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Old 4th July 2011, 01:34 PM   #1
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Default 6L6, 6L6GT, 6L6GC, 5881, 7027, KT66...

Hello all,
Has anyone ever seen a comparison of these tubes? They seem to be listed as interchangeable by most sellers. Does one sound better than another? I mean is the variation between type greater or lesser than by manufacturer?


Kevin
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Old 4th July 2011, 01:39 PM   #2
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There are differences in anode dissipation, and the KT66 requires slightly different bias.
Don't, for example, put 6l6's of any kind into a Quad II, unless you change the cathode bias resistor.
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Old 4th July 2011, 09:58 PM   #3
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...EL34/6CA7,KT88,KT90,6550,et al.

They all have the same socket/pinout (more or less),but I'm not sure I'd go as far as "interchangeable". They are all fairly similar tubes,and can be subbed into most circuits with some adjustment of the bias voltage,etc. !But not always!

Just be sure to do a little homework before you start swapping tubes around,you don't want to blow up your amp/tubes.
If you aren't quite sure,ask here and someone will steer you in the right direction.
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Old 4th July 2011, 10:54 PM   #4
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Another thing about the KT66 is increased heater draw.

The best deal around in 6L6 family tubes may be the Russian 6П3С-Е (6p3s-e). Be sure to buy thoroughly tested stock from a reputable dealer.
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Old 4th July 2011, 11:02 PM   #5
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Quote:
Originally Posted by toprepairman View Post
There are differences in anode dissipation, and the KT66 requires slightly different bias.
Don't, for example, put 6l6's of any kind into a Quad II, unless you change the cathode bias resistor.
Just curious, to what value? That's R12 (180R) for KT66s... the good ones are getting harder to find!
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Old 5th July 2011, 03:01 AM   #6
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Hey all,
I have a collection of NOS 6sn7's. I need two good tubes for the amp I intend to build. I have two RCA GTB's, one CBS, one Sylvania, and one GE. I also have one GE GTA, one Sylvania GT and one Zenith GT. All these tubes are NOS and tested great. The obvious choice is to use the RCA GTB's because I have two. But if one of the others is inherently better it might make sense to buy one to match?
I found the attached review.
Kevin
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File Type: jpg 6SN7 comparison.jpg (271.9 KB, 331 views)
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Old 5th July 2011, 07:59 AM   #7
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Hi Carbon.
From memory optimum value would be around 240R.
You might get away with 220R if you made sure you used 6L6's with highest dissipation.
If you don't mind a small drop in power then 270R is a safe value.
Henry
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Old 5th July 2011, 08:29 AM   #8
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The 5881 with 20% higher dissipation than the 6L6, has in comparison been out of the race. On paper the 5881 should be better. Why hasn't it ?

richy
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Old 5th July 2011, 01:01 PM   #9
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The few Russian 'short' base 5881's I've used have been really good.
Of course I don't thrash them to within an inch of their lives like some do.
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Old 7th July 2011, 03:56 AM   #10
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And do not put a 6l6 in the socket labeled 7027 in an Altec amp. All well be lost.
The extra pin is hot.
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