I didn't get electrocuted the first time...let's try another!!!

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Greg_L
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I didn't get electrocuted the first time...let's try another!!!

Post by Greg_L »

New build time..... :eep: :coolstorybro:

This will (hopefully) be a clone of the mighty Fender 6G15 tube spring reverb unit. You know that slapback drippy springy reverb sound all over surf and rockabilly guitar recordings? Well this is the reason.

My last kit build went well, and continues to go strong, so I got this kit from Weber too. They call it the 5G15.
https://www.tedweber.com/5g15-c-kt

This thingamajig goes between the guitar and amp, like a great big tube powered spring reverb pedal. It's about the size of a small amp head, and it is essentially an amp all in itself. It has all the ingredients to be an amplifier except a speaker. The spring reverb tank acts as the "speaker load". And like a pedal, it can be used in front of any amp. Being a tube unit, I'm also wondering if it can act like a dry tube clean boost? I don't know. Time will tell.

So this is where we begin....

Chassis and board. I'm thinking this eyelet board will be too long and need to be trimmed. I suspect this is just a generic type board. Like my last Fender build, the brass plate will not be used. I will rig up a buss-bar type grounding scheme like the other amp, which works beautifully. That amp is silent. There is also some concern about ground loop hum using the old Fender circuit design now that 3-prong power cords and safety grounding is required. Two devices earth grounded being used together can present ground loops. But we'll see. I'm gonna buss bar ground it and maybe build my own ground lift option. More on that later.
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Power cord, reverb cables, assorted wire, jacks, and tubes and small parts and shit. The tubes are a 12AX7, 12AT7, and a 6V6 - just like the reverb/reverb recovery in the Deluxe Reverb build I did.
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Reverb tank, footswitch, caps, resistors, power/output/choke transformers, etc. I've already inventoried and verified the values of the caps and resistors. All is well. Props again to the Weber people for getting all this tiny shit right.
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And the visually appealing part of the whole thing...the box it's all gonna live in. Because I live in a world of organized chaos, naturally this will not "match" anything else I own, so it's perfect. My amp kit build was purple and checker cloth. The wife picked the colors. She did it again. This time it's a more subdued gray with salt and pepper basket weave.
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So this is ground zero. I still need to come up with a general plan of attack. I learned some things to do and not do from the last build. Two things right off the bat that need some planning are the transformer locations and heater wiring. The power transformer normally lives inside the chassis on these things. I'll need to figure out if it will fit that way and if I wanna even do it that way. I took some liberties with my last build that strayed away from the traditional Fender wiring scheme. It worked for that amp. This one is way more cramped. I used a Marshall style heater wiring for the other amp. This one might need to be Fender style with the heater wires flying over the top of everything. But we shall see. I'll do whatever I think is best and hopefully only have to do it once.
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Re: I didn't get electrocuted the first time...let's try another!!!

Post by Minerman »

Awesome Greg, I'm pretty sure this is gonna turn out epic like your amp build...
I'm already impressed & you haven't even un-wrapped all the parts... :lollers:

Funny you mention none of your gear "matches", my white cab & silver amp doesn't match anything either...

And since it's on my mind, & you're the "go-to guy" on most of this stuff, how hard would it be to re-tolex a cabinet???
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Re: I didn't get electrocuted the first time...let's try another!!!

Post by Greg_L »

Minerman wrote: Wed Jan 01, 2020 12:52 am Awesome Greg, I'm pretty sure this is gonna turn out epic like your amp build...
I'm already impressed & you haven't even un-wrapped all the parts... :lollers:

Funny you mention none of your gear "matches", my white cab & silver amp doesn't match anything either...

And since it's on my mind, & you're the "go-to guy" on most of this stuff, how hard would it be to re-tolex a cabinet???
I've never re-tolexed anything, so I have no idea. But I've seen it done, for whatever that's worth, and it doesn't seem too hard. It's not something I'd want to do myself, but I probably could if I had to. Hopefully never. I think you should probably practice on something small, like a wooden box or something. Get some cheap vinyl from a fabric store and do some testing. You'll need the right kind of adhesive, a hair dryer, and some sharp ass razor blades.
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Re: I didn't get electrocuted the first time...let's try another!!!

Post by Greg_L »

So I know it's New Years Eve, but I still got an hour to go and I'm getting this thing ready while billions of dollars in fireworks are being set on fire in my neighborhood.

First two issues have reared their ugly heads...
1) The power transformer can go in the chassis, or mount to the outside of the chassis like a normal amp. If I mount it in the chassis I will definitely have to cut the eyelet board. If I mount it outside the chassis, the eyelet board can stay as-is and the whole unit can be built like a normal amp. I'm leaning towards outside the chassis, but...

2) The reverb tank has to mount vertically behind the front panel of the cabinet. It's a 4AB3C1B reverb tank. All of that means something. Every single one of those letters and numbers means something specific. For my purposes, right now, the 7th digit is important. My 7th digit is a "B", and that means mount horizontally, open side down. Cool, great, except it won't fit in the bottom of the cabinet, and the inside of the front panel has studs installed just for the purpose of mounting the reverb tank vertically, just as Fender did it. So I'm gonna have to mount the tank vertically against it's wishes, or notch the mounting flange to mount it on the bottom of the cab. I might notch the tank and try it both ways. It doesn't matter that much, but the way the spring transducers hang in the assembly, in theory, kind of depends on it being mounted a certain way. All of that aside, back to issue #1 above, mounting the power transformer on the outside of the chassis gets it really close to a vertically mounted reverb tank. Having all that AC current right next to the sensitive delicate reverb tank might not be a good thing.

So....tl/dr....I have to figure out how and where to mount the power transformer and reverb tank so things will work as they should and not interfere with each other. I'm thinking, fuck it, external chassis power transformer and notch the reverb tank flange for horizontal bottom-of-the-cab mounting.
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Re: I didn't get electrocuted the first time...let's try another!!!

Post by rayc »

I look forward to hearing the results and some happy snaps as well.
Cheers
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Re: I didn't get electrocuted the first time...let's try another!!!

Post by Greg_L »

rayc wrote: Wed Jan 01, 2020 6:02 am I look forward to hearing the results and some happy snaps as well.
Thanks Ray!


I see the problem now....the eyelet board they sent me is the wrong one. I thought this board was awfully long and super busy for this circuit. That's because it's for a reverb/tremolo unit. I was thinking maybe it's for a do-anything type circuit and I'd have to modify it. The board I need is about 1/2 the size and has far fewer eyelets....and no tremolo. But no, this is clearly their "ReVibe" board. So, email sent. I'll have to wait for the right board. It doesn't slow me down from starting the other stuff though.

With the correct eyelet board I can mount the power transformer and filter caps inside the chassis with no problem. Then I can easily use a vertical mount reverb tank. That's what I wanna do. I'll probably order a new reverb tank for vertical mount. That's the way Fender intended it.
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Re: I didn't get electrocuted the first time...let's try another!!!

Post by Greg_L »

Weber got back to me immediately and is sending the correct eyelet board.

In the meantime, I will be getting started with other stuff. I also ordered a vertical orientation reverb tank..$23.00. Cheap enough to get just for an experiment.
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Re: I didn't get electrocuted the first time...let's try another!!!

Post by JD01 »

Good stuff, Greg. Hope this turns out as well as the amp.
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Re: I didn't get electrocuted the first time...let's try another!!!

Post by Greg_L »

JD01 wrote: Thu Jan 02, 2020 6:42 am Good stuff, Greg. Hope this turns out as well as the amp.
lol thanks, me too. :coolstorybro:
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Re: I didn't get electrocuted the first time...let's try another!!!

Post by JD01 »

You reckon you're in a position yet where you think you could actually design and build an amp? Like combine all the things you like in an amp into one amp?
Like a two channel amp with a Fender clean and a JCM800 crunch channel or something?
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Re: I didn't get electrocuted the first time...let's try another!!!

Post by Greg_L »

JD01 wrote: Thu Jan 02, 2020 11:17 am You reckon you're in a position yet where you think you could actually design and build an amp? Like combine all the things you like in an amp into one amp?
Like a two channel amp with a Fender clean and a JCM800 crunch channel or something?
Yeah, I think I could do that. I could do something like that right now with my Deluxe Reverb build. I could convert the Normal channel's preamp to a 2203 pretty easily.

But starting from scratch? That'd be tougher, but it could be done. The preamps are obviously different. The tone stacks are very different. I'm not too sure on the electrical switching required to make it footswitchable though. I've never studied that stuff. And there would have to be some compromises to make both styles run through the same power amp. It could get complicated!
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Re: I didn't get electrocuted the first time...let's try another!!!

Post by JD01 »

Greg_L wrote: Thu Jan 02, 2020 11:32 am But starting from scratch? That'd be tougher, but it could be done... there would have to be some compromises to make both styles run through the same power amp. It could get complicated!
Yeah, I imagine it would be tricky - was just thinking that it would seem like the logical conclusion of all this amp building/learning you've been doing.
Make yourself something truly bespoke and what would be your "desert island amp".
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Re: I didn't get electrocuted the first time...let's try another!!!

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JD01 wrote: Thu Jan 02, 2020 11:38 am
Yeah, I imagine it would be tricky - was just thinking that it would seem like the logical conclusion of all this amp building/learning you've been doing.
Make yourself something truly bespoke and what would be your "desert island amp".
I have thought about it. I've been kicking around the idea of converting my Fender kit's never-used Normal channel to a Plexi preamp. I could do that. The problem in my mind is I don't know what else I don't know to make something from scratch. I can understand and copy and do a build on tried-and-true circuits that already exist. Combining all that into one bad ass switchable amp is above my skill set. The tone stacks alone would be tough, never mind the power amp section.

For me, if I ever really wanted one amp to do it all, I'd convert the clean channel of the JVM to Fender Blackface spec and use this not-yet-built reverb unit in front of it. I'd still be without Tremolo, but that'd get me close.
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Re: I didn't get electrocuted the first time...let's try another!!!

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Greg_L wrote: Thu Jan 02, 2020 12:13 pm
JD01 wrote: Thu Jan 02, 2020 11:38 am
Yeah, I imagine it would be tricky - was just thinking that it would seem like the logical conclusion of all this amp building/learning you've been doing.
Make yourself something truly bespoke and what would be your "desert island amp".
I have thought about it. I've been kicking around the idea of converting my Fender kit's never-used Normal channel to a Plexi preamp. I could do that. The problem in my mind is I don't know what else I don't know to make something from scratch. I can understand and copy and do a build on tried-and-true circuits that already exist. Combining all that into one bad ass switchable amp is above my skill set. The tone stacks alone would be tough, never mind the power amp section.

For me, if I ever really wanted one amp to do it all, I'd convert the clean channel of the JVM to Fender Blackface spec and use this not-yet-built reverb unit in front of it. I'd still be without Tremolo, but that'd get me close.
I know you're not a pedal guy but the Strymon Flint would give you both the classic reverb and tremelo. I finally got a recording of the pedal using my early 70's Twin Reverb. I think it sounds very close.

Here's the reverb comparison. Feel free to let me know which one you think is which. The first solo part is completely dry and then added both reverbs (not at the same time, obviously) as I went. I used my 76 Les Custom, no other pedals. I used a Sennheiser E609 on the left side and a SM 58 on the right mixed equally, no eq or compression.
Lester Twin Reverb Shootout Mk 2.mp3
I'll upload the tremelo comparison when I get a chance.

BTW, I'd love one of those reverb tanks you're making. I'm envious.
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Re: I didn't get electrocuted the first time...let's try another!!!

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Bill L wrote: Thu Jan 02, 2020 1:56 pm

I know you're not a pedal guy but the Strymon Flint would give you both the classic reverb and tremelo. I finally got a recording of the pedal using my early 70's Twin Reverb. I think it sounds very close.

Here's the reverb comparison. Feel free to let me know which one you think is which. The first solo part is completely dry and then added both reverbs (not at the same time, obviously) as I went. I used my 76 Les Custom, no other pedals. I used a Sennheiser E609 on the left side and a SM 58 on the right mixed equally, no eq or compression.

Lester Twin Reverb Shootout Mk 2.mp3

I'll upload the tremelo comparison when I get a chance.

BTW, I'd love one of those reverb tanks you're making. I'm envious.
Cool man. I'm gonna guess the second reverb is the amp reverb. It has a deeper 3D wash to it that sounds like a natural Fender spring reverb to me. Just a guess though. Both sound nice.

My reverb wants and desires are not the usual add-a-little-ambiance thing that most reverbers would use. I want savage stupid drippy over-the-top psycho surfabilly craziness. I also love the "crash" of kicking a reverb tank. :lollers2:
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Re: I didn't get electrocuted the first time...let's try another!!!

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Greg_L wrote: Thu Jan 02, 2020 2:06 pm
Bill L wrote: Thu Jan 02, 2020 1:56 pm

I know you're not a pedal guy but the Strymon Flint would give you both the classic reverb and tremelo. I finally got a recording of the pedal using my early 70's Twin Reverb. I think it sounds very close.

Here's the reverb comparison. Feel free to let me know which one you think is which. The first solo part is completely dry and then added both reverbs (not at the same time, obviously) as I went. I used my 76 Les Custom, no other pedals. I used a Sennheiser E609 on the left side and a SM 58 on the right mixed equally, no eq or compression.

Lester Twin Reverb Shootout Mk 2.mp3

I'll upload the tremelo comparison when I get a chance.

BTW, I'd love one of those reverb tanks you're making. I'm envious.
Cool man. I'm gonna guess the second reverb is the amp reverb. It has a deeper 3D wash to it that sounds like a natural Fender spring reverb to me. Just a guess though. Both sound nice.

My reverb wants and desires are not the usual add-a-little-ambiance thing that most reverbers would use. I want savage stupid drippy over-the-top psycho surfabilly craziness. I also love the "crash" of kicking a reverb tank. :lollers2:
Cool man. I'm gonna guess the second reverb is the amp reverb. It has a deeper 3D wash to it that sounds like a natural Fender spring reverb to me. Just a guess though. Both sound nice.

My reverb wants and desires are not the usual add-a-little-ambiance thing that most reverbers would use. I want savage stupid drippy over-the-top psycho surfabilly craziness. I also love the "crash" of kicking a reverb tank. :lollers2:
[/quote]

I've been shocked at how close the pedal sounds to the real thing. And I certainly understand what you're looking for in the reverb. At least in my case, having shit in a pedal for live use on my amps that don't have reverb or tremelo is worth it. Lugging around a Twin and keeping the volume in check for the room/gig is not always that easy. I would love to have a reverb like you're building. I can't wait to hear some clips when you're done.
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Re: I didn't get electrocuted the first time...let's try another!!!

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Bill L wrote: Thu Jan 02, 2020 2:19 pm

I've been shocked at how close the pedal sounds to the real thing. And I certainly understand what you're looking for in the reverb. At least in my case, having shit in a pedal for live use on my amps that don't have reverb or tremelo is worth it. Lugging around a Twin and keeping the volume in check for the room/gig is not always that easy. I would love to have a reverb like you're building. I can't wait to hear some clips when you're done.

I bought a TC "Drip" for like 40 bucks. It's a passable drip-verb to put in front of a Marshall. Passable, not great. I also use a Boss TR-2 for occasional tremolo on amps that don't have it. Again, passable, not great. Tremolo sort of vanishes though in front of gained up amps. It really needs to be *in* the amp, IMO. Nevertheless, one of my musical projects is a dark punkasurfabilly rock thing that needs these effects.

The Deluxe Reverb amp build I did last year has great reverb and tremolo. Nothing sounds quite as good as the external reverb unit though, for my needs, so hopefully this thing will be awesome. At the very least it'll be a fun project and a cool reverb to put in front of anything else that doesn't have reverb.
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Re: I didn't get electrocuted the first time...let's try another!!!

Post by WhiskeyJack »

This is awesome Gerk. Youve been talking about a reverb tank i think for as long as i have known you. A big nod to you for building exactly what you want man. I cant wait to hear and see the finished product dude.

What are the tubes going to do to the reverb?! Is it just like a preamp thing?!
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Re: I didn't get electrocuted the first time...let's try another!!!

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WhiskeyJack wrote: Thu Jan 02, 2020 3:50 pm This is awesome Gerk. Youve been talking about a reverb tank i think for as long as i have known you. A big nod to you for building exactly what you want man. I cant wait to hear and see the finished product dude.

What are the tubes going to do to the reverb?! Is it just like a preamp thing?!
Thanks man. :coolstorybro:

This is basically an amp - a very small low power single ended amp. Think of the reverb pan as the speaker. It has a power transformer, choke, and tiny little output transformer. It has a preamp and output stage, just like any other amp.

Very basically speaking, the guitar signal goes in and gets split. Half of it gets pushed through the reverb tank via typical tube preamp gain stages and the power tube is the "driver". This typical gain stage network is necessary to cram the signal through the logjam that is the reverb tank....not unlike driving a speaker. After the reverb tank the signal is full wet and very weakened, so it hits one last "recovery" gain stage to get pumped back up. The other half of the signal bypasses all of that and is waiting on the wet signal. The dry signal passes through the other half of that last recovery tube set up as a cathode follower buffer to freshen up the dry signal for it's increased trip through extra cables and wiring. The full wet and dry signal is then mixed to taste through the mixer pot and sent on to the guitar amp.
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Re: I didn't get electrocuted the first time...let's try another!!!

Post by Greg_L »

Minor progress today....installed tube sockets, pots, switches, transformers, etc. Most of the external bolt-on stuff. I'm waiting on isolating washers and grommets for the jacks, so they'll go on later.

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Image

You can see here the power transformer inside the chassis. That's how it's supposed to be...even though I waffled on it earlier. This will let me hang the reverb tank from the front panel, like it's also supposed to be.
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