Sorry, I don't know the exact mods, but certainly there are things that will improve the sound of the DRRI considerably.
But if you haven't done it already, the two most significant mods can easily be done by yourself: change the speaker (try a Weber instead) and change the stock tubes, especially the second preamptube (vibrato channel) and output tubes.
Other than that, an experienced tech will switch some capacitors and resistors for better sound.
I did a comparable mod to my '77 SFDR, and although that amp alledgedly is a lot like a BFDR even stock, the "blackface" modded amp sounded better, IMHO
i don't know that this will make it sound more like an original, but have you tried jumping the channels together? you get this awesome crunch out of it by driving the normal channel and using the vibrato channel as a master volume. just plug into input 1 of the normal channel, take a chord and connect input 2 of normal into input 1 of the vibrato channel. thats the coolest thing about that amp. sorry if you already knew how to do this, but it might be just what you're looking for.
just plug into input 1 of the normal channel, take a chord and connect input 2 of normal into input 1 of the vibrato channel. thats the coolest thing about that amp. sorry if you already knew how to do this, but it might be just what you're looking for.
Whoa - I didn't know that - will try it tonight...
I just bought a DRRI and took it straight to my amp tech for mods. He took out the bright cap on the reverb channel, and replaced all capacitors and resistors with better quality ones. He did a few other little things that make the amp more reliable, he mentioned taking a particular component off of the PCB in the event that it burns out it wont harm the PCB I forget the rest of the details. The amp sounds amazing, my next upgrade will be a Celestion Gold speaker. Look around online for the best/most common mods. If you do it yourself, be very careful with that PCB.
I had a client bring in a Blues Deluxe Reissue and said he wanted "more" out of it. I ended up studying the schematic and attempting a master volume mod unlike what others have been doing to these units. Its a little more work, but if you put a 1M Audio pot in the PW3A-2 line, it allows you to load up the preamp before it hits the power stage. This provides a considerable amount of grit and gain to the tone, but also adds touch sensitivity and volume control of the grit.
I can email more details if anyone is interested. Basically, you have to remove the circuit board that the tubes mount to, unsolder the one line on the PW3 ribbon (wire PW3BA-2) that goes to R40 and put a 1M Audio pot in between it. If you are careful, you can trim out that one wire from the ribbon with a blade and isolate it from the rest. Mount the pot right in between the two preamp tubes in the chassis, theres just enought room for it. My client wanted to "try" it before drilling any holes so I just ran the wires out to the pot externally mounted on the bottom of the chassis with some double sided tape.
Side effect - You lose some level of reverb control since this mod acts to dilute it as you lower the master volume (it essentially bypasses the reverb section) and increase the preamp volume, but the affect on tone was staggering. It brought the amp to life with minimal changes. My client wanted to keep it original and not do any "permanent" mods (basically telling me dont go crazy). He was very happy with the results in live gigs. (It would be possible to retain the reverb level control by using a double level pot and running both wires (PW3B-2 and PW3B-3) going to R40 and R38. This will control both signals equally, I just didnt have a double level pot on hand).
Unfortunately, the day he was bringing it back to make the mod permanent, the amp was stolen out of the back of his car. Thought I would share the mod with you all here as I havent seen anyone take this approach.
Mod at your own risk! Let meknow if you have questions.
Here's a quick one that'll make a DRRI distort more easily, and is reversible if you don't like it.
1) Looking at the amp from the back, take out the rightmost preamp tube (12ax7a), but don't throw it away, you'll need it for step 2.
This will render channel 1 inoperable, but will send more input signal to the vibrato channel.
2) Take out the Phase Inverter tube (12at7). This is the last small tube before the power tubes, coming from the right. Replace it with the 12ax7 removed in step 1.
This should further reduce the channel's clean headroom.
If you prefer channel 1's sound and don't need reverb and vibrato, you can apply step 1) to the 2nd 12ax7 tube from the right instead.
With PAF's, my DRRI starts getting a nice crunchy OD around 5 on the volume, and from 7-10 I begin to feel like Neil Young. A nice clean boost in front (Xotic EP boost in my case) is my "channel switch".
There's something about Fender distortion that is so distinctly seventies' rock 'n roll to me...
Holy grail speaker for a Deluxe Reverb (or reissue) is a Kendrick Black Frame. They also cost $140.
Warehouse Speakers G12C is about half that and sounds great.
What Weber did you try? There are so many different varieties, alnico vs. ceramic, wattage level that you can't call them all the same.
In Fender amps, the Phase inverter is actually a critical tube in the signal flow; I've found in my Fenders that a Mullard CV4024 sounds significantly better than the JJ's, and it's only $30 from KCANOSTubes.com.