H&H IC100 Combo 100 Watt amplifier

Not seen a H&H amplifier for years. This Combo 2 x 12” speaker cabinet fitted with a 100 Watt IC100 chassis. With, wait for it, vibrato. This amp dates back to the early 1970s, took me right back to when the trees were green children played in the fields,  no metal shuttered shops on Streatham High Road. And, Lambeth council and the Flying Squad were totally incorruptible. Well, perhaps that going a bit far.

These amps were quite bullet proof, in my opinion. I have had quite a few of these through my hands over the years and can only remember having to deal with the power amp sections on only a few occasions. This set suffered with all the usual problems. It had been stored in probably a less that dry environment. The user potentiometers were all scratch and some were open circuit. An injection of Zeta’s cleaning cocktail sorted that.

The main smoothing capacitors were swollen and tested positive for Covid. So, those were replaced. No reverb is a common fault. Normally the pig tail wires break away from the reverb tank. If you are unlucky, you may have an open circuit sender or receiver coil. In this case, both ends of the tank had broken wires and, the reverb control had an open circuit wiper. Damn, fiddly to fix.

Here is a tip for all the restorers out there: With all the above sorted, the amp worked well, save for a nasty intermittent crack and pop. Now,, the only criticism I have with the build of this chassis is the 0V connection from the main toroidal  transformer. This is taken to a tab and secured under a rivet on the chassis. The problem is that over time, corrosion builds up around the aluminium sleeved rivet and the cadmium plated chassis. This causes a bad connection and the OV no longer becomes well behaved. What I always do is to run a cable from the OV from the transformer to the center connection of the two smoothing capacitors.

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