SJB Audio AMP's

07/07/2024

02/11/2023

A technical problem....
Gordon Summerlin has raised.
Hi - I wonder if you'd mind posting this query on the SJB page for me?

The band I play in uses 3 SJB Ants. 2 of them are what I believe to be the earlier design with the 6SJ7 pre-amp valve (though with slightly different cab dimensions) and the 3rd is a later one with more "standard" pre-amp valves and what looks to be an extra transformer on the chassis (a choke? I'm not an expert).

One of the 2 earlier ones has developed a problem and my go-to amp tech is stumped by it. He's tested it, run signal through it and can find nothing wrong. But a few minutes after it's been on, output power lessens and the sound becomes spluttery/more distorted. To my ears it sounds like the kind of issues created by a faulty cable or a dying battery in a pedal.

We've tried all the obvious stuff - switching guitars, cables, plugging straight in to both inputs, wiggling controls etc etc. But it does seem to be the amp as the problem remains consistent.

We've switched the 6SJ7 valve for 2 other ones that test fine and the problem remains. All other tubes are testing fine.

Anyone got any ideas what could cause a problem like this that isn't permanent but seems to occur under certain conditions?

Thanks...

27/10/2023

SJB Audio Hornet for sale from Ben Coles in SW England

29/09/2023

Bill Smith has been in touch and will hopefully fill in the gaps of knowledge and some images around his Ant head and cab which was in the corner of another image recently

17/09/2023

At the cabin with Grizzly & the grasshoppers

14/09/2023

David Garrity has contacted me to show a rare
140 watt sjb in a green cab
1x15
8 graphic equaliser

14/09/2023

Shane Swindells Hornet and Ant

14/09/2023

Bill Smiths SJB Valve specials and 2x12 cabs, also something interesting lurking to the right???

14/09/2023

Rhodri Davies recently came to collect the 2x12 cab and he is a long term SJB fan, he has given me the story of when he met Brian in the 1990's who was in full flow when he arrived......Anyway, here's my recollection of meeting Brian Jeffrey:

Back in the late 80s I saw a Frome band called the Havana Fireflies and their guitarist had an SJB Head and cab which sounded absolutely awesome! A friend of mine knew Brian Jeffrey and introduced me to him so I went up to his place in Mells enquiring about getting a custom made Valve Special head built. Brian was a really nice guy and I met him in his garden where he was building speaker cabinets (he did all the woodwork too whilst his wife did all the Tolex covering) - he set me up with a Valve Special and cab in his farmhouse kitchen and said “ Play about with it and turn it up as loud as you want – I’ll be back in 10 minutes.”
I was really impressed so I ordered a two-channel Valve Special with reverb & tremolo and a 2 X 12” cab with Fane speakers...Brian agreed to angle one of the speakers so it pointed upwards at a 45 degree angle in case I wanted to stand it up horizontally.
I collected the amp and cab only to find that Brian had completely forgotten my cab instructions and he’d angled both speakers...the wrong way around! However the cab still sounded great! The channels of the amp however suffered from extreme ‘crossover’ which meant that the controls of one channel significantly affected the other channel meaning that you couldn’t set any controls and jump between channels effectively! Brian couldn’t work out how to fix this so he accepted the amp back. I wish I’d kept it now as I met Steve Rowse from Steve’s Amps some years later who is an amp wizard/genius and I've been using him ever since - he can fix/mod anything and he could surely have solved the problem. I’d probably buy a Valve Special again if I saw one going cheap – I have a tweed covered SJB Ant which I’ve upgraded with a Weber speaker (I had to make a new baffle) which is great too so I’m still a huge fan of SJB Audio Power.
Anyway, I’ve been gigging the SJB cab ever since with a Marshall 50 watt Master Lead head and it’s been great. I’ve just bought another 2 X 12” cab from Lee Holliday so I can use both 2 X 12” cabs with the Marshall head in lieu of a 4 X 12”...this way I can get everything in the car and not (hopefully!) put my back out!