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Banana plug question
- Thread starter Lumper
- Start date
KEF Blade 2 Meta
This question rightly belongs in this thread.
Lads, I recently got hold of some CMC BFA plugs. I went ahead and plugged them into my speakers(Focal, Mission) & amplifier(NAD) terminals and found them not going in anything more than about 5mm or so. The plugs have a contact pin/rod in the middle to keep the thin, rolled protruding tube from being deformed or losing its shape if pressed too hard, etc. Strangely, I could get my other hollow BFA plugs into these fully as they should with a little force. I feel that the hard rod-like pin is causing the malleable tube not to narrow when inserted.
What do you think I should do? Should I use a pair of pliers and gently squeeze around the tubes to reduce their thickness and allow them to go in easily? Or is this a tolerance issue that can be attributed to poor QC on the manufacturer's part? Please let me know. Thank you.
Lads, I recently got hold of some CMC BFA plugs. I went ahead and plugged them into my speakers(Focal, Mission) & amplifier(NAD) terminals and found them not going in anything more than about 5mm or so. The plugs have a contact pin/rod in the middle to keep the thin, rolled protruding tube from being deformed or losing its shape if pressed too hard, etc. Strangely, I could get my other hollow BFA plugs into these fully as they should with a little force. I feel that the hard rod-like pin is causing the malleable tube not to narrow when inserted.
What do you think I should do? Should I use a pair of pliers and gently squeeze around the tubes to reduce their thickness and allow them to go in easily? Or is this a tolerance issue that can be attributed to poor QC on the manufacturer's part? Please let me know. Thank you.
Not all binding posts are the same internal diameter. Some are 4.0mm, and some are 4.1mm. I've used these kind of nanners in both sizes without much issue. The BFA-Z style you got are more durable than the BFA without the pins; good call there. They won't snap off the end curl. I don't know what the cause of your issue could be. Do you have pictures?
Thanks for the reply, Wolf. Mine is a 4mm plug (CMC-0658-AG) and can accept wire from 4mm to 6.45mm in diameter: Banana Conductor 4.5mm X 16mm, overall length 40mm.
The picture below shows the plug having around 6-7mm of the tube visible after it has been pushed in as much as possible. I had a friend suggest that I use a flat nose plier and some cloth over the teeth(to prevent the plating from chipping away) to gently squeeze the tube connector where the rod is covered to narrow the overall thickness. I got them to move a little further in with around 4- 5 mm remaining visible. I had to twist and force it in hard, and it sits airtight. I am quite sure the plug is not inserted with such force, as I found it a real struggle to get it out later!
The question now is this: how much of the tube connector must be inside the terminal's cavity for the signal connection to be 100%? It was the same with the amplifier's side.
Got it. Is there a minimum amount of contact that must be present with these plugs? Though I am not able to have it fully inserted, would this suffice or am I better off getting these returned?
sam_adams
Major Contributor
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BFA (British Federation of Audio) plugs are not designed to work with banana plug sockets.
This is a 'true' BFA connector:
Manufactured by a company called Deltron.
Assembled:
This is the 'socket' that it is inserted into:
This (which from your description seems to be what you have):
is not a BFA connector, either.
The center 'rod' is there to address the fact that the outer shell of these connectors have a distinct tendency to snap off if there is no support in the center. See below.
Something like this:
is not a BFA plug, either.
It is usually referred to as a Z-style banana plug.
While it might work in a BFA socket connector:
its flimsy construction is certain to be failure prone.
Readers in the UK/EU can get the Deltron plugs from Compass Audio:
DELTRON BFA AMP SPEAKER PLUGS 595-Series
DELTRON BFA AMP SPEAKER PLUGS 595-series are safety compliant connectors developed for use with compatible high quality amplifiers
compassaudio.co.uk
or Newark:
Readers on the left side of the pond can get the Deltron connectors from Mouser:
Good luck finding the Arcam, Linn, Cyrus sockets for the BFA plugs.
For the electric contact you don't need much. A few mm can give enough easily. But this is more about a proper, secure and not too spacious fit. I think your picture looks OK. But if you actually have the wrong plugs I would replace them, working or not.
Roland68
Master Contributor
The plugs are the right ones.
How deeply they can be inserted depends on your socket, so using different hollow banana plugs wouldn't change anything.
For quite some time now, I have been using either 4mm plugs with an internal locking mechanism or the ones shown here—available from Audiophonics at €6.90 for a set of four—which provide excellent contact.
The BFA plug is a long-established standard for 4mm hollow banana plugs that featured an additional (removable) guard to prevent them from being accidentally inserted into mains sockets.BFA (British Federation of Audio) plugs are not designed to work with banana plug sockets.
This is a 'true' BFA connector:
View attachment 542819
Manufactured by a company called Deltron.
Assembled:
View attachment 542824
This is the 'socket' that it is inserted into:
View attachment 542820
This (which from your description seems to be what you have):
View attachment 542821
is not a BFA connector, either.
The center 'rod' is there to address the fact that the outer shell of these connectors have a distinct tendency to snap off if there is no support in the center. See below.
Something like this:
View attachment 542822
is not a BFA plug, either.
It is usually referred to as a Z-style banana plug.
While it might work in a BFA socket connector:
View attachment 542823
its flimsy construction is certain to be failure prone.
Readers in the UK/EU can get the Deltron plugs from Compass Audio:
DELTRON BFA AMP SPEAKER PLUGS 595-Series
DELTRON BFA AMP SPEAKER PLUGS 595-series are safety compliant connectors developed for use with compatible high quality amplifierscompassaudio.co.uk
or Newark:
Readers on the left side of the pond can get the Deltron connectors from Mouser:
Good luck finding the Arcam, Linn, Cyrus sockets for the BFA plugs.
They were designed for both standard 4mm jacks and the very rare internal plugs for BFA hollow banana plugs.
In the very rare internal plugs for the BFA hollow banana plugs, the hollow banana plug functions as a socket.
Inakustik, among others, offers BFA-compliant plugs.
Poorly designed hollow banana plugs are just as likely to break in standard 4mm sockets as they are in BFA terminals; there is no technical difference in that regard.
The Deltron plug is actually a special case, as it is compatible only with the BFA terminals found on a few amplifiers and not with standard 4mm sockets; however, it is certainly a good, recommended solution for such devices.
