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Old 5th November 2012, 03:27 PM   #4451
torrence is offline torrence  United States
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Originally Posted by aroS3 View Post
Take a ready made snapshot, Just use a 5 way selector ....Hope it's quiet clear now ...
Regards,
George
Is this really an ammeter, or a 100 mV voltmeter with the scale changed to read mA?

Most inexpensive moving coil 100 mA ammeters have an internal resistance of order 1 ohm, so putting this in parallel with a 1 ohm resistor will give you a current reading which is around half of the actual cathode current. This still works fine for checking balance, but it won't give an accurate current measurement.

Perhaps you found a very low internal resistance ammeter?
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Old 5th November 2012, 03:53 PM   #4452
aroS3 is offline aroS3  Greece
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Quote:
Originally Posted by torrence View Post
Is this really an ammeter, or a 100 mV voltmeter with the scale changed to read mA?

Most inexpensive moving coil 100 mA ammeters have an internal resistance of order 1 ohm, so putting this in parallel with a 1 ohm resistor will give you a current reading which is around half of the actual cathode current. This still works fine for checking balance, but it won't give an accurate current measurement.

Perhaps you found a very low internal resistance ammeter?
In my case is really an mAmeter. It's definitely in series, between cathode and ground. Measurements checked also with fluke meter, seem right, so it's the one for the job...
Regards,
George
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Old 5th November 2012, 05:15 PM   #4453
ovpopov65 is offline ovpopov65  Russian Federation
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I agree with Torrance post #4451.
Hm... I will need to check...
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Old 5th November 2012, 08:45 PM   #4454
regiregi22 is offline regiregi22  Europe
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Quote:
Originally Posted by aroS3 View Post
Take a ready made snapshot, Just use a 5 way selector ....Hope it's quiet clear now ...
Regards,
George
Now I get it, thank you!!

Best regards
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Old 6th November 2012, 08:21 AM   #4455
torrence is offline torrence  United States
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Quote:
Originally Posted by aroS3 View Post
In my case is really an mAmeter. It's definitely in series, between cathode and ground. Measurements checked also with fluke meter, seem right, so it's the one for the job...
Regards,
George
As drawn, the ammeter is in parallel with the 1 ohm resistor between cathode and ground. If you place an external ammeter at the same spot (in parallel) you could likely get the same result. The real test would be to measure the voltage across the 1 ohm resistor with the ammeter disconnected (switch in center position).

I am glad you are happy with this, I just don't want others thinking this solution is guaranteed to work.
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Old 8th November 2012, 09:08 AM   #4456
dolphin123 is offline dolphin123  Poland
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Looks superbly!
Chassis made ​​yourself?
Yes. All is my projects...
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Old 8th November 2012, 12:40 PM   #4457
male42 is offline male42  Russian Federation
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SE Amp. 2*mono .Tube 6C15P, 300B .no caps, no coil,
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Old 8th November 2012, 01:33 PM   #4458
Osvaldo de Banfield is offline Osvaldo de Banfield  Argentina
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The last photo make me remember "His masterīs voice" drawing in RCA disks.
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Old 8th November 2012, 01:41 PM   #4459
felixx is offline felixx  Romania
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Looks good.
What speakers do you have for those?
The tiger looks even better.Take care of him.
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Old 8th November 2012, 01:44 PM   #4460
male42 is offline male42  Russian Federation
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JBL LXE990
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