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-   -   Ebay 1200 watt amp board. (https://www.diyaudio.com/forums/solid-state/313952-ebay-1200-watt-amp-board.html)

GeorgeM59 25th October 2017 11:33 AM

Ebay 1200 watt amp board.
 
Has anyone seen or bought these amplifier modules.
Assembled 1200W Powerful amplifier board/mono amp board with heatsink | eBay
I think the power may be a little optimistic but in the photo and on paper look like pretty good value with on board protection, balanced or unbalanced input. I thought about getting 2 and making a stereo PA amplifier.
Don't think I could even come close to buying the parts and heat sinks for the money.

poynton 25th October 2017 05:40 PM

The heatsink is too small !!!!


.

Fusion916 25th October 2017 06:20 PM

https://www.thehighroad.org/styles/d...lies/uhoh2.gif

sevenup2278 25th October 2017 06:46 PM

Quote:

Originally Posted by poynton (https://www.diyaudio.com/forums/solid-state/313952-ebay-1200-watt-amp-board-post5224054.html#post5224054)
The heatsink is too small !!!!


.

These need to be fan cooled.
You can put 2 channel s with heatsinks close together and form a tunnel. Then use a fan on the end for active cooling.

GeorgeM59 26th October 2017 12:20 AM

Quote:

Originally Posted by sevenup2278 (https://www.diyaudio.com/forums/solid-state/313952-ebay-1200-watt-amp-board-post5224121.html#post5224121)
These need to be fan cooled.
You can put 2 channel s with heatsinks close together and form a tunnel. Then use a fan on the end for active cooling.

Thanks for the replies.
The last amp I built which was only mono got a fan in the middle of the heatsink and plated either side to ensure even air flow.
My initial plan was to only run +-85v to it which if I'm correct would lessen the heat load and of course the output but I have several 60v toroids I want to use and only want around 400watts at 8 ohms per side.
There is a version without heatsink which saves a bit of money but the supplied version looks like a good fit for the transistor spacing.
Do the output driver C5200/A1943 look like they would be reliable?

Shhh its me 26th October 2017 07:51 AM

Surely thats not a relay being used for speaker protection / disconnection.

Bruce@bluff 26th October 2017 07:53 AM

If the buyer can guarantee they are authentic 2SC5200/A1943

GeorgeM59 26th October 2017 08:03 AM

Quote:

Originally Posted by Shhh its me (https://www.diyaudio.com/forums/solid-state/313952-ebay-1200-watt-amp-board-post5224651.html#post5224651)
Surely thats not a relay being used for speaker protection / disconnection.

I believe it is a relay. From picture of other models it looks like a 30Amp 250vac rated relay. I have relay switching on my other amps but they are many years old. Is there a newer more reliable option?

GeorgeM59 26th October 2017 08:16 AM

I found this one from the same supplier, claimed 650watts max but 500w from +-90 supply which sounds about correct.
Assembled 650W Powerful amplifier board/mono amp board stage amplifer board | eBay

Shhh its me 26th October 2017 09:22 AM

Quote:

Originally Posted by GeorgeM59 (https://www.diyaudio.com/forums/solid-state/313952-ebay-1200-watt-amp-board-post5224661.html#post5224661)
I believe it is a relay. From picture of other models it looks like a 30Amp 250vac rated relay. I have relay switching on my other amps but they are many years old. Is there a newer more reliable option?

It won't be 30A break rated at >60V DC.
A subject that can go off-topic as there are prior threads regarding the only reliable switch method for higher power amps - MOSFET switching.

I only mentioned this due to use of a relay.... a device sure to fail a break at the most critical time lest you destroy speakers in a worst case scenario [welded contacts] or degrade audio quality due to consequence of pitted contacts.

It's a 'red flag'. The amp maybe all well and good for what it is, but the use of a relay in output stage indicates lack of design consideration... maybe indicating other design flaws too. Relay could be replaced with MOSFET driver chip and correctly rated MOSFETs still using the existing fault indication/disconnect circuitry. Has been done as a module board by folks here to install in place of the relay....just like some folks have suffered the grief of welded relays not disconnecting a full rail DC voltage applied to expensive speakers.

Your choice. Be warned.


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