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Old 26th Mar 2023, 8:06 pm   #1
Cruisin Marine
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Default Taylor 45B mu setting for an EL33?

The data sheet for the valve is s= 9mA/V, I assume that "s" is the same as mu?
Anyway, the 45B has two mu settings which give vastly differing results with this particular valve.
Do I use 3mA/V or 15 mA/V setting to get the correct reading?
I am guessing the latter.
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Old 27th Mar 2023, 1:40 pm   #2
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Default Re: Taylor 45B mu setting for an EL33?

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Originally Posted by Cruisin Marine View Post
The data sheet for the valve is s= 9mA/V, I assume that "s" is the same as mu?
Yes.

http://www.r-type.org/exhib/aad0112.htm

This matches the info given in the AVO Valve Data Manual.

I'm not familiar with the Taylor 45B, but I would expect mA/V to be something you measure rather than set?
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Old 27th Mar 2023, 2:25 pm   #3
ms660
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Default Re: Taylor 45B mu setting for an EL33?

According to the valve chart I'm looking at the expected mutual conductance for a full emission valve is 5.5ma/V @ Va = Vg2 = 100 Volts & Vg1 = 2 Volts -ve, so set to read the 15maV scale if that's the case:

http://bee.mif.pg.gda.pl/ciasteczkow...5b_46a_47a.pdf

Lawrence.

Last edited by ms660; 27th Mar 2023 at 2:31 pm. Reason: link added and addition
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Old 27th Mar 2023, 3:36 pm   #4
Lucien Nunes
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Default Re: Taylor 45B mu setting for an EL33?

To avoid possible confusion it's worth clarifying that mu (μ) is the amplification factor of a valve, whereas the tester measures mutual conductance (gm) which is a different parameter.

μ = gm x ra, i.e. amplification factor is the product of mutual conductance and anode resistance.

Quote:
I would expect mA/V to be something you measure rather than set?
I think the OP was referring to which setting of the test selector, as the Taylor offers two ranges of 3 & 15mA/V FSD.
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Old 27th Mar 2023, 3:58 pm   #5
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Default Re: Taylor 45B mu setting for an EL33?

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Originally Posted by Cruisin Marine View Post
The data sheet for the valve is s= 9mA/V, I assume that "s" is the same as mu?
S in the data sheet is mutual conductance (transconductance)

Lawrence.
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Old 27th Mar 2023, 4:26 pm   #6
Cruisin Marine
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Default Re: Taylor 45B mu setting for an EL33?

Quote:
Originally Posted by Lucien Nunes View Post
To avoid possible confusion it's worth clarifying that mu (μ) is the amplification factor of a valve, whereas the tester measures mutual conductance (gm) which is a different parameter.

μ = gm x ra, i.e. amplification factor is the product of mutual conductance and anode resistance.

Quote:
I would expect mA/V to be something you measure rather than set?
I think the OP was referring to which setting of the test selector, as the Taylor offers two ranges of 3 & 15mA/V FSD.
Thanks, I hadn't realised the difference tbh, but I do now
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Old 27th Mar 2023, 5:43 pm   #7
Cruisin Marine
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Default Re: Taylor 45B mu setting for an EL33?

I just re-measured the EL33 on the 15mA/V setting.
According to the valve chart booklet that comes with the Taylor Windsor 45B the mutual conductance reading should be 5.5, the measurement I get is just under at 5.2 ish, The thing that confused me is that 5.5 is in the "REPLACE" region of the meter scale
After reading the instruction manual (you know the book you read after trying everything else) it Implies that the GOOD or REPLACE area of the meter only refers to Rectifiers.

See uploaded image.
https://prnt.sc/D9V5xpPi73_1
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Old 27th Mar 2023, 8:56 pm   #8
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Default Re: Taylor 45B mu setting for an EL33?

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Originally Posted by Cruisin Marine View Post
the GOOD or REPLACE area of the meter only refers to Rectifiers.
Yes, that's right. It's for the rectifier test only.

Hugh
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