Sunn Concert LeadSimple amp sounds great!Mmmm was 110 V model and someone has added a rather two small “autotransformer”should be at least 400 VA.. and after the switching..sinsolations tape… lovely job..Always love this sign!some dust here!Auto transformer too close to preamp board for comfort…Mmm no earth… Looks like new screws on the transformer..bit bent looking..Love the cloth England sign!Welded on fixing points.. this has suffered a big break at sometime!All clear and a fuse holder added for UK supply. Just needs a nice new Toroidal transformer and she will sing sweetly again!New Toroidal Transformer in with +/-25 volt outputOoops will not fit with the power supply caps positioned as they are..Pot rivets holding the cap holder in place need to be drilled out to move the cap holderDrilled out!Capacitor moved to fit in the new transformerYep she fits…A;; wired up and working again! Now I remembered the neon in the switch runs on 110V so gave her power from the centre tap of the primary which is half the input voltage. Pleased with that solution!Looking good and sounding sweet just need to make a sign for the back to indicate the supply voltage and fuse side then she is good to go!Back in the case Lovely sounding Sunn Concert Lead in for some work… power supply a bit under engineered for UK supply… so in with a new Toroidal Transformer. Great sounding powerful Solid State amp. Great overdrive sound!