69 Spec 1987

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revolver1
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69 Spec 1987

Post by revolver1 » Sat Apr 13, 2019 11:03 am

I really fancied doing a 69 spec 1987 with the rectifier diodes coming straight off the P.T and the snubber off the fuse holder. I had also managed to get a set of Iskras together all but the swamp resistors that are Piher. So I ended up doing a West Coast mod on my other 1987 and set about getting this one done.

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revolver1
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Posts: 454
Joined: Thu Jul 28, 2011 1:37 am
Just the numbers in order: 7

Re: 69 Spec 1987

Post by revolver1 » Sat Apr 13, 2019 11:38 am

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I explained in detail in another build post (Late 68 early 69 Superlead) about the damp circuit boards causing leaking DC onto the inputs, well this was the other amp. I explained how I fixed it so I won't repeat myself. In short I ran the amp wide open on soak for about 7 to 8 days till it quietened down and stopped crackling and popping, essentially the board dried out from the heat of the trannies and perhaps a bit of mild tracking of voltage. I now use a Lihel DC filter for insurance to make sure no DC can get into my effects but regular use should keep it in check.

revolver1
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Posts: 454
Joined: Thu Jul 28, 2011 1:37 am
Just the numbers in order: 7

Re: 69 Spec 1987

Post by revolver1 » Sat Apr 13, 2019 11:48 am

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revolver1
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Posts: 454
Joined: Thu Jul 28, 2011 1:37 am
Just the numbers in order: 7

Re: 69 Spec 1987

Post by revolver1 » Sat Apr 13, 2019 12:57 pm

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I got this Head Shell from Chris Uff here in the UK. I ended up putting my West Coast modded 1987 into this shell and this 69 spec 1987 went into the StoneAge head shell.

Specs;

It's pretty much a stock 69, only a few slight variations.

Split Cathode
220uf / 820r on V1
.68uf / 2.7k on V1
No .68uf cap on V2
.0022uf on second coupling cap
500pf caps on mixer and tone stack
47k negative feed back on 8ohm tap
2x 8.2k 2watt preamp dropper resistors
5000pf bright cap

Filtering;

100uf Mains
50uf Screens
50uf Phase Inverter
32/32uf Pre amp

Tubes;

pre amp = NOS Mullard Ecc83
power = NOS Svetlana Winged C


So It sounds great, needs more playing in but it's great. This will pretty much be my number 1 amp. :thumbsup:

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