1964 JMI Era VOX AC30 replica layout and chassis plans

[Turret]

Hi again

Here's JMI era AC30/6 1-to-1 replica layout I've done some time ago

http://www.turretboard.org/?p=1108

And the chassis plans:

http://www.turretboard.org/?p=1168

Hope you like it

[chief mushroom cloud]

a man after my own heart...Vox AND HiWatt

site bookmarked

[M Fowler]

Good stuff Torg thank you.

Mark

[Turret]

Thank YOU

[crbowman]

That's awesome Torg!
Loves me a good AC30.

[Turret]

Cheers mate

BTW

I've seen JMI era correct chassis and copper faceplates on ebay yesterday (not sold by me), and another one without faceplates but cheaper

I wont link it as I didn't read the forum rules and I don't wan't to be kicked before I really started

[crbowman]

Man, I've got 5 of the old Paxolin tag boards. I could........
Oh hell, I need to just step away from the computer before I get into more trouble.

[Masco]

Nice. I see you've kept c-41 at .047uf

[Turret]

Nice. I see you've kept c-41 at .047uf

Thanks, and yes

Two reasons:
- I did my layout from actual unit carried by my British friend - his AC30/6 had 47nF cap at this position
- other reason is I seen no other AC30/6 with 5nF for C41 myself (both in person nor on the web). I haven't looked hardly on the other hand. My knowledge concerning AC30 history is limited, but till now I was sure that 5nF/C41 is common with AC30/4 only

[Masco]

Nice. I see you've kept c-41 at .047uf

till now I was sure that 5nF/C41 is common with AC30/4 only

Yes, it appears that way. Looks like it happened when they dropped one extra RC filter network(1Meg/4n7) before the Vibe/Trem volume pot. They had to make up for the extra 6dB/octave loss to trap out the LFO. Probably had something to do w/ needing more room on the lower tag since they eliminated the small oscillator feedback tag bd. and moved those components and the depth preset pot to a slightly larger bottom tag bd.
I believe the larger c41 is worth mentioning in Stephen's book, since most 30/6 have them. He simply copied the layout from the 1960 schematic which didn't reflect the change.

One small thing: You're layout drawing has a 16ohm load connected to the 8 ohm tap. Blue=16 green=8

[Turret]

Very cool, thanks for correction and further explanation

I'm very humble and always happy learn new things, could I quote you on my website regarding C41 issue?

I'll do the corrections i revision.6 later this week (as well as some other cosmetic corrections). I'm working on schematic to, after that finally I'll put it to bed, and I move on

Stephen Grosvenors AC30 Service Engineers Guide is alright, I'm hoping he'll extend the info in further book revisions

[Masco]

Well, the two changes seemed to happen at the same time, but I'm doubtful now that they're related. The 5nF was probably an old mistake on Vox's part (not Stephen's). The removal of extra 1Meg/.0047 RC before the volume pot was probably mainly for real estate. The .047 is clearly a better choice, the V/T channel is weak enough as is.

[Turret]

ERROR ALERT

it was brought to my attention that fallowing error is in my drawing:

Looks like you've omitted the plate supply wire that goes to R-39 on upper left tag. The wire should come from the bottom of R-60 on lower tag.

I'm working to fix it, I just have to sort out my server issues

Thanks to Amp Garage members Matt (JMJ Amps) and Charles

[Turret]

Rev 7 done

[rooster]

I appreciate the layout but you guys are actually able to read the part values? When I zoom in on this image everything is digitized to the point of non-readable. What are you guys doing different than myself please?

I have Stephen Grosvenor's book and I assume you borrowed from this but used a hipper drawing tool?