Bought a Deluxe Reverb RI!

[HamishR]

For years now I have been very happy with my home-brew amplifiers, especially my beefed-up 5F4 tweed Super 1x12 combo. But recently I have felt the need to (a) try something else and (b) find an amp I like with my Strat! I remembered that the amp I liked best for the Strat was the Super Reverb RI I used to have. But I didn't want an amp that big. So I thought why not make a "stealth" amp... an amp which looks like a small amp, is easy to carry like a small amp but which sounds at least as good as a Super Reverb for my Strat? It should sound good with my other guitars, mainly a 335, a Les Paul and a Gretsch Duo Jet.

So I bought a recent Deluxe Reverb RI. I don't know if Fender have made any significant changes recently but this DRRI certainly sounds better than the last one I played a few years back. Stock it is a pretty decent sounding amp. It has a Jensen C12K speaker which actually sounds alright. Previously I had played DRRIs and they sounded thin and a bit nasty but this one is quite full and crisp sounding - a good start.

My plan is to go slowly and make some changes, listen, try something else, listen...

So after comparing the schematic with a Super Reverb the first things I did (after installing a Celestion G12H and testing it - good but not necessarily that much better than the stock speaker) was open it up and try a few things with the tonestack. Firstly I removed the bright cap - instant improvement for my ears. Then I swapped the 100K slope resistor for a 56K but to me it didn't sound quite right - yes there was a bit more midrange but it just sounded wrong to me. So back to 100K for the slope resistor. Then I swapped out the 6K8 midrange resistor off the bass pot to 10K - so now I'm simulating a Super reverb with mids on full. Better! Replaced the treble cap with the same value but in silver mica, the bass cap with a .1µF blue Sozo and the mids cap with a .022 blue Sozo, again as per the Super reverb and now it sounds a lot fuller but still very BF Fender. I was surprised at how much difference the .022 mids cap made over the .047. It really does add mids which seemed kinda counter-intuitive.

And lastly for now I added a .0022 cap across the 220K resistor off the reverb pedal socket. It stops a lot of the noise from the reverb. This is a tip I picked up from the AB763 Mods page: https://robrobinette.com/AB763_Modifications.htm#Reduce_Reverb_Noise

I'll play the amp like this for a while, but I have a feeling this won't be the end. With an upgrade power transformer from Mercury Magnetics and a few dropping resistor changes I can run KT77 power tubes which will really make it punchier and louder. This is a fun project.

 

[Jovi Bon Kenobi]

That's so cool. Is it the silverface RI or the black one?

 

[HamishR]

The '65 BF version. I think the silver one is ugly. Plus I learnt that converting the '65 to a '68 is easy and I have Celestions anyway. If you have a '65 RI you can convert it to a '68 in minutes. They use the same board.

What has surprised me is that working on the RI is not so bad, other than time-consuming having to remove all of the knobs just to change a resistor in the tone stack. But if I use a solder sucker to gently remove the solder from a part it is easy to replace bits.

 

[Barry]

The '65 BF version. I think the silver one is ugly. Plus I learnt that converting the '65 to a '68 is easy and I have Celestions anyway. If you have a '65 RI you can convert it to a '68 in minutes. They use the same board.

What has surprised me is that working on the RI is not so bad, other than time-consuming having to remove all of the knobs just to change a resistor in the tone stack. But if I use a solder sucker to gently remove the solder from a part it is easy to replace bits.

I did some mods on a few Blues Juniors for some friends and the boards on them were easy to work with also

 

[HamishR]

I found a reverb tank that I had bought years ago today - it's a 3-spring accutronics in a black tray and it's the same exact size as the 2-spring unit in the DRRI. So I swapped 'em over and the 3-spring unit sounds waaaay better. I also did a little cap mod to tidy up the sproinginess and it seems to have helped keep things quiet and less sproingy. Put a 12ay7 in as reverb driver and now the reverb sounds a lot more natural than before. I have to keep the reverb down to around 2 1/2 but that's ok because I like stupidly OTT reverb sometimes, and this can get plenty OTT.

The tremolo is something I can only fix if I go the whole hog and replace the PCB with a tagboard. I've done that before with a SRRI but I'll wait before doing that here. I have a Flint if I want great tremolo. I am really quite happy with the reverb now.

The big shock for me was trying out just cranking the amp. I pulled out my Les Paul and turned the amp up to around 6 and it sounded surprisingly good. I had to turn the bass and treble down, but I have never heard a BF Fender sound as throaty as this when breaking up. I usually hate the sound of a cranked BF Fender.

So I think my job for tomorrow is to redo the entire tonestack of the normal channel, which I haven't touched yet. I have been waiting to see what I wanted to do with it. So I think I'll swap the treble cap to a 500pF silver mica, the midrange and bass caps to .022µF Sozos and make the mid resistor 15K for a start. I may even try 20K.

I'll try to remember to take some pics too!

 

[HamishR]

Quick update in case any sad people out there are interested - changed the Normal channel tonestack as in the post above except I used Mallory 150s instead of Sozos and it sounds great! It makes the Normal channel a very usable alternative to the Vibrato channel. It's really good for low drive settings with neck and middle pickups. In fact with my G pedal set to low gain the middle setting on my Duo Jet sounds awesome - almost clean but jangly with bite. It's a crazy good sound and incredibly useful.