Note: Hoffman style refers to the changes in the tremolo circuit, where instead of using the Opto-tremolo approach, the bias vary tremolo was used instead (which leads to richer and deeper effect).
I experimented with a few speakers (Eminence Cannabis Rex, Weber 12A125A, Scumback M75/H75, Celestion Blue) but in the end i always preferred the stock Jensen C12K 100w speaker for deep, clean sounds. That's what stayed in there until I tried an Altec Lansing 417-8H series II. I was very happy with that speaker and had it not been for the weight it would probably still be in there. But seeing how the massive Altec speaker made the amplifier difficult to move, I decided to try a Jupiter 12LC (Jupiter's take on Jensen C12N) and I have been very pleased so far.
I replaced all the pcb boards with a new ptp turret board, switchcraft jacks and alpha pots. The board was populated with carbon composition signal resistors, precision flameproof resistors in the power section and signal caps chosen for tone (Sprague, Poly, Mallory). Vintage cloth-covered wire was used throughout and much attention was given to the grounding scheme and lead dress to keep the amp hum-free.
I made a few twists to the original circuit. Firstly, i installed a push-pull pot in order to toggle the bright cap in the second channel. Contrary to its larger siblings, the Deluxe Reverb lacked a Bright switch to engage and disengage the bright cap and that made a few pedals sound harsh. The push-pull pot solved that issue.
Secondly, i added a switch to simulate "removing" the tremolo circuit, in which way the gain of the amp is increased a bit. This switch is really hidden and one would have a hard time finding it. I used a switched pot (just like the old radios' volume pot which at the same time acted as an on/off switch) in place of the tremolo intensity pot. Turning the pot fully counter-clockwise beyond '1' you can hear a 'click' sound and the switch is disengaged. Notice in the next picture how the pot is turned beyond '1'. Being bias vary style, the tremolo cannot be disconnected, as can be done in Opto-tremolo circuits, but instead a resistor which shunts some of the signal to ground is disconnected, hence the increase in gain.
The last mod i did to this amp was adding a 3-way switch to toggle between different negative feedback configurations. Some find that the stock resistor in the negative feedback loop makes the amp sound a bit stiff and doesn't let it breathe. The switch toggles between the original value, double of that value (so half negative feedback) and no negative feedback at all. The difference is very noticeable and that way you can tailor the sound of the amp according to your needs. I usually prefer the half negative feedback setting as it lets the amp breathe better - notes bloom and don't sound congested. The stock is a bit more stiff and muffled and the no negative feedback option sounds too bright and 'uncontrolled' most of the time, so i find the 1500R a good middle solution.
I used F&T caps for the filtering and i also replaced the output transformer with a Classictone Deluxe Reverb transformer.
The amplifier was fine stock but it is on a completely different level sound-wise after the upgrades!
Sound Files
Fender Baja Tele straight into Fender Deluxe Reverb. Recorded with M-Audio FastTrack C600, AKG Perception 420 & Shure SM57. No post-processing.
Fender Baja Tele straight into Fender Deluxe Reverb. Recorded with M-Audio FastTrack C600, AKG Perception 420 & Shure SM57. No post-processing.
Rhythm: Gibson Tribute 60's Les Paul bridge pickup into Deluxe Reverb (Normal channel), pushed lightly with Klon
Lead: Tokai Les Paul (Alnico 2 Pro Slash) straight into Marshall 2555SL
Recording Interface: Two Notes Torpedo Live
