Y148 maximum input voltage

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Hey all,

Before I start, I am aware of the data sheet provided by Yamaha stating the maximum voltage at 16vdc.
I have so far found that to be a little bit of an underquote, as I am currently running mine at 18.8vdc.

I wanted a little boombox that I could take to work, but didn't want to spend $200+ on a Makita one. So I decided to make one.
I also didn't want to have to carry any extra power supplies, chargers or batteries, so I decided to try and run my home made y148 boombox off the 18v makita batteries.
So far, so good.
It has been running great, powering two 8ohm, 20w speakers all day.

Now comes the issue.
I purchased a new tool kit and even though the batteries are rated at 18v, I am getting 20.8v out of them.
Would it be safe to hook them up to my boom box, or should I look into a way to step it down?

What is the maximum safe input voltage on a y148 without heat sinks.

The data sheet I found ( http://download.yamaha.com/api/asset/file/?language=ja&site=jp.yamaha.com&asset_id=46252 ) for the YDA148 says operating voltage of 16.5.

The data sheet for the Y148 may say the same or not, I have not found a copy.

On page 27 ( Absolute Maximum Ratings ) it lists the "Power Supply terminal (PVDD) Voltage Range" as 20V.

and :

"Note) *1: Absolute Maximum Ratings is values which must not be exceeded to guarantee device reliability and life, and when using a device in excess even a moment, it may immediately cause damage to device or may significantly deteriorate its reliability."

Lower down is the "Recommended Operating Conditions"

Suggests 16.5V with the note: "Note) Do not use under a condition other than the recommended operating conditions."

Hope that helps.

P.S. If you need to run higher supply voltage / higher power look into a TPA3116 / TPA3118 type of amp.
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Thanks for the reply. Sorry for the delay in response.
I completely missed that part in the data sheet.
I thought I would risk it anyway, and I have been running the amp on 20V for a few days now. Seems fine for now.
It is a $6 amp, so if anything happens, it's not like I'm going to be breaking the bank to get a new one.

On another note, does anyone know the best and most efficient way to get 18V down to 5v? Maybe I should start another thread.
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