Yet another locked-down /clear that drawer project ...
Finally I have time to sort my junk and find out that I had most bits for a vintage AC4 build, "à la" :
I'm going to stick to the original as closely as reasonably possible (budget-wise) but a toroidal PT and possibly the addition of a trem/depth 250k pot in place of the fixed value R9 (100k) ...
... any comments/questions/criticisms?
I also wish I could read some suggestions about the assembly of the TV front ...
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Last edited by ChopSauce on Tue May 12, 2020 9:03 pm, edited 2 times in total.
So ... I'm pretty much on my own this time, does it seem. I couldn't find no information at all beyond the above picture of the front & what's mentionned on the Vox showroom website, which claims that:
http://www.voxshowroom.com/uk/amp/ac4.html wrote:In 1961, the TV front cabinet styling of the AC-6 was replaced with what what now be known as "traditional Vox styling" and the amp name went back to AC-2.
Several listings on the internet show AC-2 (pre AC4 name for the same circuit, as well as AC-6) dated from 1960, although with the "traditional Vox styling" front. My guess thus is that the TV front was available only before 1960. I changed the title of my post accordingly.
One more question, if you don't mind:
- do you know what these (picture below) "studs" are, which rise the ground bus well above the chassis
(to be continued...)
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Last edited by ChopSauce on Tue May 12, 2020 9:02 pm, edited 1 time in total.
For the ground bus I think you could just use a small screw (like M3) and fasten it to the chassis with a nut and locking washer. Maybe use a small file and cut a notch in the top for the wire.
Last edited by voskarp on Fri May 01, 2020 8:37 pm, edited 1 time in total.
They're isolated turrets. They have a screw in base that you can use to mount them through a chassis, and then solder to the top part. I've used them, got a few in the past in a shipment from I think Sluckey or Bob S. (Or maybe both?) At any rate, I love them. I use them sparingly as my supply is dwindling
You're feeding my curiosity beyond what I thought I needed. The kind of turrets I was talking about actually are ground points so isolation is not needed, but now that I know, I can see one of these isolated turret, which seems to be used as the connector for the tremolo footswitch...
8€ plus shipping to France seems overkill, but at least you helped me with the layout.
So far, I'm still working on that thing I'd like to call "cab", though. I'm keeping the best for the end...
ChopSauce wrote: ↑Fri May 01, 2020 12:41 pm
Thanks for the suggestion! I'm not sure how a zinc-plated (mostly) screw will "take" the solder but that's an idea...
My best B plan remains a solder eyelet screwed above a spacer, though.
Heat is the solution to everything (except soldering germanium transistors)
I think you're right, afterwards. I'll probably machine 2 screws to be used as ground turrets. Once screwed through the chassis & welded in place, they will be closer to the original design...
Those isolated turrets are another kind though, but as it is a "clear that drawer" kind of build, I'll probably use some pieces of eyelet boards...
Soundwise, I'm not sure at how it will sound. I've read that several builders changed the grid resistor R8 (5M6) of the EF86 for a lower (eg: 1M5) value, following the example of the AC15 (out the top of my head) which has otherwise different values, to make the amp sound "fuller" but I'm not sure at how it translates in terms of EF86 settings. I'll do the maths as per Merlin's instructions (1) but so far I am only concerned by copying the schematic as closely as possible.
Anyway, so far, not so bad...
DSC_5885.jpg
DSC_5890.jpg
... & I'll weld the two parts together when I'm done with the drilling for the isolated turrets, of my own...
DSC_5892.jpg
To paraphrase Uncle Doug:
- when I write "clear that drawer" well, I mean it!
_
I used a router and a copying bit to follow an aluminium ruler screwed from behind, where it won't show after assembly - for the large portion. The sides I sawn roughly, then reworked following pencil marks, using the router.
Welded chassis, almost ready for paint...
DSC_5894.JPG
... but the woodworking is a pain - even though I did not event attempt to make finger joints - as shown by the poor alignements on the left.
My small workshop is all dedicated to metalworking and mechanics...
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