1st time builder - 12xxx '68 EVH spec kit journal

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Re: 1st time builder - 12xxx '68 EVH spec kit journal

Post by YMI5150? » Wed Jun 16, 2010 2:33 pm

I've been doing some homework and for my clarity and any other new builders that reference this thread, the 4 caps on the power board (see attached) are equivalent to F2-F5 caps mounted directly to the chassis on the later 68 kits, and can be wired to the overall circuit in a similar fashion, correct?

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Re: 1st time builder - 12xxx '68 EVH spec kit journal

Post by YMI5150? » Wed Jun 16, 2010 4:47 pm

Just noticed that the 100w plexi instructions only say to jump pins 4 & 5 on V3 (red heater wire) and run to pin4 of V1 and V2. Older 68 wiring diagrams show pins 4&5 jumped on V1 and V2. Which option should I choose?

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Re: 1st time builder - 12xxx '68 EVH spec kit journal

Post by Vegard » Wed Jun 16, 2010 5:39 pm

Ok, read the manaul to see what you was talkin about. At least one of the red wires needs to jump pin 4 and 5 on V1, V2 and V3. I always run the (red) wires both through pin 4 and 5...
Metroamp builds : 68` 50w (x2), 69` 100w, 68` 100w 12xxx (x3), JTM45/100, JTM50(x2), 2203

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Re: 1st time builder - 12xxx '68 EVH spec kit journal

Post by YMI5150? » Thu Jun 17, 2010 9:29 am

Did a little work on it this morning before work. bridged pins 4&5 on V1 and V2, added buss wire to ground F1 (negative to ground lug). Also built out the power board. as always, please check my work. Thanks guys!

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Re: 1st time builder - 12xxx '68 EVH spec kit journal

Post by YMI5150? » Thu Jun 17, 2010 10:10 pm

okay, so I tried interpolating the PT wiring from several different schematics. there's not one exactly like this setup that I have found. one has the power board but a different transformer and no variac switch. anyway, please verify my effort. I think its correct.

Cheers

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Re: 1st time builder - 12xxx '68 EVH spec kit journal

Post by YMI5150? » Fri Jun 18, 2010 9:04 am

wired the 6 volt indicator light to the heater circuit at V7.

Looks like step 10 is about complete, minus the F5 connections.

If I could get verification on progress, that would be great. A lot of that step involved the filters which I have on the power board of course...

Thanks!

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Re: 1st time builder - 12xxx '68 EVH spec kit journal

Post by Vegard » Fri Jun 18, 2010 10:11 am

Looks good so far :)
Metroamp builds : 68` 50w (x2), 69` 100w, 68` 100w 12xxx (x3), JTM45/100, JTM50(x2), 2203

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Re: 1st time builder - 12xxx '68 EVH spec kit journal

Post by YMI5150? » Fri Jun 18, 2010 10:27 am

thanks. does it matter where the 110 red wire routes? I have it along the outside but it runs on top of the twisted pair secondaries. might not be good.

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Re: 1st time builder - 12xxx '68 EVH spec kit journal

Post by Vegard » Fri Jun 18, 2010 10:34 am

Do you mean the 220V primary tap on the PT?
Metroamp builds : 68` 50w (x2), 69` 100w, 68` 100w 12xxx (x3), JTM45/100, JTM50(x2), 2203

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Re: 1st time builder - 12xxx '68 EVH spec kit journal

Post by YMI5150? » Fri Jun 18, 2010 12:26 pm

120 for US but yes.

see attached with arrow pointing to wire in question. is it okay to lay on top of the secondaries?

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Re: 1st time builder - 12xxx '68 EVH spec kit journal

Post by Vegard » Fri Jun 18, 2010 1:29 pm

Not sure about that one. Probably works...
I have routed mine along with the blue bias tap
Metroamp builds : 68` 50w (x2), 69` 100w, 68` 100w 12xxx (x3), JTM45/100, JTM50(x2), 2203

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Re: 1st time builder - 12xxx '68 EVH spec kit journal

Post by vanhalen5150 » Sat Jun 19, 2010 9:17 am

Brought mine(red) around with the blue and twisted with the black from the AC cord to the switch. Here is a photo from NightOwls. I did the same but moved the black/red bundle to the inside outer edge of the aluminum tranny mount.

Here is one of Georges builds. He just budles everything tigether.

You need to get this moved to the 12000 threads! Nobody knows your here. :lol:

PM George to move ya..
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Re: 1st time builder - 12xxx '68 EVH spec kit journal

Post by YMI5150? » Sat Jun 19, 2010 12:56 pm

thx for the pics. hope to get some work done this weekend. is now the time to consider upgrades to grounding schematics?

I've PM'd George and no reponse or action so if you there are any other moderators that could move the thread that would be great.

Cheers and happy fathers day to any dads out there. milk the day for lots of build/play time... :D

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Re: 1st time builder - 12xxx '68 EVH spec kit journal

Post by YMI5150? » Sat Jun 19, 2010 9:53 pm

installed power cord
rerouted tap to 16 ohm
started assembling pots. need to grab a new tip for the iron to get more heat to the backs.
laid the power board in and attached two blue wires to variac switch, black to ground on power wire ground pin, and red to HT fuse
rerouted 120 lead from primary like other builds

look about right?

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need closeup of low voltage pot attachment on standby switch. cant tell which leads to attach.

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Re: 1st time builder - 12xxx '68 EVH spec kit journal

Post by YMI5150? » Mon Jun 21, 2010 12:05 pm

wrapped up the controls and input jack yesterday. prepping the main circuit board now. kit only came with 6 board posts (believe it should have come with 8) please confirm.

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Starting to think about testing. Need to research biasing methods. can anyone provide a link?

Cheers

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