Hi Trevor; I know this is DIY, but since you posted this, have any
properly built boards materialized ?
The Chinese are too competitive with each other to build it properly. Sure considers themselves the high end of the bunch.
But they have no trouble responding to requests for better parts or topologies if they think someone is going to buy them.
In fact my experience is, that they will deliver it for less than I can buy the parts.
Thanks again for this diagnostic/revamp.
properly built boards materialized ?
The Chinese are too competitive with each other to build it properly. Sure considers themselves the high end of the bunch.
But they have no trouble responding to requests for better parts or topologies if they think someone is going to buy them.
In fact my experience is, that they will deliver it for less than I can buy the parts.
Thanks again for this diagnostic/revamp.
Hi guys I was thinking connecting parallel for 4 ohm. Can anyone explain why I shouldnt connect before filters, like tda7498E.
If I look at ebay tda7498 parallel stuff, they are all made after filters.
If I look at ebay tda7498 parallel stuff, they are all made after filters.
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Well I has the answer, nothing will happen, chip protection circ doesnt allow that.
Anyway what has happend here:
DC protection with an output relay on sure amps
Hi,
Thanks for writing this great article.
I have a question?
I'm worried that when because of a failure in the sure-amp their comes DC voltage at my speakers !!! and they don't like that 🙂
So is it usefull to add a DC (Midpoint dc offset detection) protection with an output relay, see protection board on ebay .... link below
Speaker Protection Board KIT Suitable FOR BTL Circuit | eBay
Our do you have a better solution/advice?
Thanks,
Hohan
Hi,
Thanks for writing this great article.
I have a question?
I'm worried that when because of a failure in the sure-amp their comes DC voltage at my speakers !!! and they don't like that 🙂
So is it usefull to add a DC (Midpoint dc offset detection) protection with an output relay, see protection board on ebay .... link below
Speaker Protection Board KIT Suitable FOR BTL Circuit | eBay
Our do you have a better solution/advice?
Thanks,
Hohan
Thanks much for the above discussion and mod info. I've been wanting to build poweramps for off grid use, as in batteries, for camping or use in trailers or motorhomes, but I've been worried about switchmode amp stability. Some blow up when driven with no load... The output filter circuits appear to be very sensitive to load impedance, and that varies substantially with most speakers. So finding people who have worked out some good mods appeals to me. I may give this Sure AA-AB32165 board a try.
Personally I would never parallel two power amps that use negative feedback, because they will constantly tug-of-war with each other for the slight differences in gain, distortion and noise. It may be much worse with switchmode circuits. The least this will cause is higher heat generation, and the most it will cause is bowing your speakers when it blows itself up. I wouldn't trust the current and temp limiting circuitry enough. And it's apparently a rare switchmode amp (class D etc.) that can be bridged since most already are inside, so each output doesn't work against Gnd. Trying to do that would be foolish unless you're sure you really know what you're doing.
Personally I would never parallel two power amps that use negative feedback, because they will constantly tug-of-war with each other for the slight differences in gain, distortion and noise. It may be much worse with switchmode circuits. The least this will cause is higher heat generation, and the most it will cause is bowing your speakers when it blows itself up. I wouldn't trust the current and temp limiting circuitry enough. And it's apparently a rare switchmode amp (class D etc.) that can be bridged since most already are inside, so each output doesn't work against Gnd. Trying to do that would be foolish unless you're sure you really know what you're doing.
I ordered one of these boards as a learning project, and it seems they have an updated version now:
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