Speaker Impedance

[k9tdw]

I just finished putting together the UpTech Aliexpress kit and everything seems to work very well so far. My dilemma is that during the build, I managed to damage the speaker while soldering it to the board.I have an identical sized speaker to replace it with but it is 8 Ohm. Will it be ok to install this 8 Ohm speaker when the build calls for 32 Ohm???

[Luca66]

My opinion 32 Ohm

[DL2MAN]

The speaker impedance was determined according to the max current available from the atmega.
With an 8 ohms speaker, we would reach processors current limit at volume 13 of 16.
With a 32 ohms speaker, we would reach that limit at volume 15 of 16.
So we went with 32 ohms, as it still was available widely enough.

73 Manuel DL2MAN

[k9tdw]

The speaker impedance was determined according to the max current available from the atmega.
With an 8 ohms speaker, we would reach processors current limit at volume 13 of 16.
With a 32 ohms speaker, we would reach that limit at volume 15 of 16.
So we went with 32 ohms, as it still was available widely enough.

73 Manuel DL2MAN

Thank you Manuel for the response.
So is it safe to use the 8 ohm speaker I have on hand or should I order the 32 ohm speaker?
73 Todd K9TDW

[DL2MAN]

(...)
So is it safe to use the 8 ohm speaker I have on hand or should I order the 32 ohm speaker?
73 Todd K9TDW

I don´t think it is safe to leave an 8 Ohms Speaker permanently attached to the rig, and while you could try it for sure, I would not consider it a safe or even expedient solution.
Reason is the omnipresent pwm signal on the audio pin. You will know, once you try it. It sounds really crappy.

73 Manuel; DL2MAN

[k9tdw]

(...)
So is it safe to use the 8 ohm speaker I have on hand or should I order the 32 ohm speaker?
73 Todd K9TDW

I don´t think it is safe to leave an 8 Ohms Speaker permanently attached to the rig, and while you could try it for sure, I would not consider it a safe or even expedient solution.
Reason is the omnipresent pwm signal on the audio pin. You will know, once you try it. It sounds really crappy.

73 Manuel; DL2MAN

OK. I probably will not try the 8 Ohm speaker then. Is it ok to not have any speaker attached?? I have been using an external speaker and it sounds great through that.

73, Todd K9TDW

[DL2MAN]

Hi Todd,

let´s take a step back here:
When I mean permanently attached, I mean soldering it to the speaker pads (above 3,5mm Audio Jack).
When you connect it instead to the 3,5mm Audio Jack, different rules apply, as there is an additional 270 Ohms Resistor in line, preventing the worst.
Active speakers -connected to the 3,5mm Audio COnnector are always OK, as they ususally have really high Impedance (in the order of kOhms)
It is also OK to not attach any Speaker (to the Speaker Pads).That´s no disadvantage at all, exept for the fact, you don´t have an emergeny speaker. I´d simply follow Faraaz Link (in the Groupbuy Organizer Thread for sourcing Parts) and buy that speaker. It´s just a few dollars shipped. Once arrived, built it in and be good.

73 Manuel; DL2MAN

[k9tdw]

Hi Todd,

let´s take a step back here:
When I mean permanently attached, I mean soldering it to the speaker pads (above 3,5mm Audio Jack).
When you connect it instead to the 3,5mm Audio Jack, different rules apply, as there is an additional 270 Ohms Resistor in line, preventing the worst.
Active speakers -connected to the 3,5mm Audio COnnector are always OK, as they ususally have really high Impedance (in the order of kOhms)
It is also OK to not attach any Speaker (to the Speaker Pads).That´s no disadvantage at all, exept for the fact, you don´t have an emergeny speaker. I´d simply follow Faraaz Link (in the Groupbuy Organizer Thread for sourcing Parts) and buy that speaker. It´s just a few dollars shipped. Once arrived, built it in and be good.

73 Manuel; DL2MAN

Thank you Manuel for all of your help. I ordered the new speaker through the link you provided.

73, Todd K9TDW