Plexi please.....

[Lt. Bob]

man you do good work .... keep it up so when I croak my wifey'll have two of the earliest gergamps to sell at inflated prices

Well if she can't sell them for huge prices they can always come back here with me.

trust me ...... when you've heard I'm dead plan on calling my wife and renting a truck! lol

[Greg_L]

Moving along....finished wiring up the output tube sockets. They're all paired up, plates and screens linked, screen grid resistors and bias checking resistors installed, all cathode grounds done. All that's left for these tube sockets is two wires from the PPIMV which will come later. Also some preliminary filter cap connections got done.


And this is the point where now the rear panel stuff can get started. AC inlet, mains fuse, power switch, done. I could technically turn it on now. Nothing else is hooked up but the power transformer can get some juice if I wanted to....which I do not. The bundle of green/yellow/orange wires are from the output transformer secondaries and they correspond to the 4/8/16 ohm speaker taps. They'll get connected to the impedance selector. I'm also gonna put the presence control on the rear which will negate one speaker jack...unless I drill a new hole for it. Haven't decided yet. The presence is going to the rear because I wanna put the PPIMV on the front. It gets adjusted way more than presence does. Ideally I'd like the presence to be on the front like normal, and also have the PPIMV up there too, but it won't all fit. More on that later. But this is where it's at for today.

[rayc]

PPIMV - Post or Pre?
Very tidy stuff.
My presence control is in a speaker jack hole on the back. It is, pretty much, set n forget as is the cab connection so I'm fine with it there.
Very tidy stuff. Almost abstract art if I squint.

[Greg_L]

PPIMV - Post or Pre?
Very tidy stuff.
My presence control is in a speaker jack hole on the back. It is, pretty much, set n forget as is the cab connection so I'm fine with it there.
Very tidy stuff. Almost abstract art if I squint.

Definitely POST on these things. Pre phase inverter volumes do not work well on these types of amps.

[Greg_L]

Pretty much finished with the power supply and rear panel stuff. Again I'm going with a custom grounding scheme which hopefully makes sense and works out. Not much to describe in today's pics. Just little steps of progress. Front panel stuff coming together too now. It looks messy but it'll be buttoned up later.





And this is about to happen. Had to draw up the board. I'm using a period correct size and type board but I have to make the layout from scratch. Old Plexis had the rectifier and filter caps on a separate board. I was gonna do that myself but I decided to use a more modern chassis mounted filter cap configuration and make the rectifier fit onto the same board as everything else. I think it'll work.

[rayc]

Tidy hand writing too.
Excellent stuff.

[Armistice]

You should collaborate with @Tadpui - he lives just up the road, right? - and do a video of one of these builds. I only know what you're doing at quite a high level but I find it fascinating, and given how many guitarists there are in the world all searching for the Holy Grail of tone via various amps, I reckon you'd get a real following.

I know. You can't be bothered. I probably couldn't be either if I was that good at doing something. Video is just too much work.

[Tadpui]

@Armistice I'd really love to film @Greg_L making an amp. I know it's a lot of boring stuff inbetween all of the cool milestone photos that we see here, but I agree that there'd be an audience for an amp build video if we could find a way to pace it right. I was actually just thinking of that the other day. I'm not sure that Greg would want me hovering over him with a camera for 2-4 weeks though

[JD01]

@Armistice I'd really love to film @Greg_L making an amp. I know it's a lot of boring stuff inbetween all of the cool milestone photos that we see here, but I agree that there'd be an audience for an amp build video if we could find a way to pace it right. I was actually just thinking of that the other day. I'm not sure that Greg would want me hovering over him with a camera for 2-4 weeks though

[Greg_L]

There are two significant problems for me specifically with video:
1) I don't know how to do video. Not something good anyway. I can prop my phone up and film whatever it sees as one continuous shot, but I can't edit video. No idea how. It would take someone skilled like @Tadpui to hang around and put it all together.
2) An amp build takes long enough without adding another equal or greater amount of time fucking with cameras, angles, filming, editing, etc.

And really the parts that matter the most are the parts that are the most time consuming and would be the least interesting to watch. Do you want to see me sitting there staring at a schematic while my internal dialogue goes through the figuring out process? I guess I could narrate it maybe? Or drawing the board layout? That's not exactly riveting stuff lol. The "action" bits...the parts where I actually put things together are stuff that really anyone could do. It's not anything special to mount a pot to a chassis and solder a wire to it. I wish I could make an interesting video of one of these builds but I don't think it's possible for someone like me.

Having said all that I'll give something a try maybe when I get to building the board.

[Armistice]

I completely get what a pain in the arse it would be and how long it would take to do, but I think it'd be interesting.

And I think it's actually some of those bits that you don't think are all that exciting that highlight the skill of the work and the intensity of the process.

I seem to recall in a previous build you telling us about what a pain in the butt it was to twist all those wires the way you have, but that it was the proper way to do it from an engineering standpoint. And where and why you would use expensive componentry and where and why it doesn't matter so much.

You're right, it would be monstrously difficult to film yourself doing all this stuff, and so that's sort of why it will never happen - who has the time? But it would be fascinating to a lot of people, nonetheless, I suspect.

[Greg_L]

I completely get what a pain in the arse it would be and how long it would take to do, but I think it'd be interesting.

And I think it's actually some of those bits that you don't think are all that exciting that highlight the skill of the work and the intensity of the process.

I seem to recall in a previous build you telling us about what a pain in the butt it was to twist all those wires the way you have, but that it was the proper way to do it from an engineering standpoint. And where and why you would use expensive componentry and where and why it doesn't matter so much.

You're right, it would be monstrously difficult to film yourself doing all this stuff, and so that's sort of why it will never happen - who has the time? But it would be fascinating to a lot of people, nonetheless, I suspect.

Maybe I'll make a crappy little video explaining what I've done so far.

[WhiskeyJack]

But it would be fascinating to a lot of people, nonetheless, I suspect.

Seconded.

it would be monstrously difficult to film yourself doing all this stuff

Also Seconded.

[WhiskeyJack]

Stuff is looking good @Greg_L

You should get those board sketches tattooed on you. those would be pretty bad ass little pieces of skin art.

[Greg_L]

Stuff is looking good @Greg_L

You should get those board sketches tattooed on you. those would be pretty bad ass little pieces of skin art.

Haha and a handy reference too! As long as it's somewhere I could see it myself.

I have thought about maybe getting a 12AX7 pinout....

[WhiskeyJack]

Stuff is looking good @Greg_L

You should get those board sketches tattooed on you. those would be pretty bad ass little pieces of skin art.

Haha and a handy reference too! As long as it's somewhere I could see it myself.

I have thought about maybe getting a 12AX7 pinout....

Yea dude. that would be pretty killer actually.

if you get it as a tramp stamp I will pay for it. Scouts Honor! NVM. You can't see it there. Scouts Honor revoked.

[Armistice]

God, just imagine having to explain to everyone what your obscure circuitry tattoo actually meant...

[Greg_L]

God, just imagine having to explain to everyone what your obscure circuitry tattoo actually meant...

I wouldn't. I'd just say "it's a vacuum tube pinout" and I guarantee no one will want me to go any further.

I actually just got back from my bro-in-law's tattoo shop. I was gonna get the 12AX7 tonight but he's too busy. There were like 18 people ahead of me.

He said he'd fit me in but I didn't wanna take the spot of a full-price-paying customer. I can go back whenever.

[Greg_L]

Okay today's work.....

PPIMV. This is in the "Presence" spot. This will allow me to use this amp for things other than non-mic'd stadium tours.



And the Presence control has been moved to the back. I drilled a hole. I wanted to keep the two speaker jacks. I don't really fiddle with presence so it's fine back here. I leave it around 5 and forget about it.


I also re-did some of the wiring around the power supply and output tube sockets. You probably won't notice unless you A/B against previous pics, but trust me some of this is different, and I think better.


Looking at the back of the front panel...the pots, where the four input jacks will go, and pretty much where the board will be.


And the "star ground". This is one of three main signal grounds in the amp. I made this star ground out of four solder lugs for the preamp filter cap and to collect all of the preamp and tone stack grounds at one spot. Each part of the circuit will have it's grounds grouped together. This is the preamp spot. This amp *should* be very quiet.


Next will be the input jacks and building the board. I'll try to make some video of that stuff.

[Lt. Bob]

man ..... so nice!