Fender Reverb 6G15 Knockoff

[CJ]

Fairchild iron on the way, so cool your jets, 

nuthin as cool  like a juicy reverb, if you never played this unit, then just listen to a dick dale album or something,

1/4 inch plywood for the ultimate in cheapness and it is easy to hack and drill so wtf, over?

6 by 18 22 ga from Lowes for 5.99 because we would rather spend money on drugs,

Acutronics pan for 23 bucks, looks lioke they sold the farm to China, Beltron to be exact, which means we will need to:

1) shim up the loose transducer coils to prevent mechanical loss,
2) put a dab of jb weld at the junction of the springs to prevent mechanical loss
3) hard wire the connectors that feed the transducers for less signal loss,
4) bolt the pan directly to the baffle board so we can save more money on the silly springs that always break, besides, the pan sounds better bolted down to the baffle board, who takes road trips at 5 bucks a gallon and pay to play? screw that, this tank ain't goin nowhere,

ok, bend the chassis with 2 pieces of angle iron clamped on both sides then pound away with a hammer,punch some socket holes and we are on our way,

 

[CJ]

6X4 tube rect instead of the cheeze ball 1/2 wave circuit which polarizes the transformer,

should be less noise and better sound,

no cap hassles with the multi section cans, one hole punched and you have all your filter caps installed at once,

heaters are wired, check the 6.3 as the Hammond trans comes with a pri tap for 115 or 125.

worked best at 125.

 

[CJ]

if we skip the 16 dollar turret board we can spen the money on more drugs,

so lets go white trash circuit board made from solid oak that Bubba chopped down with a porcupine saw, maybe a few wood screws for a little bling bling,

 

[CJ]

all wired up and stuff,

 

[CJ]

stuff it in the cheap box and order some tolex and grill cloth since we want it to look all pimped out and stuff,

just mount the oak board on another oak board, a couple of thru holes with #6 and you done.



we have a left over can section, 20 uf at 450, so another 10 K resistor and i have a cleaner supply for V1.

now i have to wind a 30:1 transformer.

stock is 50 to 1 in twin reverb, etc, but this guy takes a different reverb output, some folks used a champ output since the driver is a 6k6 or 6v6 depending on your tastes.

bolt a 220k resistor across the reverb foot sw jack to improve sound and reduce clicks, you lower input Z which makes it mellow,

try 12AX7 instead of 12AT7 for more gain, Ken Fisher of Trainwreck likes a 220 K plate resistor on v1.

notice the chicken heads? thats where you get your sound, the funk comes from the chicken heads, ask Kent, jus sayin...

 

[Sredna]

Wow, colored woodworms! 

 

[CJ]

yes, those are gummy worms,

here is a cabinet that really does not need a full chunk of wood in the front, just a 1 by 1 frame, so don't make my mistake and you save cutting out the center section and you save wood also! 

 

[okgb]

Zowie , you're on a mega roll Man ! and surely the wood turret board has to be Johnson / Dumble approved !
When I get to it , I want to build an 80's super champ without the verb and a 6sn7 for the phase splitter
Rock on !

 

[Kid Squid]

Lovin' it, CJ

 

[fazeka]

Ole skewl DIY, jus' bangin' it out. Refreshing, love it.

 

[buildafriend]

CJ, I really wish I was on your level.

and, the wood with nails is a sick turret board.

 

[CJ]

thanks you guys!

i have some cream colored tolex and a black and brown weave grill cloth on the way,

they do not sell fender logo stuff anymore, too many knock offs,

winding the rev out right now, gonna try sec - pri sec with sec bi fi both sections,

should be better than the sec pri stuff they sell.

however, what is the response of the springs?

has to be low.

 

[jackies]

They actually do sell enough fender logos on ebay - I got one recently for my "Super-Princeton" build.
Keep em coming CJ!

 

[fazeka]

They actually do sell enough fender logos on ebay - I got one recently for my "Super-Princeton" build.

Yeah, but they ain't priced what they used to be pre-Fender putting the brakes on 5 (?) years ago or so...

 

[CJ]

what is a super princeton?

i was thinking that somebody should build a reverb unit, then add in a princeton reverb power amp and speakers, since you already have the pwr supply and some preamp tubes, all you would need is a phase inverter and a push pull circuit,

anybody try the 6 spring pan?

there is a company making retro pans, about ten bucks more,

revisit reverb, are they still in bidness?

http://amprepairparts.com/reverb.htm

 

[jackies]

what is a super princeton?

Nah, it's just a regular princeton which I'm building with 15" speaker, deluxe output, etc.
Hence "super"
;D

 

[CJ]

ok, this reverb  project is complete, sounds really great, no hum, surf city, pictures at 11,

i tried some mods on the circuit,

bridged 0.1 coupling caps on output tube with 0.68 uf - no change
tried 6V6GT and 6Y6 in place of 6K6- i like the 6K6 the best
tried 12AX7a in place of 12AT7 - not much change, dwell comes on a little quicker, but if you turn the dwell pot down, you are right back where you started with the 12AT7, so the 12AT7 is better because you get finer tuning with the dwell pot, this thing has way to much gain anyway, if you use it on full, then people will think you flipped out on some dick dale acid or something, but use a good 12AT7, some sound like crap, try the 6201 or whatever the mil number is,

the only mod i found worth while was to change the bypass cap on the 6K6 from 25/25 to 10 uf at 63 volts, non polarized (non lytic, regular foil)
this drops the gain down a bit which gives the premium pan overtones,
no wonder a lot of Fender reverb amps sound different, these pans are pretty sensitive to circuit changes,

this spot in the circuit really changes the tone of the reverb depending on the cap.
no cap sounds really cool also, maybe a switch here would be cool.
or a rotary switch with different cap values.

with solid state rectifiers, the Hammond 269CZ put out about 325 volts into the choke,

the 6X4 vacuum tube rect drops this down to Fender specs, right around 305 volts,

i have 250 feeding the output tube which is like the schematic and 220 feeding the input tube which is 30 volts below stock.

there is a lot of compression with the 6X4 so you can make a clean amp really grind and have sick reverb at the same time.

using the stock acutronics 8 ohm in and 2500 out 2 spring model,

power supply voltages are important in this circuit, you have to hit the pan just right to get those cool treble overtones, too much gain and you get the wrong type of fizz,

one last mod, the power trans has no center tap on the 6.3 heater coil, so i had to run a couple of 100 ohm 2 watt resistors o off each leg to ground, bad hum problem solved.

running a Champ output trans for the reverb, i stuck the DIY reverb trans in a champ amp and it sounds cool,

 

[dissonantstring]

awesome build report and mod info CJ!  man, you've been working on so many projects lately it's been too difficult to keep up.
back to the 670 dungeon you go!   keep it up!
-grant

 

[CJ]

wonder where the pacrat went,

ok, after about 3 hours of surfin the web and cutting up road maps as templates or tolex,

there are a lot of ways to do tolex, most of the drama is of course, in the corners.

Fender slices the tolex in the corners at a 45 degree angle and then butts the two pieces up tight to each other so that you can hardly see the splice,

Marshall has metal or plastic corner covers so you do not have to make perfect splices,

there is a youtube vid on a guy doing a fender rhoads cover, that is what i went for,

more of an overlap approach.

use a piece of paper to practice corners before you slice up the tolex.

here is the final solution to the corner problem below>

 

[CJ]

here is a pic of the front,

since i used 1/4 ich plywood, this thing is pretty light, no speaker and a small pwr trans,

so i ordered a guitar case handle instead of the fender dogbone,