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SurfGuitar101 Forums » Gear »

Permalink 6g15 reissue rebuild questions!

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Hi everyone. First off, I'm new! I've been a lurker/reader for a few years and I have enjoyed many builds on this site. So, thanks for that and forgive me asking a bunch of questions out of the gate.

So, I'm planning on rebuilding my '63 reissue reverb unit in it's original s. raymond ave style. I've got circuit board material, and eyelets ready for stage one. BUT, I don't have an original circuit board. Can any lucky owners of an original unit share the measurements of the circuit board. Main board, the rectifier board and the board under the doghouse. I can't find that info anywhere. I figured I'd ask before I roughed it by looking at photos.

I appreciate any help and I'll document my build here with photos.

Oh, and will the existing Output/Power transformers and choke compatible with the original 6g15 layout? Or must I replace them.

And finally, for this first post, no, I am not doing this for any practical reasons. I love my reverb unit, I just really really want to build something like this and this is the best way to do it without bringing any new gear into the house (married) and without spending too much money (recycled chassis/any other parts that aren't on the PC board)

So, thanks for any help in advance. I promise to do my best to document things and in general be a stand up poster.

Here is the sheet of Formex that arrived. I'll be using it for my boards. It's an updated material that resembles the old "fish-paper" and should do the job. I hope so.

Eyelets and eyelet flaring tool arrived today too.

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Last edited: Feb 03, 2012 21:27:31

Got my eyelets from Watts, with staking tool...

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jbennett wrote:

...will the existing Output/Power transformers and
choke compatible with the original 6g15 layout? Or must
I replace them.

No need to get new iron. Layout has diddly squat to do with iron specs. The iron is perfect for the 6G15 circuit.

He who dies with the most tubes... wins

Surf Daddies

Thanks. That's what I thought/hoped. I guess there are better replacements out there but I will move forward with the stock pieces for now. I can always swap in components later if I want to experiment.

Yep - do your board first and get that working.

He who dies with the most tubes... wins

Surf Daddies

Can anyone explain the purpose of the AC receptacle that is used on some old Fender's, including the 6g15? It looks like it's just a single two-prong outlet that the power chord runs into and then out of before going to the fuse/switch. What purpose does this serve? Except that I suppose you could get a male/male power chord and plug it in to the outlet and the wall and power your amp that way. But why would you? I don't see the reasoning for this extra piece.

Originally, I believe it was there to power your outboard reverb tank. It's just an extra AC outlet. We used to daisy chain the power chords of a couple of amps to a single outlet. Fewer extension chords. I use mine now for either power to the 'verb or my pedal board depending on which amp I have the venue's power availability and how much gear I brought. My '69 Super has a two prong outlet, the amp, of course, was originally built with a 2 wire power chord. My '78 Vibrolux Reverb, however, has a three prong outlet on the back panel, as it was supplied with a 3 wire power chord from the factory.

Thanks. That makes sense. To draw power from one outlet and run a short extension cable up from your amp to your reverb unit. Interesting.

So in a modern rebuild it might not be worth drilling a big hole in my chassis? I could just run my existing cable to the fuse/switch/ground.

If your amp doesn't have a spare AC outlet, then just run the phase/active wire from your mains cable to the Mains fuse, and thence to the mains switch, and thence to one end of the PT primary, and run the neutral/return wire from the mains cable to the other end of the PT primary. Use a 3-wire mains cable and make sure the earth wire is tightly clamped to a lug that is secured to its own separate dedicated chassis bolt with a locking (nylock) nut. I know the old 6G15 layout doesn't look like that in the picture, but what I just described is the proper way to go about it.

He who dies with the most tubes... wins

Surf Daddies

Last edited: Feb 06, 2012 13:15:18

jbennett wrote:

Thanks. That makes sense. To draw power from one outlet
and run a short extension cable up from your amp to
your reverb unit. Interesting.

So in a modern rebuild it might not be worth drilling a
big hole in my chassis? I could just run my existing
cable to the fuse/switch/ground.

You're choice, the RI tanks don't have it. With it being mounted on the chassis inside the cabinet on the same surface as the tube sockets, it's not the easiest thing to get at without taking the back cover off.

Crosspost from TDPRI... sorry for those on both sides of the fence.

Put together a rough rectifier board. Just to see how it cuts and drills. It's a bit plastic, but with deep score on a straight edge, a bend and a slice, it cuts pretty easy. Drilling was a cinch and that eyelet spreader works well.

(I know, pretty rough. Next time I'll smack each hole with a center punch.)

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Last edited: Feb 07, 2012 22:59:35

Looks like about what you need for the rectumfrier. Also make sure you have another blank piece of that board underneath the eyeleted board to keep the wires at the back insulated from anything else.

He who dies with the most tubes... wins

Surf Daddies

I've got one there if you look again. Just the same size but with no holes. It will have two holes when it is screwed onto the chassis. X marks the spot.

So, is the traditional three diode rectifier board going to be a "half-wave" rectifier? From what I've read, it looks like I'll only have one wire leading from the PT into the rectifier and then it's into the caps and circuit.

Last edited: Feb 08, 2012 06:33:32

FYI the RI uses a bridge recto. Just saying..... Big Grin

Sure, but I'm re-doing all my guts. Will the existing PT now work with a three-diode rectifier board like on the original? I only plan on keeping the PT the OT the choke the tube sockets the power cable and the pilot light and fuse stock. Everything else will folow the original 6g15 layout.

While I'm on it... I know the job calls for 1N4007s, but I've already got a few others, 1N4005 (600v) and a 1N5399 (1.5 amp/1000V).

Could either of those be used for the same job?

Last edited: Feb 08, 2012 14:28:55

jbennett wrote:

Sure, but I'm re-doing all my guts. Will the existing
PT now work with a three-diode rectifier board like on
the original?

The RI PT is spec'd for FW bridge recto, so stick with that and the voltages will be right. (FW rectification is better than 1/2-wave anyhow - just like surfin' Wink

While I'm on it... I know the job calls for 1N4007s,
but I've already got a few others, 1N4005 (600v) and a
1N5399 (1.5 amp/1000V).

Could either of those be used for the same job?

The minimum specified for the RI are 1N4006. I always like to over-spec on electronic parts, so I'd use the 1N5339.

Silicon rectifiers need a PIV rating of 2.8 times the RMS voltage being delivered by the transformer.

He who dies with the most tubes... wins

Surf Daddies

Last edited: Feb 08, 2012 14:43:26

Hmmm. So I can either go full wave and hang ten, or get a new PT. Or can it be done with the existing PT? Could I run it through the old rectifier circuit?

If I did got with a replacement PT, where do you get the right transformer with the 7 wires that matches a 68319-A? Every replacement for an Fender Reverb Unit has 6 leads coming out of the transformer.

Looks like Weber makes one for a good price. It has an extra primary lead, I'm guessing this is if you need more juice?

On the secondaries, how do you know which Red wire goes to ground and which goes to the rectifier? Sorry, newbie questions, I know.

Last edited: Feb 08, 2012 15:41:52

half-wave rectification is inferior to full-wave rectification. There is more ripple current because of the longer time lag between current pulses, and that increases the likelihood of humminess, which you don't want in a sensitive reverb unit circuit. The load regulation is worse (bigger differences in voltage drops as the current demand increases), and the B+ voltage will be lower. I would choose FW bridge rectification for that RI PT- that is what the PT is spec'd for.

The way you hook up the secondaries is:

1) For a FW bridge rectifier, each end of High Tension (HT) winding goes to its respective rectifier pole. Red is the usual HT winding wire colour. In a FW bridge rectifier you don't use a center tap on the HT winding - just each end of the winding (but if your HT winding does have a centre tap then you should either insulate the end of it with shrink wrap and tuck it neatly into a corner somewhere, or use a 2-phase FW rectifier (see 2) below).

2) for a 2-phase Full Wave rectifier (one where there is a centre tap on the HT winding), each end of the HT winding goes to its respective rectifier anode (the non-banded end of an SS diode), and the winding's centre tap (usually black coloured wire) goes to ground at the same ground return point of the first (reservoir) filter cap.

3) For a half-wave rectifier, one end of the HT winding goes to the SS diode's anode, the other end of the winding goes to ground at the same ground return point of the first (reservoir) filter cap. But this is inferior as I said earlier.

He who dies with the most tubes... wins

Surf Daddies

Last edited: Feb 08, 2012 19:45:02

Tubeswell, thanks for all your info. I'll read up on all of this following your suggestion. I might still try the inferior half wave rect. with the proper PT, just because I'm interested in creating a 100% accurate 6g15. Plus, I'll also make a full wave rectifier board and try that with the existing PT. (I'll probably do that first actually) and see if I notice a difference.

Another concept I haven't really thought about too much is the idea of ditching the cab and mounting the reverb unit in the bottom of my combo cab. I'll save that for down the road. I guess there would be the danger of hum due to having the amp PT in the same box as the reverb chassis?

Just thinking outloud as they say.

Anyway, a big thanks for your help so far. If you ever need a custom decal for a guitar, I feel like I already owe you one for taking the time to help out a clueless guy.

J

So, is this the full wave rectifier circuit that I'll need with my current PT?

image

If so, in the original unit there is ONE wire that leaves the rectifier and goes to the choke, and the caps under the doghouse. With a full wave rectifier the two wires that leave the rectifier circuit would then go to the same eyelet on the board, right? Wrong? From that point on can I get back onto the original path of the original layout/circuit?

image

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