Pass Labs amp cooked my Epsilons!

[Hyendfriend]

Apparently these amps do not have any kind of speaker relay to prevent DC
voltage from burning up the coil..

 

[c.coyle]

Apparently these amps do not have any kind of speaker relay to prevent DC voltage from burning up the coil..

Is that the cause? Measure the DC offset. Volume at zero. All tone controls off or at center, unused input like aux, no speakers connected, speaker switch to on, DC miilivolt meter connected to speaker terminals. See what you get.

 

[TLS Guy]

Is that the cause? Measure the DC offset. Volume at zero. All tone controls off or at center, unused input like aux, no speakers connected, speaker switch to on, DC miilivolt meter connected to speaker terminals. See what you get.

Probably nothing now as the fuse is blown. When power transistors blow the amp rail voltage gets connected directly to the woofer voice coils and blows them before the fuse blows. So every direct coupled amp needs cast iron protection from DC at the speaker terminals.

Relays are problematic as they cause resistance and intermittent connection to the speakers.

A sure method is thyristor clamp circuits. However they increase the damage to the amp in fault states.

Current limiter circuits that cut the voltage fast are effective. Probably optocoupler protection is the best solution now.

I did not know that Nelson Pass thought his amps could never fail!

 

[highfigh]

Probably nothing now as the fuse is blown. When power transistors blow the amp rail voltage gets connected directly to the woofer voice coils and blows them before the fuse blows. So every direct coupled amp needs cast iron protection from DC at the speaker terminals.

Relays are problematic as they cause resistance and intermittent connection to the speakers.

A sure method is thyristor clamp circuits. However they increase the damage to the amp in fault states.

Current limiter circuits that cut the voltage fast are effective. Probably optocoupler protection is the best solution now.

I did not know that Nelson Pass thought his amps could never fail!

I think it's a UL thing.

 

[slipperybidness]

I did not know that Nelson Pass thought his amps could never fail!

Surely you are familiar with First Watt? Nelson's kind of hairbrain audiophile DIY stuff?

You know audiophiles will take a risk on speakers to "insure the cleanest possible audio path".

I've been happy with this DIY speaker protection kit. TLS, any thoughts on this kit? It does use relays
http://www.parts-express.com/velleman-k4700u-2-channel-loudspeaker-protection-kit--320-264

TLS, do you know of any optocouple DIY kits or schematics for the DIYer?

 

[TLS Guy]

Surely you are familiar with First Watt? Nelson's kind of hairbrain audiophile DIY stuff?

You know audiophiles will take a risk on speakers to "insure the cleanest possible audio path".

I've been happy with this DIY speaker protection kit. TLS, any thoughts on this kit? It does use relays
http://www.parts-express.com/velleman-k4700u-2-channel-loudspeaker-protection-kit--320-264

TLS, do you know of any optocouple DIY kits or schematics for the DIYer?

On the first point, yes, vaguely. I tune that sort of nonsense out pretty quickly. The second point is that I don't hold Nelson Pass in high esteem. As far as I'm concerned he plagiarized Peter Walker's work on his current dumping amps. He continues to deny this, but his disguise is very thin. In my mind there is no doubt that he infringed Peter's patents.

I am familiar with the Velleman unit. I have a couple round here some place I think. The problem is, it uses small mechanical relays. For the power he needs, it requires MosFet switching.

As usual Eliot Audio discuss this topic in depth.

Here is an optocoupler speaker protection circuit using MOSFETS.

I will post on the OP's other thread, but this Infinity Epsilons are an accident waiting to happen, and they are now done and just need a decent funeral.

 

[slipperybidness]

On the first point, yes, vaguely. I tune that sort of nonsense out pretty quickly. The second point is that I don't hold Nelson Pass in high esteem. As far as I'm concerned he plagiarized Peter Walker's work on his current dumping amps. He continues to deny this, but his disguise is very thin. In my mind there is no doubt that he infringed Peter's patents.

I am familiar with the Velleman unit. I have a couple round here some place I think. The problem is, it uses small mechanical relays. For the power he needs, it requires MosFet switching.

As usual Eliot Audio discuss this topic in depth.

Here is an optocoupler speaker protection circuit using MOSFETS.

I will post on the OP's other thread, but this Infinity Epsilons are an accident waiting to happen, and they are now done and just need a decent funeral.

Thanks! I haven't looked at the Eliot Audio site in quite a while. I may just have to build one of these optocoupler protection circuits.

That Velleman kit has worked well for me, but granted I'm not cranking to earbleed levels. Mostly I wanted it to kill some transient thumps, and offer protection when testing out new builds etc.

 

[slipperybidness]

Yeah, the First Watt stuff is all about low power minimalist amp designs.

You know, asking for trouble.