pins and switches

[steve-o]

Hey all,
I'm drawing up the layout for my first 18-watt combo build. I'm sure those of you with a lot of experience have answered this question for beginner's before, so feel free to just direct me to any webpage or post where this is answered.
How do you wire the pins of 12ax7's, EL84's and EZ81's?
Also (as I'm building this circuit in the chassis of a blues Jr.), I'm using a carling 3-way switch so that I have a standby mode. I'm having trouble finding an amp schematic where it shows how this should be wired. Any hints?
Thanks so much for your time!

[jimipage]

How do you wire the pins of 12ax7's, EL84's and EZ81's?

check this out:
http://www.18watt.com/storage/18watt%20 ... 20Gabi.pdf

[dehughes]

Hey Steve! Sorry I didn't call you back right away...busy days...

That 18watt Layout that jimipage pointed you towards is perfect. That'll explain all that you need, especially if you use the tube info from http://www.nj7p.org/Tube.php Use this for detailed pin-out schematics...

Regarding the on/off/standby switch, what about asking the place that sold it to you? Was that Apex Jr.? I can't seem to find anything online at present that would show you how to wire it up...

Lemme know when you'd like to come by and finish the schematic and layout. I'll be around...

[steve-o]

Hey guys, thanks for your help!
Us Oregonians have to look out for each other. (It's been a while since I've been through Monument.)
I'll talk to my man at s2 to see if he's got any hints. But, in looking at the switch, there are four leads. So, I'm thinking that the 18-watt schematic will work fine since the power and standby switches each have two leads on them. I'll just need to figure out which leads on the 3-way switch correspond to standby or power.
Here's to schematics!
And to pastries and peets coffee!
Alright, I'm off to bed...

[David Root]

That switch is called the DPTTP, or Double Pole Triple Throw Progressive, at least that's what Westlabs calls it. One side of it has "Circuit 2" printed on it. The two lugs on that side are for the standby to play connection. I've used three of 'em so far but I'll be a monkey's uncle if I can remember how I wire the whole thing without having the switch in front of me. (Which reminds me of a little couplet I saw on a wine bottle cork years ago, "I'd rather have a bottle in front of me than a frontal lobotomy").

Allen Amps also has it, for $2.00 less, but Westlabs only charges $5.00 delivery, so if Allen charges $7.00 delivery, it's the same deal.

Anyway, it's an excellent heavy duty switch. Just put your DMM on it and switch it, you'll be able to figure it out, that's how I did it.

[David Root]

It's coming back to me now. The off position is with the switch set opposite from the end of the switch body that has no connection lugs, the middle position is for the AC on and the third position is HT on, "Circuit 2" side.

[dehughes]

I can't wait for your amp to be finished, Steve. I'm really curious to hear how it sounds.

FWIW, today I wired up V1 in my 12AX7 channel with paralleled triodes and don't really care for it. It's a bit too "hard"....and I even wired it up in such a manner as to more thoroughly emulate what a jumpered AC30 front end would sound like... You can still try yours in parallel, though, as the preamp topology is different and may actually benefit from it....but then you'll need your new soldering iron wand first.

[steve-o]

Thanks David(s)!
Yes, I just got the switch figured out with the DMM like you (David R.) suggested. I think the old blues jr. circuit had some sort of delay on it from the time you would flip the switch to "on" to the time the tubes would amplify. I'm really excited to have an actual standby position!
As for the parallel triodes in the first stage, I'm probably just gonna' stick with the schematic as drawn for now.
See my post on the iron...
peace out.