Anyone have an SE speaker?

[Phipli]

Excellent

The bulk of the power ends up in R10.

Good point, 3/4 of the power ends up in R10.

What is R10s rating?

Accounting for the power dissipation in R10 the speaker is within spec.

header was 6.8V

The supply to the transistors is between -12 and 12v - I'm surprised peak to peak was only 13.6V. Guess they have some overhead.

I'm rusty on AC power calcs, it's a little while since I've done any so would need to dig out my databooks to check the numbers. Do I remember the frequency is pertinent though? What frequency was your sine wave?

 

[ymk]

What is R10s rating?

My best guess based on its size, 250mW.

The supply to the transistors is between -12 and 12v - I'm surprised peak to peak was only 13.6V. Guess they have some overhead.

No, the peak to peak was only 6.8V. I set the volume to 7 and played all kinds of sounds. 6.8V was the max Vpp the scope recorded.

I'm rusty on AC power calcs, it's a little while since I've done any so would need to dig out my databooks to check the numbers. Do I remember the frequency is pertinent though? What frequency was your sine wave?

I used a 100Hz sine, but it doesn't make a difference. I simulated the speaker as a resistive load, which is worst case. Real speakers' reactance increases around their resonant frequency and also increases with rising frequency:

 

[Phipli]

No, the peak to peak was only 6.8V

My bad - my phone wrapped the text so when I looked back up at what you wrote I saw "peak of" and missed the "peak to..." on th line before.

 

[maceffects]

A youtuber says it's fine phil we should all sit down and know our places

To be fair, the reason I shared the link is because JDW is an electrical engineer and I figured that might support the view that it’s perfectly acceptable and won’t hurt the sound circuitry of an SE. Of course, others had validated before I proposed the solution and I cannot see a material impact. If a speaker did fail, I’d certainly replace it.

 

[David Cook]

I ran across this thread as I searched for a replacement speaker for my Macintosh 512K. It is a Regal 63 ohm 0.25W. Interestingly, my other 512K has a Samsung brand.

I scrounged my junk box and found a 32 ohm speaker. It works fine, but is quieter (as expected). However, the speaker does not have the square mounting bracket. Hence, a cobbled-together set of hold-downs from washers.