Converting a Deluxe Reverb to 6L6?

Marc Jenkins · From: Victoria, British Columbia, Canada

Anyone have any experience with putting 6L6's in a SF Deluxe? Are any mods necessary to make it happen beyond re-biasing?

Also, I've heard different theories regarding the wattage once converting. Some say 30, some say 35. Any truths?

And! Anyone played through a converted Deluxe with a steel? How would it compare to a Pro Reverb?

b0b · From: Cloverdale, CA, USA

I think you'd have to upgrade both transformers to switch from 6V6 to 6L6. The 6L6 draws more power and outputs a much bigger signal.

I'm pretty sure that the tube sockets are different, too.
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Jon Light · From: Saugerties, NY

I have done the following to a SFDR:

6L6 tubes
Weber copper cap
Weber Cali ceramic speaker

It sounds outstanding with pedal steel. It can only deliver acceptable sound in a quieter small room (coffee house singer/songwriter type gig.) If you need to drive it hard, I am not crazy about the type of distortion this circuitry delivers on chords and lower strings. But within limits, the bit of hair, overall, sounds great and musical.

I did the conversion a few years ago and the only actually techie thing was biasing the tubes (I vaguely recall needing very little adjustment but that would be just a coincidence, I think. Biasing should be considered an essential step.)

I haven't a clue as to actual wattage numbers. And the only Pro Reverb I've ever played was in a studio and it sounded awful (maintanence/biasing issues) so I can't comment except that my DR eats that Pro and spits it out. The Pro has bigger transformers and would have better headroom and volume--the two speakers helps that too. I don't know the weight specs but the DR is a lot lighter than the Pro---it's a pleasure to haul. Unfortunately I rarely play gigs that it can handle.

Dave Mudgett · From: Central Pennsylvania and Gallatin, Tennessee

Yup - I generally don't do it, but it can be done. I think 6L6 filaments take a bit more current. But I've seen lots of guys just put in the 6L6 tubes in there, rebias, and perhaps put in a heavier duty speaker. This does raise the apparent clean volume of the amp somewhat. But the caveat is that it's possible to have problems with the power transformer. The same goes for the output transformer. Deluxe Reverb output transformers are not real overdesigned, and pushing them hard with extra clean power for a long time can burn them out. Of course, I've also seen them burn out with 6V6 tubes in there.

My experience is that just swapping power tubes doesn't so much raise the power a lot, but raises the clean headroom on the power that's there. So it does change the clean power rating some. But to really raise the power a lot would require modifying the circuit with higher plate voltages and other circuit changes to really extract, let's say, a Pro Reverb level of power. I've seen that done - it significantly changed the sonic character of the amp to my ears, but did give a pretty powerful and good-sounding amp in a small package. But this is a major overhaul.

There are a couple of simple changes on a SF Deluxe Reverb that can be useful. One is to put a switching pot on the tremelo intensity, and set it up to switch the tremelo out of the circuit when the switch engages at "0". The tremelo circuit does weaken the preamp signal a bit, and you can hear an audible difference when it's pulled out of the circuit. Of course, one can also put reverb on both channels and revoice the "normal" channel to get two distinct and very usable channels. I've had amps with these changes, leaving the 6V6 tubes in there, adding an EV SRO speaker. It sounds wonderful for PSG with a 5751 front-end preamp tube, to deal with typically hotter PSG pickups. But still, although it's loud enough for a lower-volume electric or semi-acoustic gig, it doesn't cut it on a loud electric band PSG gig, for me anyway.

From a vintage value point of view, I wouldn't do anything irreversible on a real nice SF Deluxe Reverb, at least one of the late-60s versions. The best sounding DR I ever heard was a '68 SF with the drip-panel around the speaker grill. They are actually pretty valuable right now. I'd probably only mess around significantly with one of the later 70s versions with the pull distortion switch. I'm sorta on the lookout for a beater to upgrade to a Vibroverb or Pro Reverb circuit with bigger transformers and 6L6's.

I'll admit that the DR is without much question my favorite 6-string guitar amp ever.

Marc Jenkins · From: Victoria, British Columbia, Canada

Thanks guys.

It sounds like I might not get what I need out of a Deluxe without really going all out. I play through a modified Blues Jr, and it's not enough for the steel. I borrowed a Hot Rod Deluxe for a gig last weekend, and it's 40 watts was definitely loud enough for the LOUD band I played with. I can't imagine needing any more juice, which in a hand-wired vintage amp, lines me up with a Pro Reverb power-wise. I just don't really want that big of an amp in my one-bedroom apartment! Might have to go with a Bandmaster Reverb head into a small cab...

Dave, there's a late 70's deluxe on the forum. I contacted the seller yesterday, and it is still for sale.

Dave Mudgett · From: Central Pennsylvania and Gallatin, Tennessee

Thanks Marc - I saw that one. I've really been looking for a real beater, ideally with a transformer or two fried, and priced to match. I want to gut it and go with something with double the power in the small DR box. I still have hope that I might be able to get something like real DR tone and size at a PSG-practical volume. I really hate to do that to one that's in good shape. But that is a good deal for a nice-looking DR. Maybe....

Marc Jenkins · From: Victoria, British Columbia, Canada

Dave,
That's pretty much exactly what I imagine to be the perfect amp: Deluxe tone, size and weight, with about double the power.

I keep thinking the 40 watt Blackbird at the bottom of this page is a good idea, although more expensive. But at least I know I could buy one and it would work right away. If ONLY it had tremolo and 2 channels!

Or if I was an electronics genius, I'd order one of these!

Brian LeBlanc · From: Falls Church, Virginia, USA

"Re-Voice" Normal Channel??

...Can you describe /detail this a little more

I use a 72 Deluxe ...lots of small places!
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Dave Mudgett · From: Central Pennsylvania and Gallatin, Tennessee

There are quite a number of ways to revoice an amp.

One of the simplest is to use different kinds of preamp tubes. Like I said earlier, I use a 5751 - which has lower gain than the 12AX7 - in the Vibrato channel. In contrast, I use the hottest, most midrangey 12AX7 I can find in the Normal channel.

Another way is to change the tone stack in one channel. I usually set up my normal channel with more midrange, so it honks a little more with, let's say, a Les Paul.

There are also lots of tricks that involve messing around with various other resistors and capacitors to try to get a bit more Marshally sound. This website, devoted to harp amps, has some suggested approaches: http://www.harpamps.com/micKfender/Fender-Normal-Channel.html I find harp amp ideas useful, since amplified blues harp tends to sound better with a much warmer and midrangey sound, at least to my tastes. Those little lap steel amps with the warm sound tend to sound great with harp.

There are lots of websites around that discuss this, and plenty of amp gurus around who can do this kind of thing. It's definitely not for the amateur. I absolutely do not recommend going into a tube amp with 400-500 VDC floating around if you don't really know what you're doing. To me, a certain amount of experimentation is needed to really get good results with this, but you can fry both yourself and the amp. A little knowledge can be a dangerous thing.

I'm not sure I'd do too much to nice '72 DR. The earlier, let's say pre-74 versions, are very much coveted and they are worth more if they're not messed with. I'd stick with simple, easily reversible mods.

Jon Light · From: Saugerties, NY

My DR started its current incarnation as a hacked chassis in a new cab---this is how I bought it. Therefor I wasn't too concerned about doing anything that might devalue it. It is a player. I put reverb in ch 2. Ch 1 had been messed with and the tone stack is just about non-functional. I tried to restore it and gave up---I'm just not that good at following schematics. Not really a worry--I only need one channel. I forgot to mention that I also added a mid control, mounted in the ext. speaker jack hole. Funny thing is, I think that after playing with it, it ends up getting set in what would have been the standard fixed resistor position, had I not put the pot in. I guess someone knew what they were doing when they designed the circuit.
A lot has been written about DRs on this and the old forum. It has been said, and I agree, that the biggest bang-for-the-buck upgrade re: clean volume (headroom) is in the speaker. An efficient, loud speaker would be the #1 'steel mod' for a DR.

Jay Ganz · From: Out Behind The Barn

I put Tung-Sol 5881's in my old '65.
They don't draw any extra filament current, and 6L6's don't either.
I just had to re-bias them. I also have a solid state rectifier plugged into the GZ34 socket as well.
The speaker is an original Jensen C12N. All these mods can easily be reversed at any time.
All this does is add more headroom, but not much wattage.
Another way to avoid overdriving the preamp stages is to
lift one end of the cathode bypass caps on one (or more) of the 12AX7's.
That will reduce the gain of the preamp, so you'd have to turn up the volume a bit more....
but it will stay cleaner at that higher volume.

Jim Peters · From: St. Louis, Missouri, USA, R.I.P.

I don't understand why everyone wants to do these mods on a Deluxe. There are much better choices to start with, like bandmasters, bassmans, and especially pro reverbs. A twin is there already.
It's like hotrodding a 65 VW to tow a boat. It can be done, but it'll never be as good for towing as almost any pickup truck!
I use my Deluxe with 2 channel mod with guitar for my low to medium volume gigs, the amp screams and is perfect. It is awful for steel except at the lowest volumes. Doing the mods as described by others will only make it marginally acceptable as a steel amp. Just my opinion of course. JP
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David Doggett · Posted 31 Aug 2007 9:28 pm

If you want 40 watts of Fender tube tone in a smaller package than a Pro, why not take a Vibrolux chassis and put it in a new custom cab with a single 12" or 15" 4 ohm speaker? I've plugged a Vibrolux speaker cable into a 15" 4 ohm speaker, and it sounded just like a Twin with the volume on about 5.

Dave Mudgett · From: Central Pennsylvania and Gallatin, Tennessee

One of the biggest advocates of just plugging in 6L6 tubes in a Fender is Lord Valve. But even he acknowledges that filament currents aren't the same for 6L6 and 6V6 - for example, here's an excerpt: http://www.harpamps.com/micKfender/6L6-in-Champ-Again.html

I agree with him that it isn't that big an increase and probably not a big deal in a Fender. But I don't think it's accurate to say that there is zero additional filament current load. The reason it's generally OK is that Fender transformers are typically somewhat overdesigned. But filament current increases can be an issue in other amps where the transformers are not as robust.

I think it's fine to use a Bandmaster, Bassman, and Pro Reverb as a platform. But I prefer the size of the DR, and I think it's entirely reasonable to take an already hogged-out DR and hot rod it. I have heard rodded DRs with 6L6's with double or more the power by replacing transformers and making circuit changes, plus a heavy-duty speaker, that were just unbelievable.

Honestly - by most PSG players standards - a Pro Reverb or comparable amp is underpowered. But for someone for whom that is fine, I think a rodded DR should do the trick. And I would much rather haul around a rodded DR than a Pro Reverb. To me, I might as well drag around a Twin Reverb as a Pro Reverb as far as weight and size are concerned.

Marc Jenkins · From: Victoria, British Columbia, Canada

I'm seriously considering having a Weber kit built for me. I got a couple quotes, and they are VERY reasonable. Then I can get a 40 watt Fender-ish amp with a single 12. Bang on!

Henry Nagle · From: Santa Rosa, California

I used to use two Deluxe Reverbs. That was a good sound! Just turn one up till it sounds right, then add the other till you have enough volume. And, you'll have a backup amp if one breaks down.

Marc.... Pro Reverbs sound great, but they are nearly as heavy as a Twin.
These days I'm using a Vibrolux Reverb for the medium volume gigs. Not quite as loud and clear as a Pro, but almost as light as a Deluxe. I do have a Twin that I bring if need to hurt people with sound.. Smile

Jon Light · From: Saugerties, NY

I've got a booteek amp--a Tone King Comet 40B. This is a 4 x 6V6 amp with 2 X 12" speakers. I was very interested in it because I had the idea that it might be like two DR's. It actually is like two amps side by side, each pair of tubes has its own transformer into its own speaker. It is indeed a great sounding amp with the added feature of having a switch that takes it from blackface to 'tweedy'----I have no idea what it's about but it definitely gives the amp two very distinct flavors.
Although I was hoping for a super DR, it sounds considerably 'harder' than my DR--it really sounds a lot more like a small twin or, I guess, a Pro Reverb (when it's in BF mode). Maybe it needs NOS tubes---I've got JJ's in it. I think of the DR as having softer edges. Woody. Lousy word descriptions.
This amp is self-described as "Class A, cathode biased" so that makes it a different circuit than a BF/SF so comparisons are probably futile.

Donny Hinson · From: Glen Burnie, Md. U.S.A.

Generally, I'm against major amp mods to increase power, as they tend to make the amp less reliable. If you want a powerful tube amp in a small package, BUY it. Trust me, anything you're looking for has already been made. You don't have to go re-inventing the wheel.

Marc Jenkins · From: Victoria, British Columbia, Canada

I'm all for going with what's already out there, myself. What I want is a 2 channel 40 watt Fender amp with 1x12" speaker. To my knowledge something like this has never been made...

Pete Burak · From: Portland, OR USA

About 2 years ago I acquiered a '79 Fender Deluxe Reverb in a buy/sell/trade deal that had been converted to 6L6's and also had an oversized output transformer, and BF mods on the Reverb channel (channel 1 was left stock).
It measured just over 60W on a bench.
It had an EVM-12L in there.
It was tonally "O.K." for both steel and guitar, had plenty of volume and acceptable headroom for most gigs (always mic'd to the board).
I heard some RI's that sounded better for Tele tone, though, to my ears.
I recently traded it for an Alembic F2B, and am back to a rack rig now.

Jay Ganz · From: Out Behind The Barn

Marc,
Well, wouldn't that be either a Blues DeLuxe or a
Hot Rod Deluxe? They're both 1X12 40 watt. Only thing
is, I think the "2nd" channel is mainly for overdrive.

Henry Nagle · From: Santa Rosa, California

Marc.... If you found a Bandmaster Reverb head, you could have a cabinet made for it. I did that once and it was just fine. You can still find Bandmaster Reverbs for reasonable money too.

Some of the later, Rivera Fenders were 1x12, 40-60 watt combos, but they don't have two independent channels and are not as "Fendery" sounding.

Ivan Posa · From: Hamilton, New Zealand

Marc, the short bottle 6L6WGB tubes are the ones. Just plug them in and rebias. Ihave them in my DRRI and they are great. Much nicer than the 6V6 and more headroom.

Marc Jenkins · From: Victoria, British Columbia, Canada

Jay,

You're right about those amps. In fact, I have a borrowed Hot Rod Deluxe right now, but I'm not super happy with the tone. I find it a bit too bright in an unfriendly way, plus I'm not happy with the reverb. I'd also really like to plug in a guitar and a steel at the same time on separate channels.

I'm also trying not to deal with circuit board amps anymore, either...

Dave Mudgett · From: Central Pennsylvania and Gallatin, Tennessee

To my ears and taste, a Blues Deluxe or Hot Rod Deluxe is not comparable to an AB763-style point-to-point wired amp. This is nothing against those amps, but if I really thought they sounded like a nice old Fender, I'd have one and be done with it - it sure would be a lot simpler and cheaper. YMMV, but to me, the clean sound doesn't have the same shimmer. My sense is that they had distortion on their mind more than clean sound when they designed these, and it shows - again IMO. I also think modern PC boards are a lot harder to reliably modify or tweak.

To Pete's point - I agree that trying for a single amp for both Tele and PSG is tough. Making changes to a stock old BF/SF Fender to improve it for PSG tend to detract from its sound for the typical blues/country/rock type of thing - at least to my ears. For a clean country guitar picker, perhaps there is a middle ground on heavier-duty speaker choices that warm it up a bit for guitar, but still have enough clean headroom for PSG. My favorite of these is that old-style EV SRO with the white frame and no fins. I imagine that Weber VST or others make a speaker in that vein also. But I think that if one is going for traditional blues and rock guitar sounds, there is a zero-sum game between clean PSG and less clean guitar attributes.

To Donny's points - if mods aren't done well, reliability will likely be an issue. But IMO, there are definitely people who can do it right. As far as being able to just go out and buy whatever one wants, perhaps if one has enough coin. These boutiquey amps have gotten pretty pricey. But I also don't think that, for example, a Boogie is the same as a rodded old Fender. Both are fine amps, but I think appeal to somewhat different sonic tastes. Sure - lots of stuff has been done. But for me, I think the best way to get something to sound the way I want is to tweak or customize it. I can't remember the last tube amp I bought that didn't at least need some significant tweaking.

One of the nice things about old Fenders - or a modern clone - is that they are very simple designs that one can go in and easily tweak to taste. Not to mention the fact that a lot of silverface Fenders are still fairly reasonable - there was even a late 70s SF DR in For-Sale for $675, and the bigger amps like the Pro or Twin Reverb are often even a better deal than Deluxes. If one can find a DR with dead or missing transformers for $400-500, that makes a great platform to work with, IMO. Or the modern clones like Weber or Allen also seem like a reasonable option.

Perhaps my ideal setup for anything but the loudest PSG + guitar gigs would be a pair of DRs - one heavily rodded for max power and headroom and one stock. Guitar would be primarily the stock amp, with the possibility of adding a little clean bottom with the rodded amp. PSG would be primarily the rodded amp with maybe some of the stock amp if I wanted a bit more. I think a pair of these would be a slightly smaller and perhaps even lighter package to carry around than a pair of NV-112's, which seems to be a pretty common and very manageable setup these days. Maybe not for everyone, but most of the time, I probably don't have to play as loud as a lot of PSG players. In fact, the guys I play with would probably come after me with hatchets if I played as loud as a lot of PSG players. Naturally, YMMV.

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