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Old 9th June 2014, 10:25 AM   #1
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Default KT120 upgrade from KT88 6550

Hello everyone I have a Yaqin MS 110B KT88 INTEGRATED AMPLIFIER currently I'm running the supplied Chinese tubes. After browsing around I found people are recommending TUNG SOL KT120 as a upgrade. Has anyone done this at all I believe the KT120 draws slightly more voltage and it's because of this I'm asking if it would damage my amplifier in any way or is it within parameters.
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Old 9th June 2014, 11:26 AM   #2
multi is offline multi  Australia
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The KT120 draws a lot more current. Why not EH 6550's?
Phil
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Old 9th June 2014, 11:28 AM   #3
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Voltages are fine it is the heater current that is the issue.
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Old 9th June 2014, 11:32 AM   #4
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Kt88 heater current is 1.6Amps per valve the KT120 is 1.9Amps!
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Old 9th June 2014, 11:35 AM   #5
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So Mr Jonsnell are you saying the KT120 is not recommended for my amp. What would you recommend as a upgrade to the KT88. I'm also looking to upgrade the 12AU7 and 12AT7 tubes supplied. And Phil thanks for your reply to I'm bit of a caveman when it comes to this stuff.
Thanks Cosmicalien
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Old 9th June 2014, 11:38 AM   #6
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And this difference is enough not to go for KT120 tubes. The manufacturer is in China can't seem to get a answer from them as to what KT88 draws but you done it wow man.
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Old 9th June 2014, 03:23 PM   #7
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Over the years I have seen many warnings about the extra heater current and that many power supplies cannot handle it.
Does the power transformer get hot now? If so, don't take the risk on overloading it (more).
If it runs cool now you could take a chance on it.
The qustion you should really ask, is what do you want to achieve? Plugging in a beefier valve will not make the amp produce more power. You could run the outputs hotter (more towards class A), IF the power transformer can handle the extra idle current.
Personally I would be looking for a good and affordable KT88. Which version do you have now? The chinese ones with oval or round holes in the anodes? In my book oval is ok, round not so much.
I wouldn't be surprised if changing the 12AU7 to something like a 5814a makes more of an improvement than changing the outputs. I don't know your amp so it's just a guess.
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Old 9th June 2014, 04:05 PM   #8
ColinA is offline ColinA  United Kingdom
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Knowing the poor build quality and component selection of Chinese valve amps.
(I had one go up in flames and smoke!)
I would not risk it. It's not just the transformer but the other components that may be running close to their limit.
But it's your money!
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Old 9th June 2014, 11:26 PM   #9
multi is offline multi  Australia
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Knowing the poor build quality and component selection of Chinese valve amps.
(I had one go up in flames and smoke!
You certainly have to be careful buying Chinese amplifiers. There are some very good ones too. Always check you have been sent an amp for the voltage at your place.
Twice I have been shipped 120 volt when i was told; I would receive a 240 version, one box even had 240 Volt printed on the box. I always check on a 120 volt supply to be sure.
Best to buy Russian made 6550's, there is no difference between 6550 and the KT88's they are the same and the 6550's are cheaper, can't understand why anyone would want to use KT120's when they are so expensive and when the amp is not designed for them.
Genuine KT88's can handle 100K on the grid, just check the Rating's for current production and the 6550 and KT88 recommend max of 50K. The KT 120 is 50K too.
Phil
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Old 10th June 2014, 01:07 AM   #10
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Hi Parafeed, multi and Colin A thanks for your advice. The build quality is excellent I took to a highly regarded electronic engineer he said it was beautifully put together. The sound is excellent but tweaks to tubes will make it awesome bit of kit. I'm not after more power just a crisp clear sound with a deep deep tight bass. I think I'm nearly there I use the amplifier with Dali suite 2.8 speakers and rega apollo r cd player. I use a Yaqin cd buffer inbetween the amp and cd player that's the extent of my system. Well the sound is excellent and upgrading the tubes will make it awesome. I think you guys are right although beautifully put together I shouldn't really chance it. Are the Tung Sol KT88 reissues any good a dealer nearish to me is selling a matched quad set for 96 it's definitely the safe option. I haven't fitted the smoke alarms as yet lol ��. But thanks guys just needed to hear your expert advice. Thanks Cosmicalien
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