Gulsekt-88!

[EtherealWidow]

A=Polyester
B=Polyprops

Yes?

[Meat&Beer]

A=Polyester
B=Polyprops

Yes?

Um, close.

The comparison has majority Polyester, with two of the eleven being Polystyrene for one, either A or B. Then the other A or B is Orange Drops throughout.

[EtherealWidow]

Whoops. I completely misunderstood. Alright then, B is orange drops.

[Meat&Beer]

It's been a while! Lots been happening behind the scenes though. Gutting the Proto and starting to install parts into the freshly painted new chassis has begun tonight!

I won't give away any surprises yet, but some really cool stuff is in the works for the final build. It should happen relatively fast into the new chassis, then I'll be making the head cabinet.

For those interested, it's about to get interesting-er.

(ps, OD's are Caps A, sorry Etheral! I was probably too vague and mysterious from the start about that whole thing. I still found it an interesting experiment even though it's been done to death.)

[Meat&Beer]

Things are coming together rather nicely... A couple hiccups from some unforeseen things, but I think recovery was pretty much seamless. Otherwise, very smooth and right to the plan!

I wanted access to the bias adjustment on the back. Having the probe sockets back there was easy enough, because the output tube got relocated back there. But then how do I get to the pot? Top of the chassis like in the prototype, BOO. Couldn't move the bias ckt back there, no room. Didn't want to run long wires back to the pot either.

For the life of me, I couldn't find a super long locking shaft 50K(ish) pot. They probably don't readily exist... I've seen many old radios and receivers with an extended shaft, so I adopted that idea. The shaft coupler is from a dilapidated oscilloscope. (A lot of parts in here are, surprisingly!)

The 1st filter cap was suspended by itself, and I didn't really like that. Not everything transfers 100% from layout to creation, so a support off the turret board turned out a treat. Hiccup averted!

Hoping to have it roarin by this coming weekend.

Stoked!

[Meat&Beer]

Well here it is, done! Finished it up this past Sunday night.

It fired up with zero problems, thankfully. (Aside from me wiring a pot backwards, and forgetting to install the Zobel network.) Really loving this amp, and so is everyone who tries it out.

You'll notice a jack on the back labeled "Hell Hole". This is the other half of the PI, and will send to an external box (yet to be created/designed) for direct recording purposes additional to the traditional mic'd cabinet. It'll have a full on tone stack, switchable line/mic level, bal/unbal, with 1/4" and XLR outputs. Can't wait for that, gonna be such a useful and fun toy!

The only thing I've been trying to "fix", is that there's a very slight hum. A "b" note on the guitar. It's not coming from any of the preamp tubes, as pulling them doesn't get rid of it, so focus is on the KT88 filaments. I've tried DC elevating them, hum-bal pot, faux center tap... Any ideas? It's a single ended amp, so there's bound to be noise due to their nature, and not having the PP canceling benefit. The hum was in the prototype, so it's nothing new.

Hoping to get around to recording some clips soon! So busy though, most everyone can relate I'm sure. Sounds essentially just like it's previous form though, if you couldn't guess.

[jazbo8]

Looks awesome! How did you do the lettering on the panels?

[Meat&Beer]

Thanks jaz!

I use a program called Flexi Sign Pro, but anything that can save as a vector file would do. Draw up a rectangle and circles to scale of the amp, load in the font you want to use and lay out all the words. I had them printed at a local sign shop for $40, this was for two sets in case I screwed up...

At this point, the chassis was drilled, painted black, and sanded with 800. Apply the decals "wet" to allow wiggle room, let dry for at least 24 hours to expel all moisture. Then, clear coat!

I like this method because you can do absolutely anything you want. It's very well protected in the end, and looks as good as you make it. The only downfall that I can tell so far, and I'll let everyone know just in case they want to try it, is when you tighten hardware down, the clear gets a little pushed away and makes a ridge.

A lot of people like to leave their chassis/ blank lumnum I've noticed, you could always have decals made for it in this fashion also and stick em right on. I'd just worry about longevity that way, thinking of fingernails and cleaning cloths catching an edge of a decal, or leaving little cloth fibers stuck in places.

[matt h]

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[LeftyStrat]

Somehow I missed this thread. I've always disliked single ended amps. Stiff and lifeless. That a PPIMV works well in a Marshall suggests there's magic in that long tailed pair.

Great idea on this. Where do you buy the 'something' that the other side goes to?

[matt h]

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[statorvane]

I've always disliked single ended amps. Stiff and lifeless.

I used to think the same thing until I built a AX84 SEL poweramp driven by a 1987 Plexi preamp. http://s165.photobucket.com/user/JKCavi ... exi?sort=3

It is an "upgrade" to a P1 eX I had build about 10 years ago. Pictures show a TungSol RI 6550. I have since tried several Sovtek 6550WEs and they have a bit more headroom. Both sound good.

[EtherealWidow]

It'll have a full on tone stack, switchable line/mic level, bal/unbal, with 1/4" and XLR outputs.

What sort of values were you thinking of for the tone stack? Is it only going to be for guitar?

The amp looks great.

[xtian]

Your control panel wiring is especially nice!

What technique is your panel labeling?

[Meat&Beer]

What sort of values were you thinking of for the tone stack? Is it only going to be for guitar?

The amp looks great.

Thanks Ethereal! Since this output is so big, something like 85V p-p, and I'll be using it for the input of a mic/instrument level preamp (.5v-4v), I can deal with a lot of loss. I haven't experimented yet, but I'm pretty sure a 4 knob stack is going to go in it, just like a guitar amp tone stack.

Yes, this recording box will be mostly proprietary to this amp, so just for guitar played through the amp, and then from the amp into a recording console or interface.