06-12-2016, 11:14 AM
(This post was last modified: 06-12-2016, 11:15 AM by Valvebloke.)
Indeed this wasn't the only problem with this amp Alan ! As well as the gassy valves the HT choke was open circuit. It's also a sufficiently early one that the EF86s are wired with a 1kohm common cathode resistor and 680kohms in the screen grids, rather than the 680ohm and 1megohm values that Peter Walker changed to very soon after this. The original values are preventing me (just) from meeting the distortion spec with the original valves (I can get there with the later resistors). The Hunts caps and the KT66 cathode cap were all shot and all the critical Erie resistors have had to be padded back down to their original values. The KT66 cathode resistor had been replaced with one of the wrong value. The fuseholder was bust (and the wreckage had been wired across !). One of the speaker sockets had been replaced and the other one was missing. Apart from that it was fine !
I should say again though that the amp in the picture is not the one I'm working on. The pictured one has a very scary bitumen ball oozed out of the output transformer (bottom left corner of the chassis) which would be a more expensive problem than all of the above stuff put together.
Fiddly though it is, I like the tag removal and re-gluing idea Jeffrey. It preserves as much of the original as is possible, including the look of it if I'm careful, and that, in the end, is what restoration (as opposed to repair) is all about, I guess.
VB
I should say again though that the amp in the picture is not the one I'm working on. The pictured one has a very scary bitumen ball oozed out of the output transformer (bottom left corner of the chassis) which would be a more expensive problem than all of the above stuff put together.
Fiddly though it is, I like the tag removal and re-gluing idea Jeffrey. It preserves as much of the original as is possible, including the look of it if I'm careful, and that, in the end, is what restoration (as opposed to repair) is all about, I guess.
VB
Ampregen Ltd http://www.ampregen.com