Paradise Builders

[Simon1972]

It's actually surprisingly good, 0.1mv Input offset due to aging on input stage parts, the caps on the shunt are toast, 16v parts seeing 18v and 25v, the esr on a couple of them was several ohms...

 

[PierreQuiRoule]

Good to know. Thanks for sharing!

 

[Simon1972]

I figure they're good for five years before a service. Just the shunt, the rest is fine.

 

[hesener]

I think the heat coming from the heatsink is not helping with lifetime.....

 

[Simon1972]

The 16v rating on parts seeing between 18v-25v ain't exactly helping...

I tend to solder the 10/100uf caps by the heatsink under the boards.

That said I do know one guy who had his plugged in and turned on 24/7 for five years before the caps fried, it was a low -current build though, 10ohms. Well ventilated though.

 

[slav]

Hi Simon
any reason to not use 2SK170 regulator in the input stage , there are few parts missing on the photo you’ve posted or these weren’t populated yet ?
Good idea about soldering electrolytic caps underside btw

 

[Simon1972]

Jez built the entire circuit up in spice and it made no difference whether it was fitted or not, even with variance in the transistor values to give a channel mismatch.

 

[slav]

I'll have a look as I have Paradise circuit modelled in Spice

 

[Simon1972]

Got a Paradise in today for service and upgrade, one of the local supply rail caps is loose on its pins, perfectly soldered, just wobbling away. It's a Panasonic FC, I've never seen this before in any circuit I've worked on. Mouser sourced parts...

Anyone ever seen a similar failure?

 

[Salas]

I have seen such after an electrolytic has been pulled and then pushed back in a failed removal attempt.

 

[Simon1972]

Hopefully no one has messed with this apart from me.. one never knows though...