Valve amp question

[Lawrence001]

Yes but that's both not one!

Sent from my POT-LX1 using Tapatalk

[bumpy]

It's counter intuitive, but sometimes the same valves can be employed in different parts of the circuit. My 211 amp has two E182cc valves that serve different functions in the circuit.

[anthonyTD]

Is it always the valve that's in the same position ?

I've bought a brand new integrated by Mistral. It has 4xEL34, 2xECC83 and 2xECC82. I noticed that when switching on one of the small valves glows very bright for a fraction of a second initially then goes back to normal. The other three are always normal. I thought this might be a function of the cheap Chinese valve but when I switched to NOS valves (all except the power valves) the new one does the same.

Does anyone know what the most likely cause is? If it was both of one type I would presume it's just part of the design but as it's only one of them (presumably in one channel) then it doesn't seem right. Should I be worried, at least about valve life if nothing more?

Thanks in advance for any advice.

Sent from my POT-LX1 using Tapatalk

[Lawrence001]

It's counter intuitive, but sometimes the same valves can be employed in different parts of the circuit. My 211 amp has two E182cc valves that serve different functions in the circuit.

Yes I thought that, they're double triodes so rather than each valve being left or right, one valve could do one task for both L/R and the other a different one. They could just be placed left and right to look symmetric. (Rather than suggest it myself I thought I'd see if anyone else would first.)

Sent from my POT-LX1 using Tapatalk

[Lawrence001]

Is it always the valve that's in the same position ?

Yes with a sample size of two pairs of valves, one pair stock Chinese and one pair NOS. I could try another pair.

Sent from my POT-LX1 using Tapatalk

[anthonyTD]

What i meant was; does the initial brightness always happen with every valve you put in that position ?
A...

Yes with a sample size of two pairs of valves, one pair stock Chinese and one pair NOS. I could try another pair.

Sent from my POT-LX1 using Tapatalk

[Lawrence001]

What i meant was; does the initial brightness always happen with every valve you put in that position ?
A...

I meant yes, with the 2 valves I have tried so far.

Sent from my POT-LX1 using Tapatalk

[anthonyTD]

Ok,
If this only happens in that one position with any valve you put in there, then it is not the usual heater filament diffrences you get in diffrent types of valves that's causing the valve to come on bright, its posibly a heater circuit issue, especialy if this amp has DC heaters on the first valve, which many amps do!
I am not saying for certain that your amp does indeed have an issue, but i just find it odd that it only seems to do this in one position. A look at the schematic for this amp would be a useful start.
A...

I meant yes, with the 2 valves I have tried so far.

Sent from my POT-LX1 using Tapatalk

[Lawrence001]

Ok,
If this only happens in that one position with any valve you put in there, then it is not the usual heater filament diffrences you get in diffrent types of valves that's causing the valve to come on bright, its posibly a heater circuit issue, especialy if this amp has DC heaters on the first valve, which many amps do!
I am not saying for certain that your amp does indeed have an issue, but i just find it odd that it only seems to do this in one position. A look at the schematic for this amp would be a useful start.
A...

Thanks I'll see if I can find out more about the amp.

Sent from my POT-LX1 using Tapatalk

[da2222]

For several valve types it's not a quirk or an anomaly but a characteristic of certain tube/ brand types- completely within the norm. In your case it depends: when you swap the tube to the other position does it glow there too?