Vintage EL 84's in Dual Terror ?

[Mezzamort]

I have heard that Vintage EL 84 s don't have enough Voltage for the newer Orange Amps ? I have vintage 84,s RCA in my DT and it sounds Great ! Just wondering if that hurts the amp ?

[bclaire]

It shouldn't....

[Les Paul Lover]

Some amps (actually a lot of amps running EL84) run them quite hot.

So whilst your not hurting your amp running it with RCA's, you may not enjoy the longest life for these valves.

To be honest, I don't know if the DT runs them hot or not. Vox AC30 and Orange AD30 are well known for running their EL84 pretty hard, and vintage EL84 aren't recommended there simply because the amp is going to get through them like modern EL84.

That said..... if you have vintage EL84 in hand, it isn't to store them in a drawer and look at them occasionally.....

[a.hun]

"Don't have enough voltage?" Well, the amp supplies the voltage to the valves, so I've no idea what that means... LOL

Some amps (actually a lot of amps running EL84) run them quite hot.

So whilst your not hurting your amp running it with RCA's, you may not enjoy the longest life for these valves.

Am with LP Lover on that. Yeah the DT is a hot running cathode bias amp. Older valves like those were much higher quality than any modern production valves. Very often though the bias current they'll draw (basically the idling current, think car engine at tickover) will be fairly different from most modern valves. If they draw too much current they will a/ run hotter than needed or wanted and b/ burn out sooner than they should. Because they are so well made they would probably take it for a long time, but running the right sort of current (for the amp!) should actually mean that you'd still get several times the life expectancy of any modern EL84s. Running too hot you won't, and the sound and power output would probably also be affected.

While not normally needed for 'cathode biased' amps like yours with modern valves, I'd actually suggest having a good valve amp tech do a bias check to see how those ones are running in the amp. It is a quick job and would only involve a cheap resistor value change to re-bias if needed. Probably come in at a fraction of the value of those old valves!

FWIW I don't actually believe in running old production valves in that sort of hot running cathode biased amp myself, (explained why in a very long post on biasing etc some time back.) But again, well yeah there is no law against it!


Andy.