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12xxx build with a couple of pics

Posted: Mon Jan 28, 2013 10:48 pm
by BrownSound1
Ok guys, finally getting to post a couple of pics. Not as pretty as most of the ones I see built from you guys, and certainly not my best wire work.

Now in the power section pic, I have the 5.6k grid stoppers...those have since been changed out to the period correct style with 1.5k ohm resistors. Also, forgive me for the lar/mar PPIMV.
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Re: 12xxx build with a couple of pics

Posted: Tue Jan 29, 2013 12:17 am
by julkke
Very very nice man!! Change your power cord black and white wire positions aroud as now you are fusing the neutral instead of the live. I know it is that way in Metro instructions and old marshalls but it's wrong! Live has to go to the fuse right after entering the amp!

Re: 12xxx build with a couple of pics

Posted: Tue Jan 29, 2013 1:04 am
by BrownSound1
*Deleted

Re: 12xxx build with a couple of pics

Posted: Tue Jan 29, 2013 1:33 am
by BrownSound1
julkke wrote:Very very nice man!! Change your power cord black and white wire positions aroud as now you are fusing the neutral instead of the live. I know it is that way in Metro instructions and old marshalls but it's wrong! Live has to go to the fuse right after entering the amp!

Thank you very much.

Yes you are correct that technically the neutral should not be fused. It is against the code for sure here in the US as you can't fuse neutrals or grounds.

Re: 12xxx build with a couple of pics

Posted: Tue Jan 29, 2013 1:00 pm
by Strat78
Looks great, think I'll pick up one of those PT's this week, though it is odd having the heaters not exit on one side only. You should still grab an attenuator so we can really hear that PT in action. What value do you have for the mix cap?

Re: 12xxx build with a couple of pics

Posted: Tue Jan 29, 2013 1:40 pm
by BrownSound1
Strat78 wrote:Looks great, think I'll pick up one of those PT's this week, though it is odd having the heaters not exit on one side only. You should still grab an attenuator so we can really hear that PT in action. What value do you have for the mix cap?
Thank you! That is a 500 pf that I got from Valvestorm.

The PT heater wires do irritate me a bit being on opposite sides, but for the price I can't complain. I do plan on getting an attenuator. The master volume is just a stand in until I do. Got to keep the wife happy. :)

Re: 12xxx build with a couple of pics

Posted: Wed Jan 30, 2013 2:46 pm
by vanhalen5150
What PT is that?

Yeah, I always wondered about that neutral to fuse. So your just switching the black and white from the wall around? I havent followed the path on that but how does that work with the switch?

Re: 12xxx build with a couple of pics

Posted: Wed Jan 30, 2013 3:19 pm
by BrownSound1
vanhalen5150 wrote:What PT is that?

Yeah, I always wondered about that neutral to fuse. So your just switching the black and white from the wall around? I havent followed the path on that but how does that work with the switch?

The PT is a ClassicTone.

To switch the fuse, you unhook the wires connected to the fuse (white on the cord and whatever neutral is on your PT) and splice them together. You then unhook the black wire in the cord from the switch and hook it to one side of the fuse, then add a second wire from the fuse to the switch.

Julkke was right to bring that up, as the old way is very dangerous. I hooked it up the old way because I was just following the instructions, and not really thinking. I know better, and should have done it right. I guess if you are trying to make a period correct replica, then you can pass it off that way...kind of like George does on his, as well as using the Bulgin connector on his 45/100. Those aren't legal anymore either, and it seems he mentioned it years ago. At any rate I switched mine to the hot being fused, which took 10 minutes tops to change. The added black wire matches my power cord wire, which is 18awg.

Re: 12xxx build with a couple of pics

Posted: Wed Jan 30, 2013 5:59 pm
by emmjaydubya
Funny, I did exactly the same thing, blindly followed the 100 watt instructions when common sense was tellling me otherwise. I'm changing the fuse over to the line side also, before I fire it tomorrow.

Re: 12xxx build with a couple of pics

Posted: Thu Jan 31, 2013 12:13 am
by julkke
The instructions should say something about this, and there should be a sticky of this in the forum! There is no reason anyone would want to fuse just the neutral!

Re: 12xxx build with a couple of pics

Posted: Fri Feb 01, 2013 4:03 pm
by BrownSound1
I fired the old girl up last night...no sparks or disasters, but I haven't opened her up good yet as it was a single speaker. Played it whisper quiet. Next weekend I'm getting a proper cab and hope to do some sound clips.

I must admit it was very satisfying to hear a guitar through an amp I built. Of course, I looked at damn near every thread in this section multiple times, and couldn't have done it without you guys, even if I didn't ask a million questions. I had them, mind you, but I used the search function. :D I have EH6CA7s and JJ 12AX7s in now (thanks Valvestorm, you are a true hero). Had a bit of a time biasing, and had to go down to a 27k bias resistor to get the proper bias. That bothered me a bit, because I was being overly cautious and worried at that point. I do have a couple of old Raytheon 12AX7As that I got out of an old Akai reel-to-reel from the early 60s that I might try out just to see how they sound. They look pretty good, but I know they have never been changed. Anyway, what a rush!

Re: 12xxx build with a couple of pics

Posted: Fri Feb 01, 2013 7:15 pm
by emmjaydubya
Congrats!! What a coincedence, I'm firing mine up tonight too! :clap:

Re: 12xxx build with a couple of pics

Posted: Fri Feb 01, 2013 8:10 pm
by Strat78
BrownSound1 wrote: Thank you! That is a 500 pf that I got from Valvestorm.
I only mention the mix cap because with a PPIMV, having something like a 250pf seems to make it less brittle, though that might only apply to a mod5 type set up. Anyway, let her brake in nicely then go back in and do the fine adjustments, though I aways come back to the basic 12XXX spec. Hell, you might as well try the mod5, since you are half way there. :)
:popcorn:

Re: 12xxx build with a couple of pics

Posted: Fri Feb 01, 2013 11:06 pm
by BrownSound1
Mod 5 isn't for me I don't think. Fact is this MV is gone as soon as an attenuator enters the picture.


Emmjaydubya, congrats! I hope it blows your doors off.

Re: 12xxx build with a couple of pics

Posted: Sat Feb 02, 2013 9:39 am
by Tone Slinger
Post a pic of the fuse/ground thingy you were talking about. I have mine wired per NightOwl instructions (there's no Metro 12xxx build istructions, only '69 super lead, as y'all know).

I hear ya about the MV/s. I yanked mine and UNcascaded the the front end. Getting mine to stock for the FIRST time. THANKS again Vanhalen5150 for making me 'see the light' with the great clips of your stock Metro 12xxx/kit clips. Now, WHICH attenuator do I need............ The dual volume UA looks good (but wow what a price :shock: ).