What the hell is this??!!
This rather heavy amplifier for it’s size, came in with a report of noisy controls and various issues.
No markings as to what the make was, but some silk screening on the back chassis saying power rating etc.. So, powered it up whilst looking at the power being taken from the mains. Upon initial switch on for about 10 seconds, there was little power being drawn, about 10 Watts if that. Strange, given the customer said it was a valve amplifier. Switched the STANDBY switch on and still nothing. After another 10 seconds or so, the power taken from the supply started to rise to around 30 watts, then, the STANDBY light slowly came up to brightness and we had a working amplifier. So, does this have a sophisticated soft-start circuit, with heaters and HT coming on slowly. Unusual?? Now drawing 80 Watts.
So, we set about trying to gain access to her insides. I say TRY. Logic would say the remove the back. This is a large wooden panel, inset into the cabinet. You have to remove the cabinet corner protectors which were held in with a variation of screws that any hardware store would be pleased to have. You then have to remove another 12 odd size screws to try and lever out the rear panel. This is so tightly inset, along with the fact the rexine covering has turned to gum. 30 minutes later, it was obvious this panel was not coming out and seemed to be attached to the chassis internally. OK, try and remove the front.
To gain access to all the additional odd size screws, the corner covers have to come off, the loudspeaker removed, and the remaining screws removed. Haha.. The front is off and we can now see what appears to a set up designed by Frankenstein’s best mate. A big toroid transformer for the power I guess and a reasonable size output transformer connected to what appears to be 2 X 6L6Gs. These valves are hidden behind a metal plate with a fan in front. We then have what seems to be a power supply and control PCB, looking quite complicated. I guess this is where all the slow start stuff comes from. Now for the interesting bit (see photos) there is another Veroboard PCB with 2 X ECC83s and a whole load of components. I assume preamp and output stage phase splitters and drivers. This looks very Homemade. Reminds me of early WEM, Charley Watkins equipment.
The chassis is fixed to the inside of the cabinet by another selection of screws and 4 X threaded posts which also hold on the feet. These of course have been varnished, so trying to undo the posts to remove the chassis is almost impossible as the fixings to the chassis start to rotate. Great. The valve cans from the ECC83s were rattling around the cabinet, along with various nuts and bolts. Getting this thing to bits took an hour and a half to spend 30 seconds injecting cleaning fluid into the user controls. Thankfully, the electronics seemed to work well and the output was clean with symmetrical clipping.
What I though to be a 20 minute job turned into a stressful 3 hours, requiring a heavy intake of Class A drugs and triple distilled Whiskey. And I still don’t know the make of this damn thing?
