ARC VT80SE with KT170 tubes: audio art without artifice

[Al M.]

I think so much of high end audio falls into this category. Case in point: I temporarily switched from the VT80SE to a much more powerful class D amplifier with the budget Topping D90 DAC for the two 90+ degree days we just had in the Bay Area. On the surface, these two components have great specs. But our ears tell a different story. Midrange textures suffer and there’s bleaching of the harmonic structure that is so essential to reproducing live music. Switched back to my ARC 6SE with the VT80SE and the Lampi Pacific today as temperatures went back into the 70s. Even though the VT80SE has much less power, it’s so much fuller in harmonic richness. It’s not loudness that matters as much as harmonic richness. It’s what makes high end audio worthwhile. Yes, it’s a pain to maintain tube gear and large speakers. But at the end of the day, the musical satisfaction of the sound makes it all worthwhile.

Agreed on harmonic richness. Have you teased out if the Topping DAC or the class D amplifier was the bigger problem? I have heard a Topping DAC, and while the sound was clean, it also was rather thin with, indeed, a bleaching of harmonic structure.

 

[godofwealth]

It might indeed be the Topping. I am using the Lampi Pacific with an eclectic set of Western Electric 101D tubes with the WE 274B rectifier. It’s amazing how these 100-year old tubes bring new life to digital. The jazz recording I’m listening to now was recorded in 1959 and sounds so rich and mesmerizing through this tube gear.

 

[watermad]

Yes, ARC sanctions the use of the KT170s with the VT80SE. They’ve tested it in the factory. They personally prefer the sound with the KT150s. But that’s a decision influenced by what speakers you use. In my case the KT170s work well with the G9-7c’s. In any case, it’s a relatively inexpensive experiment since you only need four output tubes. They don’t need to be sourced from ARC. I also got the optional grill cover with mine. It makes for a nice clean look.

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I am a very happy VT80SE owner, been running with the KT150s. I asked Audio Research about running the VT80SE with KT170s when they came out, but they were untested at the time. Did you try running with the KT150s before using the KT170s, how did the sound change? The KT170s come at a 25% premuim over the KT150s in Europe so not a cheap experiment, I would be wanting more low end bass control/extension.

 

[godofwealth]

The VT80SE that I bought originally came with ARC-supplied KT150s. I ran those for a few weeks before changing over to the KT170s. I did it for curiosity, more than anything else, but I'm still using the 170s. I like them better with the 170s, personally. I think the 170s take all the good aspects of the 150s and improve upon them: a bit more power, smoother in tonality, and even quieter as a tube. Tube life is about the same. We are talking about 4 tubes, so it's not a king's ransom. If you want to compare, you should see what ARC charges for tube replacement for the monster 750SE's I use in the winter months: that's a king's ransom! Unfortunately, the 750SE's are notoriously picky and one is forced to use ARC-branded tube replacement sets. With the VT80SE's, you can use any supplier, although I recommend a reliable one who can test the tubes for you by doing a 24-hour or 48-hour burn-in. I test all the tubes I buy with an Amplitrex tube tester (which ARC also uses), but it's probably overkill for new tubes from a reliable vendor.