I own a ‘68 Custom Deluxe Reverb, so maybe I can shed some light on the subject. There are several differences between it and the Deluxe Reverb RI. Both channels operate in phase with one another, and both have reverb, on the ‘68 CDR. The first channel has a .022 mFd capacitor which controls the midrange, as opposed to a .047 cap, which is standard for the Deluxe Reverb. This gives a stronger midrange, which brings you a little closer to the sound of the early ‘60s amps used in most Surf recordings. They call this a Bassman tone stack, and it is similar to what you’d find in a blonde Bassman. This is also similar to the tone stack of the Super Reverb, which has a rich sound with a solid midrange.
The ‘68 Custom series amps use a higher value negative feedback resistor, which reduces headroom, slightly. They are deliberately going for earlier breakup. For myself, desiring a clean Surf sound, this was not a plus. In my case, the solution was to install a second negative feedback resistor of the same value in parallel. This restored the headroom and made things better.
The 6V6 vs. 6L6 power amp makes for about 3 dB more headroom. Basically, every time you double the power, you add 3 dB of headroom. 3 dB is the minimum change of volume that the average person can detect. So, if you look at the line of Fender amps, the 22 watt Deluxe Reverb is 1.66 dB louder than the 15 watt Princeton, the 40 watt Pro is 2.59 dB louder than the 22 watt Deluxe Reverb, and an 85 watt Twin Reverb is 3.27 dB louder than the Pro. The decibel scale is logarithmic, so it’s a bit tricky to comprehend, but it’s reasonable to say that each step, from the Princeton to the Twin is a slight increase in clean headroom, but this does not account for difference in speaker efficiency and other factors. (Nothing is ever as simple as we would like.) I would opine that the changes in the negative feedback resistors in the Vintage Modified Series probably account for about 3 dB of reduced clean headroom. It’s not dramatic, but when the negative feedback resistor value on my amp was reduced (by connecting a similar resistor in parallel), there was a noticeable increase in headroom.
One other difference between the ‘68 Custom Deluxe Reverb and the Deluxe Reverb Reissue is the “Bright Cap”. Some explanation might be in order. The Bright Cap is a high pass filter, which allows high frequencies to bypass the volume control, giving a brighter sound. Amps with a Bright Switch, allow you to switch this capacitor in, or out, of the circuit, but on a stock Deluxe Reverb, there was a 47 pF cap, permanently in the circuit on the Vibrato channel, only. This works in parallel with the volume pot, so the amount of upper harmonics passed will vary in proportion to the position of the volume pot. In simple terms, the higher you turn the volume control, the less effect the Bright Cap has on the overall sound.
On the ‘68 Custom Deluxe Reverb, neither the Custom or Vintage channel has a Bright Cap. To my ear, the Vintage channel sounds a bit listless at living room volumes. To the best of my knowledge, the circuit board on the ‘68 CDR has the pads and traces for C10, the Bright Cap, so it would be a simple matter to install a Bright Cap, at the sacrifice of your factory warranty.
My ‘68 CDR had a terrible problem, when I first bought it. It had a harsh, crunching noise, which always seemed to show up at gig volumes, but couldn’t be duplicated at home volumes, or when I took it to the shop of the local Fender Repair guy. He is a good fellow and spent no little time in trying to find the source. Finally, he was able to produce the sound by wiggling the reverb cables. Yes, some genius at Fender sought to save a few pennies per unit by specifying the cheapest RCA cables known to man. One simple change, and that problem was solved.
The stock speaker in these amps must have been spec’d by the same cost accountant, because, while it sounds ok at lower volume levels, if I push it, the amp sounds like it’s been eating a lot of beans, if you get my drift. Simply stated, the lows become flatulent at higher volumes, with the stock speaker. I wouldn’t be concerned for home use, but if you are trying to compete with a drummer, you might feel the need to install a different speaker.
One last matter, is the difference between the Princeton and the Deluxe. Princeton amps, use a Cathodyne Phase Inverter, while the Deluxe Reverb uses a Long Tailed Pair. The difference is that the Cathodyne PI is a zero gain device which uses a single triad, while the Long Tailed Pair uses two triads (both sides of one 12AT7 tube) and provides some gain in the phase inverter.
For home use, I would think that the 22 watt Deluxe Reverb would remain clean, but the ‘68 CDR might end up at the edge of breakup. A Princeton is probably adequate, but a Princeton from the Vintage Modified series will have somewhat lower headroom and may be marginal for clean sounds, even at home volumes.
I would suggest that you might want to consider a Winfield Elizabeth, which is basically a refinement of the mid ‘60s Fender circuit. The Elizabeth can handle 6V6 or 6L6 power tubes, so you can operate at Deluxe Reverb or Pro Reverb power levels by swapping power tubes and re-biasing. Mine has 6L6s and is docile enough for living room use, but also sounds great at gig levels. Its last outing was an outdoor venue, and it held up quite well, at fairly high volume levels.
Even better, there is a Bright Switch, so you have flexibility that the Deluxe Reverb lacks. It also has a three-band tone control, so midrange response is adjustable. You might be able to persuade Winnie Thomas to use a .022 mFd cap in the midrange control, which would get you that Bassman/Super-Reverb tone stack, just like the ‘68 CDR. It is a single channel amp, and weighs about 8 pounds less than the ‘68 CDR. The price for one of these is comparable to a ‘68 CDR.
My last point is a matter of taste. While the Princeton Reverb is a lovely amp, I find the stock 10” speaker, not to my liking. As I said, this is a matter of taste, but I strongly prefer 12” speakers for a beefy sound on the lower strings. I have a Winfield Tremor, which is basically a refinement of a ‘62 Princeton circuit, with a single 12” speaker and truly spectacular bias-varying tremolo, but no reverb. This is my favorite Surf amp, and offers a nice balance of midrange, lows and highs. The Tremolo is world class.
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The artist formerly known as: Synchro
When Surf Guitar is outlawed only outlaws will play Surf Guitar.
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