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Re: KT-150

PostPosted: Wed Jul 29, 2015 9:51 pm
by tony
if i may say, plugging in the KT150 into an existing amp using the kt88 does not give you extra power, only extra heat....

but for new designs where operating points are different and transformers may be bigger, then by all means go ahead...

the thing i dislike about these newer tubes is the lack of design operating points on the datasheets,
unlike in the old mullard KT88 or even american RCA 6550, where the tube manufacturer gives a complete set of operating points
where builders can easily apply in their tube amp builds...

Re: KT-150

PostPosted: Wed Jul 29, 2015 10:00 pm
by Mamimili
tony wrote:
Mamimili wrote:Interesting stuff!
How about tubes? Do we get to see or hear any warning signs?

red plating is one, in this case just turn off the amp and then have it check by a qualified tech to find out why...
any tube near the end of its life will exhibit flash gettering fading out and disappearing altogether...

Thanks Tony!

Re: KT-150

PostPosted: Wed Jul 29, 2015 11:25 pm
by jadis
tony wrote:
jadis wrote:I'm just curious, in the event of a power transformer failure due to overheating, will it go out with a bang or just die out quietly. What I'm worried about in such a case is when you are riding the crest of a 'high' in the music being played (with eyes closed and feeling like Leopold Stokowski), and BANG! or BOOM! It's going to be a horrible feeling. :sweat:

have no fear.....
fuses will keep on blowing most likely...
capacitor failures will most likely produce a bang,
but in a well designed amp, that is highly unlikely...

thanks for the info, Tony.

Re: KT-150

PostPosted: Wed Jul 29, 2015 11:51 pm
by Mamimili
Tube or transformer failure has to be rare?
I have never had a failure or either, and some of my kit is getting on, early 70's SS amps still in use....i have no idea how old my ASL 211 amps are.
I do know i have a lifetime (mine or the equipment??) stash of tubes that have been in a dusty box, untouched for at least 16 years.

The worst and best thing to ever happen to me was a rotted driver surround 8)

Re: KT-150

PostPosted: Thu Jul 30, 2015 5:32 pm
by jadis
Mamimili wrote:Tube or transformer failure has to be rare?

I guess so, Paul. So far I've only heard about a tranny failure from a friend, on his Jadis JA200 amp because he played music the whole day since it was Sunday. Replacement of his tranny was really bloody.

Re: KT-150

PostPosted: Sun May 15, 2016 12:33 am
by JackD201
Plugged in two quads of 150s into the VA910 Monos today. Nice to have had a small breather now that elections are over and enjoy the lull as the 16th Congress ends and the 17th begins.

I am shocked that only after 4 hours of burn in, these "little" amps sound crazy good (and not just for the money) driving the VR-11s with absolutely no strain at all no matter what I threw at it. They had that classic 88 sheen at lower levels but that seems to evaporate when volume is brought up to a certain point. There things lock in and there is a cohesiveness that just makes the soundscape sound right. Nice tone, nice layering, not too smooth that the bite of cymbals or steel strings disappear. You still get the sinew of bows and the sweetness of tone from Piazzola and Heifetz. All in all methinks all future orders of 910s will be requested with 150s instead of 120s. As of today I think it is a superior output tube. From experience I know things will get even better, the only question is, by how much?