Modded Fender reverb tank

[5F6-A]

I know most guitar players really  like reverb as it helps getting a very special, richer touch.

With that purpose I've found that the Fender reverb tank is a nice effect but more so with some mods I've performed.

I had a look inside and I noticed some very so-so looking coupling caps... uhmmmmm... time to plug the soldering iron in. ;)

I got some Mustard type caps (Sozos and  TAD ). They sound fairly smooth and a bit darker than others like Auricaps which are sooooo transparent. I've found out that that very slight dullness is not bad in such circuit. I used an Orange Drop in one slot as I didn't have a mustard type cap for that particular slot there and then.
The infamous C10 cap was cnahged for a silver mica type and following Mike Fuller's suggestion I went for a much bigger value  than stock ( 250 pF ). I used a 1000 pF which sounds better to my ears.
The output tranny is a Mercury Magnetics replacement as the original looked and sounded weak.

Some pics;










Any comment will be greatly appreciated....

[dave_mc]

so that's just a reverb unit, yeah? looks cool!

mercury magnetics? aren't they super-expensive?

[BloodMountain]

so that's just a reverb unit, yeah? looks cool!

my thoughts exactly!

the inside looks so confusing though, it will give me a nightmare!

[noodleplugerine]

so that's just a reverb unit, yeah? looks cool!

my thoughts exactly!

the inside looks so confusing though, it will give me a nightmare!

Would give me a haemorrhage!

[HTH AMPS]

I've always fancied one of those outboard reverb units - I'd be temped to rip the PCB out and hardwire everything with a turretboard, it's a fairly simple circuit afterall.

What tonal difference did the MM trannies make?

(not having the schematic to hand), I'm guessing the change of cap from 250pF to 1000pF sets the EQ of the reverb???? - if not, what DOES it do?

 :twisted:

[5F6-A]

dave_mc,

Yes it's only a reverb but it shapes the sound a bit like a preamp does. Highly recommended for vintage clean sounds. MM stuff is a bit expensive but sounds fantastic ; all my amps have them except my JTM45 clone which has an obsolete electronic OT which sounds very sweet as well.



HEAVIER THAN HELL,
The MM tranny made the reverb deeper and richer but keep in mind that I changed the caps at the same time so it could be a combination of both. There's a little bit less boing and rattle ( well, it happens at higher settings ) which is a good thing.  To my knowledge the C10 cap controls the frequencies affected by the reverb ... the higher the value the deeper the reverb affects the frecuencies , especially the low end.
Mike Fuller enjoyed a 0.002 uF ( 2000 pF ) plastic cap there. It ended up sounding like a plate reverb.
LOL!!!


BTW, I forgot to mention that I used NOS valves as well.... Marconi ECC83, Mullard ECC81 and RCA 6K6GT.

[jpfamps]

The old Fender Reverb units were designed to use a 6K6-GT NOT a 6V6. Although you can substitute a 6V6 for a 6K6, they are differnt valves. The 6K6 is a true pentode and likes to see a higher reflected impedence.

From what I understand the reflected impedance of the re-issue Reverb unit is about 12-13 k, ie around what is suggested for a 6K6 and not a 6V6. From my experience a 6K6 sounds better in vintage style units, and this might well be the case for the RI Fender unit.

Because 6K6s are not widely used there is a plentiful stock of cheap NOS valves out there, so will be a cheap experment if you want to try it with your tank.

I only have a partial schematic for a IR Fender unit. The 6V6 looks to be fixed biased. Is this correct? The originals were cathode biased with quite a small cathode bypass cap. I expect this would make a difference as well.

[PhilKing]

The old Fender Reverb units were designed to use a 6K6-GT NOT a 6V6. Although you can substitute a 6V6 for a 6K6, they are differnt valves. The 6K6 is a true pentode and likes to see a higher reflected impedence.

From what I understand the reflected impedance of the re-issue Reverb unit is about 12-13 k, ie around what is suggested for a 6K6 and not a 6V6. From my experience a 6K6 sounds better in vintage style units, and this might well be the case for the RI Fender unit.

Because 6K6s are not widely used there is a plentiful stock of cheap NOS valves out there, so will be a cheap experment if you want to try it with your tank.

I only have a partial schematic for a IR Fender unit. The 6V6 looks to be fixed biased. Is this correct? The originals were cathode biased with quite a small cathode bypass cap. I expect this would make a difference as well.

BTW, I forgot to mention that I used NOS valves as well.... Marconi ECC83, Mullard ECC81 and RCA 6K6GT..

He is saying he uses RCA 6K6's isn't he?

[jpfamps]

Yes that's right.

The RI tank comes with a 6V6 though, so a swap for a 6K6 is worth experimenting with. I've also seen 6V6s in original Reverb units as well.

[Ratrod]

So you have a customized reverb tank, a tweed amp and a Strat. I'd say that calls for a surf clip.  :D   8)

[dave_mc]

dave_mc,

Yes it's only a reverb but it shapes the sound a bit like a preamp does. Highly recommended for vintage clean sounds. MM stuff is a bit expensive but sounds fantastic ; all my amps have them except my JTM45 clone which has an obsolete electronic OT which sounds very sweet as well.


BTW, I forgot to mention that I used NOS valves as well.... Marconi ECC83, Mullard ECC81 and RCA 6K6GT.

thanks! sounds excellent.

[5F6-A]

So you have a customized reverb tank, a tweed amp and a Strat. I'd say that calls for a surf clip.  :D   8)

Unfortunately I play fingerstyle so surf  guitar playing ( at least in the most orthodox way ) is out of the question....

BTW.... these are the guts of those two mice amps next to my reverb. One is a tweed Deluxe clone and the other a very much Matchless DC-30 clone.

None of them are mine ......