I did the following to a Hot Rod Deluxe and the results were astounding! Sounds like an old Blackface era amp to my ear now. No more boomy bass!!!

1- "changing the bass cap (C5) to .022uF, changing the treble cap (C7) to 500pF, silver mica, and changing the slope resistor (R12) from 130K to 56K."

2- "The Mid control on this amp is a 25kA pot. (“A” stands for audio taper). Thus, the stock circuit in this amp puts 25,000 ohms at all times between the bottom of the bass control and ground. On vintage Fenders without a mid control, the resistor in its place was usually only 6.8k. On models with a mid control, such as the Twin Reverb, the pot was only 10k, so even with the mid turned up all the way, it didn’t have the same low-end response as the stock circuit in this HR Deluxe. The larger the value of this midrange resistor, the more bass and low-mid the amp has, regardless of the setting of the bass control.

Have you ever seen a “Loudness” switch on an older stereo? The Loudness circuit boosts the bass and treble and is intended for low-volume situations to compensate for the fact that the human ear hears midrange frequencies (where most speech resides) more acutely at low levels than deep lows or high trebles. As volume increases, this effect reduces. If you play a stereo at high volume with the Loudness switch engaged, it can sound flabby because the bass frequencies are now over-amplified for our ears. This is precisely what’s happening with this Fender HR Deluxe. It sounds great at low levels, but the bass overwhelms the tone at higher volumes.
Justin's comments: Instead of using wire I took a small piece of solder and melted it into place. This creates a very unobtrusive jumper that's easy to remove. Be sure to test your jumper with an ohm meter to make sure it passes current.

Fixing this takes very little effort:

Follow steps 1 and 2 above. Solder a jumper between the left and middle terminals of the mid control (when facing the amp from the rear, as you would be when working on it). That’s it. You can now reverse steps 1 and 2 and try it out. If you did it right, you should now be able to turn your volume down to 0 by turning all of your tone controls to 0. More importantly, you can now dial in just the right amount of low end with the mid and Bass controls. Remember, they’re interactive. The higher you set the mid control, the more bass you will get."

link to web site: http://studentweb.eku.edu/justin_holton/jvmods.html#bass

Other changes I have made to many of these amps is to replace the input jacks with Switchcraft shorting jacks, the real deal!

Also the false channel switching is these amps is due to overheating of resistors in the + and - 16 volts supplies. The resistor change out and jacks mods can be found on the same website.

[This message was edited by Ken Fox on 03 December 2006 at 08:57 AM.]

Thanks,

The Deville series has a lot more headroom, even though it is a 2-6L6GC amp. They ran the plate voltages hotter to get more power. A good choice if you need less distortion/early break-up in the sound.

The tone stack in the Blue Deluxe is identical to theh Hot Rod with exception that the slope reisitor is 100K (conventional Fender) not 125K.

The mid pot is the still a 25K. Traditional Fender tone stack was 10K. The mod makes it a 12.5 K.

[This message was edited by Ken Fox on 04 December 2006 at 04:55 PM.]