SJB Audio Power Atom Service

The SJB Atom is the one on the left these two British Amps came in on the same dayThe SJB Atom is the one on the left these two British Amps came in on the same dayDSC_7437DSC_7377Issues with the input jack squealling.. cleaned up sockets and resondered some of the dodgy looking connections seemed to cure the problemIssues with the input jack squealling.. cleaned up sockets and resondered some of the dodgy looking connections seemed to cure the problemSimple rear controlsSimple rear controlsLovely old Fane 10 Ohm speaker!Lovely old Fane 10 Ohm speaker!DSC_7376Two inputs normal and brightTwo inputs normal and brightVolume and tone! dead simpleVolume and tone! dead simpleDSC_7378DSC_7382Interesting shrink tubing on the preamp tube.. I think someone was worried about microphonics but this was actually not an issue So I removed themInteresting shrink tubing on the preamp tube.. I think someone was worried about microphonics but this was actually not an issue So I removed themAll components is fresh air with just one tag strip. Many components looked second hand but all working well.All components is fresh air with just one tag strip. Many components looked second hand but all working well. Mmmm3 caps replacing one power supply can that had gone leaky.. not elegant but works. I discussed with the owner and he agreed to pull the none working cap and replace it with  a dual cap and one floating capMmmm3 caps replacing one power supply can that had gone leaky.. not elegant but works. I discussed with the owner and he agreed to pull the none working cap and replace it with a dual cap and one floating capAfter the work she looks a little neater!After the work she looks a little neater!Much better power supply capacitor arrangementMuch better power supply capacitor arrangementGaffa and stickers now cleaned off! New cap in place.Gaffa and stickers now cleaned off! New cap in place.All finished with the back back on!still sounding good!All finished with the back back on!still sounding good!She sounds great especially on the Bright input and cranked a bit!She sounds great especially on the Bright input and cranked a bit! SJB Atom came in with a squealing input and in need of a general service. This is an interesting amp made in Mells near Frome by one Brian Jeffery who is no longer with us. He used to repair amps and then made his own small range (from bits and pieces from the look of the components inside (although this one may have been a one off for a local Guitar Teacher, prior to batch production). I have seen reviews of them from the USA so he shipped then abroad as well!. But pretty rare. Output tubes are a couple of 6V6GTs and 6SJ7 preamp with a 6N7GT gain and phase inverter with a 5Y3 rectifier. Sounds Fendery and after I had finished with her she was reliable and sounding great! Nice to see a locally made amplifier!

4 thoughts on “SJB Audio Power Atom Service

  1. I have an SJB ANT that needs some TLC,cos its been in a cupboard for a while. years ago I did use it for guitar but if you check my bands website,you,ll find I,m primarily a harmonica man & I would like the amp set up for that purpose. I tend to use an old Shure Unidyne B 515,through an Ibanez AD9 delay pedal, .
    So if you would undertake this task please let me know. PS. Brian had moved from Mells to Radstock which is where I collected the amp from all those years ago.

    Cordially yours

    Robert Spence

    Torquay, Devon

    • Would love to work on the amp. I could also change the gain structure slightly if you find you have feedback issues (like Marble do for their amps). I can arrange a courier collection for the amp if you can wrap it. Would probably cost around £15 each way.

  2. Hi , Does anybody have a schematic for the SJB Audio ‘Valve Special’ Head please. ( two EL34 in the output stage) Many thanks Bob.

    • Sorry I have never come across any of his schematics.. but they are simple amplifiers and I be that one is pretty much a Plexi Marshal Style amp

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