Aroma ARC-1000A Manuel d'utilisateur télécharger pdf (Page 118)

tubes age 118

Subject: [R-390] Done to death, delete at will: 6DC6 surrogates

I picked the word "surrogate" with care. These are not substitutes. They are

enough to keep you on the air while you look for a 6DC6.

For reference: 6DC6 (5500, 12.5V=3D50umho)

RC-29 is inconsistent about cutoff ratings, some are at various currents, others

at various transconductances. A couple of these are from memory. Others

don't have any cutoff data. Except for the 6AS6, I didn't check max ratings.

Remember, it's temporary and who cares if you burn it up. A lot of these are TV

tubes, so if you have a box of pulls, odds are you have a few. Some of these

didn't exist in 1952; I bet they'd have picked the 6GM6 or 6DE6 for example. Out

of the list below, I tried a very weak 6BZ6, a 6EW6, and a 6HZ6. All worked, but

of course not as well as the real thing. I didn't check sensitivity, IP3, cross-

modulation, or what-have-you. Don't expect the same carrier readings in any

case, because the AGC is different. I worried about oscillation with the 6EW6,

but I didn't see any.

7CM pinout (same as 6DC6):

6AS6 (way over max ratings)

6BH6 (low gm, too sharp)

6BJ6 (low gm, too remote)

6BZ6 (8000, 19V=3D50umho. Runner-up to 6DC6 in Cost Reduction Report.)

6CB6 (8000, 6.5V=3D20uA)

6CF6 same as 6CB6

6DE6 (8000, 9V=3D20uA)

6DK6 (9800, 6.5V=3D20uA. Used in large numbers in Tek 500-series

scopes.)

8136 same as 6DK6

6EW6 (14000, 3.5V=3D20uA)

6GM6 (13000, 15V=3D60umho)

6JH6 (8000, 19V=3D50umho)

6JK6 (15000)

7EN pinout (same except internal shield connected to cathode instead of G3):

6DT6

6GX6

6GY6

6HZ6

These tubes are designed so G3 can be used as a second control grid. All

have lower gm than the 6DC6. I didn't write down their cutoffs. I think they're all

sharp.Some RF decks have pins 2 and 7 wired together. These decks can

also use a slew of tubes with the 7BK pinout, which includes 6AH6, 6AG5,

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Aroma ARC-1000A Manuel d'utilisateur Page 118