6L6 Tubes in a Fender Deluxe Reverb

[crunchee]

I've heard of people using 6L6 power tubes in their Deluxe Reverbs, instead of the spec'd for 6V6, for a bit more clean headroom. Normally, you shouldn't use 6L6 in a amp that calls for 6V6 (they go Boom), but the transformers in the DR usually can handle the extra current draw, so it's said. Anybody here do this, and how was the results? How did it sound, and were any mods needed to the amp other than rebiasing? TIA!

[crunchee]

I have two Smith Custom CS25 amplifiers (boutique Deluxe Reverb type 6V6) one of which I decided to convert into a 6L6. They have cathode/fixed bias switches and while the transformers are hardy enough to handle the 6L6s, I did have to change the resistor coming off the cathode switch (chg'd to a 450k). I suspect you may need to do something similar. Wish I could give you more definitive instructions but my knowledge is limited, the amp builder did the mod for me.

Cool amp! What is the difference in sound/tone/output between the two amps and the different power tube setup, with all else being the same? Which is best/worst, and/or what are the advantages/disadvantages to the power tube selection, besides it being essentally a modification?

[Thundernotes]

Off the top of my head, I'd say since the output transformer of a DR was already slightly undersized as configured, I would think running 6L6's would be dangerous. They were also running 420 volts on the plates of a tube (6V6) that was designed for 300, but there are ways around that...

I think with bias changes, you might get away with it so long as you're careful.

[crunchee]

Off the top of my head, I'd say since the output transformer of a DR was already slightly undersized as configured, I would think running 6L6's would be dangerous. They were also running 420 volts on the plates of a tube (6V6) that was designed for 300, but there are ways around that...

I think with bias changes, you might get away with it so long as you're careful.

The 420 volts on the plates is actually one of the reasons why I was thinking about putting in 6L6, because that's a lotta voltage on a 6V6. Seems like I remember reports that, when tubes from Russia and China were first coming out, that some of their 6V6 tubes couldn't handle that voltage, and that the early Sovtek 6V6 was actually a small bottle 6L6. I dunno if that's still the case, as I have a stash of NOS US made tubes, and never needed Russian or Chinese power tubes. Anybody know?

Still looking for a tone/performance report on the DR/6L6 setup.

[Wizard333]

There are a few problems.

The OT for a stock DR converts 8ohms on the secondary to 6.5k at the primary, slightly high for a 6L6 but not completely out of the ballpark. Also low-ish for a 6V6.

The big problem is the pt cannot handle the extra heater current of the 6L6 without heating up quite a bit. Will it blow immediately? No, but the extra heat (think, fry an egg on it) will reduce its life significantly, not something I'd recommend on a vintage PT.

If you really want to do it, remove the vintage iron and put in modern iron. This saves your vintage transformers and protects the amp's value.

As far as tubes, 420v is low. My '73 DR runes 475 on the plates, and most I see are between 450 and 480. I wouldn't even think of using anything but a JJ 6v6 in there. They are a very robust tube and handle that Vp quite well.

[crunchee]

There are a few problems.

The OT for a stock DR converts 8ohms on the secondary to 6.5k at the primary, slightly high for a 6L6 but not completely out of the ballpark. Also low-ish for a 6V6.

The big problem is the pt cannot handle the extra heater current of the 6L6 without heating up quite a bit. Will it blow immediately? No, but the extra heat (think, fry an egg on it) will reduce its life significantly, not something I'd recommend on a vintage PT.

If you really want to do it, remove the vintage iron and put in modern iron. This saves your vintage transformers and protects the amp's value.

As far as tubes, 420v is low. My '73 DR runes 475 on the plates, and most I see are between 450 and 480. I wouldn't even think of using anything but a JJ 6v6 in there. They are a very robust tube and handle that Vp quite well.

Day-UM! Is there a classic Fender amp that is EASY on power tubes? I like the sound of my old, unmodified, Blackface Bassman heads, they supposedly only have 425 V on the power tubes in the schematic. What voltages have you run into with those?

[ArnieZ]

I am not an expert, or even a novice but I think there might be an impedence issue. I do have an amp that can run 6l6's and 6v6's. The amp was designed around 6l6's but when i run the 6v's I have to cut the impedence in half!

ArnieZ

[kenjones]

I have a 76 Deluxe Reverb. It has 6V6s and runs really hot. If I lean it against a wall while I play I almost have to use gloves to flip the power or standby switch! I have never measured the voltage.

A former bandmate had a 60s BFDR that was modified for 6L6s. The mod was done before he owned it and he didn't know what all mods had been done. I never looked at his amp very closely but his amp was quite a bit louder than mine. It sounded really good. He played a G&L tele and that combination of guitar/amp/pickups sounded great.

[Brewmaster]

Changing out 6v6's for 6l6's in a Deluxe Reverb is more common than you think. With the oversized output tranny usually all that is required is to rebias the amp. Sometimes the bias resistor on the bias pot needs to be changed as well.

Basically what you are doing is changing your Deluxe Reverb into a 1x12 version of a Vibroverb. In BF amps it's the same AA763 and AB763 circuit just 6v6's vs 6l6's and 1x12 vs 1x15. The Vibrolux circuit was slightly different and had 6l6's and 2x10 speaker configuration.