One More Of Those 6G15 Reverb Questions

[RH53]

Hi to all I'm Robert on my first tube kit project, to build a 6G15 reverb unit in a National NC-57 Ham radio case and chassis, I put in a post down in the effects section a couple of weeks ago but was told not much goes on down there, so I thought i'd enter deeper water. The last couple of weeks i've spent on line getting as much information as I could find, looking over the schematics and layouts, and putting together parts. I went with the older model kit from Triode Electronics, then ordered a turret board, turrets, bridge rectifer, carbon 1/2 watt resistors and misc. parts from Hoffman.
I now have a coulpe of questions that I hope are not to basic.




 

[TIMBO]

Hey robert, That looks to be a good layout as i am thinking of building one my self. I usually have it as an onboard FX but it always makes for a crowded build so to have it as a stand alone, might be a big +

Good luck and fire away with the questions. 

[RH53]

Hi to all I'm Robert on my first tube kit project, to build a 6G15 reverb unit in a National NC-57 Ham radio case and chassis, I put in a post down in the effects section a couple of weeks ago but was told not much goes on down there, so I thought i'd enter deeper water. The last couple of weeks i've spent on line getting as much information as I could find, looking over the schematics and layouts, and putting together parts. I went with the older model kit from Triode Electronics, then ordered a turret board, turrets, bridge rectifer, carbon 1/2 watt resistors and misc. parts from Hoffman.
I now have a coulpe of questions that I hope are not to basic.

 Sorry for the incomeplete post I must have double clicked enter?

First question in the hoffman schematics it shows the green and black from the output transformer going to a RCA jack marked out, and the RCA jack comming from the foot switch marked in all other schematics have the RCA jack from the output trans. marked reverb input, and the RCA off the footswitch marked reverb output. Is Hoffman saying that the green and black from the ot is the output of the reberb unit that goes to the input of the tank, and the other plans Fender, Triod, Webers marked as going to the input of the tank?  

Second question the Triod kit came with 2 10k resistors one 1watt and one 1/2 watt, hoffman lists both as 3watt, is it ok to go with Triod supplied or go with the larger ones as Hoffman suggests?

Getting this post up has been hard my laptop going nuts, it's been like   beating my head against a wall! maybe 5th times a charm

Thanks for any information or input

Robert

[tubeswell]

First question in the hoffman schematics it shows the green and black from the output transformer going to a RCA jack marked out, and the RCA jack coming from the foot switch marked in all other schematics have the RCA jack from the output trans. marked reverb input, and the RCA off the footswitch marked reverb output. Is Hoffman saying that the green and black from the ot is the output of the reberb unit that goes to the input of the tank, and the other plans Fender, Triod, Webers marked as going to the input of the tank?

Most 'fender' reverb transformers had green and black wire insulation of the secondary winding (the winding that goes to the Pan input), and red and blue wires for the primary winding (the winding that is connected between the High-Tension supply, and the plate of the reverb driver tube).  A lot of current manufacturers copy that convention.

The footswitch in most 'fender reverb' circuits is connected to the grid of the reverb recovery (gain) stage - which is also connected to the RCA jack that comes from the pan output. When the footswitch is 'on'/connected, it grounds the grid of the reverb recovery stage so that there is no signal from the pan getting back into the amp's signal path.

Does that answer your question(s)?

Second question the Triod kit came with 2 10k resistors one 1watt and one 1/2 watt, hoffman lists both as 3watt, is it ok to go with Triod supplied or go with the larger ones as Hoffman suggests?

The 1W will be fine for the dropper in the power supply rail, (as this doesn't see more than a handful of mA) and the 1/2W will be fine for that split load resistor in the pre-amp stage (as it only sees 1/2 of what the other resistor sees). 3W is overkill in both those applications.

[RH53]

Thanks for the quick replys to my questions, yes it does, I've switched computers so maybe this post will go a little better.
here's the 2 schematics I was trying to load.



and a few photo's of the project.







Thanks again
Robert

[HotBluePlates]

Robert:

Hoffman's layout matches the original Fender 6G15 layout, in that they mean the RCA jack with the green and black wires are an "output" from the 6G15 chassis which then enters the reverb tank. That makes the signal returning from the tank an "input" into the 6G15 chassis.

Triode's diagram is arranged backwards of that, but how you might think about it when considering just the reverb tank. The output of the 6G15 chassis is going to the "input" of the reverb tank, and vice versa.

Summarizing, using Fender/Hoffman terminology:
6G15 dry signal -> 6G15 "Reverb Out" -> Reverb tank Input -> Reverb tank Output -> 6G15 "Reverb In"

So the difference of out/in is just whether you're talking about what the signal is doing at the chassis, or at the reverb tank.

If you build it, you'll see they both come together exactly the same. The 6V6/6K6 output goes to the reverb tank input.

[Willabe]

You need to add a 220K R across the reverb output jack. Look at Dougs drawing.


                 Brad     

[sluckey]

Which reverb tank will you use? Will you mount it on that chassis?

[RH53]

Thanks again for the information, that is what I was thinking on the in / outs for the tank but just wanted to make sure. Tanks I have 2 a MOD 8AB2C1B  9 1/2" and a MOD 4AB3C1B  16 3/4". If I go with the 9 1/2" I mount it inside the case, if I like the 16 3/4" better i'll try to make it look like an antenna. can I get your idea's on the lay out I have set up, if I should move things around, is the OT to close to the PT and can a reverb tank be mounted that close to all, ect. layout I setup I have the power switch, power lamp, dwell, mix, tone and input jack on the front of the case, power cord, fuse, output and footswitch jack on the back.




[imghttp://i.imgur.com/zm3fTef.jpg]http://[/img]

[imghttp://i.imgur.com/iux14GB.jpg][/img]



Thanks again to all

Robert

[RH53]

again

[HotBluePlates]

I would have the output transformer's wires run through grommeted holes right at the transformer, to connect to relevant circuit pointsinside the chassis. That allows the chassis to act as a shield.

You green and black output wires from the output transformer will then connect to an RCA jack. The cord running from this jack to the tank will be a shielded wire. Same with the Reverb Return out of the tank and into the chassis. You have the transformer cores at 90 degrees, so that shouldn't be a problem.

Also, the open side of the tank is now down against the chassis, again, providing shielding.

Seems like a plan to me.

[RH53]

Ya that's my plan, I just have the OT sitting there for now so I could see the best area to mount it without interfering with the turret board.

Thanks
Robert

[sluckey]

I very interested in this project. Please share your opinion of the short tank when you get it all together.

[sluckey]

Any progress?

[RH53]

Not much yet, have got the hardware mounted, and started on the wiring, but my daughters getting married in a little over a week, so people have showed up and taken over my guitar room, slowing the build down, I knew I shouldn't have put a hide a bed in there, will keep new information updated, when I get going again.

Thanks for the interest in the prodject.

Robert