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Components and Circuits For discussions about component types, alternatives and availability, circuit configurations and modifications etc. Discussions here should be of a general nature and not about specific sets.

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Old 3rd Sep 2017, 2:23 am   #41
Radio Wrangler
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Default Re: Can anyone identify these valves?

Some electrical measurements are unavoidable to discriminate between the 12.6v and 6.3v heated versions of almost all the candidates.

Aspect ratio wise it looks taller than the common 6SJ7, 6SG7 so I wondered about 6V6 and 6L6, but I'm not sure about missing pins and whether all makers missed them.

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Old 3rd Sep 2017, 8:28 am   #42
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Default Re: Can anyone identify these valves?

Number 8, 6N7 or 6AG7?

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Old 3rd Sep 2017, 8:57 am   #43
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Default Re: Can anyone identify these valves?

6L6, like 5T4, is h-u-g-e, so quickly ruled out, 5Z4 (another prolific quiet-place breeder....) too few pins, though envelope size about right. I'd forgotten about 6AG7! 12A6 I think also a size possibility, but likely a missing pin- the makers weren't going to miss the opportunity of saving a fraction of a cent per base if they could with IO's rolled and crimped pins it seems.
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Old 11th Sep 2017, 10:05 pm   #44
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Default Re: Can anyone identify these valves?

Number 7 tests OK as an EBL21.

I'm wondering about measuring inter-electrode capacitance to identify the pinout of number 8?
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Old 12th Sep 2017, 1:12 am   #45
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Default Re: Can anyone identify these valves?

What is the text on the bottom of number 8?
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Old 12th Sep 2017, 8:07 am   #46
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Default Re: Can anyone identify these valves?

It says "LICENSED ONLY TO EXTENT INDICATED ON CARTON".
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Old 12th Sep 2017, 10:03 am   #47
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Default Re: Can anyone identify these valves?

Quote:
Originally Posted by Station X View Post
I'm wondering about measuring inter-electrode capacitance to identify the pinout of number 8?
It's possible I would have thought, what about a hum test, heaters powered up then probe other pins to the input of a valve amp?

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Old 12th Sep 2017, 8:19 pm   #48
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Default Re: Can anyone identify these valves?

Heater resistance cold is 1.5R.

The highest capacitance to the heater pins, by far, is to pin 1, so I'll assume that's the cathode.
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Old 12th Sep 2017, 8:33 pm   #49
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Default Re: Can anyone identify these valves?

Pin 1 is usually the metal.

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Old 12th Sep 2017, 9:08 pm   #50
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Default Re: Can anyone identify these valves?

Indeed it is .

With three pins identified there's only five to go.
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Old 12th Sep 2017, 9:12 pm   #51
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Default Re: Can anyone identify these valves?

I like it.

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