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Group Buy - Very Simple Almost Universal Speaker Protection

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woodturner-fran

Member
Joined 2006
#1
What is offered:

4x pieces of a speaker protection module as shown in the thread here:
https://www.diyaudio.com/community/...-universal-speaker-protection-circuit.415149/
enough for 2 stereo amplifiers.

Since the MOSFETs used are tricky to solder effectively at home, the boards will be provided with the MOSFETs already soldered. The rest of the parts will need to be supplied by the subscriber. They are easily available and in stock at Mouser, DK etc. The modules use SMD parts with the smallest at 0603, but most are larger than this - I'm only saying this as some people do not like using SMD parts. Full BoM and build/test instructions will be provided on paper as is usual.


Technical details:

The built units can be used for amps with total voltage from 24V to 100V, either single or dual rails. It must be run from the existing amplifier rails and you do not need an additional auxiliary supply. Current draw is less than 15mA per rail. The boards are designed to be mounted on the amplifier heatsink - one TO-126 transistor is configured to be bolted to the heatsink - it will dissipate up to 1W.

If using BoM values the units provide a start up delay to avoid turn-on thumps of about 3s and will trigger after the DC level exceeds the threshold for around 2s. The trigger voltage is around 1.2-2V depending on components used.

Board dimensions are 30x58mm

The boards are designed so that a mirrored pair can be made using the same PCB, making input and output wiring simpler and neater for each channel in a stereo amp.
By design, the protection is latching - i.e. it does not automatically reset for a long period. You will want to figure out why there is DC on the output before resetting the latch! It is also possible to manually reset the latch for testing etc.

Costs:

€60 for a set of 4x boards, with 2x MOSFETs per board pre-soldered. Tracked and insured postage anywhere in the world is €15. The rest of the parts will cost about €30 per stereo pair without any volume discount, depending on where you shop for them.

If you would like to take part, please add your DIYaudio name below here along with the number of sets you would like to sign up for. 1 set = 4 channel protection PCBs (2x stereo amps).

Example:

woodturner-fran - 1 set

The group buy will require a minimum of 20 participants/sets. When the group buy closes, it is expected that ordering and delivery will take about 3 weeks, and once the units are here and verified, I will send invoices to each participant. As usual, no payment until the boards are here and ready to distribute. Previous experience shows it will take an average of 2 weeks to arrive anywhere else in the world.

Thanks for your interest!
 
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