Valves KT88 or 120

[John]

I have a SAC KT 88 Glowmaster
I just noticed one of the valves seem to be on the way out. It reading 09ma instead of about 40 to 50
Would it be best to replace the whole set up with KT120? The amp seems to burn out valves once a year even with Sweatvana C
The 120 is better at dealing with high current draw so might be a better investment?

[jantheman]

PM AnthonyTD..I think he's the best one to answer this.
Although I have KT88's in my Quad 40's I dont know if I would be happy swapping to another type.
Whatever happens, I think they should last more than a year under 'normal' usage. Quad quote about 6000 hrs for a KT88.
Anyways...PM AnthonyTD....he'll sort you out.

EDIT...Let me point you to here..http://www.diyaudio.com/forums/tubes-valves/163862-kt-120-a.html
Worth reading.....

[John]

The rest seem ok I will email Anthony a its more his knowledge base

[Ali Tait]

That seems a lot of valves to go through John. How much listening do you do? The amp could be caning the valves too hard, and lowering the dissipation might be a good idea.

[John]

Yes it seems really high

[spendorman]

A quick look around, it appears that the heater current for KT120 (and KT90) are higher than for the KT88. This would put more loading on the power supply. As to whether that is a problem?

[Marco]

The new Tung-Sol KT120s, which I'm now using instead of KT88s, were a drop-in replacement in my Copper amp (and sound utterly superb), but I think compatability may vary from amp to amp, so John, I'd check with Anthony (or Nick first) :)

I'd agree though that your amp seems to be caning valves. They should be lasting MUCH longer than that.....

Marco.

[alfie2902]

Back from the dead...

Marco what do you think the KT120's give over the KT88's? Do they run UL or triode in the copper amp?

[Marco]

Hi Alfie,

Not sure about the answer to your last question. However, it certainly isn't triode. I'll ask Anthony and let you know :)

As for whether KT120s are better than KT88s, you'll have to listen for yourself in the amp you intend to use either in. What I would say, though, is that if your amp has the ability to take advantage of the full performance capabilities of KT120s, then they should be better than any KT88s :cool:

Marco.

[alfie2902]

Hi Alfie,

Not sure about the answer to your last question. However, it certainly isn't triode. I'll ask Anthony and let you know :)

As for whether KT120s are better than KT88s, you'll have to listen for yourself in the amp you intend to use either in. What I would say, though, is that if your amp has the ability to take advantage of the full performance capabilities of KT120s, then they should be better than any KT88s :cool:

Marco.

That's quite interesting, Marco. The KT120's will be better than any KT88, but in what way? I know it's a bit of a leading question, but I'm having a play with an Art Audio Cencerto atm, It came with a quad of EI KT90's that must be getting long in the tooth but are sounding very nice still.

The amp can use KT88, 6550, KT90 & Tom Willis say's works well with KT120 too.

I'm not sure atm if the Art will stay or my NAF, so i'm trying to get an handle on what people think of these output tubes & perhaps having a punt on a quad without wasting loads of money trying all the options, Especially as I'm not sure which amp stays. So any thought you have would be appreciated mate!