Question Levinson ML-3 Binding Post

[loonman1]

I recently got a Levinson ML-3 amp, but it doesn't have the binding posts. I've scoured the Internet but I cannot find a replacement set that looks like the receptacle on the back of the amp. Anyone know what kind I'm looking for or where I could find them?

 

[Gray]

....look similar to RCA sockets 🤔
But aren't they just receptacles for standard 4mm plugs?

 

[loonman1]

....look similar to RCA sockets 🤔
But aren't they just receptacles for standard 4mm plugs?

They are not. The inner plug is a larger diameter than banana plugs, maybe 5 or 6 mm.

 

[loonman1]

....look similar to RCA sockets 🤔
But aren't they just receptacles for standard 4mm plugs?

Here's a size comparison with RCA.

 

[Al ears]

Those plugs you are trying to insert do not look like standard RCAs, what are they attached to?

 

[Gray]

The inner plug is a larger diameter than banana plugs, maybe 5 or 6 mm.

They would be different, wouldn't they? 🙄
Apart from the bodge of expanding the peeled 'skin' part of some banana plugs, it would seem you have 2 options:
1) Contact ML or owner forums to aid your search.
2) Buy and fit some chassis mount 4mm sockets - they're readily available (though not so common when gold plated). Of course, you could fit binding posts.

 

[loonman1]

Those plugs you are trying to insert do not look like standard RCAs, what are they attached to?

They're just cheapo RCAs but are standard size

 

[loonman1]

They would be different, wouldn't they? 🙄
Apart from the bodge of expanding the peeled 'skin' part of some banana plugs, it would seem you have 2 options:
1) Contact ML or owner forums to aid your search.
2) Buy and fit some chassis mount 4mm sockets - they're readily available (though not so common when gold plated). Of course, you could fit binding posts.

I'm trying to find the binding posts, but I cannot find any online that look like they fit that receptacle. All the ones I'm finding online thread into the receptacle but the ones on my amp are not threaded.

 

[Al ears]

Yes, apparently as it's a power amp they use CAMAC conectors, whatever they are, because they assume you are using their preamp and leads...ho, hum.
looks like you are going to have to buy into THEIR system.

 

[loonman1]

Yes, apparently as it's a power amp they use CAMAC conectors, whatever they are, because they assume you are using their preamp and leads...ho, hum.

The inputs on his amps are CAMAC/NEMO, yes, but the outputs are typically binding posts. However, mine are missing, and I can't source new posts.

 

[Gray]

I'm trying to find the binding posts, but I cannot find any online that look like they fit that receptacle. All the ones I'm finding online thread into the receptacle but the ones on my amp are not threaded.

When I said you could fit binding posts, I meant instead of what's currently fitted.

If there's no warranty to be invalidated, it would involve opening up the amp - removing what's there completely - the thin, threaded bolt of the binding post pushes through the panel hole and is secured, together with internal wire, with nut and washer (from behind the panel).

Of course you may not want the hassle, but it's what I'd do for the sake of 4mm compatibility.
Having said that, if it is only 5mm, then the banana skin bodge might appeal 🙈

 

[loonman1]

When I said you could fit binding posts, I meant instead of what's currently fitted.

If there's no warranty to be invalidated, it would involve opening up the amp - removing what's there completely - the thin, threaded bolt of the binding post pushes through the panel hole and is secured, together with internal wire, with nut and washer (from behind the panel).

Of course you may not want the hassle, but it's what I'd do for the sake of 4mm compatibility.
Having said that, if it is only 5mm, then the banana skin bodge might appeal 🙈

Oh, I see, sorry I misunderstood. Yeah it was made in the 80s and I'm the second owner so definitely not under warranty. It's also has the CAMACs replaced with RCA so it's been worked on.

I'll consider the banana method! I'm afraid the difference in diameter is too large though.

I've got to say, it's very tempting to direct solder speaker cable to the terminal in the chassis... Am I a fool for considering that?

It's just so frustrating knowing that there are pop - in adapters to fit 4mm connectors, but not being able to find them! I guess that's the downside of using old high-end gear. Thanks for the help.

 

[Gray]

I'll consider the banana method! I'm afraid the difference in diameter is too large though.

Yes, the plug wouldn't need much expanding but any looseness would be undesirable.

Before soldering anything, the best first move would be just to open up the amp and look behind the panel - at how the current sockets are fitted....is it an easy removal.....is there a wire to it, or is it directly connected to PCB?

Maybe remove, push your speaker wire through the hole and solder direct to PCB
I wouldn't solder direct to what's currently there - looks like it could be a meltable panel.

Good luck. Maybe show some pictures, we like seeing inside amps.

 

[loonman1]

Yes, the plug wouldn't need much expanding but any looseness would be undesirable.

Before soldering anything, the best first move would be just to open up the amp and look behind the panel - at how the current sockets are fitted....is it an easy removal.....is there a wire to it, or is it directly connected to PCB?

Maybe remove, push your speaker wire through the hole and solder direct to PCB
I wouldn't solder direct to what's currently there - looks like it could be a meltable panel.

Good luck. Maybe show some pictures, we like seeing inside amps.

I opened it up this morning and it's PCB mounted, so it might be tough... I'll be back there later and I'll send some photos!

 

[loonman1]

I finally found the product I have been seeking. Sure enough, it's a friction-fit binding post made by Fischer, the company that also supplied Levinson's CAMAC connectors. Unfortunately, they don't make them anymore and they cannot be found...anywhere, it seems. So it would appear that the answer is either hard-wire or replace it with a different connector.

 

[Gray]

Unfortunately, they don't make them anymore

No surprise there. Hardly a mass-market product.
(Not as if there's zero demand though, as you've proved).

Black and red versions of these are plentiful.....but not gold plated:

https://cpc.farnell.com/deltron-enclosures/563-0100-01/socket-4mm-panel-black-10a/dp/CN15660?st=4mm%20test%20chassis%20socket

This type have the gold plating. More expensive, not least due to the 'safety' aspect - but they will also take the unshrouded (normal speaker) 4mm plugs:

https://cpc.farnell.com/mc-multi-contact/23-3060-22/socket-4mm-shrouded-red-pk5/dp/CN15675?st=4mm%20test%20socket%20gold

...All depends on your distance from panel to PCB etc.
you might have to go hardwired, though that makes things a bit permanent....

 

[loonman1]

As promised, here are some photos of the interior of the amp. I don't know much about amps, but those caps seem pretty significant! The red arrow indicates the backside of the receptacle in question. Looks pretty tough to remove...

 

[nopiano]

Plenty of US muscle on show there! I’d suggest enlisting a suitable electronics engineer to replace the sockets, or even a return to ML. Have you an audio dealer you can ask?

 

[loonman1]

Plenty of US muscle on show there! I’d suggest enlisting a suitable electronics engineer to replace the sockets, or even a return to ML. Have you an audio dealer you can ask?

There's a shop I'll call Tuesday that the original owner had replace the CAMAC input connectors. They should know what's up!

 

[nopiano]

There's a shop I'll call Tuesday that the original owner had replace the CAMAC input connectors. They should know what's up!

Sounds perfect! Let us know what they say.

 

[Gray]

Is there a continuous hole front to back through the tube you've arrowed?***
If the end had been flat, a nut and washer could have easily secured the bolt of a pushed-through binding post.

As things stand, your arrow is pointing to a perfectly angled and aligned solder 'bucket'.
Only one of the 4 is slightly less accessible. With a hot enough (non-precision) iron....
they were (almost literally) made for soldering the bared ends of pushed-through wires into place.
If you're concerned about the permanence, you could easily fit flying 4mm banana sockets on the wires say 3-4 inches from the back panel.

Unless you D.I.Y., the alternative of removing what's there and fitting 4mm posts / sockets looks like it might be pricey .....might steer you toward the solder option.

***Looking at your photo in post #4 there's no hole through - but a drill will make sure there is. May sound a bit drastic but, short of finding the correct size of plug, I can't see as you've got anything to lose by drilling / soldering - provided you ensure no metal shards / solder blobs are left floating within.
(Look where the metal strip from the socket passes under those 2 diodes....where the strip's lifted, it's not far off shorting to them as it is).

P.S. Don't fancy soldering? Get it to me, I'll gladly do it.....probably for around a quarter of what you get quoted for socket replacement 🤑

Do you know if the amp works by the way? 😏

 

[loonman1]

I'm a DIYer for sure, but this was a gift from a good friend and thus I'm being more careful than I would ordinarily be. Gray, I appreciate the offer though! I did find a product I think will work. Parts Express sells gold-plated expanding banana plugs, that will supposedly expand up to 7-8mm. For $20 a pair or so, I think it's worth giving a try! I'll keep y'all posted. Thanks so much for the advice!

Home

Expanding Banana Plug with Dual Set Screws and Poly Carbonate Shell 2 PairThese locking, expanding banana plug connectors are manufactured with color-coded polycarbonate shells for quick polarity identification and protection from possible short-circuiting contact.Milled from solid brass and...

www.parts-express.com

 

[Gray]

I'm a DIYer for sure, but this was a gift from a good friend and thus I'm being more careful than I would ordinarily be. Gray, I appreciate the offer though! I did find a product I think will work. Parts Express sells gold-plated expanding banana plugs, that will supposedly expand up to 7-8mm. For $20 a pair or so, I think it's worth giving a try! I'll keep y'all posted. Thanks so much for the advice!

Home

Expanding Banana Plug with Dual Set Screws and Poly Carbonate Shell 2 PairThese locking, expanding banana plug connectors are manufactured with color-coded polycarbonate shells for quick polarity identification and protection from possible short-circuiting contact.Milled from solid brass and...

www.parts-express.com

Excellent, the easy answer 👍