gerardsweeney Posted May 24 Posted May 24 All.. We have multiple Promethean classrooms where the PCs are connected to ceiling speakers via Promethean amplifiers. A bit like the Promethean AV-3016 if you need to look it up on EBay. The amplifiers are starting to give in after nearly 20 years worth of use (who knew?!). Can someone recommend a cheapish alternative? We contacted Richer Sounds with a similar query (including a note of the old model), who are quoting £250 for a Cambridge - I don't know if that's good/bad/indifferent. It's the same price on Amazon, if that goes for anything. They don't need to be fancy. A couple of phono inputs to speakers. The old ones say they're 100W - which'd surprise me, but what do I know?
FN-GM Posted May 24 Posted May 24 I am not quite sure what you're asking but I believe Promethean amps were rebranded Cambridge anyway and are quite robust. I binned around 100 of these amps back in 2016 all working. At the time I couldn't give them away.
gerardsweeney Posted May 24 Author Posted May 24 Urgh... that's killing me! I'm basically looking to see if anyone can recommend a budget amp.
ovenchips Posted May 26 Posted May 26 I use a couple Fosi audio bits at home for my PC & Vinyl setups, they make some bloody solid kit for the price. Just had a look on Amazon and they have a fairly basic Phono in / out amp for £80 which could be worth a punt? 300W so plenty of power behind it: https://www.amazon.co.uk/Fosi-Audio-V3-Amplifier-Component/dp/B0C36S8DCT
SamanthaD Posted May 26 Posted May 26 Are you using all the outputs or just the 2 main channels? Affects any recommendations! Also - can you define "budget"?
synaesthesia Posted May 26 Posted May 26 (edited) They're not going to need any more than 30watts - if you really still need to use them, you can get in-wall mounted amps from Vision relatively cheap or amazon special for under 20 quid! Edit: Eek, they weren't this expensive when I last bought them! https://www.jp-uk.co.uk/sound-systems/amplifiers/vision-techconnect-tc3-amp-amplifier.html El Cheapos : https://www.amazon.co.uk/XRLUC-Amplifier-Channel-Powerful-Streaming/dp/B0D623QCGQ Edited May 26 by synaesthesia
ColonelPogs Posted May 27 Posted May 27 On 26/05/2026 at 14:33, synaesthesia said: They're not going to need any more than 30watts - if you really still need to use them, you can get in-wall mounted amps from Vision relatively cheap or amazon special for under 20 quid! Edit: Eek, they weren't this expensive when I last bought them! https://www.jp-uk.co.uk/sound-systems/amplifiers/vision-techconnect-tc3-amp-amplifier.html El Cheapos : https://www.amazon.co.uk/XRLUC-Amplifier-Channel-Powerful-Streaming/dp/B0D623QCGQ If you want the wall wall mount form factor, but for cheaps CPC have something for you. https://cpc.farnell.com/pro-signal/psg3394/24w-wall-plate-audio-amplifier/dp/AV29005 1
gerardsweeney Posted May 30 Author Posted May 30 Sorry for the delayed response, folks. So most cases it's just the PC connecting to the amp via a 3.5mm stereo to 2x phono. In a few, they have standalone DVD/bluray players connected the same way - so more than 1 input would be handy, but not a deal breaker. The amps then have a left pair of speaker cables and a right pair. They connect to a wall panel, which goes to the relevant ceiling based speakers. Budget? Less than what Richer quoted us. Ideally double figures, rather than triple Amazon could be problematic, thanks to the ... "firm" (shall we say) control our Procurement department have. The CPC one looks interesting. I take it the speaker cables attach to that terminal block, so the PC would connect to the AUX via a 3.5mm to 3.5mm stereo cable. My only concern is the lack of BT/AUX selection... "The audio from Bluetooth always got the 1st priority, even if your Aux-In audio source still hook-up to this In-wall amplifier. Once people switch off the Bluetooth from their cellphone, otherwise music always comes from Bluetooth" Which - to my untrained mind - means that they device sits in a state of being discoverable. Meaning pupils could pair their phone to the device, and override the Teacher's audio. Or am I overthinking this?
Andrew_C Posted June 1 Posted June 1 Nasty... Unless we've both misinterpreted that. CPC do offer these - no name, but I've had plenty similar from them over the years. https://cpc.farnell.com/qtx/kad-2/digital-amplifier-2x-35w/dp/DP34982
gerardsweeney Posted June 2 Author Posted June 2 On 01/06/2026 at 09:49, Andrew_C said: Nasty... Unless we've both misinterpreted that. CPC do offer these - no name, but I've had plenty similar from them over the years. https://cpc.farnell.com/qtx/kad-2/digital-amplifier-2x-35w/dp/DP34982 I'm sure one of my colleagues had tried one of these, and said that they were underpowered for the ceiling speakers. Pity. Thanks for the suggestion, though..
Andrew_C Posted June 3 Posted June 3 (edited) 35W in a classroom isn't that shabby. They aren't 100V speakers are they? They'd have a transformer on them if so... Re-read OP. 100W speakers is A LOT for a classroom. You don't have to drive them flat out. Edited June 3 by Andrew_C
gerardsweeney Posted June 3 Author Posted June 3 1 hour ago, Andrew_C said: 35W in a classroom isn't that shabby. They aren't 100V speakers are they? They'd have a transformer on them if so... Re-read OP. 100W speakers is A LOT for a classroom. You don't have to drive them flat out. Hard pass, I'm afraid. If the speakers are mains powered with a transformer, I've no earthly idea how they get their power. They're what were fitted as standard in all of the rooms when the school was built 24 years ago. I'll catch up with the colleague who's primarily responsible for this kind of thing, and see what he actually said about the mini unit you mentioned. They're off on annual leave just now - hence my slightly fumbling in the dark about the whole thing
BKGarry Posted June 3 Posted June 3 We never had those Amps, but I have used these kits in many classrooms and actually quite large spaces https://cpc.farnell.com/vision-av/tc3-amp-sp-1800/techconnect-sp-1800-wall-speaker/dp/AV26424 I have HDMI to the Projector or Interactive panel then take a 3.5mm out and strip one end and plumb it into the input block on the rear. The speakers are a good quality and would probably be a nice tidy option for replacements. Even better if you have some full sized trunking that you can pop a back box in, but it does come with a wall mountable back box IIRC 1
Andrew_C Posted June 3 Posted June 3 (edited) Nah - there's two three principle systems for speakers. One is your standard HiFi type, scaling up to arena sized boxes. The amp drives the speaker directly. At home you would typically have 8 Ohm speakers. The impedance should match the amplifier (not critical unless you are driving hard). Third would be a system with the amp, ore indeed amps, built into the speaker cabinet. These would require power, and low level signal. But that's not what you've got. For distributed systems, like shops, and possibly classrooms, the amp is connected to a transformer (probably internally) that boosts the voltage of the signal to typically 75 or 100V). The speakers then have small transformers to drop it back down. The transformer may have several taps, with the wattage marked. To size the amp, just total the wattage. Edited June 3 by Andrew_C Added powered speakers 1
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