Quote:
Originally Posted by nauxolo /img/forum/go_quote.gif
1) Kind of a dumb question, but what happens if you have tubes of different types in each slot?
2) Also... would sound go through if you don't put any tubes in at all?
3) Lastly, why does the 408A family have to have the jumpers be switched... would harm come if I decide to swap the 6FJI in without switching the jumpers/ it's kind of annoying to have to undo the chassis and switch jumpers everytime...
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There are no dumb questions, just dumb answers...
1)
If you stay within one tube familiy...
(EF91 = 6AM6 = Z77 = 6F12 = 8D3 = N79 = CV138 = 6064 = M8083 = CV4014) or
(EF92 = 6CQ6 = W77 = 6F21 = 9D6 = CV131 = 6065 = M8161 = CV4015) or
(EF95 = 6AK5 = 6j1p = 6069 = 6F32V = 6F32 = 5654 = 6ZH1P = M8100= 403A [=408a {heads up, higher heater voltages}])
...then nothing harmful will happen. But you will hear the difference...
If you mix them and one tube is driven below its specs, you would hear nothing or sound at lower volume on this channel.
If you mix them and one tube is driven with too high heater voltage it will "burn".
EF92 has a different pin-out to the other two.
Mixing those may burn something somewhere.
I dont know whats the effects of the other tube values on the amp or the tubes itself when mixing them though. Anyone?
2)
No
3)
The 408a has higher filament (heater) voltage than its sister, the EF95.
408a: 20V, 50mA
EF95: 6.3V, 175mA
Swapping EF95 for 408a would not do harm.
But swapping 408a for EF95 would overheat the EF95s filament, leading to burn the tube.
If you need to lookup some tube values:
The National Valve Museum - Search Page
Antique Radios, Old Radios: 135 000, Radio Museum, Catalog