Vox AC30 Custom Classic Common Issues

sallyg

Junior Member
Joined
May 1, 2012
Messages
7
Reaction score
0
Well, it took me weeks but I finally have time to try and fix this amp. Here are some pictures; if there are no obvious errors I'll re-solder all of the modded caps.
I'm no expert, but it looks to me like you put 68pf cap across lugs 2 and 3, not 1 and 2. Also, to jumper the resistor at R49, I think you will remove the resistor and put a metal wire in it's place.

Here's a link with pictures that show you what I'm talking about.

Marshall Heads Forum • View topic - Vox AC30 / AC30CC2 Mods.

I'm about to attempt these mods myself. Hope I do it right.
 

sallyg

Junior Member
Joined
May 1, 2012
Messages
7
Reaction score
0
Resistors to use -
Metal oxide for 1-2W resistors in the power supply.
.5W or 1W carbon film resistors in the signal path.
This might be a dumb question... Is the Pre-Amp board part of the signal path or the power supply?
 

jorri

Junior Member
Joined
Jun 1, 2012
Messages
2
Reaction score
0
These mods are just what i've been looking for!

I first tried bypass loopers in the FX loop, then was looking for a way to switch the loop on a footswitch, but I'm going to try this mod to see if i don't need to do any of that! (i'm actually hoping for my amp to have the error so it can be fixed).

My question regards the reverb mod, posted on page 2. I have this schematic http://www.cowboymafia.net/frankie/ac30cc_manual.pdf but i am yet to look inside my amp for these mods(changed tubes and did the bright cap months ago that's it).

On the diagram there are actually two R18s! on the first page near IC1. and on the second page near the choke. Neither are obviously connected to the reverb unit, the problem is the diagram i don't know where the 'connectors' actually go to.

Which is correct? Is there a better reference point when i open up the amp itself?

-an unrelated question... will the plate resistor give more gain and less headroom? i Know it should improve harmonics, but i find my amp sometimes lacks headroom already.
 

jorri

Junior Member
Joined
Jun 1, 2012
Messages
2
Reaction score
0
I also happen to have some components that are slightly different values lying around:

3.3uF 50v cap for the effects loop
either 33k or 47k in parallel 2W massive things for the reverb.

are these ok?
 

bierce85

Member
Joined
Oct 31, 2012
Messages
63
Reaction score
53
These are just a part of the mods I perform on these amps, but these are simple, inexpensive, very important mods that many AC30CC owners could perform themselves. So here they are.
Hey, thanks very much for posting the mods. I was just wondering what else you do on the cc2s beyond the aforementioned stuff. I know the obvious one would be speakers but would be very interested to hear more.

Cheers
 

redddog

Junior Member
Joined
Oct 18, 2011
Messages
5
Reaction score
0
I'm no expert, but it looks to me like you put 68pf cap across lugs 2 and 3, not 1 and 2. Also, to jumper the resistor at R49, I think you will remove the resistor and put a metal wire in it's place.

Here's a link with pictures that show you what I'm talking about.

Marshall Heads Forum • View topic - Vox AC30 / AC30CC2 Mods.

I'm about to attempt these mods myself. Hope I do it right.
Wondering this, too. Although to me, it looks like the guy in the Marshall forum has it wrong.

Clarification from someone in the know? It seems like Mr Caldwell has given up forums.
 

redddog

Junior Member
Joined
Oct 18, 2011
Messages
5
Reaction score
0
Anyone?

Is there a better forum to address these questions? Seems like ac30 cc interest has waned in these parts.

Just curious about the 68pf cap on the normal channel volume and which lugs are 1& 2. Looks like Bluedot had it right but the guy from the marshall head forum has it different (what appears to be lugs 2&3).

Also looking to find out if a 27k 1/2 watt resistor would work for the reverb mod instead of a 28K 1/2 watt.

Thanks guys.
 

Syphonear

Junior Member
Joined
Jan 30, 2013
Messages
1
Reaction score
0
This is a two year old post, but I feel I needed to stop lurking and come on board.
I have two AC 30's from the mid 2000's, a CC1 and CC2. I was looking for a way to lessen the bass in the Normal channel and improve the warmth and clarity of the tone. I usually play through the TB channel linked to the Normal. The more I roll up the Normal, the more the lower end jumps out and seems to drown or overpower the highs. This thread is perfect!! Thanks to all who have contributed.

For the record, I play a Gibson SG standard, recent version with no mods, and an Gibson ES 335, also a newer version. I wish I still had the 63 ES that I sold in 1968 for three hundred bucks!!
 

voxac30dude

Senior Member
Joined
Apr 30, 2008
Messages
339
Reaction score
24
LYLE! you sir are the MAAN!!! our sound tech at my church builds computers and has an electronics shop at his house. we just did your mods on monday and i coulden't be happier with the results!
first off ill say that the treble "icepick" that was there is gone now. theres enough treble to be heard but its not over powering the other frequencies. also the overdrive is not as fizzy anymore and has now changed to a sparkly beefier and fatter tone like a good vox is known for. i never use the clean channel but we modded it anyways for shits and giggles and WOWEEE! i think im gonna use the clean alot more then i did before the mods were done! my next mod to this is gonna be celestion ceramic blues and mercury magnetic's tranny swaps. ill get a video up soon
 

bendelzer

Junior Member
Joined
Jul 29, 2013
Messages
1
Reaction score
1
This post is pretty old, but I just did these mods to my AC30cc2 and am really pleased. The normal channel is so much more usable now and really just came alive. I have to say that the master volume really needs to be up at about 50% for this amp to really get good tone. I'd really like to upgrade to a classy set of tubes and better speakers. The wharfdales just sound a bit thin. I'm thinking about a set of celestion vintage 30's as I really like the way these sound in youtube demos. any thoughts?

I'd be glad to share pictures or other details with anyone interested in these mods.
 

redddog

Junior Member
Joined
Oct 18, 2011
Messages
5
Reaction score
0
Well. I'd be interested in some detailed pics if you're still offering. I'm still sussing out why my amp still doesn't work.

Did the reverb mod and it's a crackling mess. And the amp is at about 1/3 power after all the other stuff.

Lyle's gone so I'm about to dig in and try to figure out stuff soon.

Thanks so much.
 

Johanb

Junior Member
Joined
Jan 13, 2015
Messages
1
Reaction score
0
Hello.I read the article about the mods on a AC30CC2,It made me very curious.I opened my AC30 and jumpered The 330K resistor R49 ,and changed the 100K resistors R6 and R7 they are now 220K. The result is a lot more gain,which I like very much.But I also have a lot of very irritating 50 Hz hum.Did I forget something.
 

iluvtojag

Junior Member
Joined
Feb 18, 2015
Messages
1
Reaction score
0
Anyone know if capacitor (C23), which the schematic shows as 0.0047 500V can be replaced by a 0.0047 400V one?

Also, for the effects loop fix, would C109 be a 2.2uf 63V electrolytic capacitor?

thx
 

HF1600ie

Junior Member
Joined
Sep 27, 2016
Messages
6
Reaction score
0
Hello, I know the thread is too old, but I just got an AC30CCH which I totally adore.
I was able to lift enough the preamp board (without completely remove it) and replace those two 220K resistors in R6 and R7. R49 was not removed, but was jumpered (from the back of the tone board) which is the same thing as jumping it anyway.

Now, this is where the problem comes. I tried to remove those conical metal caps from the switches and they don´t come out. I can actually rotate two of them with my hands and they should unscrew !! Then the switch should have a small piece to unscrew as well that when unscrewed totally detaches de switch from the panel.
It should work the same as i did in my other Vox, the AC50CPH. In that model I can remove the tonestack this way.
But in the VOX AC30CCH, I can rotate, and rotate and keep on rotating the metal caps.... they just dont unscrew ! :-( They seem to be stuck and they should come up as I rotate.

How did you remove them ? The modification are so easy to perform and actually logical, but I can´t get the tonestack board out.
Cheers everyone !
 
Last edited:

HF1600ie

Junior Member
Joined
Sep 27, 2016
Messages
6
Reaction score
0
Can anyone come over and help with the tone-stack removal ?
I´d like to remove those toggle switches, but not even turning them around (which I can), enables me to remove them. They should come out by turning them. At least, this is what I did on a VOX AC50CPH (classic plus head).
 

HF1600ie

Junior Member
Joined
Sep 27, 2016
Messages
6
Reaction score
0
Hmm, I was trying again today and it is impossible. It should be dead easy !!
Any suggestion ?
 


Latest Threads



Top