[JeffreyB]

I've been reading some about the KT120 output tubes, and there was the beginning of a discussion about using this tube in Music Reference amps back in December.

Has anyone tried the KT120 tubes in a RM 200 mk II?

Thanks.

Jeffrey

[kngale1]

Roger,

Any update rolling KT120 output tubes with RM300 and RM200 MKII?

Thanks!

[hoppy08520]

Same question for a RM-9 MK2.

[JeffreyB]

Hello All,

I received the following from Roger via AudioCircle email.

"i think they will work. I have them on the tube store. You can set the bias 25% higher as long as the power transformer doesnt get too hot"

Has anybody tried them?

Jeffrey

[jgb0194]

I received a quad from Roger in Saturday morning's mail.

My amp is the RM 200 MKII-T, class A output version.

The KT120 tubes were easy to bias at 70mA (Roger suggested 60-80mA).

I've about 10 hours use on the tubes now, most of it "other room" background listening. Summer's just not a time that I do much dedicated listening.

I like what hear so far, a somewhat different animal than the Gold Lion KT88 I've exclusively used until now.

When I've heard enough different music with dedicated listening I'll report back.

John

[Roger A. Modjeski]

I've tested my third batch of KT-120 tubes and I think they are marvelous. They work fine in the RM-200 and you can bias them safely at 40 ma and up to 60 ma but just keep an eye (hand) on the transformer cover to make sure it doesn't get so hot as to be uncomfortable to the touch. Make sure the amp has lots of airspace from behind (where the air comes in) and above where the hot air goes out the vents above the power transformer.

For RM-9 owners you can use them in one row across the front leaving the back row empty. The increased filament current for all 8 tubes is more than I think advisable. You can run the 4 tubes up to regular (LED lit) setting as they will be dissipating 30 watts each, well within their rating. You could even run the LED a bit bright as these tubes have a 60 watt dissipation rating.

I have looked at several sites selling this tube but they still don't have the matching down properly.  I have them matched and on sale on tubeaudiostore.com at $75 each.

http://tubeaudiostore.com/tungsolkt120.html

[khal]

Hi Roger
Would that include the rm9 mk2 as well?
many thanks

[Roger A. Modjeski]

Hi Roger
Would that include the rm9 mk2 as well?
many thanks

Yes the MK-II will take 4 the same way as the MK-I. I have a customer who has installed them recently and loves them.

[ponger]

Hello khal,

I have a RM-9 Mk ll with a quad of Roger's KT-120s.  My setup is probably a little different than most.  I have a three way active system using RM-9 Mk lls on the midrange and tweeter.  I have been using the KT-120s on the midrange.  Prior to the KT-120s, I was using Roger's NOS Siemens EL-34s.  I was pleasantly surprised with the improvement in detail and richness in the vocals.  As I would have expected, the upper bass has also improved.  Since I cross the midrange to bass at 150 hz, I can't comment on the lower bass performance.  Now the next decision is whether or not to use the KT-120s on my tweeter amp as well.

I would certainly give them a try. 

Mas

[GEORGEGIM]

I've tested my third batch of KT-120 tubes and I think they are marvelous. They work fine in the RM-200 and you can bias them safely at 40 ma and up to 60 ma but just keep an eye (hand) on the transformer cover to make sure it doesn't get so hot as to be uncomfortable to the touch. Make sure the amp has lots of airspace from behind (where the air comes in) and above where the hot air goes out the vents above the power transformer.

For RM-9 owners you can use them in one row across the front leaving the back row empty. The increased filament current for all 8 tubes is more than I think advisable. You can run the 4 tubes up to regular (LED lit) setting as they will be dissipating 30 watts each, well within their rating. You could even run the LED a bit bright as these tubes have a 60 watt dissipation rating.

I have looked at several sites selling this tube but they still don't have the matching down properly.  I have them matched and on sale on tubeaudiostore.com at $75 each.

http://tubeaudiostore.com/tungsolkt120.html
[/quote

Hi Roger,

I tried several tubes on my RM 200 like 6L6, EL34, KT88, 6550, best sounding with NOS Philips EL34 (1962) and Gold Lion KT88 (1960 Genelex). Considering your post referring to KT120, just wondering whether I can safely put them on my RM 200 (no MkII as I bought it on August 2000). Positively, please advise me of proper bias value.

Regards
George