First time biasing an amp - is this procedure correct?
- Thread starter Archer250
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Myaccount876
Amira-Maker
Re: First time biasing an amp - is this procedure correct?
That blue resistor looks like the 1 ohm resistor on pin 8, am I correct? If so, then the pin next to it with the red wires seems to be pin 7 (the heating pin). Did the wires start to burn/melt when bossing, or did you find it like that? If you found it like that, change the heating wires to 18 gauge 105*C. Those wires would obviously benefit from good insulation from heat, although that wouldn't explain the burnt insulation on pins 6 and 3. They could be burns from a shaky soldering iron in a cramped space. I'm guessing this is what you're referring to as a fire hazard.
That blue resistor looks like the 1 ohm resistor on pin 8, am I correct? If so, then the pin next to it with the red wires seems to be pin 7 (the heating pin). Did the wires start to burn/melt when bossing, or did you find it like that? If you found it like that, change the heating wires to 18 gauge 105*C. Those wires would obviously benefit from good insulation from heat, although that wouldn't explain the burnt insulation on pins 6 and 3. They could be burns from a shaky soldering iron in a cramped space. I'm guessing this is what you're referring to as a fire hazard.
Last edited:
Archer250
Well-known member
Re: First time biasing an amp - is this procedure correct?
Blue is connected to 1 and 8
I was measuring the plate voltage from pin 3 with a pair of alligator clips. It slipped and made contact with pin 2. And I don't think I've seen a brighter flash in my life before.
Blue is connected to 1 and 8
I was measuring the plate voltage from pin 3 with a pair of alligator clips. It slipped and made contact with pin 2. And I don't think I've seen a brighter flash in my life before.
Re: First time biasing an amp - is this procedure correct?
I was going to guess slipped test lead probe before seeing your post. That's why I use two meters and those hook clips ... so I don't have to move leads to switch checking between tubes and risk shorting the probe to something. Actually, if I'm not being lazy, I'll use my 3rd meter just to check plate voltage but I usually wont keep that one hooked up so the risk is still there if one slips. If nothing else, you learned why it's a good idea to not stick your hands in there :bigok: Free hand in back pocket. If the worst thing you did was smoke the insulation on a couple of wires, you're ok.
'
I was going to guess slipped test lead probe before seeing your post. That's why I use two meters and those hook clips ... so I don't have to move leads to switch checking between tubes and risk shorting the probe to something. Actually, if I'm not being lazy, I'll use my 3rd meter just to check plate voltage but I usually wont keep that one hooked up so the risk is still there if one slips. If nothing else, you learned why it's a good idea to not stick your hands in there :bigok: Free hand in back pocket. If the worst thing you did was smoke the insulation on a couple of wires, you're ok.
'
Archer250
Well-known member
Re: First time biasing an amp - is this procedure correct?
Yeah, I tested it for 30 mins to make sure everything's working fine. It does. Plate voltage is 436 after 30-45 mins, I biased the tubes to 38-39mA. Everything's working quite well. Sounds great, too.
Yeah, I tested it for 30 mins to make sure everything's working fine. It does. Plate voltage is 436 after 30-45 mins, I biased the tubes to 38-39mA. Everything's working quite well. Sounds great, too.
Archer250
Well-known member
Re: First time biasing an amp - is this procedure correct?
Only had the JJs in prior to the Tung-Sols. I'd say that the Tung-Sols respond slightly better to dynamics and sound slightly clearer. The JJs sounded slightly darker and felt slightly more compressed.
Only had the JJs in prior to the Tung-Sols. I'd say that the Tung-Sols respond slightly better to dynamics and sound slightly clearer. The JJs sounded slightly darker and felt slightly more compressed.
moshpit817
Member
Re: First time biasing an amp - is this procedure correct?
I had a pair of 6l6-GC's that were 8mv apart..I got some Apex matched ones from an Ebay seller I have used for 2 years now and the difference is usually 1.5-2 mv..super impressed with them..best deal is to find a seller you like and stay with them,but it is ok to experiment.
I had a pair of 6l6-GC's that were 8mv apart..I got some Apex matched ones from an Ebay seller I have used for 2 years now and the difference is usually 1.5-2 mv..super impressed with them..best deal is to find a seller you like and stay with them,but it is ok to experiment.
