A lovely 1964 Vox AC30/6 came along as it was felling a bit poorly. The amp sounded- well- just not like an AC30 should. The vibrator / tremolo pedal had disappeared in the mists of time. The amp had been recovered in the proper basketweave Tolex and had a new grill cloth so it looked the part. The exact model is the Vox AC30/6 and while not a Top Boost model it is the “Treble” model.
First job was to PAT test and just to make sure it was safe. A fail! The issue was that the earth resistance was too high at over 1 ohm. This means basically the amp could light you up like being in the electric chair under the right (or wrong !) circumstances.
This Vox AC30/6 is over 50 years old and metal corrodes over time. I dismantled the earthing points and gave them a thorough cleaning to remove the 50 years of oxidation and then re-assembled the earths. The PAT test now showed 0.15 ohms and this is within the safety zone. Safe at last !! At the same time I clamped and re-glued the Tolex which had parted company on the top panel.
The amp had many capacitors replaced but not in the vibrato section so my concern was that this could be an issue.
The valves ( tubes) were Heinz = 57 varieties. The owner reminded me to keep costs down. Luckily the valves were mostly ok. The GZ34 rectifierwas really worn and had lost 50% or more of its emission so it was replaced. AC30’s are hard on rectifiers and they often fail suddenly so this is a sensible thing to do especially with it being so worn. JJ GZ34’s are good value for money so in it went.
One other valve was dead. Unfortunately it was a nice Mullard ECC82. It had gone short circuit. As it is in the oscillator circuit a JJ ECC82 did the job.
The lead for the foot pedal for the vibrato had been cut off and shoved inside the amp. This switch when closed allows the oscillator in the vibrato to run. I put a piece of wire with croc clips across the pins on the tag board where the footswitch should be connected . I was pleasantly suprised to find the vibrato worked perfectly.
I odered a latching foot switch and wired it up to the tagboard using the original clamp for the lead. The amp was now totally functional again.
One area of concern on these amps is the mains voltage selector and the mains lead itself. I checked the mains lead and it is rated for 5 Amps. Perfectly adequate for this amp. However the mains selector is somewhat dangerous by today’s standards. The owner wanted to keep the amp original so i have documented this for the owner and recommended that it should be re-wired. On the one hand there is safety in a gigging amp and on the other, there is a collector who wants total originality. I strongly recommend any gigging amp has this voltage selector dis-connected.
The pots, switches and all the valve sockets were cleaned.
I would love to own this amp. The sound of these early Vox amps has to be heard to be really appreciated. I did some of my rubbish playing using my USA Telecaster and Les Paul. This amp definitely works better with the tele. It captured that 60’s clean sound and was really repsonsive. Much more responsive than Fender amps.
It was loud too, having a pair of those highly efficient Alnico blues . Completely original too.
The last job was to get rid of all the dust and make it look nice.
Gee! I wish I could afford to buy this amp !! Sad to see it leave …
Update: This amp is up for sale by the owner and is located in Filey, North Yorkshire. Drop us a message and we will put you in contact if you are intersted in a really well looked after vintage Vox AC30