Panasonic SA-XR50

[serengetiplains]

Say, does anyone know the value of the output inductor used in this model?

Also, does anyone know where I can obtain a service manual for this amp? I tried Panasonic Canada but they said "authorized fix-it people only!" I suppose their greatest concern is possible liability to some newbie DIY mucking around with lethal voltages?

Thanks!

[kims]

Hi

The output inductor for the SA-XR series are all a 7uH Toroid would on a T80-2 core from Micrometals.

This core is known as extreemly linear with very low THD, and can take quite high currents without saturating, like more than 25A.

Sound quality is also very good, but perhaps a rod core from Micro metals could be better, a possible alternative could be a P2440-202 with 20 turns 1.0mm wire

rgds,

Kim

[serengetiplains]

Originally posted by kims
The output inductor for the SA-XR series are all a 7uH Toroid would on a T80-2 core from Micrometals.

This core is known as extreemly linear with very low THD, and can take quite high currents without saturating, like more than 25A.

Sound quality is also very good, but perhaps a rod core from Micro metals could be better, a possible alternative could be a P2440-202 with 20 turns 1.0mm wire

Thanks, Kim. Any comments on an air-core Jensen coil?

Also, I can't tell from simple observation if the ouput electrolytics solder to both sides of the pcb. I'd like to replace them, but don't want to open a can of worms for a single capacitor. Have you any advice for me?

[motherone]

Serengetti,

If you do this upgrade, let me know how it turns out. I'm using this panasonic as the core of my current home entertainment system.. Very happy with it sound-quality wise.. But always looking to improve.

I think it runs out of steam a little bit, but the sound quality more than makes up for it.

[blouis]

Hi,

Does someone know wich chipset is used in the SA-XR50.

I'm interested in buying one and to do some mods.

Thanks!


Bruno

[spots25]

yeah, since we're on the subject, i don't suppose there is a way to mod it to take a 4 ohm load, is there?

[motherone]

I'm sure it'll work into a 4 ohm load, you just won't get as much power out of it due to current limitations.

[spots25]

Originally posted by motherone
I'm sure it'll work into a 4 ohm load, you just won't get as much power out of it due to current limitations.

Panasonic rates it at only handling a 6-8 ohm load though, and my Maggies are 4 ohm. Otherwise, its the perfect reciever for me. You SURE it can handle a 4 ohm load?

[motherone]

If you're familiar with how impeadences work, you know that in order to put the same amount of voltage through a 4 ohm load as an 8 ohm load, you need to double the amount of current.

A great example is the LM3886 chipamp. When you power it with +/- 35 volts, it can put out ~50-60 watts into an 8 ohm load. If you try to drive a 4 ohm load with the same power supply, you'll only get about 30 watts or so, as the output into the 4 ohm load is limited by the current the amplifier can supply. If you drop the power supply rails down to +/- 22-25volts, you can then put 68 watts into the 4 ohm load.

The point of this is that most likely, the panasonic will drive your 4 ohm speakers. Will it drive them as well as it drives 6 ohm loads (for which the instruction manual seems to indicate it's optimized for)? I don't know. I would guess that you would get a little bit less output due to current limiting on the output devices.

I highly doubt that a 4 ohm load would make the amp unstable, or any speaker that dipped into the 4 ohm region would destabilize the amp.

Asking it to drive a 2 ohm load would probably be too much. I'm sure it would try to do it, but it would probably complain and/or shut down if you tried to crank it.

[spots25]

ahhh, thanks! I always wondered how that worked, but never really thought about asking. So if I understand, its not really the 'amplifier' itself that determines what load it can drive, its the design and voltage of the power supply.

I'm gonna go look at ebay now