Not sure how 2 post if this is the right place, but had a question on this product, how long in Lm could you the speaker cable be in run metre’s please.
Thanks
Ernie.
3 Likes
Hi Ernie, Welcome to the forum 
Was this the module you were asking about?
I would try to keep cable length to a minimum as the amplifier is designed for 2.5 Watts of output power with a 4Ω load. By adding extra cable length you are increasing the impedance of the load by adding extra wire that is not part of the speaker’s voice coil, which wastes power. Additionally, the further the load impedance gets from the ideal 4Ω load the less power can be transferred, this is known as impedance matching and is explained in this tutorial.
The short version is the longer your speaker cables, the quieter your speaker will be.
3 Likes
Hi Trent thanks 4 getting back, yes that is the module i was talking about, i think i might try this adaftruit module, as i have previously built a op amp amplifier circuit from a YOU TUBE subscriber called Afrotechmods, which he made a circuit 11 years ago using a LM324 which i built up using an LM358 & extended both the Electret microphone cable several metres, as well as the head phone shielded cable many metres. Works a treat.
I used shielded cable rather than figure8 speaker cable, is that a good idea or would of figure8 cable worked as well do u think ?
Thanks
Ernie.
3 Likes
Hi Ernie,
Figure 8 speaker cable and shielded cables are designed for different tasks.
Speaker cables are designed to have as low impedance as possible and heavy gauge conductors to minimise voltage drop along the length of the cables.
Shielded coaxial cables are designed to match a specific impedance (often 50Ω) and for a single conductor to be shielded from outside electromagnetic interference.
While it may work anyway, it’s not using the cable to its strengths.
2 Likes
Hi Trent, thanks again 4 your time & answers on this PAM8302 query, i think i’d like 2 try that module with your electret module one day.
What brought this whole thought about is how do i get audio from my shed into the house so i can plug it into my OZspy DVR security system, as it has 4x audio inputs. I have tried those 2.4Ghz audio/video transmitters with limited success, way to much noise/distortion. Do you have any idea’s on that please.
Thanks
Ernie.
4 Likes
Hi Ernie
At what level (Mic, Line, Speaker) are you going to transfer this audio. There are probably wireless systems like the 433MHz TX/RX pairs but I have no idea of the audio fidelity. Any cable except speaker longer than 2 or 3 metres should be balanced screened or interference will be a problem. As most domestic systems will be unbalanced this will require 2 transformers. One to convert unabalanced to balanced at the sending end and one to convert back from balanced to unabalanced at the receiving end.
Cheers Bob
3 Likes
Hi Bob, thanks 4 your comment, u asked what “level” of transfer, i was thinking of extending the speaker cable, but i have had some success extending the electret mic as well as using shielded cable & extending it as well. I’m thinking the project i made based on You Tube channel “Afrotechmods” LM324 op amp (i used a LM358) isn’t powerful enough to be extending the cable to approx 30Lm so i can get any sound from my shed to my house.
Thanks
Ernie.
3 Likes
Hi Ernie
Depends how far. Public address systems have sometimes very long runs of speaker cable but they also have another facility called 70V or 100V line which is far higher impedance so the resistive losses in the copper wire are no where near as great. But for your home use that is a bit exotic (read expensive).
Any microphone from your shed to your house would almost certainly need to be balanced or you would have all sorts of interference problems. If your electret Mic has not got a battery it would need to derive power from the amplifier which presents its own set of worries.
A wireless microphone might be an option. They are not very expensive these days. Once again this depends on range and if your shed is corrugated steel it might be struggling. They operate in the 500MHz range and you have to be careful as there are only a couple of bands that are legal, they fit in amongst the TV stations. But if sourced from a reputable supplier they should be OK in this regard.
Cheers Bob
3 Likes
Hi Bob,
A very good point there about going back to the problem and looking at other solutions rather than just going forward with the assumption that a long cable run will be easier/more effective just because the idea is simpler.
Definitely a few different options to explore here, each with their own strengths and weaknesses.
3 Likes
