Audio Research VSi55 Tube Rolling


i am very happy with my new ARC VSi55 integrated amp, but have been thinking about trying a bit of tube rolling. the amp now has about 400 hours on it, and to this point i have only used the stock tubes.

i would very much appreciate specific suggestions that you might have. i am also interested to know if anyone has tried "cryoed" tubes in their VSi55.

FYI - speakers are coincident speaker tech partial eclipse II's, and CD player is musical fidelity A5.

thanks!
skuras
I have the VS-55 and love it (probably very similar sound to the VSI-55). You likely have stock 6550EH's (Electro- Harmonix). I very recently had a retube. ARC informed me that because of quality and longevity issues with the EH's, they are now recommending use of 6550 Winged C's for the VS-55 and VS110. The winged C's have a different sound...different strenghts. Overall, I like them better. You may want to start there...

NOTE: Rather than 65mV bias, they should be set to 55mV (per ARC).

Another tube to consider might be the (New Stock) Tung-Sol 6550's...I've hear a mix of things...mostly good.

(IMPORTANT: I encourage you to check with ARC before proceeding--...there may be special considerations with the VSI-55.)
I would recommend that you contact Dave Gordon at Audio Research--he is a great guy and a real industry veteran who could be an invaluable resource for you.

lrsky
I've got a VSi55, and would like some tube recommendations...rather than start a whole new thread, let's resurrect this thread after an 8 year hibernation...

Lots has happened since 2006...KT120s have been introduced to the mix (and fully compatible with the VSi55), and the KT150 (about which ARC is still mum regarding compatibility, and I have followed the other KT150 threads here but didn't want to hijack them), and I think the introduction of the reissue Gold Lion KT88s is a relatively new thing as well.

Has anyone done A/B comparisons between the 6550WE and/or the 6550 Winged C vs. KT120? Or maybe found a newer KT88 variant they liked better than anything else?

My VSi55 is in a smallish living room, powering a pair of Proac D2, and I listen to everything but country...from 80s rock to bossa nova to Charlie Haden to Yo Yo Ma, so I'd prefer a tube with a balanced presentation (rather than one that favors midrange presentation, for example).

Thanks in advance!
If you can still find winged C 6550's don't use them. The last of the production was not reliable. Apparently the plant burned down and are no longer available.
Bcgator
I've got a VSi55, and would like some tube recommendations...rather than start a whole new thread, let's resurrect this thread after an 8 year hibernation...

Lots has happened since 2006...KT120s have been introduced to the mix (and fully compatible with the VSi55), and the KT150 (about which ARC is still mum regarding compatibility, and I have followed the other KT150 threads here but didn't want to hijack them), and I think the introduction of the reissue Gold Lion KT88s is a relatively new thing as well.

Unless that ARC amp was designed for KT-120s I would just plug and play. Call ARC and verify the new design KT-120 is compatible without modifications.

Hifigeek1
If you can still find winged C 6550's don't use them. The last of the production was not reliable. Apparently the plant burned down and are no longer available.

The plant did get destroyed but there are some of us with a supply of Wing C tubes from years ago. I bought about 200 of them several years ago and still have 55 or 57 of them matched and new in box,

The Wing C is the best sounding modern KT-88/6550 there was (in my opinion).
Above should read unless that ARC amp was designed for KT-120, I would not just plug and play.
Hifigeek1, thanks for the input - I have seen mention of the quality decline elsewhere, so I'm on board with what you're saying.

Albertporter, I've already confirmed with ARC (and others have posted previously to the same effect) - the VSi55 takes the KT120 no problem. No word yet on the KT150, but the 120 is a go.

I'll probably go with the KT120 and see how they compare.
You will like the KT-120
I am running the vs55.
Curios if kt 150 would work?
Using solvtek ATM.
What's up in 2016?
Well I don't have good news for you guys...!
Recently, It was time to re-tube my good old VSI-55 so I called my local ARC dealer who said I could easily upgrade from the stock 6550  tubes to KT120 or even better the newer KT150...! To double-check I've called Audio Research directly and here is the BAD news the tech told me: While it will work to re-tube my amp with KT120 or KT150, the power transformer has not been designed for this, thus it will overheat tremendously and this will  seriously compromise its lifespan (a new power transformer of this type costs around $500-600 including labor). Instead he recommended to use the 6550's or KT88's... More interestingly, I asked if I could re-tube a VSI-60 (very similar amp to the VSI-55) with KT120 or KT150 and he said the same thing: NOT recommended! Then I asked him why they still offer the VSI-60 with KT120 on their website? He answered that thuis model was discontinued but there may still be some units are resellers. And the newer VSI-60 models had an upgraded power transformer to accomodate KT120's while older ones did not...

So be careful if you think this is a good upgrade... You may have better sound but you will inevitably toast your power transformer!!!

I called back the local dealer about this contradiction, he retracted and said ... listen to the ARC tech...:-)

Anybody had issues ...?


ARC separates are so much better than its integrated amps.
Ditch the Vsi-55 and go separates! Keep me posted & Happy Listening!