Perhaps you mean the MK-I vs the MK-II. The ARC web site makes no mention of a MK-III. I did have my unit updated to MK-II in the spring. The update includes fitting a removable IEC power cord, addition of a fan, and adding two small circuit cards containing additional power supply capacitance. The update yielded better dynamics and more of a sense of "sonic ease". At some time, I would like to explore updating the power cord.
Sparky57: You are basically screwed. The MKIII is out. It is an $1,850 upgrade (I think).
Cool! I'm always looking for better. I bought the unit used for $2800 and spent $600 on the upgrade. I couldn't care less that I don't have the latest. I will be curious as to the changes / sonic improvements. What I would really like is the ability to bridge the channels to offer the ultimate upgrade - another!
The newer model has a longer tube life besides better (possible?) sonics. I probably will go for it!
The Mk3 adds a switch for bal/single ended, 12V power on/off trigger. Internally, it now has JFET for input, followed by a 6H30 driver/gain, and a 6H30 follower driving the 6550Cs. There are now four internal bias instead of two. The upgrade will set us back 1895 from Mk2 and 2695 from Mk1. I do not know how different the sound would be from the Mk2. BAT has been using this tube in their preamps for over a year now. Why ARCs moving away from 6922 for their new design? Could REF 3 preamp replace REF 2 next year to correct the tubey sound of REF 2? Oh! well.....
ARC has experienced high failure rates on the Russian 6922. In addition ARC is having problems with the factory. I own both the ARC LS25 and the VT100 mkII. I am not in a hurry to upgrade to the LS25 mkII or the VT 100 mkII. Leonard at ARC claims that the LS25 mkII wallops the LS25 mkI in every respect and is in fact clearly better than the Reference I. I guess we will see.......
I wasn't aware of the mkIII version. I have a LS15 and VT100 mkII and I'm completely satisfied and have over 500 hours on the original set of tubes. I think ARC upgrades are evolutionary not revolutionary, so spend your money wisely fellas. Isn't great to be an audiophile!!
I've experienced the 6922 tube failure that Gmorris mentioned (at locations V-7 and V-8). However, I do love the sound of this amp. That's why I'm curious about the sound of the upgrade. ARC has the technical info on the upgrade available as a fax (they're delaying, they say, posting to their website to coincide with other product introductions). The changes are as Ttl2000 says, which basically is the driver stage from the ARC VTM200-200W monoblock. BTW, I've also heard from an ARC dealer that 6922 failure was one thing that prompted the revision. However, what does this new version sound like? The guy I talked with at ARC said that the bass on the MkIII made the Mk II's bass response sound "wooly" by comparison. He also said that the new amp just sounds like a more powerful amp overall . But, what do less partisan ears think? America wants to know!
I talked to my dealer yesterday...he advised that ARC will be upgrading the entire line to the new tubes and set-up. He also said there is a clear difference in sound and said pre-amp upgrades will make a bigger difference than amplifier.The new tubes are of higher quality and will last substanially longer. The high upgrade cost should cause us all to analyze this fully before investing. Thank you ARC for upgradability and fantastic products.
Djbaudio and the rest of you and any fans of ARC's current products. Do you know where I can find a nice SP-10 Mk2?
Hey, I agree with Djbaudio. spend you money wisely. If your current ARC equipment bring you happiness then don't rush into the upgrade. System matching is everything in this hobby. ARC has a history of putting out tons of upgrades. Just go to their website and look at the upgrade page. How does one determine that an upgrade actually sounds better than the old version? - depends on your taste - Shortly after the REF 1 was introduced, there was an upgrade to it, replacing some old caps with infini caps. Nothing changed in the circuit topology, just upgrade to infini caps. Why ARC did not use the inifin caps right from the start is a mistery to me. Now, REF 2 uses tube power supply and it sounds warmer??????? If you already have a warm sounding system, would you change to REF 2? I think not.
I talked with Leonard at ARC too. On the extended tube life, he mentioned that the life of the input tubes has gone from 5000 hours to 10,000 hours, but the power tube life at 2000 hours remains the same. The thetubestore.com 6550C power tubes cost 240 a matched set and the input tubes are 95 a set. He said the failure of the 6922's is actually caused by overheating when you place the vt100 in an enclosed area instead of an open rack/amp stand. That amp does generate a lot of heat. He also mentioned that the bass response would be improved and that a new 12v on/off input would be available. This presumably is for future control from another source to turn the amp on and off.
I have a VT100MKII and LS25, and formerly had a VT100MKI that had the FET upgrades and Infini Cap upgrades that the later model VT100's had. I understand that the new MKIII is quite an improvement over the MKII, but I am reserving judgement until I audition one in my system. I have mixed feelings regarding the switch to the new 6H30's, because I have gotten great results by upgrading the Sovtek 6922's. Several years ago, I began using Amperex 7308's, Siemens 7308's and Mullard CV2423 (6922's) to replace the Sovteks. This tube change results in a very,very large improvement in the amp (can you say "liquid"?). Care must be taken to match and have strong readings for the tubes in V7 anbd V8, in that these two tubes set/maintain the bias voltage for the 6550's. Unfortunately, 6922-type NOS tubes are hard to find and are insanely priced. When I upgraded to the MKII, I upgraded from the ARC 6550C's to a matched octet of EI Type 3 KT-90's that Upscale Audio recommends for the VT100. Once again, I obtained a very significant improvement in performance over new 6550C's. Anyway, I have said all of this to explain my hopes that with a better tube compliment in my MKII, I may not be as disappointed when I do an A/B with a MKIII.
I heard the MkII at my dealer's showroom. I fell in love with the sound. By the time I was ready to make the purchase the MkIII came out, so I didn't have the chance to audition the MkII at home. I am in awe of the sound of the ARC MkIII. First thing I noticed was improved bass response and even more detail from my Dunlavy VI's. I just made the purchase a couple of weeks ago and although I paid close to manufactured suggested retail (5 grand), it looks now like I got a great deal. My salesperson called me today and said ARC has just raised the price of the MkIII to $6.000.00. The new ARC VT 200 MkII is also going up a thousand bucks to $11,000.
iam researching both products, choice is tuff considering i live on the island of guam. and shipping is so rediculous. my system is wadia 861 via synergistic des. ref active sheildig. to pass x 350 via synergistic des. ref speaker cable to dunlavys sc 4as.