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Trying to choose new tubes for an Elekit TU-8200 amplifier

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HarryY

HarryY

Member
Joined 2017
I recently built an Elekit TU-8200 amplifier for my Den/Home office.
I have the speakers on each end of my desk about 3 feet away from me.

The amp came with Chinese 12AU7's and Russian Electro-Harmonix 6L6EH tubes.
The amplifier will take a variety of power tubes: 6L6GC, EL34, KT66, KT88 6550 & KT90

As for budget probably about $300 for the power tubes.

I know some like the KT66 and KT88 as they tend to give a fuller sound
(I'm looking for a fuller sound) while others prefer NOS GE & Sylvania 6L6GC.

So my question is what tube I should be looking at?

A secondary question what brand of 12AU7
should I look at to replace the stock 12AU7?

Thank you
 
45

45

Member
Joined 2008
Well, with $300 you can buy both one pair of good quality current production KT66 and one pair of NOS 6L6GC.

Current KT66, I would go for Gold Lion or, if you can still find them, the Valve Art (these were made with original GEC tools to high standard, a true quality copy). Just make sure they are really selected and performing as premium tubes.
I would stay away from NOS KT66 as there are a lot of fakes around....

For 12AU7 the choice among NOS is almost endless and prices are still acceptable.
 
A

audiowize

Member
Joined 2005
Yeah, those OT's look like they are probably good for 2-3 Watts. Select your speakers accordingly.

The feedback loop around the amplifier will tend to neutralize the differences between tubes, other than perhaps the 12AU7. There are oodles of nice, used old stock 12AU7's available on eBay for a few bucks a piece.
 
kevinkr

kevinkr

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Joined 2004
kta-hifi.net
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Surprisingly decent sounding little amp for this sort of application. I've heard several, of the tube combinations I've heard in this amp KT88s were about the best sounding, followed by the KT66. 6L6 were OK, but the others clearly sounded better.

Try Mazda (French) ECC82/12AU7A for the small signal end of things.
 
45

45

Member
Joined 2008
audiowize said:
Yeah, those OT's look like they are probably good for 2-3 Watts. Select your speakers accordingly.

The feedback loop around the amplifier will tend to neutralize the differences between tubes, other than perhaps the 12AU7. There are oodles of nice, used old stock 12AU7's available on eBay for a few bucks a piece.
Click to expand...


I actually have plenty of volume, even into a old pair of RCA Branded Minimus 7's.

kevinkr said:
Surprisingly decent sounding little amp for this sort of application. I've heard several, of the tube combinations I've heard in this amp KT88s were about the best sounding, followed by the KT66. 6L6 were OK, but the others clearly sounded better.

Try Mazda (French) ECC82/12AU7A for the small signal end of things.
Click to expand...

Measurements in the link above also look good with the exception of distortion at low frequency. But that is normal for that small transformer.
It also works well with speakers that I would never use with a valve amp. With that roller coaster impendance with 3 huge peaks over the full range 1-1.5dB deviation from flat response is not bad at all.

45 said:
Measurements in the link above also look good with the exception of distortion at low frequency. But that is normal for that small transformer.
It also works well with speakers that I would never use with a valve amp. With that roller coaster impendance with 3 huge peaks over the full range 1-1.5dB deviation from flat response is not bad at all.
Click to expand...


I'll admit I took a chance ordering the kit, I enjoy building kits (mostly for Amateur radio).

The reviews looked good so I took the chance. Admittedly I breathed a sigh of relief
once it was done since I was concerned it was not going to have enough volume for me.
 
45

45

Member
Joined 2008
HarryY said:
I'll admit I took a chance ordering the kit, I enjoy building kits (mostly for Amateur radio).

The reviews looked good so I took the chance. Admittedly I breathed a sigh of relief
once it was done since I was concerned it was not going to have enough volume for me.
Click to expand...

If I were in your position I would first find good speakers and eventually after change tubes. For good speakers I mean mainly those with with flat impendace, well balanced and with sufficient efficency. High efficiency is necessary for really load volume but not necessary in general. It also depends on how you listen to music and the kind of music of course.
 
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