Comments on: Vox AC15CC Mod Guide

By: babiuk

babiuk — Sun, 22 Jan 2012 00:38:00 +0000

Hi, what a great article…
I have this amp I had real bad luck: someone stoled the input part with the jack and pcb so I cannot use the amp. I tried to use a jack and wires direct to the minisocket with 2 holes but it sounds nothing just some strange noises sometimes.
Please could you help me to fix it in any way to use the amp again?

By: Ryan

Ryan — Wed, 28 Dec 2011 15:10:34 +0000

Just curious if the bright cap mod can be applied to the older UK made Korg era AC15TB models?

By: Vox AC15cc1 mods(Bright cap, tone cut and plate resistor). « Tetsuo Electronics.

Sat, 12 Nov 2011 01:40:00 +0000

[...] From here: http://www.guitarpug.com/2008/06/vox-ac15cc-mod-guide/ [...]

By: Vox AC15 Mods | end of the game

Vox AC15 Mods | end of the game — Fri, 02 Sep 2011 07:13:27 +0000

[...] journey of me and my Vox AC15 amp. Most of the mods I performed were inspired by the guide found here, you should definitely check it out if you’re considering doing some mods of your [...]

By: end of the game

end of the game — Fri, 02 Sep 2011 06:12:27 +0000

Thank you so much for writing this guide! It is ‘the’ tome on Vox AC15 modding! I followed a few of the mods detailed here: (tube/speaker change and bright cap) and have taken pictures of the process at my blog which can be found here: http://endofthegame.net/2011/09/02/vox-ac15-mods/

By: James

James — Wed, 27 Jul 2011 20:39:50 +0000

When doing mods to the Vox AC15CC1, try to bear in mind that this amplifier is not exactly the same amp as an old, original AC15.

If you compare schematics, the newer amps have quite a few differences, and some mods will work better than others.

Because the newer amps have solid-state tremolos in them, and the tremolo is in a different place in the new amps, there are a couple of 10K resistors isolating different things from each other. The Master Volume on the new amps is really where the “Cut” control should go, for example.

Also, the tone controls in the original amps were a “cathode follower” type of arrangement, with the second stage of V1 being used as an impedance converter, which adds no gain. In the new amps, the tone controls are connected to the high-impedance anode of the tube stage. This stage adds quite a bit of gain. This is almost like taking an old, original AC15 and modifying it by adding an extra gain stage.

So, anyone trying to get the “original” AC15 sound would have to start by rewiring the stock amp to the old specs first. Then, you’d have to add the right choke, an EZ81 rectifier tube and everything that goes with it. The cabinet material also makes a difference, and of course, the speaker.

So, with my AC15CC1, I just approach it as it’s own amp—not necessarily an AC15.

By: Peter Roest

Peter Roest — Thu, 07 Jul 2011 18:29:02 +0000

It’s very simple.
I changed the C5 capacitor (470pF) in a10nF capacitor. The amp is now perfectly in balance. I have now the needed low tones. The bass and treble pot are both in 12 hour position for the best result (with the Wharfedale speaker).

Peter

By: Gavin V

Gavin V — Sat, 19 Mar 2011 23:46:51 +0000

Hi Dave,

Thanks for the informative article which I found whilst performing repair work on one of these voxes. Just wondering, from the photo it looks as though R72 and R73 are the 82R as designated on the schematic I have. However, I pulled 220R resistors out of these positions, both O/C and both causing board burnout and arcing to ground. They were super cheap resistors and didn’t quite look ‘factory installed’ if you know what I mean. The only thing is, the customer is adamant that he bought the amp brand new so someone is either lying to him, the amp was messed with in the store or Vox had a revision at some point with this value, possibly indicated by Rev2D in the schematic notes. SInce Vox and their Australian distro Yamaha seem to be really unforthcoming with support email addresses I thought I might check here to see if anyone has encountered this problem before I try to wade through the appalling mire that is any Non-American amp company’s technical support services.
Cheers, gavinv@valvolux.com

By: aaron

aaron — Sat, 12 Mar 2011 23:52:21 +0000

I just wanted to say thanks for posting all the great info for people with the desire to improve their amps! This is a very helpful page!

By: babiuk

babiuk — Sat, 05 Mar 2011 23:57:12 +0000

Hello,
I have an AC15CC for some years, I have used it in concerts a lot of times and I never had a problem. But now I´m in troubles: tha input jack was very loose and I opened the back of the amp for fixing it, and I didn´t remember to close it, so sadly that the next week I went to rehearsal place and I discovered that the input jack with the PCB board wasn´t there, it was stoled! What an incredible thing! It´s a big problem because I cannot use the amp and I cannot find replacement, I´ve been looking in google but nothing… So please, do you know any solution? Or at least give me a picture of the board for trying to build myself a board like this? Thanks in advance