2. amps-preamps
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Tube Amp question:TUBE replacements: explain MATCHED?

I don’t get the mystery behind it all.  I have a Cary CAD- 808…( I’m buying early before I need to replace)… so far, I have bought SOVTEK, in the EL 84, ( new)… I have bought 12AX7WC SOVTEK TESTED STRONG MATCHED PAIR (difference = 0%) TUBES=ECC83, and now I’m looking at (4) Lightly Used SOVTEK KT88’s… I…but I’d rather buy NEW KT88’s… does MATCHED mean I cannot buy another brand/make of a KT88? I believe this would fulfill needs to properly replace what I’m running now…I bought the amp with tubes installed… I am a novice… amp sounds great… however I need the plug-in to check the Bias, and I guess a meter? 

Does matched mean I have to stay with the same brand? I need (4) more KT88 tubes. Do they need to be (4) matched tubes?

SOVTEK only?

Thanks 

Dave
 

moose89

Showing 1 response by carlsbad

carlsbad's avatar
carlsbad
1,551 posts
 

Your amp uses 4 kt88s.   You should install 4 of the same brand.  You can buy 4 more of any brand you want.  

Matching refers to tubes within the set of 4.  Since tubes have inherent variability in their responses, people test a large lot and pick out groups of 2 or groups of 4 with very similar responses.   Nice to have but not required.

Now isn't a great time to buy tubes.  But it is good to have a spare.  Your KT88s probably have a log expected life so it isn't urgent to get a spare set.  I would buy a single tube of the same brand you have installed to use as an emergency spare and wait for prices to go down.

Jerry

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