Audio Research REF 3 and REF 5 Tweaks

Ref5se

Tung Sol as noted by others in 6550 is a massive difference....Andy at Vintage Tube helped source mine

Ayre myrtlewood blocks under

i hear a slight change with display off. bigger change when I have DAC display off

My Brand new black ARC Ref 6 came in the other day and to my big surprise was the new twice as thick plexiglass cover that comes with the new 6s now. The front and 2 sides are beveled to making it very attractive also. It came with the smoked plexiglass with black screws prob because i bought the black 6. It will prob come with the clear cover if bought the natural silver finish. Anyway there is no way this new thick cover will dip from the heat. 

Hmmmm, I'm not sure that's true. It's certainly not mentioned in any of the ARC owner's manuals that I've seen. It would also pose a potential shock hazard so it's a hard practice to recommend - even if some users with no children or pets do it anyway.

 I remember Leonard telling me many years ago that my preamp will sound better with the cover off. This was back when you could actually call ARC and talk to someone knowledgeable.

That won't happen with adequate ventilation. The plexi cover is a bit like the "canary in the coalmine."

 Yes it will. The top of the 6550 tube is extremely close to the Plexiglas cover. If you have the preamp on for long periods of time the top will melt. I usually listen for 4 or 5 hours at a time on the weekend. When I first got my Ref 5se it sat on the top shelf of my rack. There is a still a slight dip in my Plexi cover right where the 6550 sits. When I complained, ARC sent me a replacement metal cover. According to my dealer this was a very common problem.

Oh and one other surprising realization.  Preventive tube changing is a great idea. I’d got about 2000 hours on my set of 6h30s in my Ref 40 but had an increasing sense that there was something a little off in the sound. A bit of tightness perhaps.  I was also suffering from odd (once every 3-4 sessions) channel drop outs. ARC say the amp should be good for 4000 hours on a set of tubes

As a new set of cryod tubes from Kevin Deal are not that expansive I decided to go for it - wow wish I’d done this sooner! It’s like a whole new amp.  Even at 20 hours in the sound is so much crisper and more open. I’d recommend all owners plan on swapping out every 1000-1500 hours or so, I think you can go longer on the power supply tubes

i half suspect that power up down may be as much an issue as absolute hours.  I tend to listen for shorter (1-2 hour) sessions so put the tubes through a lot of on and off cycles. With my Ref 2SE phono I needed to change at 500 hours. Anyway certainly if you listen for shorter times as I do don’t expect to get maximum tube life

Covers on, covers off ... relatively minor differences and if you’ve not got a dedicated space with a guarantee of no one poking their fingers in then the cover is mandatory

On the two box models I’ve found that removing the cover on the signal tube section helps, likely the signal tubes are more sensitive to the extra vibration the cover might pick up and transmit

However on my one box Ref 2SE phono I find it works better with the cover on -- as others have observed this cover does tend to bow around the large and hot 6550 tube, not a great design

But while we’re talking tweaks you will get a much bigger impact from using better footers under your Ref series pieces -- the problem is that there’s not much real estate under the amp as the under plexi cover is pretty close to the front plate and stands proud. Putting feet under the plexi sounds awful - you need to anchor to the metal case that surrounds it. I get good results from Marigo Mystery feet but they need very careful placement -- part on the metal casework and the back of the footer (with a small attached boss) touching the plexi. Frankly once you get it right the effect of the feet is profound -- much more impact then fiddling with the top plates or the display

lostbears

ARC use to recommend no cover. before they introduced the Plexi covers.

Hmmmm, I'm not sure that's true. It's certainly not mentioned in any of the ARC owner's manuals that I've seen. It would also pose a potential shock hazard so it's a hard practice to recommend - even if some users with no children or pets do it anyway.

The problem is that the Plexi cover will start to melt over time and dip slightly above the 6550 tube if you leave in on for long periods.

That won't happen with adequate ventilation. The plexi cover is a bit like the "canary in the coalmine."

I don't know how it effects the sound, but when folkfreak had me over to hear some music on his system, I saw that he runs his 40th Anniversary pre with it's covers off, and it's interior is a thing of beauty! 

  ARC use to recommend no cover. before they introduced the Plexi covers. The problem is that the Plexi cover will start to melt over time and dip slightly above the 6550 tube if you leave in on for long periods. There is no way that the Plexi cover with small slotted vents would give you better ventilation than no cover. My guess would be that the the metal top would radiate heat and provide slightly better ventilation than the plexi as well. 

I too have not heard a difference in sound with the display off. As for the covers being left off ARC told on the phone when i ordered my 5se clear cover its best to leave the cover on for sound performance and tube vibration. 

 The Plexiglas covers  tend to melt and create a small depression above the 6550 tube. Audio Research sent replacement metal covers at no charge to people that complained. I have compared the metal to the Plexiglas cover as well as no cover. I can't hear any difference. I do run both my Ref 5se and Ref Phono 2se without tops for better ventilation.

 ARC also says that they sound better with the display turned off. I again have not been able to hear any difference with the display on or off.

Yes it is $250.I just bought one for my 5se and now that i sold it i will be selling my brand new clear cover. BTW you cant get a piece of cardboard from ARC for $25. 

I'll have to talk to my dealer who charged me $250. Thanks Scousepasty.

Gpgr4blu, think you've put your decimal point in the wrong place or the price of plexiglass has risen faster and higher than the price of copper!
Mine were $25.00 dollars if bought afterward, no charge if ordered with the units.

It is $250.00 if you don't buy it with the unit.

Let us all know how much the new coverss are.

Sgr:

I heard an improvement in overall air with no degradation in the bass at all. I removed the top covers in both my Ref 3 and the new PH-8. By the way ... the PH-8 now has 220 hours and is killer! According to my trusted source, the PH-8 will continue breaking in for 600-1000 hours. Zowie!

Scousepasty ...

Thanks, I'm going to call ARC to ask about the cost of the clear covers.

Oreganpapa; The plexiglass top covers can be ordered as an alternative to the 'tin plate' originals. They [plexi]don't ring or rattle, as I've experienced with the earlier material.
Cost for GNS Statement upgrade was $3000+ plus return shipping from UK. New high grade components & piggy backed extras added, wiring shielded and lots of anti-vibration padding can be seen.
Sound is superb and has improved steadily over about 500 hours break-in.
Soon to be replaced by a 40th Anniversary, so we'll see what that brings to the party!
I've always checked tubes if I move any equipment and have often found some do loosen-up during moving.

I tried various tubes, like classic Mullards in the PH-7 and found the stock tubes sound best.

Never tried Mullards, but 6DJ8 Orange Globes or USN white label 7308 Amperex were a substantive enhancement over the stock Sovtek 6922 in my PH7. Nicely extended top end, considerably more detail and improved tonal depth across the frequencies.

Be that as it may, I agree that ARC optimally outfits their Reference components with tubes. The NOS 6H30-DR do offer improvement, but since that tube has really shot up in price the relative value equation may not be their favor. Never tried the NOS Tung Sol 6550 but the GE6550A is not a good choice in the power supply.

Upper echelon Shunyata power cords work very well with ARC Ref - try the Anaconda, Python or King Cobra.

Oreganpapa,
So what did you think when you removed the covers?
Scousepasty,
What did GNS do to your preamp and what did it cost?
One thing I've noticed about my REF3s is that the sound which is usually open, dynmamic and has great bass, tends to fade away, I at firts thought this was worn out tubes, but I've found a good cleaning of the tube pins with Caig DeOxit and the magic comes back. I've also found that anytime you move or reposition the preamp, the 4 6H30 tubes toward the back of the preamp tend to loosen and hang down just a little bit overtime. The cleaning process and restoring them to their 90 degree horizontal position brings the sound right back without having to retube. I'd not be surprised if this is where the discrepancy between ARC's claim for tube life and other audiophile's findings comes to life. Because of course a person putting in new tubes would probably clean them before inserting and they would be inserted correctly into the tube sockets. And viola, the the spectacular, natural sound is back.
Thanks,
Steve

My Ref 5 tweaks: GNS 'Statement' upgrade, Nordost Valhalla power cord supported on maple blocks, Gingko Mini Clouds under feet. Plexiglass cover with Note Pad damper.

I've been told by a trusted friend that removing the covers from the ARC preamp and the phono stage is a significant improvement. I'll try it tomorrow and report back. I have a couple of audio enthusiasts coming over for a listening session so we can compare notes. By the way, placing a VPI brick on top of the phono stage helped a little too. With the cover removed, that eliminates that option. We'll see.

Thanks for all the input so far. I concur on the feet. The REF 3 feet seem to be the best. I did put a VPI Brick over the transformer in the right front corner, that was a benefit. I've also used Mpingo discs successfully on the top. Purchasing a tube damper for the 6550 from Herbies Audio Lab paid off too. With the help of RTN1, I replaced the 6h30 tubes with some NOS, I forget which ones, they did make the preamp sound different, but I'm not sure better though I didn't spend hours listening to the change, I just knew I was not going to pay $250.00 per tube no matter what.

- Run them without the top cover. 2nd choice - use the optional new plastic cover (for the Ref 3 - the Ref 5 already ships with the plastic cover).

- Upgrade the power cord; I use Nordost Valhalla.

- I agree that the feet it comes with are best - but every ARC piece seems to benefit from a top notch shelf and/or rack under it. I use Black Diamond Shelves for the Source with their cones supporting the shelf.

- My Ref 3 did benefit from tube rolling; haven't tried that with the Ref 5 yet.

- Finally, when they say it needs 500 hours of break-in time, they are not kidding.

3 sistrum points underneith
hifi fuse
stealth power cord
running it balanced

Unhappily the best tweak I found for my ARC system was expensive - a Finite Element Pagode Master Rack. You have to try it to believe the difference it makes.
I have not tried them but a friend reported improvements using the Nordost Quasar Points.

I've tried various tweeks with my Ref-3 that normally work on other equipment, but not on ARC stuff. All of my ARC equipment )REF-3, CD-7, and PH-7 sound best by using nothing except the stock feet. The high end fuses improve the sound and using Pro Gold on all interconnects AND the tube pins make a definite improvement. I even Pro Gold the fuses. I tried various tubes, like classic Mullards in the PH-7 and found the stock tubes sound best.

I recently re-tubed my ARC monoblocks, the supplier had Svetlana "Winged C" 6550`s which were also "Cryo-ed" 100 hr treatment by Pearl. These tube`s made a great difference in resolution and detail.

Wondering if replacing the single 6550 in the Ref 3 with the "C" cryo-ed version would or would not be a good idea.
Len w

This one is sure to work and is cheap cheap cheap!! Put one of those high end fuses in it, cost maybe $45. Everyone has their preference as to which brand works best of course, but bottom line, can't lose for the money!!

I like EAT tube dampers on my 6H30s. The NOS 6H30 may be worth a try. I like to use a couple NOS 6H30s on the BAT, but feel that using all 8 is a bit too much.

Putting 1950's TungSol Black Plate 6550 was a big step up for my Ref-3.

Well to be specific, although the bass on the REF 3 is very good, my listening panel and I found that the additon of the tube dampers on the 6550 and 6h30 that control the power supply, made the bass tighter, more refined, and with more resolution. We also found that the placement of the tube damper from top to bottom on the 6550 could also influence the sound. In my system we liked the tube damper placed about 1/3 down from the top. So far this is the only tweak I've found that after the initial placement and careful listening was taken off, listened to and replaced again. All the other tweaks I've tried have not withstood these tests. I've always gone back to stock. I believe if you read some of the posts about Herbie's products on his website, you'll find ohters have heard similar results.

I also removed the ARC tube dampers from the 4 6H30s in the rear of the preamp and substituted Herbie's Ultrasonic Tube Dampers. This was definitely not a good idea, as the soundstage and dynamics collapsed no matter where I place the new dampers. As soon as the ARC dampers were replaced, the normal sound of the REF 3 came back, which of course is quite good.
Yes, I should have been more specific than "cleans things up" but the phrase does overall convey what happened and I've tried to descibe the changes in this new post.
Thanks.
Steve

"the addition of Herbies tube dampers really cleans things up."

Really, you cleaned up the sound of your Ref 3.