KT-120s... anyone using them?

[AlexM]

Hi All,

I'm thinking that my GL-KT88 re-issues may need replacement next year, and I've been thinking about what I want to replace them with.

I have a Rogue Audio Stereo 90, and Mark from Rogue says that they perform very well in his amp, as well as being 'safe' to use in terms of heater current etc. The Stereo 90 is a fixed bias amp that can use EL-34w, KT88/6550s, KT-90s as well as KT-120s.

I am tempted, as they will be likely to last for quite a while at the operating point they would be run at in the Stereo 90.

Any views as to the KT-120 in a push-pull power amp?. Any other current prodution KT-88 types worth a look?. I think that the GL KT-88 reissue is damn fine tube for the money, and has been very consistent and reliable over the last year and a half of use. I haven't tried or heard the Shuguang Black Treasure series, but know they are well regarded, albeit very expensive.

Regards,
Alex

[John]

Speak to Marco or Anthony TD I think both really rate them and Anthony can get you them

[AlexM]

Calling Marco...

[AlexM]

Calling Marco... what were your impressions of the KT120? The reviews that I have seen are somewhat confusing (i.e. very positive or slightly scathing!).

Regards,
Alex

[AlexM]

I've decided to take the plunge, given a very positive opinion from Mark O'Brien at Rogue Audion.

I've ordered a set from Hotrox, who are doing a matched quad for £116 inc vat and delivery, which seems like a sharp price!.

I'll let you all know how I get on.

Alex

[Marco]

Sorry, mate. I've only just seen this! You should've PM'd me...

Anyway, I think you'll love them, providing that your amp can maximise their advantages. They're so good, I wouldn't go near KT88s again, GECs or otherwise!

KT88s just sound soft and fluffy in comparison....

Pity though you didn't order them from Anthony, as he'd have given you a good deal, and his valves are all hand-selected and tested in optimum matched pairs and quads - not to worry.

Do let us know how you get on

Marco.

[AlexM]

Thanks Marco.

A lot of manufacturers seem to have started fitting KT 120s - ARC, Rogue and others. I view this as an endorsement of their quality and performance.I hope that they are clearer, not harder sounding than KT88s. Hard to be sure from online reviews as most of the DIYAudio crowd seem to be using them in SET rather than PP amps. My amp is adjustable fixed bias, so matching is less of an issue than with some amps, but my experience of New Sensor product is that the factory matched quads are superbly matched anyway - most of my sets have been within a ma or less. They have obviosly invested heavily in QC and test gear.

I held off deciding to give them a try until I was sure that there wasn't going to be.a problem with the power transformer from the increased heater current draw compared to a KT88. Mark assurred me that the transformer was considerably overrated, and I suppose that it is a pretty huge lump of iron, and is totally cool to the touch at the moment.
I'd advise that anyone thinking of using them should check with the manufacturer or dealer before using them as they aren't quite a drop-in upgrade.

Apparently they will also be barely ticking over in my amp, so they will hopefully be long lived too, and be operating well within their most linear part of the curve.

[The Black Adder]

KT120's... sooon, it will be sooon!!! Oh yeah, changes on the way!!!

[Marco]

Rock and roll, guys - you're gonna love it!

Marco.

[AlexM]

They arrived this morning... quite a bit taller than the Genelex KT88s. A quick visual inspection shows double getter flashes mid way up the envelope, a much larger plate structure, and that the grids have large cooling fins.

I'm just waiting for the amp to warm up so I can finish the bias adjustments, and then on to some listening tests.

Cheers,
Alex


Tung sol KT120 by alexmastersuk, on Flickr