• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

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.
Thanks Cosmicalien
 
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
 
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.
 
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!😱
 
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
 
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
 
You might also try pulling the Yaqin buffer out of the system. My experience (limited) is with good quality components the buffers do don't much for the sound and can take some of the clarity away. On lesser gear they can sweeten the sound. I tried it in several configurations(Elite PD-93 player,also a Mark Levenson /Proceed transport with Counterpoint DA-10 DAC going into Meitner Pa6i preamp both tube and SS amps and sold it to a guy that on his system it gave it a more "analog sound".
 
You have to try to find out. A lot of us have used KT120 on YAQIN MC-100B without problem. The PT temp is the same. Some bias between 0.55-0.60v but mine is at 0.50-0.51v. Been running over a year without problem. You would get better sound than KT88.
 

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