weight, and the wonderful handles, make it a much easier amp to move around for the physically challenged. Eddie and I wrangled the LP275Ms into their boxes with significant effort. It was far easier to wrestle the REF 250SEs out of their boxes and into place.

I do like the CJ layout better though. I don’t have useful listening experience yet. The amps are pretty. There are 18 (count them … 18) screws to R or R the cages. Yuck.

I like the external transformer taps for 4, 8, or 16 Ohm loads.

There are 6 power tubes per side, but the drivers are KT150s too, so still 8 big tubes per side.

I think my next amp might be a Burmester 036.

[admin]

I have found AFCI breakers to be a lot more "fidgety" than regular breakers. I don't see any problem replacing them as you know the source of what is causing the trip.

[Big Dog RJ]

Good stuff AJ! In finding the culprit... these things are all part of the chain. Who would ever think of CB's... until they trip of course! I wonder what the heck they use down unda at our home... never bothered to look.

The only thing I did do and made very sure of, is that I powered up the system once they had installed the dedicated lines just to make sure that nothing tripped or was at fault. Only then did I sign and release the AC mains installation document, which I was sitting on until I got the system fully set up. The wifey rolled her eyes .... several times, "not the damn hifi maaate, seriously!" Gotta love her!

So each side has a total of 8 KT150 tubes... yep that's slightly different to the non SE version, which uses KT120's I think, if I can remember from initial auditions.

Not to worry, I'm sure you'll get those big beauties up and running in no time! It's our passion to do so...
Cheers mate, keep us updated
Woof! RJ

[AnotherJohnson]

It is interesting to me that I can run refrigerators, air compressors, table saws, and ALL other manner of mechanical equipment OR AUDIO EQUIPMENT from these AFCI breakers. NO problems.

But stick a pair of honking monoblocks on them, and pfffft!

Sigh ….

[AnotherJohnson]

So each side has a total of 8 KT150 tubes... yep that's slightly different to the non SE version, which uses KT120's I think, if I can remember from initial auditions.

I am no expert, but as the tale has been told, the REF 75, REF 150, and REF 250 all started out as KT120 designs. Then in their development of a new model, ARC discovered that with appropriate mods, they could achieve a more robust and refined sound with the new KT150s. So the SE models of these amps were born.

They offered factory upgrades to current owners, as it appears they often do. Of course now that series of amps has been retired … just in time for me to start to buy them.

[AnotherJohnson]

Well, the REF 250 SEs are up and running.

650EF092-109F-485F-98FB-4F133205E7DC.jpeg (3.28 MiB) Viewed 5445 times

They are dead quiet. No noise at all in the listening position with the fans set on Lo. On Hi I can hear them if I strain to do so. Lo seems like the best setting for now.

They’re still warming up … but they sound glorious.

They’re plugged into the P20.

My power cord and interconnect situation had to be shuffled a bit.

I’m using the 2 meter Nordost Frey 2 from the wall to the P20.

The amps are plugged into high current outlets on the P20 with Transparent MM2 Powerlinks (?). I may have the name wrong, but they’re the top power cord in Transparent’s last generation.

The preamp is plugged into the P20 via a Shunyata, probably middle of their range.

The phono preamp is using its stock 2.5 meter OEM cord to get to the P20, as is the SACD player. The network player and TT motor/controller are not plugged into the P20.

I’m using balanced Transparent Ultras between preamp and amp. Balanced Thunderbirds between the preamp and phono preamp and between the preamp and SACD player. Single ended AQ Mackenzies beteeen preamp and network player.

Speaker cables are still AQ William Tell Zeros.

The warm up enough to show it off now I think. About 40 minutes.

Well, first impression is that the advice that these amps would be a step up was on the money. I’ve not lost any detail. I’ve got an even richer and fuller low end and midrange. Still sweet on the top.

I don’t know how much of the sound difference is due to the amps and how much is due to the Transparent cords and interconnects.

There’s even more snap, even more definition, even more realistic male and female vocals, even more separation, space and presence.

The meters have a more noticeable movement. If these impressions hold up, I will not regret setting the REF 75 SE aside with the LS28SE. Nice spares.

There seems to be no end to advancements. No matter how good it gets, it can probably get better. I’m stunned again.

[AnotherJohnson]

In the photo above note that Django is looking on approvingly from the lower left corner of the room.

And that’s Clarence White in the right corner enjoying the tunes.

[AnotherJohnson]

FWIW the P20 is running just under a kW. Its heat sinks are warmer than before.

The distortion figures and wave forms are about the same as before.

The meters on the 250 are more responsive than on the 75, with a shorter time constant. Still, even loud play doesn’t get them above 10 Watts.

These may be the end of my amp ride if they prove to be reliable.

[AnotherJohnson]

These are serious space heaters. The heat is set on 70 F, but the amps drive the room temp at their end of the room to 76. I’ve turned the AC on to bring it back to 72.

[Joe Appierto]

Very nice. Lots of luck with the system and continued enjoyment.

EDIT: I realize you'll be getting new Wilson speakers (next month?) but what you have now is still darn good.

[AnotherJohnson]

Very nice. Lots of luck with the system and continued enjoyment.

EDIT: I realize you'll be getting new Wilson speakers (next month?) but what you have now is still darn good.

I think there are going to be some more wire swaps. Maybe even fuses .

I had my first fuse experience where a nominally continuous fuse was not. While I was monkeying around trying to get these to run without tripping breakers, one amp would either trip the breaker, or might not … but wouldn’t start in either case. I pulled the 7 amp Slo Blo and it looked good.

I tested it for continuity, and depending on how I held the probes in place, it varied from essentially 0 up to as much as 20 Ohms. I noticed that one end cap had some play in it. The different measurements were showing the flexibility of that end cap.

I wonder if a reason the aftermarket fuses make a difference to so many ears is due to something as simple as consistency of their R values.

[Joe Appierto]

I wonder if a reason the aftermarket fuses make a difference to so many ears is due to something as simple as consistency of their R values.

I guess that's a possibility. In all the years I've used aftermarket fuses I never thought to measure them with a multimeter. Not even sure if I still have the meter since I stopped using it 20 years ago when I switched to CJ amps and no longer needed it to bias the previous amps I had.

[AnotherJohnson]

I wonder if a reason the aftermarket fuses make a difference to so many ears is due to something as simple as consistency of their R values.

I guess that's a possibility. In all the years I've used aftermarket fuses I never thought to measure them with a multimeter. Not even sure if I still have the meter since I stopped using it 20 years ago when I switched to CJ amps and no longer needed it to bias the previous amps I had.

I suspect another reason might be very very very low R value because changes in Z’s near zero, in the second and third decimal place seem to be a factor in speaker cables and power cords.

It just hit me as I am writing this that speaker cables are to speakers as power cords are to other devices. And going for 0 impedance, even when you might already be at less than 1 ohm, seems to impact both.

As for multimeters, I have had at least one on hand for nearly 60 years. I’m a sucker for lab equipment.

[Big Dog RJ]

Ah! Nice one matey! Very nice indeed.

Those ARC Ref250se monoblocks were as good as it gets. The chap whom I know quite well who had these, partnered them with a very low end Aus made tube preamp, called Supratek. That combination never took flight, he should have had a matching ARC preamp. Nonetheless, he doesn't have the Ref250se amps any longer... sold off to trade in for some huge SS amps to drive his highly inefficient MBL's... basically another disaster! Now he regrets letting go of the ARC amps... go figure!

This is a well thought out full ARC based system with excellent dynamic driver type speakers. Not just any dynamic type but Wilson's! They require the best gear to really perform optimally. Great stuff mate!

I don't see the REF75SE anywhere... is it all packed up and ready for sale? BTW, I was just wondering how all that weight is being supported by that cabinet with glass doors... must be a very solid cabinet! They don't make cabinets like those now, must be real solid thick timber weighing a ton! Nowadays cabinets are like cheese... the slightest water on them and they fall apart, cheap mdf boards used.

I'm guessing you've sorted out this huge one piece cabinet to hold all this gear, otherwise you wouldn't use it all if it wasn't sturdy. Just curious

This deserves a big WOOF!!! Now wait for the S-Daws & you'll fall off your chair!
Cheers, and enjoy those fine tunes!
RJ

[AnotherJohnson]

The cabinet is solid hardwoods, made in the USA. Stickley, and Nichols & Stone are my go to companies for furniture. I have two of the one in the picture (old Nichols and Stone).

The total weight on the cabinet is less than 200 pounds, distributed over the whole top. It isn’t a stretch. There is a custom cut tempered glass cover to protect the wood. If there were any flexing, it would shatter. So they’re safe.

[AnotherJohnson]

FWIW, the fate of the REF75SE, LS28SE, Marantz SA-KI, and Sabrinas remains to be determined.

They’d be a nice system for someone.

[AnotherJohnson]

The 6 to 6SE is turning into a trade. Rather than upgrade my 6, they’ll be sending me a new 6 SE.

Regarding the N&S cabinet with the end tables, it is an intentional plan. By using this approach, every piece has unobstructed air flow for cooling. Every piece is easy to swap in or out of the system.

I suppose some might prefer something like Solidsteel… or Stillpoint feet. I dunno. Maybe I’ll try feet … but I really like the non-marring ARC OEM feet.

That table the TT is on is the best TT stand I’ve ever heard.

[admin]

The setup looks amazing. I have to say that it would also look great as a central vertical stack. Especially with all those handles aliened from top to bottom. Yes, completely unnecessary and airflow is probably better like this, but it would look cool.

[AnotherJohnson]

Right now I’m running 2m balanced Transparent Ultras between preamp and amp, and the amps are both on Transparent MM2 Power cords.

I can’t help but wonder what the Thunderbirds and Hurricane would sound like in comparison.

But I only have 1 m long Thunderbirds and Hurricanes.

So I’ve ordered a 2 m pair of Thunderbirds and a 2 m Hurricane.

The issue is that the amp that’s farther from the preamp needs more than 1 m interconnects and the amp that’s farther from the P20 needs a more than 1 m power cord.

I’m going to use 2 m Thunderbirds on both to maintain symmetry of preamp load. I’m going to use a 1 m and a 2 m Hurricane on the theory that symmetry at that stage is unnecessary.

I know I lost some protection by removing the AFCI breaker. But the P20 has all the protections built in and it’s the only thing on that circuit.

[AnotherJohnson]

I recently criticized the two channel Chesky SACD mix of David Hazeltine’s “The Jobim Songbook in New York.” The trio seemed properly placed relative to each other, but somewhat distant from the microphone position. I came to this conclusion over several listening sessions distributed over several months. I would prefer more intimacy.

I got it out tonight to see if the presentation had changed with the new amps and wire changes.

This presentation is much closer to the listener. I’m sitting at a table 5’ to 10’ from the stage with David on my left and Nat and Joe to my right. It is a seat I’d have chosen.