Audio Research VS115 power amp
LDA -- Sat, 01/08/2011 - 12:59
Hello all;
I'm considering buying a new ARC VS115 amp to drive my Proac D28 speakers. I'm using an old Sonic Frontiers Line 2 as the line stage. The listening room is about 40 square meters and I am usually listening to classical, opera, classical jazz, vocal jazz and folk.
If you could give me your ideas about the mentioned amplifier as well as its marriage with Proac I would deeply appreciate.
Best regards,
LDA
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In the future I can also upgrade the pre amp to a new ARC LS 27 or to a second hand REF 3.
Hello, LDA I have experience with the VS-115 that may be of interest to you. A few months ago I took delivery of a pair of the new Magnepan 1.7s. I had previously been listening to jazz, pop vocals, some classical music and a lot of solo piano (jazz and classical) in a 14' x 19' x 8' room on Magnepan 1.6s, and driving the Maggies with a top quality big-name solid state amp capable of 150 WPC into 8 ohms and 300 WPC into 4 ohms. I was thrilled at the improvement in my overall listening experience with the new Magnepan 1.7s but I sensed I wasn't fully reaping the benefits of the new speakers, so I sold my solid state amp and bought an ARC VS-115. And this is where things get tricky because it is difficult to convey how dramatically the VS-115 changed my system without going overboard and resorting to the usual cliches.
Simply put, the VS-115 enabled the new Maggie 1.7s to deliver the goods. As you may know, the Maggies are not the easiest of loads and they do require power to realize their potential. When I cued up a big-band jazz classic, "Bluesville," from the album 88 Basie Street by Count Basie and his orchestra (Pablo OJCCD 808-2) I was really, truly stunned. I had never heard music presented like this in my own home, and my first reaction was to burst out laughing. Oh, at long last, all this money and effort -- this life-long quest for a true-to-life, involving presentation of music -- has paid off.
Powered by the VS-115, the 1.7s creation of the first solo notes of Basie's piano was startling. Then in comes the bass, with weight and roundness of tone, and next the drums and you can feel -- not just hear -- you can feel the brushes on the snare drum and the click of the high-hat cymbals. After two or three choruses and as each section of the band begins to play, the saxes, the trombones, and finally the trumpets, the whole band turns it on and I was, well, blown away by the enormous dimensionality of the wall-to-wall, front-to-back soundstage. And within this huge panorama I could hear the individual instruments of each of the band's choirs.
A few months have passed and I'm still hurrying home from work, eager to feel the solid snap of the power switch as I turn on the VS-115 and power up my system so I can take a seat -- my seat! -- in a concert hall or a night club to witness Pepe Romero playing his guitar, or Leonard Slatkin direct the Saint Louis Symphony as they whomp through the final bombast of Ravel's Bolero, or Bobby McFerrin sing "I Hear Music." Because that's what I hear. Music.
.
Greg
Hello Gregory;
This is an excellent review top to bottom. I'm very glad to hear such great things about this amp. I am so relieved... Unfortunately I'm still waiting for my new amp to be delivered with so much excitement and passion.!!! Hope I'll also experience a great improvement in my overall sound like you...
I wish you long listening pleasures with your system..Thank you for your kind reply...
Regards
LDA...Proac have shown their speakers at shows many times with ARC. Rated at 88.5db sensitivity and 8ohm nominal impedance with the impedance dropping below 8ohms once between 100Hz and 200Hz in the upper bass region (but remaining above 6ohms), this is a very easy load for a tube amp. Stereophile's measurements actually measured the sensitivity at 84.5dB but given the easy load across the frequency spectrum, and your moderately sized room, you should have zero problems driving the D28s to considerable SPLs with the VS115. I love the ARC sound and while I have not heard it with Proac speakers, I know of quite a few people who love that combo. And as I said, Proac has shown their speakers many a time with ARC amps. As for pairing the VS115s with an LS-27 or a used Ref 3 down the road, that would be highly recommended. great synergy between their pres and power amps. Good luck
Thanks for the reply cmalak... I'm glad to hear that the combo will probably be a good match since unfortunately there is no way to try the amp with my own speakers. By the way have you ever had an experience with VS115? They (and the dealer) say that it is knocking on the Ref110's door and that both are very close performers. At the moment the dealer does not have a VS115 to make a demonstration but he will order it if I am really interested in it. I know how VT100 (MK2, 3) sounds. Are you able to make a comparison for instance.?
Do you think that it will be a huge step forward after migrating from an old but nice (for me at least) power amp "Classe CA-200".
Your opinion and experiences would be highly appreciated.
Thanks again.
LDA...I have the Ref 3, Ref 110, and CD 7 and I have been told the same thing by my dealer about the VS115s (i.e., they are very close to the Ref 110s). In fact, they no longer carry the Ref 110 as a store demo since they feel the VS-115 does such a good job of delivering 90%+ of the performance at 60% of the cost. So I can't say that I have heard the VS-115s myself but from what I understand they are very close to the Ref 110s. I think you will experience a very nice step-up in performance from the Classe CA-200. Does your dealer have any other current production model ARC amps for you to listen to with your speakers (maybe the VSi-60 integrated). This will give you more than enough of a feel for the modern ARC sound and how they will sound with your speakers. I would describe the modern ARC sound as being very neutral across the frequency range, with solid bass (especially for a tube amp), clean and highly resolved midrange, and extended, grain-free highs, with plenty of bloom and a 3D holographic soundstage, Modern ARC amps are not traditionally tubey in the sense of emphasizing a syrupy warm midrange presentation with truncated or rolled-off highs and less than controlled bass. If you are looking for an older tubey sound than current ARC amps won't deliver it. I hope this helps somewhat. Good luck and let us know how you make out.
LDA...just fyi, here are Proac's latest new speakers (admittedly they retail for $24K in the US) at this year's Consumer Electronics Show in Las Vegas mated with ARC VSi-60 integrated and ARC CD8 player: http://www.theaudiobeat.com/ces2011/ces2011_bos_proac.htm. Just another data point of the two brands showing together at shows. Enjoy.
cmalak, your help is invaluable for me. Thank you very much...
LDA...my pleasure and good luck. Looking forward to hear all about it if you decide to pull the trigger. Take care.
cmalak , I am about to pull the trigger :) I just can't resist the temptation anymore ! However, I just wanted to share one of my concerns with you about the upgrade if you don't mind. . As you know, the amp is, actually, a quite old design (early 2008) considering the rapid development in the audio gear sector. Especially with the introduction of a new power tube KT120, I suppose that the designers would possibly want to create a brand new design taking into account the specifications of this new tube type. I know that in these days the amp is being shipped with the new tubes but still do you think that it is a bad time to buy a new tube amp? I mean, should we consider the VS115 as an old design to be upgraded or renewed in the near future?
Many thanks indeed.
Ps: I also tried to get Mr.Valin's opinion about the upgrade but I do not know how to reach him. I just made a reply one of his old posts.
LDA...that is a tough question. I have talked to ARC about the new KT-120 tubes and they seem to be shipping out all the current production amps with the new KT-120s and they have not made any tweaks or adjustments to the circuitry in any of their current amps to accomodate the new tube type. According to the person I talked to at ARC in customer servicee, they are running the amps with the same bias settings as when the 6550 tubes were in, which means the KT-120s are being run very conservativiely by their current production amps. They believe the benefits to the KT-120 is the delivery of a better bass foundation (goes lower and is tighter than with the 6550s), and that the dynamic envelope is greater. My personal opinion would be to wait a little bit to see if there are any updates and/or issues that arise from the new KT-120s that ARC has to make adjustments for. The flip side to that argument is that ARC is an extremely conservative culture and they would not have implemented this change (6550 to KT-120 tube change in all their current amps) without having tested it comprehensively, both from a sonic and reliability perspective. It's a tough choice. I can't tell you what to do but at least I present you with the two opposing ways of thinking about it.
LDA...are you not able to test out any ARC amps with your system (your dealer has no ARC amps for demos)?
We (I and the dealer) tested VSi60 and made a comparison with Pass x150.5. The amps were driving a pair of Wilson Sophia II which was a difficult task as they were 86db and 4ohm. Vsi60, althought not as dynamic and controlled as Pass (as expected!), did a great job especially in mids and highs with slighly better resolution and presentation. The room acoustics was a bit weak actually and the imaging was worse than that I experience at home but this was not a system fault. Unfortunately the dealer (which is one of the biggest show rooms in Europe!) does not offer a home demo. So there is no way to try my own speakers with ARC. They talk extremely positively about VS115 but at the end of the day a dealer is a dealer.... To tell the truth I am quite certain about the quality of VS115 and I am sure that I will love it. I will just be sad if a brand new design will appear in a very near future... VS115 will be the same VS115 I know.. This is just a little concern.....
By the way I totaly agree with you about the consevativeness of ARC...
LDa...understood. Well if you do pull the trigger on the VS-115s, I hope they turn out to be everything you were looking for and more. Good luck once again.
By the way, I could not convey my applouses to you for your wonderful system. I wholeheartedly wish you very pleasant listening sessions....
Thank you kindly sir
When I spoke with ARC's Dave Gordon in November, he told me there were no new amps in the pipeline. However, there is a new phono stage, the PH8!
SundayNiagara, that is a good news.... Thanks for the info....
cmalak; I made an order of a VS115 with KT120 tubes a few hours ago. Just wanted to let you know about it..
Many thanks for your kind help..
Take care..
LDA...congratulations on the new ARC amp. I hope it brings you a lot of sonic enjoyment for years to come. Looking forward to your impressions. Just make sure you give it a few hundred hours of break-in time before you start listening to it critically. Take care.
Hi, i am using VS115 mated with LS26, ProAc D28, PH7 and CD3mkII
ProAc and ARC is a very good combo, the VS115 is very very close to REF110. I had 5 yeras ago the small VS55 with ProAc D18. Also a very good match
I am interested about the KT120 ? is it new ? ARC is using them ?
Opinions and experiences would be highly appreciated.
Regards
Hello;
Thank you for sharing your experiences.. I have not listened the KT120s or VS115!! I'm still waiting for my order..... KT120 is a brand new tube type from Tungsol. ARC delivers all their amps including the reference serie with the new tubes. You can find some information at arcdb.com. They say that the overall presentation of the amps with KT120s is improved. In fact they believe that there is improvement in virtually every area particularly in the bass region. The price is about $100 if you buy directly from ARC but it is much cheaper at other suppliers.
Regards
Hello LDA,
Its very interesting all that about KT120s, so I have to contact ARC, I was not informed.
VS115 produces very smooth and liquid highs, powerful and tight bass with big, solid passages through the ProAcs D28 and maybe I can improve it.
But be careful, with your new amp, it will need more than 300 hours to break in. On first use I was very very disappointed, it exhibited a darkish character, without tubey warmth. After roughly 80-100 hours, things began to change and the soundstage opened up. The evolution continued until it reached approx. 350 hours. (In the meantime at approx. 50 hours I had also a tube blast, but amp is repaired by the local ARC dealer and everything is ok now)
Few months ago i changed my PH5 to the PH7. I was thrilled at the improvement in my overall listening experience with the new PH7
I was really, stunned. I had never heard music presented like this (approx after 150 hours)
Looking forward to your impressions
Regards
Basile.
Hi LDA,
I am also listening to classical, jazz & vocal jazz. Room approx, 50 m2 (like L letter)
For speaker cables i am using vhH the Inspiration
Regards
Hello BasileM and Gregory;
Your experiences and thoughts are so valuable to me. Thank you again for sharing them.
I have just a quick question about the after market power cord alternative to be used along with the VS115. I heard that the protruding lenght of the fuse holder prevent the IEC connectors from being securely fitted to the IEC socket. This means that unfortunately it is not possible to use Oyaide , Furutech or Wattgate plugs with this amp. This is sad actually... Then I made a quick research and found that the Shunyata products might be convenient since their IEC plugs are small and square-sectioned. Their new CX series got lots of positive reviews. I think that the Black Mamba HC would be more than enough to be a strong partner.
Your opinions and experiences would be highly appreciated.
By the way, I will share my first impressions as soon as I get the amplifier...
All the best
LDA
Hello again, LDA
Recently I spoke with a fellow named Calvin at ARC. He told me that the KT120s can be used as a "drop-in replacement" for the 6550s in my VS-115 and to bias the KT120s at the same 65 millivolts. Calvin said that ARC is still building their inventory of the KT120s and cannot sell any at this time. However, you can buy matched pairs ($88) and matched quartets ($196) of the TungSol KT120s on line at places like BoiAudioworks.com and other tube suppliers.
ARC has recently demonstrated a new amp, the REF-150 (using KT120s) at an event at my local dealer's shop. However, the fellow at ARC said the demo amp was a "pre-production prototype" and says the new REF-150 may not be shipping until summer. My dealer says it will be selling for around $13k. First, I don't have that kind of money, and second, I am so happy with my VS-115 that I have no lament. I'll spend the $400 to re-tube with the KT120s and drive on. I suspect you will be similarly satisfied when your new VS-115 arrives and is making music in your home.
Best wishes to you, LDA.
.
Greg
Hello BasileM and Gregory;
Your experiences and thoughts are so valuable to me. Thank you again for sharing them.
I have just a quick question about the after market power cord alternative to be used along with the VS115. I heard that the protruding lenght of the fuse holder prevent the IEC connectors from being securely fitted to the IEC socket. This means that unfortunately it is not possible to use Oyaide , Furutech or Wattgate plugs with this amp. This is sad actually... Then I made a quick research and found that the Shunyata products might be convenient since their IEC plugs are small and square-sectioned. Their new CX series got lots of positive reviews. I think that the Black Mamba HC would be more than enough to be a strong partner.
Your opinions and experiences would be highly appreciated.
By the way, I will share my first impressions as soon as I get the amplifier...
All the best
LDA
LDA, hello
I'm writing this on Thursday, March 10 (from my home in Bellingham, Washington, about 90 miles north of Seattle).
I would like to re-inforce that after a few months of living with my new VS-115 and the Magnepan 1.7s, I remain completely happy with the listening experiences. When the 6550s have played out and are due for replacement I will buy the KT120s but other than that I am not looking over my shoulder and I don't find myself wishing I had bought something more or something different. This is important because we can all fall into that malaise of mitigating the pleasure of our experiences through endless, grass-is-greener speculation.
Regarding after-market power cords, I have no interest in using something other than the power cord supplied by ARC. However, I acknowledge this is a hobby, and if you enjoy tweaking your system, by all means go for it!
I'll bet you can't wait for your new VS-115 to arrive! You will be pleased with your choice.
Best wishes,
Greg
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Greg
Hi LDA,
I want to listen to music. ... far more than, say, switching interconnects and speaker cables, I hate it but I did it! I don't have a dedicated power line because I don't own the house. If it were mine, that would be my first priority.
Initially I used the stock power cord. With my old VS55 I was using the vdH Mainstream power cord. So, I changed the needed 20-amp connector and removed the stock power cord. The vdH cord provided a different view of the VS115’s performance. The high-frequency noise was gone, tonality was more vivid and additional clarity. There are so many variables...I think the vdH power cord offers top performance for reasonable prices.
In the last 7-8 years with my systems I've been through 4 sets of interconnects. The vdH the first, vdH the second, Audience Au24 and Nordost the TYR
Finally I elected to use the TYR (balanced) between preamp ARC LS26 and VS115. It improved the performance by such a large degree that I was very satisfied. My sense was that TYR and ARC matched very good, so, I changed all interconnects (Phono & CD) to TYRs. You get details, smoothness and transparency, true timbre of voices etc. – I found TYR is musically satisfying.
Further I would like to try the Nordost Valhalla, but the price range ….!!!
Best Regards
Hello again BasileM;
Thank you for the recommendations.. I agree with you about the need and effect of different type of cables.. As the interconnectors I'm considering Nordost Heimdall... I know Tyr is the reference line and a better choice, but the price range is rather high for me... I do not know if you had experiences with Heimdall but I listened them with a couple of setups and I think that they are also quite good... What do you think?
My ARC dealer sells VDH and Nordost products as well. So It will be quite easy if I decide to go with these cables..
Also could you please tell me what IEC connector do you use on the power cable of the VS115.. Because as I mentioned before there is some space/dimension limitations to take into account.
Thank you
Best regards
Hello LDA,
The connector typ to my vdH powercord is the Oyaide Elec. C-279 IEC 20A
The local Nordost dealer gave to me the TYR and the Frey interconnect in order to listen and compare. So, I have tested both cables for a week.
I think the Frey interconnect should sound similar to Heimdall
I found Frey better or comparable good than my Au24, so I decided for the TYR
By the way have you listened to the newest ARC LS27 ?
They said the new LS 27 sounds better than the Ref 3 and very close to Ref 5.
Any comment?
Greetings from Athnes, Greece
Hello BasileM;
This is very interesting because I have been told that the big IEC connectors such as Oyaide do not tighly fit to the VS115's socket due to the fuse holder that is extremely closely placed to the socket.. It seems that this is just a rumor or they just have changed the rear panel design.. Could you please make it just a bit clearer..?
About LS27, my dealer gave me exactly the same information.. Better than Ref 3, very close to Ref 5 , can be considered as Ref 4 etc.. I will ask for a demo as soon as they have it on the shelf since my next purchase will probably be a LS27.
Best wishes from İstanbul....
Hi LDA,
It is a very tight fit to the VS115's socket and there is no problem – after mounting the Oyaide connector to the socket there is a small distance to the fuse holder of approx. 2-3 mm. If necessary you can replace the fuse with the power cord plugged in.
I doubt it that ARC changed the rear panel design so soon, i purchased my amp in January 2009, but for sure contact ARC
Regards
BasileM
Yes, ARC has been using the new tubes since last fall.
Hello all;
As you may probably remember, I was expecting my VS115 to be delivered at the end of the February. Due to the some problems in the customs transaction they could not clear the goods and now additional couple of months of waiting is unfortunately necessary. So in order to compensate this pretty bad situation my dealer offered me a new REF110 (with new KT120 tubes) instead of VS115 with a very attractive price option. I think telling the exact price is not necessary but I can assure that the incremental cost is much lower than it would have been normally.
I know that REF 110 will be discontinued very soon and a new model REF150 will be replacing it. But of course REF110 is REF110 and what they offer is really attractive. So in this situation, could you please share your opinions? Should I buy it (REF110), should I desperately keep waiting for my VS115, should I make a new research and find something new and good to my taste (a pain!) or should I keep listening my old Classe and put my wallet in its place..
What are you saying guys?
Thank you.
Best wishes.
LDA
Hi LDA,
I like the open architecture of VS115, to see the glowing tubes and the easy way to adjust Bias (I own it) but the REF110 is better. I have heard both. REF110 offres remarkable musicality and dynamic impact. Just do it !!!.
Regards
BasileM
Hello BasileM;
I totally agree with you about the better physical look of the VS115. Of course I know that you own it but still you suggest the REF110 considering the present conditions. Thank you for sharing your view frankly.
Regards
LDA
Hi;
This morning, I received my REF110 with the KT120s and my first impressions, of course without any break in yet, nigh and day difference with respect to my old Classe... It is simply unbelievable.. Soundstage, inner detail, dynamic range, tonality of the acoustic instruments, pace, bass control, three dimensinality, simply every aspect of the sound have radically changed! I was not expecting this kind of improvement at least without break in..
The liquidity, delicacy of the sound is just so hard to explain.. The amp is simply amazing in every way. At last, now I am a happy music listener...:)
Best ragards,
LDA
Congratulations on your new REF 110, LDA! As you may recall, I am using the VS-115 to drive a pair of Magnepan 1.7s, and I am so gratified with the musical experience that, for perhaps the first time in my audiophile / music lover's life, I haven't looked back. You were unexpectedly presented with an opportunity to bring the REF110 into your system, and you did it. You researched, you weighed many options, you made a decision to go with ARC and -- surprise! -- you ended up with the REF110. Carpe diem. Count your blessings. And love your music. I believe you, too, will never look back.
+
Greg
Thank you for your reply Gregory. Really it's getting better and better. I also believe that I won't look back! Wish you all happy listening sessions..
Regards
Hello all;
I sent the below post with a new topic in a different forum but could not get any answer at all... So I decided to give it another try from here.. Thank you very much indeed.
Regards.
Hello all;
I recently bought an ARC REF110 power amplifier. In the future I would like to match it with a new LS27 preamp. Now I think a better amplifier deserves a better cabling system so I decided to upgrade the cables as well step by step. .
I am currently using Silver Audio Hycinth ICs, DHLAbs Q-10 Signature SC and different PC from Blacknoise (Goldwire, Blackwire plus) and DhLAbs .
My dealer strongly recommend DHLAbs Revelation interconnectors. They believe that they are superbly detailed and, maybe most importantly, very musical. They even believe that they are better that Nordost Valhallas. Valhallas are out of my price range. Actually I’m considering Heimdall interconnectors as an attractive option but I think Nordost cable can sound a bit cool or dry sometimes. I am not absolutely sure that they will be good for my system.
I have separate power conditioners from an Italian company Systems and Magic for each component. They are pretty good performers. The point is they all require not one but two power cables, one before and one after the filter. Another cable is also required for the power distributor. The reviews say that Shunyata cables are a good option for ARC gear. The dealer particularly recommends Python CX for my REF110. On the other hand my DHLabs dealer underlines the exceptional performance and value of the Red Wave power cord.
Your recommendations would be much appreciated
Best regards
LDA
LDA...congrats on the Ref 110. As you may remember from my posts above, I currently have CD7, Ref 3 and Ref 110 (still with 6550s in them but will replace with KT-120s when tubes are due to be replaced), so I am thoroughly familiar with how great your Ref 110 amp is :-) As for cabling I actually use Nordost Heimdall interconnects and speaker cables. I also have Shunyata's hydra 8 conditioner and the Python Helix Alpha (model before the latest CX) connected to the Hydra 8. I have stock power cords for the equipment going into the Hydra 8. I am told the Shunyata Black Mamba power chords are reasonable in terms of price and provide performance way above their price, so if your dealer has those on hand you may want to give them a try. As for Nordost cabling, the different models all share the same house sound, you just get more of it as you go up the chain. I would say the Nordost cables are highly resolving, are very quick, and present natural timbres. Some people do find them to be a bit lean. my suggestion would be simply to try them out in your system. If the rest of your system is a bit lean sounding then I would look elsewhere. Cabling is the last thing I would tweak after you have the rest of your system figured out. Congrats once again and good luck with the final tweaks on your playback chain.
Thank you for your reply cmalak. Now I have about 100 hours on the tubes but I think it is still too soon to be sure about the stabilised character of the sound. The amp can still sound a bit laid-back or dry sometimes but in all conditions it is superb of course. Have you ever had any experience with the Revelations from DHLabs? According to my dealer it is a very challenging cable. They even claim that it is better the Valhallas, well, at least more musical.. Any idea?
Thank you again.
Sorry LDA. I have no experience with DH Labs cables so cannot provide any insight on that question. Good luck and hope you are enjoying your new Ref 110. All the best.
Hello friends;
Unfortunately I have some bad news about my new REF110.. This morning I decided to check the bias voltages as the amp completed 100 hours of run. Every reading was OK except V8 which should be around 57-73mV. The voltage value of V8 was 18-19 Volts (not mV) which was really hard to believe... There was no sign of failure at all in the sound so far. Just too hard to explain.. The amp will be going to the dealer for the servicing and of course I am terribly sad about this.. Just wanted to share it with you...
Best wishes.
LDA
LDA...the tube in psition 8 may be going bad and hence not holding it's bias. It's good you caught it at this point. Your dealer should be able to figure out if it's the tube or something else in the circuit causing the bias drift. If it's the tube, then it's a simple switch with the matching tube in the opposite channel. No foul, no harm, except that you have to be without the amp while it is being serviced. You should ask them for a loaner amp so you can continue to enjoy your system while the amp is being serviced. Maybe try something else to see what a different flavor amp sounds like in your set up. Good luck and hope all is well.
cmalak thank you for your relieving comment. I wholeheartedly hope that it is just a tube failure. I'll let you know about the news.
Hi LDA,
Firstly congratulations to your new amp. My experience is similar to yours. But don’t be disappointed. Tubes are tubes and when the system is turned on, magic appears and everyone stops to listen.
However the few malfunctions I experienced with my ARC amps were different (see below)
On first use the VS115 matched with LS26 was very very close to the sound of REF110. Then after 10 hours – it exhibited a darkish character, without the tubey warmth, dry and mechanical sound. After roughly 55 hours things began to change and soundstage opened up, detailed and smooth. I checked Bias and everything was perfect. The sound evolved during the break-in period and i heard no further changes after approx. 350 hours. Currently the sound is great intimate, detailed, smooth and truly beautiful.
So, my newer VS115 at approx. 165 hours during the warm up period suffered a fairly catastrophic failure. The V1 tube was glowing with a white colour, a capacitor or perhaps a resistor became overheated and flamed out with blast and smoke.
Luckily the rest of the equipment were not damaged.
After two weeks the local ARC service repaired the unit and I had to pay only for the new tube.
At approx. 255 hours it happens again. This time I heard only a blast. -- I checked the bias and i measured at all tubes 90mA !!!
I turned unit off and returned it to the local ARC dealer and I was very disappointed. After 3 days I got my VS115 "repaired" from the local ARC service. They told me that the amp is fine, Bias adjusted but they couldn't find anything. I also wrote to ARC about it. They answered to me by a short fax "pls. adjust the bias to 65mA". There was not a logical explanation for that. Ok, the amp sounds great but could it happen again?
Due to that I check the Bias and the wall voltage every time I hear music !!!
Best Regards
BasileM
BasileM...i had the same thing happened to me once on my Ref 110. The resistors in front of each tube are there as circuit breaker/fuse so that if a tube arcs and goes bad it does not damage any other part of the circuitry. One of the things that could cause problems apart from a tube going bad, is if one turns off the amp and then turns it back on without adequate cool down time. Whenever you shut the amp, you should always, wait a minimum fo 10 mins (but preferably 30 mins) before turning it back on. If you are in the habit of turning the amp off and then turning it back on in short order that can cause all kinds of problems with tube stability and bias drift. So make sure to give the amp adequate cool down/stabilization time after turning it off before turning it back on again.
Hi cmalac, thanks for your reply. Usually i am waiting 5-10 mins to turn it off. In the meantime, as mentioned, i am measuring the bias.
But for turning it back on, it was new for me - so i will follow your advice. Another explanation from a friend was that the 6H30 triodes in each channel for gain and cathode follower-driver don't seated well and have caused stability problems and bias increase up to 90 mV. Maybe ?!
Best Regards
Basile
Hi LDA, anything new from the tube failure ?
Regards
BasileM