Just Installed My KT-150 Tubes

[Myles B. Astor]

I know, and that's the beauty of owing an amplifier that only uses a pair of output tubes per channel. Ned Carlson of Triode Audio once told me that he wouldn't own any tube amp that had more than one pair of output tubes per channel. The more output tubes you have per channel, the harder it is to get a tight match across them when you buy them and the more likely it will be that they will drift apart as they age. I used to own a Jadis Defy 7 MKII amp and it was a freakin' nightmare to try and keep the tubes biased correctly not to mention the hit to your wallet.

I don't have any issue with my cjs. Easy to bias, not a lot of drift.

 

[joeinid]

+1

So far my CJ gear has been the most stable and easy to maintain. Love them. The bias lights are a breeze.

I don't have any issue with my cjs. Easy to bias, not a lot of drift.

 

[mep]

I don't have any issue with my cjs. Easy to bias, not a lot of drift.

Owning a tube amp that is easy to bias should be mandatory. I have owned both types-"easy to bias" and "are you freakin' kidding me?" insane to bias. CJ falls into the "easy to bias" category of tube amps. My real point was that maintaining proper bias across your output tubes is one thing, buying 8 or 16 tightly matched output tubes is another. That's the beauty of having a tube amp that only uses a pair of output tubes per channel as well as not making you and your wallet cringe when it's time to retube. In my room with my NOLA KO speakers, 75 watts is plenty of power. I barely see the power meters move even when the walls are blowing down. I have owned my share of ARC 75 watt tube amps over the years, the Ref 75 is the most powerful sounding 75 watt tube amp I have ever owned.

With the Russian Ruble value in the tank, we ought to be able to buy KT-150s for $30 each now.

 

[Myles B. Astor]

Ž

Owning a tube amp that is easy to bias should be mandatory. I have owned both types-"easy to bias" and "are you freakin' kidding me?" insane to bias. CJ falls into the "easy to bias" category of tube amps. My real point was that maintaining proper bias across your output tubes is one thing, buying 8 or 16 tightly matched output tubes is another. That's the beauty of having a tube amp that only uses a pair of output tubes per channel as well as not making you and your wallet cringe when it's time to retube. In my room with my NOLA KO speakers, 75 watts is plenty of power. I barely see the power meters move even when the walls are blowing down. I have owned my share of ARC 75 watt tube amps over the years, the Ref 75 is the most powerful sounding 75 watt tube amp I have ever owned.

With the Russian Ruble value in the tank, we ought to be able to buy KT-150s for $30 each now.

Except tightly matched tubes aren't necessarily a prerequisite with the cj. Nevertheless, I want it. That said, I prefer getting my tubes from cj since they're tempered and checked in the actual circuit so the circuit meets spec.

 

[joeinid]

Ž

Except tightly matched tubes aren't necessarily a prerequisite with the cj. Nevertheless, I want it. That said, I prefer getting my tubes from cj since they're tempered and checked in the actual circuit so the circuit meets spec.

Myles,

Have you kept track on roughly how many hours you get on a set of tubes for the ART monos? I think CJ recommends about 1500 hours (possibly 2000 hours maximum) until replacement.

 

[Myles B. Astor]

Good question. Had three KT120s initially fail but all the tubes have no been fine since. Never really keep or kept track of hours. (Though know roughly the number of hours since the time listen each week is pretty consistent.) More by sound and with say the older 6550s, when two or three went cherry red, knew it was time place all of them. Lew mentioned a while back that they expected that the 120s should last three times longer than the 6550.

 

[joeinid]

Thanks Myles!

I'll keep an eye on mine.


Mark,

Do you know what ARC recommends (hour wise) for the KT-120/KT-150 on the Ref 75?

Thanks!

Good question. Had three KT120s initially fail but all the tubes have no been fine since. Never really keep or kept track of hours. (Though know roughly the number of hours since the time listen each week is pretty consistent.) More by sound and with say the older 6550s, when two or three went cherry red, knew it was time place all of them. Lew mentioned a while back that they expected that the 120s should last three times longer than the 6550.

 

[mep]

Thanks Myles!

I'll keep an eye on mine.


Mark,

Do you know what ARC recommends (hour wise) for the KT-120/KT-150 on the Ref 75?

Thanks!

To my knowledge, ARC is sticking to their normal 2000 hour replacement recommendation for the KT-120 tubes. I don't think ARC has commented on the longevity of the KT-150s yet.

 

[puroagave]

Owning a tube amp that is easy to bias should be mandatory. I have owned both types-"easy to bias" and "are you freakin' kidding me?" insane to bias. CJ falls into the "easy to bias" category of tube amps. My real point was that maintaining proper bias across your output tubes is one thing, buying 8 or 16 tightly matched output tubes is another. That's the beauty of having a tube amp that only uses a pair of output tubes per channel as well as not making you and your wallet cringe when it's time to retube. In my room with my NOLA KO speakers, 75 watts is plenty of power. I barely see the power meters move even when the walls are blowing down. I have owned my share of ARC 75 watt tube amps over the years, the Ref 75 is the most powerful sounding 75 watt tube amp I have ever owned.

With the Russian Ruble value in the tank, we ought to be able to buy KT-150s for $30 each now.

I thought stereophile's test concluded its a 60-watt amp unless you like 3% distortion i've owned my share of tube amps around 100 watts and under and as they say in the car world, there's no substitute for cubic inches. I'm now really high on 200+ watt tube amps and thinking about more juice in the future. fortunately the early VTLs are basic by design, easy to bias and don't eat tubes. something I cant say about the early ARC amps i've owned (D70, D115, M100) you have to be part masochist to own one of those.

 

[mep]

I thought stereophile's test concluded its a 60-watt amp unless you like 3% distortion i've owned my share of tube amps around 100 watts and under and as they say in the car world, there's no substitute for cubic inches. I'm now really high on 200+ watt tube amps and thinking about more juice in the future. fortunately the early VTLs are basic by design, easy to bias and don't eat tubes. something I cant say about the early ARC amps i've owned (D70, D115, M100) you have to be part masochist to own one of those.

I don't think Stereophile's measurements mean a whole lot to me since my watt meters rarely get above 5 watts. The Ref 75 with the NOLA KOs (and the Wilson Benesch speakers) gives you a sense of effortless power is all I'm saying.