Fun with the Sigma-11 -- Your M3's new friend!

[amb]

Quote:

Originally Posted by Shahrose /img/forum/go_quote.gif should i leave the PSU on all the time and use the on/off switch of the M^3? or the other way around? or turn them both off after use?

You should keep the power switch on the M³ in the "on" position at all times, and use the switch on the σ11 to turn the power on and off. This assumes that the σ11's switch is wired on the primary side of the power transformer.

The M³ has a capacitor bank across its power rails. If you switch on the power immediately prior to this bank (which is what would happen if you use the switch on the amp), the instantaneous surge current to charge the capacitors is very high. For a brief moment it would "look" like a dead short to the PSU. Since σ11 has no current limiting protection, this could actually cause damage. For the same reason, the umbilical cable between the σ11 and the M³ should never be disconnected or connected while the power is on. Hopefully your cable has a locking connector to prevent this from happening accidentally.

If you use the power switch on the primary side of the σ11's power transformer, the σ11 has a gentle voltage ramp-up characteristics and thus there won't be a large surge on those capacitors.

 

[Shahrose]

Quote:

Originally Posted by amb /img/forum/go_quote.gif You should keep the power switch on the M³ in the "on" position at all times, and use the switch on the σ11 to turn the power on and off. This assumes that the σ11's switch is wired on the primary side of the power transformer. The M³ has a capacitor bank across its power rails. If you switch on the power immediately prior to this bank (which is what would happen if you use the switch on the amp), the instantaneous surge current to charge the capacitors is very high. For a brief moment it would "look" like a dead short to the PSU. Since σ11 has no current limiting protection, this could actually cause damage. For the same reason, the umbilical cable between the σ11 and the M³ should never be disconnected or connected while the power is on. Hopefully your cable has a locking connector to prevent this from happening accidentally. If you use the power switch on the primary side of the σ11's power transformer, the σ11 has a gentle voltage ramp-up characteristics and thus there won't be a large surge on those capacitors.

thanks Ti, valuable info. i'll use the sigma power switch from now on and leave the M^3 powered on.

 

[veloaudio]

Quote:

Originally Posted by amb /img/forum/go_quote.gif You should keep the power switch on the M³ in the "on" position at all times, and use the switch on the σ11 to turn the power on and off. This assumes that the σ11's switch is wired on the primary side of the power transformer. The M³ has a capacitor bank across its power rails. If you switch on the power immediately prior to this bank (which is what would happen if you use the switch on the amp), the instantaneous surge current to charge the capacitors is very high. For a brief moment it would "look" like a dead short to the PSU. Since σ11 has no current limiting protection, this could actually cause damage. For the same reason, the umbilical cable between the σ11 and the M³ should never be disconnected or connected while the power is on. Hopefully your cable has a locking connector to prevent this from happening accidentally. If you use the power switch on the primary side of the σ11's power transformer, the σ11 has a gentle voltage ramp-up characteristics and thus there won't be a large surge on those capacitors.

I realize from your earlier post the the STEPS would current limit. Would you still recommend turning off the STEPS instead of the M3?

 

[Pricklely Peete]

It's a nice build. The Lindberg transformers are steady and reliable, never had one give me any trouble yet with other builds. Nice quality parts, it should last you a long long time.

What V are the 4 secondaries ?

I like the chassis and need one like that for my Jaycar project.

Peete.

 

[amb]

Quote:

Originally Posted by veloaudio /img/forum/go_quote.gif I realize from your earlier post the the STEPS would current limit. Would you still recommend turning off the STEPS instead of the M3?

Yes, there has been reports that the LM317 on the STEPS would blow when using a switch between it and the amp, despite the current limiting protection.

 

[upstateguy]

Quote:

Originally Posted by amb /img/forum/go_quote.gif You should keep the power switch on the M³ in the "on" position at all times, and use the switch on the σ11 to turn the power on and off. This assumes that the σ11's switch is wired on the primary side of the power transformer. The M³ has a capacitor bank across its power rails. If you switch on the power immediately prior to this bank (which is what would happen if you use the switch on the amp), the instantaneous surge current to charge the capacitors is very high. For a brief moment it would "look" like a dead short to the PSU. Since σ11 has no current limiting protection, this could actually cause damage. For the same reason, the umbilical cable between the σ11 and the M³ should never be disconnected or connected while the power is on. Hopefully your cable has a locking connector to prevent this from happening accidentally. If you use the power switch on the primary side of the σ11's power transformer, the σ11 has a gentle voltage ramp-up characteristics and thus there won't be a large surge on those capacitors.

Hi amb

Where would I be able to get a cable with a locking connector?

Thanks

USG

 

[scootermafia]

Do you have a Rockhopper M3? Those use non-locking barrel connectors. If you redrilled the back plate and wired in a locking Neutrik power connector, then built your own cable out of male matching power connectors, that'd work.

 

[upstateguy]

Quote:

Originally Posted by scootermafia /img/forum/go_quote.gif Do you have a Rockhopper M3? Those use non-locking barrel connectors. If you redrilled the back plate and wired in a locking Neutrik power connector, then built your own cable out of male matching power connectors, that'd work.

Um, Nope

 

[amb]

If your M³ was built by a pro-builder such as Rockhopper, MisterX or YBM, then I suggest asking the builder to mod your amp and PSU to use locking connectors (and supply you with a matching cable). If your M³ was a DIY build, then you could DIY the connector/cable upgrade. These days my preference is to use Amphenol Eco|Mate C-16M series circular connectors. They are available from Digikey and Mouser in many forms.

 

[amb]

Quote:

Originally Posted by upstateguy /img/forum/go_quote.gif Um, Nope

Those two (the black one in the upper photo and the silver one on the bottom photo) look like Rockhopper's work.

 

[Vandal]

That's one super sexy rack err stack!

 

[upstateguy]

Quote:

Originally Posted by amb /img/forum/go_quote.gif Those two (the black one in the upper photo and the silver one on the bottom photo) look like Rockhopper's work.

Hi amb

I was kidding.... that's why the

Both are Stephens work.

But when I look at the jacks on the back, there is a curved arrow pointing in the direction it should lock and what appears to be two square cut outs on either side of the circle where some kind of locking male should be able to fit into....

I'll post a pic of it in a few minutes...

USG

Edit: The Pic (these are on the silver M^3 and both Black units)

 

[amb]

I know what you're talking about. Those are Kobiconn "locking" type barrel power jacks (Mouser #163-1100). The matching locking plug is Mouser #171-0725.

That said, these can easily become unlocked by self-twisting action of the wire. They are somewhat flimsy and nowhere as robust and secure as the Amphenol connectors I mentioned above. But then the Amphenols are a lot more expensive.

 

[upstateguy]

Quote:

Originally Posted by amb /img/forum/go_quote.gif I know what you're talking about. Those are Kobiconn "locking" type barrel power jacks (Mouser #163-1100). The matching locking plug is Mouser #171-0725. That said, these can easily become unlocked by self-twisting action of the wire. They are somewhat flimsy and nowhere as robust and secure as the Amphenol connectors I mentioned above. But then the Amphenols are a lot more expensive.

You're the man!!!!

Does the plug come in a cable form ?

USG

 

[amb]

Quote:

Originally Posted by upstateguy Does the plug come in a cable form ?

As far as I know, there are no pre-made cables with those plugs. You gotta DIY, or ask someone to do it for you.