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6L6 to 6V6 conversion


Lensrock

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Nope... you can't use 6V6's in an amp designed for 6L6's - at least not with some extensive mods. Going the other way - 6L6 in a amp designed for 6V6's, is usually possible, but usually requires a re-biasing.

 

The only amps I'm aware of that can use both right out of the box without any mods is the THD stuff - and even then, you have to use the low voltage setting on the amp when you're running the 6V6. You don't have to rebias when you swap tubes in a THD, which is a nice feature. I've got a Univalve, and I really like it a lot - it's a killer little recording amp. The BiValve is also good if you need something with a bit more power.

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JJ 6V6's can be used in a 6L6 amp. EH's will work also. You shoudl have the amp re-biased a little colder, but other than that, plug in and play. The JJ and EH tubes are designed to run up to (or over) 475 volts. NOS 6V's are only relliable to about 425 volts.

 

If you look in old tube substitution books, they will show 6V6 as a replacement for 6L6 in most applications.

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The plate voltage in most 6L6GC amps is way too high to safely run 6V6's (depends on the amp).

 

On the flip-side, 6L6's draw twice the current that 6V6GT's do, so they need a bulkier power transformer. In many vintage 6V6 amps, you are putting your PT in harms way by using 6L6's in place of 6V6's. Besides, since output is often hampered by small output transformers in 6V6 amps, you usually gain on a little extra volume or headroom by switching to 6L6's anyway (plus, you create a impedance mismatch).

 

In general, it is best to only use both tubes in an amp that is specifically made for that (Allen, some Mesa, THD, Fargen, etc.). There are exceptions to the rule, but if you don't know how the amp will handle the other tube, don't use it.

 

-Y.

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I'm an expert on this swap.

 

I have built several clones of the Fender Tweed Super amp of 1956 which had 6L6s in it while all other years had 6V6s.

 

the 5F4 and the 5F3 circuits are Exactly the same right down to the last resistor.. EXCEPT the OP tranformers have different load impedances. even the choke is different.

 

so even if your building the 5F4 model ( with 6L6s) you Still can't use 6V6s without changeing the transformers. even though the voltages are the same.

 

all this means is that Even if the 6V6 will work in the circuit.. it will destroy itself rather quickly due to the increase in current draw that usually accompanies the 6L6 OP transformer with it's lower impedance..

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Originally posted by ProToneThinline

JJ 6V6's
can
be used in a 6L6 amp. EH's will work also. You shoudl have the amp re-biased a little colder, but other than that, plug in and play. The JJ and EH tubes are designed to run up to (or over) 475 volts. NOS 6V's are only relliable to about 425 volts.


If you look in old tube substitution books, they will show 6V6 as a replacement for 6L6 in most applications.

 

 

But you have to know the plate voltages, many modern 6L6GC amps run at plate voltages higher than 475VDC. 500-600VDC is common and Bogner pushes it a lot higher than that. Even some vintage amps like the Traynor YBA-1A exceed 600VDC.

 

-Y.

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Originally posted by ProToneThinline

JJ 6V6's
can
be used in a 6L6 amp. EH's will work also. You shoudl have the amp re-biased a little colder, but other than that, plug in and play. The JJ and EH tubes are designed to run up to (or over) 475 volts. NOS 6V's are only relliable to about 425 volts.

 

 

Interesting. This would seem to support what I've heard about current production 6V6s--that they're really relabeled 6L6s. Which one sounds more like an NOS 6V6 in your opinion?

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Originally posted by jonny guitar

To further this a bit:


can I use a 6K6 in place of a 6V6 in my SF Champ with only bias mods?

 

 

Interesting question. I'm not sure I have the answer, except to say I wouldn't. I've subbed 6V's for 6L's in my Blues Deluxe with no problems. However, I tried a pair of 6K's, and cooked both tubes as soon as I turned the amp on. I think there was just too much current for a 6K to handle. However, in an amp designed for 6V's you MAY be okay, but I'd be afraid.

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