Boodang Posted August 28, 2023 Share Posted August 28, 2023 So, my trusty BBII has fallen silent. It started two gigs ago where there was an overheating smell, then at the end of the last gig it positively gave off that 'fried electronics' aroma. It lasted until the end of the night but now no sounds come forth. Anybody have technical experience with the Baby Blue amp? I would get it looked at professionally but there is no one here with the expertise. So, fuses are ok. Replaced the ECC83. It switches on and the DI works (in both direct and line mode), so presumably the preamp and valve circuitry is ok. But there's no sound from the speakers, not even noise, dead silent (speaker cones are free moving and measure the correct dc resistance). Which points to the power stage having gone. Oh, and no sign of burnt components in the amp. Quote Link to comment Share on other sites More sharing options...
Dad3353 Posted August 28, 2023 Share Posted August 28, 2023 The schematic diagrammes are readily available for download on t'web, along with the User manual. These, given to a decent repair technician may enable at least an estimate of what's gone wrong..? Quote Link to comment Share on other sites More sharing options...
Boodang Posted August 28, 2023 Author Share Posted August 28, 2023 34 minutes ago, Dad3353 said: The schematic diagrammes are readily available for download on t'web, along with the User manual. These, given to a decent repair technician may enable at least an estimate of what's gone wrong..? Unfortunately there's no decent repair technician in Islamabad... and I'm not exaggerating. So it's just me (I am an electronics technician but not a specialist in audio amps), and the schematic I'm afraid. Quote Link to comment Share on other sites More sharing options...
Dad3353 Posted August 28, 2023 Share Posted August 28, 2023 13 minutes ago, Boodang said: Unfortunately there's no decent repair technician in Islamabad... and I'm not exaggerating. So it's just me (I am an electronics technician but not a specialist in audio amps), and the schematic I'm afraid. Ah, I see the problem. Do you have any colleagues that travel to better-served nations on a regular basis..? A repair would take longer, of course. Have you found the schematics (a simple search brought them up immediately for me...)..? If the power output transistors are now duff, it would be possible to install another output amp module altogether, at worst case... Quote Link to comment Share on other sites More sharing options...
Boodang Posted August 28, 2023 Author Share Posted August 28, 2023 (edited) 21 minutes ago, Dad3353 said: Ah, I see the problem. Do you have any colleagues that travel to better-served nations on a regular basis..? A repair would take longer, of course. Have you found the schematics (a simple search brought them up immediately for me...)..? If the power output transistors are now duff, it would be possible to install another output amp module altogether, at worst case... I've got the schematic, so I'm just going to have to go through the amp meticulously with the multimeter. It's a discrete component amp, so if the output transistors are gone, hopefully I can find replacements. If I don't get very far with fixing it, I am back in the uk in nov so that might be an option. Quite attached to the little combo, so I definitely want it working. Bought it 20 years ago and I've worked it hard since with no issues until now. The preamp has a great sound and once i changed the cheap celestions for some decent speakers it was good for gigs as well. Edited August 28, 2023 by Boodang Quote Link to comment Share on other sites More sharing options...
Dad3353 Posted August 28, 2023 Share Posted August 28, 2023 2 hours ago, Boodang said: I've got the schematic, so I'm just going to have to go through the amp meticulously with the multimeter. It's a discrete component amp, so if the output transistors are gone, hopefully I can find replacements. If I don't get very far with fixing it, I am back in the uk in nov so that might be an option. Quite attached to the little combo, so I definitely want it working. Bought it 20 years ago and I've worked it hard since with no issues until now. The preamp has a great sound and once i changed the cheap celestions for some decent speakers it was good for gigs as well. These folk ... Pro Audio Service Ltd ... ... list SWR bass and combo amps as among their repair models, so may be worth contacting (email, telephone..?) if you need info, help, advice..? They're based in the Midlands, apparently. Worth noting..? 1 Quote Link to comment Share on other sites More sharing options...
Downunderwonder Posted August 29, 2023 Share Posted August 29, 2023 Look like Bugera drivers??? Quote Link to comment Share on other sites More sharing options...
Boodang Posted August 29, 2023 Author Share Posted August 29, 2023 4 hours ago, Downunderwonder said: Look like Bugera drivers??? Actually the drivers are from the Danish company Peerless and they are the HDS series... cast aluminium frame, polypropylene cones. As opposed to the original Celestions which were pressed steel and paper! Quote Link to comment Share on other sites More sharing options...
Boodang Posted August 29, 2023 Author Share Posted August 29, 2023 When I first got the combo, the sound from the cabinet was totally underwhelming. The preamp sounded like the 'studio grade' amp it was advertised as but the speakers most definitely didn't. When Bag End stopped making the speakers used in the first iteration of the combo, SWR installed the cheapest Celestions (BG8) drivers for the BBII. When I put the Peerless speakers in, the amp came to life.... especially with the fretless and the 'aural enhancer' control. Always surprises me when companies with supposedly high end products, use cheap speakers. Quote Link to comment Share on other sites More sharing options...
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