Wem Control HR30  ~ 1965

Here is a very rare WEM Control HR 30 head with push buttons for tremolo, vibrato presence and high/low volume.  It dates to 1965 and is in excellent shape cosmetically, although the steel chassis has some surface rust to show for its 51 years.  This was apparently Charlie Watkins' take on the Vox AC30, though I doubt it has the same volume.  You can jam both tremolo and vibrato on together for a very unique effect. 

I recently acquired this knowing it had been in an attic for many years.  The seller had it working for me when I picked it up and it sounded great, though in need of a thorough fettling.

The following essential work was carried out:
Full service and clean.
Most electrolytic capacitors were in very poor shape so these were replaced.
Two high voltage filters had literally split open so all were replaced bar one which was a "recent" replacement Daly which measured fine.  The main filter can measured excellent with no signs of leaking or bulging so it was left in place.

All resistors measured very close to nominal values and none looked damaged.

Some re-tensioning of the input jacks as well as thorough cleaning and multiple insertions to shine up the contact points.

The four power valves all seemed fine with no discolouration, but one was not a Mullard so I picked one out of my small stash which worked best with the other three.  It runs a few degrees cooler than the others but they all draw about the same current and are well matched.  Each EL84 has its own bypassed cathode resistor so it isn't too critical to have well matched sets, unlike when multiple cathodes share a single resistor.  

I considered replacing the Bulgin mains socket and lead but decided to keep it in the end.  I did not have an IEC with the same mounting hole spacing and I hate seeing a square peg in a round hole.  However, I did add an earth bond direct to the chassis for safety.  

The speaker output pins had previously been disconnected, along with the original mains out socket and wiring. Two 1/4 inch speaker jacks had been put here instead, fixed to a screwed in plate.  I feel this was a sensible mod as these days we use mains plug with a 4 or 6 gang block to cater for effect etc.

Soundwise it is similar to the ER30 with a good range of treble and bass control.  The presence button really adds some bite and chime. There is a little added gain with the effects engaged which gives a little warm distortion with hum-buckers.  Pushing the low button kicks out the trmolo and vibrato buttons but retains the effects (strangely).

All in all avery nice head.