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KT120 Oddblocks
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Author:  JanG [ 28 Sep 2016, 11:33 ]
Post subject:  Re: KT120 Oddblocks

Thanks wdecho. As you can see the heatsink is a bit oversized :) but as a result it hardly gets warm, and as it is so big I was able to suspend two tag boards with the PSU components from it through a large slot in the top plate. Besides the LM317 I also bolted the big 50R (50W) resistor to it.

Author:  JanG [ 16 Oct 2016, 17:55 ]
Post subject:  Re: KT120 Oddblocks

It's a really great amp. I'm very happy with it.

Author:  Geek [ 18 Oct 2016, 02:58 ]
Post subject:  Re: KT120 Oddblocks

I use those cases, too. They are just too perfect for making gorgeous tube amps! :D

Author:  Juancho [ 09 Dec 2016, 13:48 ]
Post subject:  Re: KT120 Oddblocks

Any ideas anyone? Just finished a pair of KT120s and current on the test points is 138ma per tube yet the KT120s are both glowing red on the back part. Any thoughts? HT is spot on 470v.
Thanks

Author:  Steavis [ 09 Dec 2016, 14:49 ]
Post subject:  Re: KT120 Oddblocks

JanG: those are great looking amps! Do I spot a B&W 805 nautilus speaker in the background?

Author:  gofar99 [ 09 Dec 2016, 17:46 ]
Post subject:  Re: KT120 Oddblocks

Hi, They should not red plate at the power level. I calculate less than 60 watts total (screen and anode) dissipation. They should be OK. I sure hope that TS has not started to put out junk and is skimping on the tubes. However if you want you can reduce the current to about 125 per tube and not hear any difference. The loss in output power when converted to audio will be quite low. I would estimate on typical speakers under 2 db.

Good listening
Bruce

Author:  Gio [ 09 Dec 2016, 17:55 ]
Post subject:  Re: KT120 Oddblocks

Great work JanG.

Geek and JanG - Where do you guys get these cases from?

Cheers

Author:  Geek [ 10 Dec 2016, 01:46 ]
Post subject:  Re: KT120 Oddblocks

Ebay or AliExpress. The best ones on Ebay are from the Chinese, as they sell direct, rather than through a middle man.

Cheers!

Author:  JanG [ 10 Dec 2016, 07:48 ]
Post subject:  Re: KT120 Oddblocks

Steavis wrote:
JanG: those are great looking amps! Do I spot a B&W 805 nautilus speaker in the background?


Indeed, you have a sharp eye. It's the first model from 1999.

Author:  Juancho [ 10 Dec 2016, 09:13 ]
Post subject:  Re: KT120 Oddblocks

gofar99 wrote:
Hi, They should not red plate at the power level. I calculate less than 60 watts total (screen and anode) dissipation. They should be OK. I sure hope that TS has not started to put out junk and is skimping on the tubes. However if you want you can reduce the current to about 125 per tube and not hear any difference. The loss in output power when converted to audio will be quite low. I would estimate on typical speakers under 2 db.

Good listening
Bruce


That's what I concluded re dissipation, which is at the lower end of the 'average use' quoted by TS. Whilst lowering the dissipation may well cure things for this set of 4 tubes I'm nervous that if they're duff, they might not last very long so I'm better sending them back for replacements and fingers crossed it's just a bad batch

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