NVAD 73 Quad Reverb hatchet job

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Re: NVAD 73 Quad Reverb hatchet job

Post by StrummersOfThunder »

Nice job

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Re: NVAD 73 Quad Reverb hatchet job

Post by tubeswell »

Slightly more progress on the cab 2-day. I'm also on the hunt for 1/2-doz 73-era amp witch-hats if anyone has a few floating around.
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Re: NVAD 73 Quad Reverb hatchet job

Post by RectifiedAmps »

tubeswell wrote:I'm suspicious of the old SF waxed eyelet board. Sometime in the past someone has jumped several components off the board, and have even remounted part of the PI circuit onto a tag terminal strip. Methinks I'll replace the main board eventually and remove all these lazy band-aid fixes.
I had a SF Twin Reverb with this issue recently. The waxed board was measuring >100VDC on its surface in places, about 5mm away from any high voltage DC eyelet. The biggest tell was the pots - they had DC on them no matter how many tone/coupling caps were replaced. Bastard of a job but massive improvement in the end.

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Re: NVAD 73 Quad Reverb hatchet job

Post by tubeswell »

Yeah the waxed boards was one of the dumbest things CBS ever thought of.
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Re: NVAD 73 Quad Reverb hatchet job

Post by tubeswell »

Cab done (bar the occasional new knobs still needed)
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Re: NVAD 73 Quad Reverb hatchet job

Post by RectifiedAmps »

It's looking great - nice job! Any luck sussing out the issues with the PT bias winding, or are you still thinking of replacing it?

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Re: NVAD 73 Quad Reverb hatchet job

Post by tubeswell »

The semi-loaded voltages are in the ballpark. 360-0-360VAC across the HT secondary and 6.4VAC on the heater winding with only pre-amp tubes loaded. The bias trannie yields a steadyish voltage with a range of -27 to -59VDC (which will need reducing somewhat - otherwise biasing will be a bit fiddly).

I've done all the caps and scraped quite a bit of wax off the main board, and I've replaced the output tube sockets. I want to tidy it up a bit more before test firing it.
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Re: NVAD 73 Quad Reverb hatchet job

Post by tubeswell »

All finished for now. I'll lug it to a gig this weekend

(Sorry about the lack of a front shot - Smallest I could get the picture file down to was 170k)
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Re: NVAD 73 Quad Reverb hatchet job

Post by Anvil Amps Alan »

CE Distribution has the knobs and chrome straps, corners etc.

Some of the stuff i have been doing recently: https://www.facebook.com/Muddlearth/
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Re: NVAD 73 Quad Reverb hatchet job

Post by mrmofo »

Single coil wrote:I understood some of that :mental:
if this was a music theory thread Anfita would have been on call.
There are still some that think the neck PU is moved to accommodate the extra frets which only proves they cannot detect the difference in length of each.

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Re: NVAD 73 Quad Reverb hatchet job

Post by StrummersOfThunder »

tubeswell wrote:All finished for now. I'll lug it to a gig this weekend

(Sorry about the lack of a front shot - Smallest I could get the picture file down to was 170k)
Good luck with the gig :)
Photo of it bursting into flames on stage or it never happened.

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Re: NVAD 73 Quad Reverb hatchet job

Post by tubeswell »

I personally haven't got a picture yet, but we did bump into Mel Taylor's (Ventures Drummer) younger sister who was in town on a tourist trek, and who walked up and introduced herself to us after we'd ripped a set of Ventures tunes. Her other brother (Larry Taylor) was the bassist in Canned Heat.
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