Problem with Ref 5SE


I recently purchased a 5se and took delivery the other day. Did not get a chance to open it up until last night. Upon installing it into system I switched it on and after it warmed up, I was very much interested in hearing how it sounded against my current 27. After listening to several tracks with the 27 I switched pre's and after a couple of minutes playing a CD I got some noise, almost a loud static sound coming from the right channel. It was not effected by changing volume controls or input selector. It went away after 10-15 seconds and then returned. At that point, as it was late, I shut everything down and figured I would take another look in the morning.

This morning I removed the top cover and pulled and reset the output tubes and then the power tubes. I fired it back up and still had the 'static' sound but now it also had a humm, like an impedance type hum and constant. I do not believe that the humm was present last night as it is quite noticeable. 

The static type load noise seemed to have abated after the unit warmed up after maybe 15-30 minutes.

Can I assume that perhaps a tube was damaged during shipping? Do you ARC guys think a new set of tubes will fix this issue or am I looking at something more severe? Any additional suggestions to try and pin this down?

I rerouted the IC going to the amps to get them further away from source IC's and no help...

I am a little bummed, as my initial impression it that it is a leap from the LS27, my current...
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I no nothing about AR, but did you switch the tubes from the right to left channel to see if the noise follows the tubes?
No, but seems a reasonable test..thanx, did not think of that
Were the tubes removed and packed separately in a box during shipping as it’s supposed to be.  How many hours on the tubes? 
Do what elrod said. If the sound follows from right channel to left, youve narrowed it down. You also have two good 6h30 tubes in your ls27 so if the sound moves channels, borrow one 6h30 from the ls 27 and replace one of the potential issue tubes at a time to isolate. The same can be done to try to isolate the hum (You didn5 say if the hum is in the right channel or both channels) but first try reversing your interconnects on that channel, etc. are you using balanced or single ended interconnects?

After its all said and done, it may need a trip back to arc. 
No, the tubes were installed in the unit, although I doubt that if they were horizontal instead of vertical that it would have helped much. I know they should have been removed...

There are about 800 hours on tubes

Balanced IC;'s, swapped out for another set I had, no difference, humm is both channels and disappears with mute on.

The static noise seems to have gone away once everything was powered on for more than 30 minutes...power tubes?
Not sure what the problem is, but as a Ref5se owner. I did find out that the 6550 power tube needs to be replaced every 2000 hours, this is not mentioned in the manual. It only mentions the 6H30 has a 4000 hour change interval. If you look at the REF6 manual, it now mentions at. My power board burnt, but ARC replaced it as a warranty claim. Just telling you this so you don’t find out the hard way.
That said , have you tried the second set of outputs to the amp to see if that gives the same result? Also the tubes really should have been shipped in the foam packing that ARC includes. If you do ship it back to them ask if they prefer the tubes not in place and maybe they can send you the foam packing cube they sell tubes in.
Moved the tube around from the 27 and hum is still present. I guess next is the 6550 power tube, which I will have to order...this is going to ruin my holiday.. :((
Okay, after a bunch of reading and research it might just be something that I am going to have to live with. Apparently the S/N is what I am hearing, hum/hiss or whatever there might be no getting around it. I do plan on replacing the power tube and ordering a set of outputs as the unit is a little over 1k on the hours and I plan on using this a lot as I get used to it so might as well have replacement on hand.

Any ARC 5se owners have similar issues? I can't have the only set up that this has become apparent. I am probably used to the LS 27 as I do not recall having any issues with a noticeable noise floor.

Have a Power Plant 20 I have to put into system (my 12 could not handle the Pass and the 27 at the same time, had to do them one at a time, the 5 draws a LOT more.

Should anyone have additional suggestions, it would be appreciated, I was already looking for new balanced cables as I need them a little longer so I can cut the cables for speakers to a minimum. I had another thread I posted earlier looking for IC's recommendations. 
Try a different power cord and if you can plug the pass ( amp Im assuming ) directly into the wall. Could be a ground loop issue.
I tried plugging the amps into wall and the pre into my PS Powerplant and then the opposite, amps into PP and pre into wall. The 5se is replacing a LS 27, also a tube unit and I had no issues with that set up.

Ordered a full set of tubes and will be trying that out in a couple of days. While at the moment I do not have any other power cords to swap out as it is a 20a but will look today and see the cost to replace with another power cord. This is turning out to be a costly endeavor...
I assume that you bough the 5SE used.  Did you contact the previous owner and ask him if he had the same issues?  There will always be a bit of tube rush noise coming from speakers, but nothing should be heard from the listening position. 
Ive had several ref 5se’s, running into multiple different amps (arc, pass, even a shindo) and they were always dead quiet with my 96db speakers. You need to send it to Arc for service.
Have you tried all of the various grounding options?  Have you tried a cheater plug on the main power cord, etc.?  Hum is usually a grounding issue.  Hum, particularly hum in both channels can be caused by a filter capacitor in the power supply going bad.  Both the 6550 and 6h30 tubes are in the power supply part of the linestage, so they are suspect as well.

The static type noise that goes away after the unit is on for a while can also be a capacitor issue or an issue with tube sockets.  Sometimes poor connection in a socket goes away when the unit is heated.  Your re-seating of the tube curing part of the problem suggests that this might be the case.  I would try cleaning the socket and pins of your tubes.  If noise problems aren't completely cured (good tube linestages  are dead quiet), you should send it in for a check up.
ghasley

That is a definite possibility, but will wait until the new tubes come in and try that, if sound remains I guess in it will go.

I did go back up late last night to see if it was something that I can live with, from listening position, once the music starts the 'noise' disappears and only reappears between tracks, even soft passages it is really not noticeable.  My speakers Shahinian Hawks are 87db with a nominal impedance of 6 ohms.

Previous owner has said it was dead quiet in his system.

I am going to hold off judgement until I get new power plant installed, then new tubes and then considering a aftermarket power cable, although the factory seems pretty substantial. 

Hopefully one of these will quiet the beast.

BTW, anyone know of a ARC authorised service shop local  in NY?
Can you take the 5SE to a friends or a dealer (call first) and see if you can duplicate the problem.
I have a Ref 5se and had a Ref 5.  Both were dead silent into multiple amps.  Speakers:  Martin Logan Summit x and B&W Signature 30’s.  Both very revealing.

Stupid questions:  Are you using the CD input and balanced interconnects?  Have you tried switching to an AUX input or single-ended interconnects, or both?
You did try both outputs, right?

IMHO.  I would stay with the stock 20 amp power cable.


I have had the 5se and now the ref 6. Both are dead quiet with and without stock power cord. I believe all of your tests you will do will be of no help. Tubes , power supply , power cord etc. I believe something happened in transit. Especially that the tubes were left in the sockets. That should of definitely not have been shipping like that. I also feel that there is absolutely no reason for u to live with your 5 se making a humming noise. I definitely would not live with that no matter how minor it is. Or that it only reappear in between tracks. There is absolutely no reason for that. Send it in to Arc for repair and get it back to normal operating condition. I would also contact the seller and tell him that he didn’t ship it the right way and see if u can work out something that it has to go into service for his negligence. Good luck. 
tattooedtrackman

Got a reply from ARC tech support, and the short answer is, to him sounds like the 6550 was damaged and a replacement is in order. I will know soon enuf. He wanted me to touch base after the swap as he did not recommend sending it in for service before trying the replacement. Fingers crossed....

He answered my question same day, still great customer service.
Good luck on the power tube. Also when you change the tube take a look at the board around the tube socket and see if it shows any sign of overheating or burning. Pull the bottom grate as well and look the bottom of the circuit board over as well. As mentioned, mine had burned from the tube being into long, I bought a demo and the dealer didn’t realize it was past it’s life expectancy. He was cool and paid freight. But if it shows a sign of overheating send pictures to ARC so they can further diagnose if the 6550 doesn’t solve the issue.
But I hope it is just the tube. Let us know how it pans out.
One last note, mine is dead quiet as well unless at full volume with no source. But really when would ever happen
+1 on staying with stock power cable...it bested everything else I tried.
It certainly does sound like a power supply issue, which could include the 6550 tube.  The advice to look for burned components (check for tell tale odors too) is good advice.  Even if such overheating of a component is not related to your problem, it is good to know if there is other trouble brewing in the future.  I hope it is the 6550 tube because that is an easy fix.  
I purchased a new 5 se four years ago and just recently have had a similar problem. The first thing that happened was the static noise. It came out of both channels. Then I started getting a loud pop out of the speakers, and the amp. would go into dc offset and shut off. After about 20 seconds the amp. reset and came back on. After a few minutes the pop happened again. This time the amp reset but the system would not come back on. I called my ARC dealer . He is a 30 year veteran ARC dealer. He said to bring the pre amp into his store. After taking the cover off the 5 se we discovered a burn mark about the size quarter. directly over the 6550 tube. He took the tube out and it was black inside the tube.  He had a used 6550 and installed it. The pre amp came back on but the static was still there. he put his thumb and index finger on each of the 6h30p tubes and rotated each one gently. When he did each tube gave out a loud static scratching sound through the speakers. He seemed to think there may be oxidation on tube pins or on the sockets. This pre amp was purchased new and had the original tubes still in it. The tubes had almost 4000 hours on them so we ordered a brand new set from ARC. we replaced all of the tubes as recommended. We got the same static problem. We took all the tubes back out and cleaned the tube sockets with de ox and a tiny wire brush. After putting the new tubs back in the static stopped and the pre amp sounded like new. After a short break in time my system was back to normal. While at the dealer I checked the cover of his 5 se demo model and the clear lucite cover had a burn mark directly over the 6550 tube just like mine.
 We also checked his Ref. 6 demo and it had the same thing. After talking to ARC and the dealer I find out that some people run their ref 5 and ref 6 amps with the covers off because of the heat from the tubes. One veteran repair man I know said the sockets of an amp this new should not have oxidized this soon. He also said the oxidation may have been caused by the excessive heat .
 I am worried about what will happen in the future when it comes time to install new tubes. I think that changing the 6550 tube after only 2000 hours is wise, only because it runs so hot. 
I hope this sheds some light on this subject. I would love to hear from other ref 5 and ref 6 owners and see if they have burn marks or melting marks over their 6550 tubes. Has anyone had a similar problem with the static, or the 6550 tube burning out? Thanks for all your help.
What would Roger have done?  
motorheadflash

I would love to hear from other ref 5 and ref 6 owners and see if they have burn marks or melting marks over their 6550 tubes. Has anyone had a similar problem with the static, or the 6550 tube burning out?
The 6550 will wear faster than the preamp’s other tubes. Burn marks, melting marks, and a deformed plastic top are all signs that the preamplifier was not properly ventilated. I’ve had no such problems with my Ref 5SE, which I bought new. It sits on top of my rack, so airflow is unrestricted.

Speaking of Roger, he recommended three feet of space above his RM-200 amp, which ran 6550 (or KT88) tubes.

But ARC has a new option for you. Right on schedule, the New! Improved! REF 6SE is now available. Step right up ;-) .

My pre amp and amp both sit on the top of a cabinet. They get plenty of ventilation. Same thing at my dealer. Both of his demos are on the top of a cabinet and not in a rack. When my pre amp has been on for an hour or so the area directly on top of the 6550 tube gets so hot you cant put your hand on it. With the brand new tubes from ARC the amp is dead quiet and sounds fantastic. It just runs hot. The demo at the dealer seems to run just as hot. The dealer has sold many ref 5 and 6's and experienced no problems created by the heat. 
I'm surprised that your 5 se has no signs of heat distortion on top of the 6550 tube. When you put your hand on top of the 6550 is it hot?
I have not checked how hot the tube had been running, currently the top cover is unscrewed (so I was able to access tubes). If I get home early enough I will take a look around the tube and see if there is any evidence of prolonged high heat exposure.

Just got word that tubes are shipping today so I should have them on Thursday and be able to answer a lot of questions Thursday night.
motorheadflash
I'm surprised that your 5 se has no signs of heat distortion on top of the 6550 tube. When you put your hand on top of the 6550 is it hot?
Yes, it gets quite hot, as all the Ref preamps do. But the plastic top does not deform - it has plenty of ventilation.
Thanks for the information. It is good to know that my heat problem may not be as bad as I thought. When I installed the new tube set it ran as hot as it did when it was new four years ago. I'm going to take your advice and order a single 6550 and have it on hand to replace at 2000 hours.
One mystery that I didn't mention before is that my ref 5SE did not come with a plastic top, it came with a metal top. I like the looks of the metal top better, but the dealer says that the plastic top sounds better. I wonder if the plastic top lets the heat out better than the metal one. The metal top has the exact same pattern of slots in it as the plastic top on the dealer demo. Thanks again for your reply . It's good to hear from another 5 SE owner

Metal top hold in more heat. As metal attracts heat. Not so much with plastic. 
So...  For what it is worth...  I have had no heat problems with either my Ref 5 (metal top) or Ref 5se (plastic top).  Even had both in a media cabinet at one point, with only about 12” of head room.
Just sayin’.
Tanks Chip
This is valuable information. I am considering ordering a plastic top for my 5SE to help with the heat. Audio Research says the plastic top actually sounds better. This was one of the upgrades from the 5 to the 5SE . I  still don't know why mine came with a metal top. 
Thanks again Chip

I would expect the plastic top to retain heat inside of the component more than would the metal top.  The metal top should do a better job of radiating heat into the air. 
Would you care to jump in on this Trackman. You think the plastic top would be cooler. I'm not shure,  Anybody else got a theory?
You think the plastic top would be cooler. I'm not shure, Anybody else got a theory?
An aluminum top will cool will dissipate the internal heat MUCH better than a plastic top.  All you need to do is look up the thermal conductivity coefficient of the material use.  Plastic acts more like an insulator whereas metal will act more like a heat sink.  If you want to increase the cooling capability of an item, build it out of copper
So...  Just an observation.  
All of my ARC amplifiers over the years have had metal tops.  My VT200 had 8 matched-pairs of 6550’s.  And, a small pile of 6922’s, as well.  It made a great space heater in the winter.  ;-)
Update, sort of.... I just installed a PSA P20 that I had ordered before the pre, was kina hoping it was a ground loop issue, but apparently not as noise is still there. The loud static pop sound is no longer evident so I guess resetting tubes helped there. As these are original tubes with just over 1000 hours, to start I will just replace the 6550 and see what happens. Once I increases playback volume to drown out the background noise it really does sound very good a leap over the 27.  

Motorheadflash, that you for describing your issue, sounds pretty much identical. Seriously considering leaving the top unscrewed and removing it when I am doing some extended listening. The pre is on the top shelf of a stand that I made, so ventilation should not be an issue. All the components are sitting on vibration isolators which are sitting on a 1/2" block (so the rubber isolations do not mark the finish on the wood) so there is plenty of free air movement.
 
Tubes will be delivered tomorrow so tomorrow night will be the test. I will be letting everyone know if this was the problem....is it is I guess I should keep a spare handy..


Some minor things to add that have partially been covered:
–If noise is coming out of both channels the problem is somewhere in the power supply. If the new tubes don't fix it then the problem is in the power supply circuit. 
–ARC feels that their products (and many others) sound better with no cover installed, but they can't recommend that. (Don't blame them.) The acrylic cover sounds like no cover at all, which is why they started shipping the Ref 5 with the acrylic, unless a metal cover is ordered. The Ref 6 has acrylic top and bottom covers.
–ARC switched to a thicker acrylic cover a couple of years ago. The original acrylic covers would often have a little dip over the 6550, which runs hot. It's an output tube that's used in the power supply!
–If a product comes from the manufacturer with the tubes packed separately then you should never ship that piece with the tubes installed. Shipping companies don't treat our stuff gently, and the tubes can come loose!
–I have my tube electronics in a cabinet but leave plenty of space above, and I took the back off. 
Well, it is official, problem is bigger than a power tube. Got replacement tubes, installed new power tubes and it made absolutely no difference. Will look for local authorized shop or send back to ARC if there are none close enuf.

Put the LS27 back into system and it is dead silent with same cables configuration, just swapped out pre's

Not that it matters, as either I get it fixed or have a paperweight, how is ARC on their repair work price wise? Am I looking at a Chevy or a BMW?
I think the price wouldn’t be tonight out of line. I have only had warranty work done on 2 Pre-amps, but they have been great to communicate with. I would send it to them because 1) you’re in the hands of the designers 2) they will only use genuine parts 3) they may discover the problem could be something they did and decide to cover or partially cover the cost. But be prepared to wait, and you are with the LS27. 
I thought and I was right about what I posted on my opinion on this problem. I still feel as I posted something happened in transit. Especially that the tubes were left in their sockets. I would still contact the seller and talk to him about your problem as it has to go back to ARC  This is the sellers fault. At least he could give u half the shipping and repair cost. 
Agree with tattooedtrackman, except to say this is entirely the sellers fault.  You expected to receive a working preamp and did not, why should you be responsible for the repairs?  Also, pardon me for not rereading the entire thread, but how good and how much positive feedback did the seller have?  I always think it suspect when an article arrives not as described, have had it happen to myself.

Although I have no experience with ARC repairs, but its definitely not BMW, its RR.
Send the amp back to the seller.  
I made the same upgrade from an LS 27 to a Ref 5 SE and it is a significant upgrade. It also seems like it is a better impedance match for the Ref 75 (now Ref 75 SE).

I would contact the seller and see if they would be willing to cover the cost of repairs or split them. This is a small hobby and many people are understanding - we've all had a problem. 

4 years ago I had an issue with the power supply in a VSi60. When the amp warmed up I got an owl sound. It turned out two resistors in the power supply had gone bad. I think they charged me for two hours of labor which included a chassis repair (my dad dropped the box while helping me move) plus return shipping. You're looking at $200-$300 plus shipping both ways.

 I don't know your financial situation, but it you're buying this kind of gear you aren't worried about putting food on the table. Hopefully you don't need to sell the LS 27 right away and can let ARC fix the issue.
I agree with testpilot, only two things could be the answer.

1. The unit was damaged in shipping. Considering that the unit was shipped with the tubes still in the unit it is entirely possible that this was the cause. 
2. The problem was already a issue when sold (really hope this is not the case). 
But ether way it is the sellers responsibility to make this right.
The seller had a lot of positive feedback, which I checked on before I purchased. He has been available during the entire process and I am currently waiting for a reply since I just found out that the issue was larger than tubes last night. I contacted two two ARC authorised service shops that are local to me and will be calling a little later today, since the issue was in shipping I do not feel like giving the shipping company another shot at it. High End Audio Repair and New York Audio Repair are both authorized shops and a half hours drive from me. Both seem to have good feedback here and elsewhere.

Fortunately I am not pressed to sell off the 27 as it was going into second system replacing a 17se, which was headed to my work system. There the Quicksilver would either be retired, sold off or kept as a spare.

Shipping large heavy pieces of equipment seems to be a real crap shoot as a brand new PSA P20 has arrived with an issue with the remote sensor. Have contacted PSA hoping for a quick fix but this also seems to be a victim of rough handling. As it is fully operational except for the remote and just a pia to go thru the menus again not feeling like sending it back as it now resides on the second floor and required help to get it there.

Really not feeling the holiday spirit.... 
Seller has started the claim with shipper, so he is holding up his end. Other than being disappointed I fully expect that this will end up working out in the end. 
You should send it back to the seller for a full refund. Heres why, you will go several weeks, maybe a month or two and the claim will be denied by the shipping company. Why? The seller improperly packed it. It wasnt the shipping companys fault. The seller will dispute the denial, and the shipper will prevail. You would have noticed the box damage. In addition, you are not a party to the contract between shipper and seller.
As time passes, things will slow to a crawl and you will see on the horizon your ability to dispute the transaction slowly fading into the sunset. Get your money back, you are already out a bundle on time, inconvenience and the tubes you purchased but may never use.

good luck.