Thanks microstrip. That would be the best solution. Are you 100% sure that I will not harm my beloved preamplifier ? I was also thinking about this, and even take out the valves out to be sure I don't damage anything.. Can another forum member approve this approach?
The cable cooker uses a 12V DC power supply and no transformers - this means that output voltage will be less than 6Vpp - the cold tubes will happily ignore them.
However, the REF6 has a lot of other capacitors that also must be burn-in, such as plenty of decoupling capacitors. And part of burn-in is applying the 90V DC or more to the capacitors - this only happens when the preamplifier is on! Do not connect the cable cooker without taking the power cable from the connector, sometimes a mains transient can switch the preamplifier on!
Summary: Yes, the REF6 is deriving an inverted “leg” out of the single-ended signal and thereby converting it to balanced. That is why the balanced output from your REF6 is 6dB higher than the single-ended output. Truly balanced products should sound better when run balanced. Your Pass Labs amp should sound better run balanced rather than single-ended.
Over the weekend, I swapped out the svetlana wing C 6550 with a KT88 in the ref 6. Initial impressions was a tighter bass, slight improvement in soundstaging and a faster more at ease presentation. Highs was abit more refined as well. However I do find that it lost out very marginally in bass extension.
As I was sharing all my good experiences with ARC (and there were many of those) I would also like to share for me a very negative and frustrating one. As mentioned above I've been swapping ARC gear for many years and during those years I managed to slowly but surely climb the ladder starting with VSi55, VS110, VS115, Ref75 and LS2b, LS16mk2 and finally Ref6. I have to state that with none of components I ever had a slightest problem, not even a glitch with a tube. And so the story comes to the latest part of my puzzle for which I was dreaming to have all along, starting with older brothers Ref3, Ref5 and Ref5se. I managed to somehow get the famous Ref6 which to me was a dream come true preamp. It sounds great (when it works), looks even better in my book, but the issues with it or with its volume control are just too much for me to comprehend. Namely several months ago one channel stopped working so I took it to service center and it took them almost a month to repair it. By the way, Swiss importer of ARC is a complete joke, so thanks god it landed in hands of the person who was/is servicing ARC gear for decades. Anyhow, he did the job perfectly and while picking up the preamp he showed me (while smiling) the volume pot in this 17k€ unit consisting of 4 DS1808 ICs costing in total 18€(https://www.maximintegrated.com/en/ds/DS1808.pdf). I was honestly shocked by this fact but was kind of in the mode of being happy as i was able to enjoy my system again. At that time I did not loudly complain to anybody. Few months after (sort of last week) almost the same crap with volume control happened, this time both channels working but left channel being more than 3dB louder than the right one. Again dismantle everything, travel for 400km to leave the unit for service and the guy is in the state of shock. He was like - I honestly can't believe what and how they've implemented as a solution in a unit of this price tag, but this time I'm ordering many more of this ICs and volume control PCBs as I foresee many units coming in my direction in the future. Me, as I am, or actually was, a faithfull ARC fan can also not believe how the ARC can allow this to themselves. This is a complete shame and to me I'm more and more getting a feeling that ARC despite the marketing mambo jambo is turning into a "big" FMCG company. As the funds for this hobby are not falling from the sky I'm more than seriously considering dumping the ARC ship and going somewhere where they treat their customers as human beings not only as numbers on P&L sheet.
So I guess I'll be soon saying Stavros (Aries Cerat) or Thomas Mayer here I come...
All I can say is WOW! You have been a loyal and happy ARC owner for a very long time and the first time you have a problem with a unit you are ready to throw them under the bus? Problems sometimes occur with electronics, and you’ve been fortunate not to have had them before. I would say stop second guessing the bill of materials as the final result is what we pay our money for. Perhaps that 18€ part sounds better than some others that cost 5x as much. Maybe they listened to 50 different ones before choosing the one they use, meaning they have to recover the R&D hours in the overall cost of the unit.
Sorry to hear of your troubles, I hope things work out. I know, when gear doesn’t work we all become unhappy. This too shall pass.
I feel your pain. In over 40 years of collecting, the most serious problems I ever had was with ARC. Loved their sound, but from my D79A's potted transformers that leaked black crud all over my shelves to my 610 Uber amps that both blew up within a week of owing them, I said sayonara. Their service issues are now legendary to many of us. If it's tubes you must have, you might wish to consider CJ, Lamm and VTL. I currently use VTL's 7.5III preamp and aside from the fact that I think its a sonic masterpiece, I know I am never more than a phone call away to Bea Lam, who deeply cares about her customers and goes the extra mile to keep them satisfied. Luke is quick to answer technical questions and aside from service superiority, Bea has excellent ears and her insights regarding tube choices are superb.
It seems to me you are simply having an issue with your local distributor or dealer, not with the brand.
I once had a similar problem with a REF5 preamplifier, that was immediately serviced by our local distributor - we have great service here. It was not a problem of the REF5 - it was simply caused by the tube DAC I was using that had no power ground connection. As it was a single ended unit fitted with RCA plugs , it made signal before ground when connecting the unit. As we were comparing DACs, I did not want to switch the preamplfier off to avoid the warmup time. The consequence it that the transient leakage voltage can damage the attenuator IC's. Remember that some fancy audiophile capacitors used in output coupling of tube DACs or phono units have high leakage.
Fortunately I had a very limited number of faults of high-end equipment, considering the number of pieces that have entered my listening rooms. But people buying equipment at a country different of that of the manufacturing place should always consider the local service and support conditions - a poor distributor can be a real nuisance, particularly as we manufacturers normally do not give direct support if we have a local representative.
There is a school of thought that the actual attenuator is the heart of a good preamp. The choice of ARC has been baffling me since the times of the LS25. These electronic pots appeared a bit marginal even in a mid price product. Yes they do sound better than a cheap pot but there is absolutely nothing high-endish about them. Apart from being cheap, easy to implement and offering a lot of steps i don't know what is good about them. Being unbuffered they are also an easy prey to transients at the inputs. But as long as people are happy with the sound...
There is a school of thought that the actual attenuator is the heart of a good preamp. The choice of ARC has been baffling me since the times of the LS25. These electronic pots appeared a bit marginal even in a mid price product. Yes they do sound better than a cheap pot but there is absolutely nothing high-endish about them. Apart from being cheap, easy to implement and offering a lot of steps i don't know what is good about them. Being unbuffered they are also an easy prey to transients at the inputs. But as long as people are happy with the sound...
IMHO the high-end is not about prices, but about performance and listener preference. A component can't be isolated from the whole equipment. ARC uses these attenuators because they are precise, reliable, stable, long lasting and their sound quality matches their intentions when used with their electronic circuits. Besides they test and match them individually - whne you get proper service you do not get a part from eBay! If the sound quality improved replacing the whole attenuator with a quality passive part I am sure that the DIY community and modifiers would have thought about it.
BTW, some expensive preamplfiers using fancy expensive potentiometers have imbalances between channels as high as 1 dB. And some passives using expensive silver and gold switches are very poorly designed.
And yes, some knowledgeable people are even very happy with them, it is what really matters!
I share Golum and marty's negative experience with ARC quality. It is now exactly 10 years since I upgraded from Ref 5 to Ref Ann. 1 year after the purchase 3 Nichicon electrolytic caps leaked right onto the PCB. SQ plummeted down. I was furious and closely examined the parts-particularly cpacitors - used in this $25000 preamp. I was absolutely appalled to discover that it was built using the cheapest capacitors they could find. I mean we are talking cents here, not dollars! To cut a long story short, I ended up overhauling my Ref Ann with the best of the best. I now realize that what came from ARC factory 10 years ago was a boom box. Now my Ref Ann will easily destroy anything for $500000.
BTW, the design of Ref Ann is brilliant. But the parts it was assembled with... OMG... simply trash...
Nichicons are considered one of the "good ones" maybe not the best of the best but there are many devices build with lesser caps, also if I remember correctly ARC is using 105 degree ones which should give longer lifetime.
Actually I have always been pleased to see ARC using quality components, such as Stealth or Teflon caps (both by TRT?), 50 or 25 ppm resistors (even got some PRP in my REF3), R-core transformer etc. Not to forget typically the most expensive component of them all, the case.
Surely everything can be further improved as can anything (build to meet a price point) but I wouldn't call ARC a parts saver by any means yeah, guess I'm bit of a fan boy but I really think you just got unlucky.
MPS, you call Teflon caps good caps? Really? The only caps that belong in Ref Ann are copper foil caps. And in my case, I replaced those 4 white, crappy giants with Duelund Cast Silver Foil caps. That's the way to go!
And the cases are nice indeed. I agree completely. Lots of room for modding! The PCB material is top-of-the-line too. Not the cheap green one they use in Ref 10 and the others...
Well, I do, good is a relative expression. Teflons have quite neutral voice, normally that can be considered preferable. I'm not saying those are the best of the crop but surely ARC must have been paying a considerable $ for such items.
Well, I do, good is a relative expression. Teflons have quite neutral voice, normally that can be considered preferable. I'm not saying those are the best of the crop but surely ARC must have been paying a considerable $ for such items.
Considerable? $10 max for each of those 10uF Teflon caps. Having soldered those out, I auditioned them extensively and compared with copper and silver foil caps. Poor, primitive sound with sibilants at the top - that's how they sound. See attached images - that's what sounds GOOD!
Considerable? $10 max for each of those 10uF Teflon caps. Having soldered those out, I auditioned them extensively and compared with copper and silver foil caps. Poor, primitive sound with sibilants at the top - that's how they sound. See attached images - that's what sounds GOOD!
10$ per pieces is a really good price even for OEM and at the same time quite expensive for a passive component. From what I have read copper foils are considered very good sounding, have no idea about silver foils but guess it will be something on the line of silver wire sound. One thing about Teflon caps is that they really do require 300-600h to burn in. The ones that ARC used might be metallized version so not up to the level of foil caps.
