Chinese Bias Volt Meters

Chinese Volt Meters for Bias adjustment....Today I received my 0-1V analog meters for installation in a custom base for the VTA St-120. I connected them to see accuracy. In a word, fantastic. Great hysteresis and dampening. I bought both 0-1V and 0-3V version. Certainly the 0-1 has better accuracy and easier to see movement. I compared the reading to my VOM. Perfect!....$8.50 Shipped! How can they do this. I sourced Simpson meters made in USA...$113 each!!!

https://www.ebay.com/itm/DC-0-1V-Round-Analog-Voltmeter-Analogue-Voltage-panel-meter-Dia-66-4mm-DH52/174353096301?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649

Rbertalotto wrote:Chinese Volt Meters for Bias adjustment....Today I received my 0-1V analog meters for installation in a custom base for the VTA St-120. I connected them to see accuracy. In a word, fantastic. Great hysteresis and dampening. I bought both 0-1V and 0-3V version. Certainly the 0-1 has better accuracy and easier to see movement. I compared the reading to my VOM. Perfect!....$8.50 Shipped! How can they do this. I sourced Simpson meters made in USA...$113 each!!!

https://www.ebay.com/itm/DC-0-1V-Round-Analog-Voltmeter-Analogue-Voltage-panel-meter-Dia-66-4mm-DH52/174353096301?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649

I just now got these gold plated 8 pin octal tube base socket plugs today and as I was hoping they are bakelite.

The inside diameter is 1-1/8".

Sadly I doubt very seriously that I'm gonna be able to find small enough analog meters to fit inside these octal plugs so I may have to go digital even if I don't want to.

Tom, where did you get those sockets. I’d rather not remove the sockets in my amp. I could use these to make my meters “plug and play”

Rbertalotto wrote:Tom, where did you get those sockets. I’d rather not remove the sockets in my amp. I could use these to make my meters “plug and play”

Also Rbertalotto..... If you don't aready know ? Put an inline fuse to one side of both meters so if one of your tubes goes bad it will not be able to send a high voltage surge and burn out your meters.


Here is the link to the octal socket plugs. https://www.tubedepot.com/products/8-pin-octal-tube-base-only-deep

Thank you. I'll do the fuse thing. Great advise.

Can I use one fuse on both grounds or does it need to go on the + side of the meter?

Rbertalotto wrote:Thank you. I'll do the fuse thing. Great advise.

Can I use one fuse on both grounds or does it need to go on the + side of the meter?

It needs to be on the + side of the meter as with all fuses. This is standard recommended practice is to place the fuse near the positive terminal of a battery or in a DC circuit, so the whole circuit will be dead if the fuse blows.

But doesn't DC current flow from negative to positive...I thought all DC current flowed this way?

"Current direction
Electrons flow from negative to positive. In a direct current (DC) circuit, current flows in one direction only, and one pole is always negative and the other pole is always positive. In an alternating current (AC) circuit the two poles alternate between negative and positive and the direction of the current (electron flow) reverses periodically."

Rbertalotto wrote:But doesn't DC current flow from negative to positive...I thought all DC current flowed this way?

"Current direction
Electrons flow from negative to positive. In a direct current (DC) circuit, current flows in one direction only, and one pole is always negative and the other pole is always positive. In an alternating current (AC) circuit the two poles alternate between negative and positive and the direction of the current (electron flow) reverses periodically."

Yes.... that is true but if the meters metal casing is grounded to the negative lead inside of the meter and to the ground of the amp cassis then the fuse becomes useless.

When I used to have my own electronics repair shop back in the early 80's it was common to find when output tubes go bad and they are not fused properly they will start taking out other components including amperage and volt meters. I have also seen a few Dynaco ST 70's taking out other components when not fused properly when someone did not put back the proper rated fuse back in the fuse socket.

"but if the meters metal casing is grounded to the negative lead "

Ah, understood! Thank You

Rbertalotto wrote:

"but if the meters metal casing is grounded to the negative lead "

Ah, understood! Thank You

I was looking at your V meters again and they look nice.... Question... is the outer casing metal or plastic ?

Plastic case

Rbertalotto wrote:Plastic case

Still a nice meter Rbertalotto.... Let me know how those work out...