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 Post subject: Plate Voltage TC-50
PostPosted: Mon Nov 05, 2018 8:58 pm 
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Bottle Rocket

Joined: Thu Mar 31, 2016 9:03 am
Posts: 9
Has anyone measured the plate voltage in EL34/6v6 and 6L6 bias modes. I am to lazy to pull the chassis and measure the voltages on the plates myself. With the plate voltages and a multimeter/bias probe with the use of my maximatcher I can figure a good range of natural current draw to try and source some good old NOS tubes that fall within that range. I really don't feel like pulling the chassis.


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 Post subject: Re: Plate Voltage TC-50
PostPosted: Tue Nov 13, 2018 9:36 pm 
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Bottle Rocket

Joined: Thu Mar 31, 2016 9:03 am
Posts: 9
Ok folks I've pulled the chassis and took some measurements. In EL34/6V6 bias mode I'm getting 419V on the plates using Mesa branded Winged C's and Mesa branded Siemens EL34's. Both pairs of EL34's have a natural current draw of 38ma using my maximatcher. In 6L6 bias mode I'm getting 429V on the plates using a pair of Winged C 6L6's that have a natural current draw of 20ma as measured using my Maximatcher. Using a pair of Russian 6V6's @ 32ma I'm getting 411V. With a pair of JJ 6V6's @ 28ma I'm getting 417V. I've also measured the bias of each set of power tubes using a bias probe in the TC-50. And I'll tell you that the 6L6's and EL34's are on the cold side. But the 6V6's are smoking in this amp. Almost as hot as the coldest EL84's in my DC-3.


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 Post subject: Re: Plate Voltage TC-50
PostPosted: Wed Nov 14, 2018 8:22 am 
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Mark III

Joined: Sun Feb 02, 2014 11:51 am
Posts: 183
So, those two sets are 6V6's are using 13.2 and 11.7 W (amps x volts)? From a quick google search, I found that 6V6s should be at around 9 W. Is that what you meant by they are running hot?

Your EL34s were 15.9 W and 6L6s were 8.6 W.

What class of amp is the TC-100 and TC-50?


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 Post subject: Re: Plate Voltage TC-50
PostPosted: Thu Nov 15, 2018 3:46 pm 
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Bottle Rocket

Joined: Thu Mar 31, 2016 9:03 am
Posts: 9
I mean hot as in running above 70% max dissipation. I have a pair of GE 6V6GT that draw 25ma on my maximatcher and they are also hot in this amp running around 80% max dissipation. I'm guessing off the top of my head that a pair of 6V6GT that have a natural current draw of 20ma would get you around 70% max dissipation. But I don't have any that cold to test.


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