Does size matter?

[Bill Fitzmaurice]

Most likely only two are active. The only reason for three is if the associated speaker has multiple drivers and the amp has dual power amps separately powering them, with the third wire a common ground.

[bremen]

Does anyone, since the invention of the excellent Speakon, still make amplifiers with xlr speaker outputs? Seems a bit risky, a connector offering big volts and amps on a connector most commonly seen on microphones.

[dclaassen]

1 hour ago, Bill Fitzmaurice said:

Most likely only two are active. The only reason for three is if the associated speaker has multiple drivers and the amp has dual power amps separately powering them, with the third wire a common ground.

Thanks! I think there are wiring directions on the back of the amp…will check tomorrow

[BassmanPaul]

It should tell you what ia what on the back of the amp. 

 

[Stub Mandrel]

7 hours ago, Bill Fitzmaurice said:

the main benefit of going larger is durability.

 

This. You really don't want a speaker lead failing just because someone caught it under the corner of a cab.

[BassmanPaul]

As someone who just went through Prostate Laser surgery yesterday I can assure you size does indeed matter!!! 

 

Moan. ;(

 

Edited May 11 by BassmanPaul

[Mottlefeeder]

On 07/05/2024 at 18:27, bremen said:

Does anyone, since the invention of the excellent Speakon, still make amplifiers with xlr speaker outputs? Seems a bit risky, a connector offering big volts and amps on a connector most commonly seen on microphones.

I think XLR connectors lack the creapage and clearance requirements to be legal at the voltages that a power amp could produce. 

The Bulgin black mains connectors disappeared at the same time for the same problem.

David

[Bill Fitzmaurice]

They're better than 1/4", but still never should have been used for speakers as they're too easily confused with mic and interconnect connectors.

[agedhorse]

On 07/05/2024 at 10:27, bremen said:

Does anyone, since the invention of the excellent Speakon, still make amplifiers with xlr speaker outputs? Seems a bit risky, a connector offering big volts and amps on a connector most commonly seen on microphones.

No, not that I am aware of. They are not “touch-proof” jacks, and are easily confused with DI outputs. They are also not rated for the necessary current, something that safety regulations have addressed through terminal temperature rise.

[agedhorse]

7 hours ago, Mottlefeeder said:

I think XLR connectors lack the creapage and clearance requirements to be legal at the voltages that a power amp could produce. 

The Bulgin black mains connectors disappeared at the same time for the same problem.

David

It’s not creepage/clearance that’s the issue. Mains plugs have to withstand reinforced insulation creepage/clearance at 375Vpk (240V high line peak voltage) whereas the insulation requirements for a speaker jack needs to be designed around basic (or possibly functional) insulation values based around no more than 150Vpk. 

I don’t have my tables handy, but I would guess creepage required for a speaker connector is under 5mm, maybe as small as 3mm. 
 

It’s more the touch-proof requirement for higher powered amps as well as temperature rise under high current density conditions which can cause arcing conditions (PIS).

[Rosie C]

On 05/05/2024 at 14:01, Stub Mandrel said:

I used to use leads made up from two-core 13A mains lead (repurposed from a lawnmower). They are all still working 30+ years on!

 

 

That's exactly what I use for our PA. Bright orange cables that make it less likely we'll trip over.  

[Bill Fitzmaurice]

An oldie but goody: Peter Walker arrived at a press showing with a new set of his Quad speakers. Realizing that he forget speaker cables, and not having time to drive back to the shop to get a pair, he went around the corner to a hardware store, where he bought what he knew would work well. At the press conference later the press seemed as interested in the cables as the speakers, being captivated by the bright orange color. Prodded to reveal the brand of what they assumed were very expensive bits of wire Walker replied: 'Black and Decker!'.

[DaleASmith]

I have 2.5mm and as I understand it even that is overkill, but they where cheap enough so why not..

[Chienmortbb]

Some sound advice here but let’s look at the real world.

 

1. You should never use 6.35 plugs (1/4”) for speakers,,,,, but some amps and speakers have them so… use the best you can and NEVER and instrument cable. 

2. SpeakON 4 way connectors are close to a standard but on cables a 2 way works fine. It mates with a 4 way socket on +1 & -1. You cannot use a 4 way plug into a 2 way socket. 

3 Cables.. You can use mains flex as long as the current rating is OK for your rig. The problem is it is not very flexible.

 

4.Speaker cable is more flexible and more suited to stage use. You do not need 4mm cable unless you are doing high powered PA speakers over long distances. They are a pain to use in the old Neutrik speakons and way over specified for bass rigs. 

5. Although Neutrik are the industry standard, both Cliff and Amphenol make fine Speakon compatible connectors. Switchcraft may also but they are not common in the UK.

6. As a general rule I use 20 amperes as the maximum current (amperage is NOT a word) that 2.5mm cable can carry and 16 amperes as the max a 1.5mm flex can carry. Although commercial flex may be rated higher, that does not account for the  losses in the cables. For bass rigs this may be negligible when using a 50cm to 1m cable but PA cables are much longer and the losses add up. 
 

7. So a 2.5mm copper cable, In my opinion, is good for in excess of 3000 watts continuous at 8 ohms. For 4 ohm use you must halve that rating to 15-1600 watts. For 1.5 mm cable, the figures are 1800 watts at 8 ohms and about 900 into 4 ohms. For longer runs I would debate those figures.

 

Conclusion, 4mm cable is overkill for a bass rig. 2.5 and 1.5 are more than enough but buy a reputable make. Some cheap cables are CCAW or copper covered aluminium wire. It is rubbish.

 

[Bill Fitzmaurice]

CCAW has the same current capacity and resistance as pure copper if you go up one gauge. However, it's more prone to breaking from repeated flexing, so it should only be used in permanent installations.

[Mottlefeeder]

On 14/05/2024 at 10:40, Chienmortbb said:

Some sound advice here but let’s look at the real world.

 

1. You should never use 6.35 plugs (1/4”) for speakers,,,,, but some amps and speakers have them so… use the best you can and NEVER and instrument cable. 

2. SpeakON 4 way connectors are close to a standard but on cables a 2 way works fine. It mates with a 4 way socket on +1 & -1. You cannot use a 4 way plug into a 2 way socket. 

3 Cables.. You can use mains flex as long as the current rating is OK for your rig. The problem is it is not very flexible.

 

4.Speaker cable is more flexible and more suited to stage use. You do not need 4mm cable unless you are doing high powered PA speakers over long distances. They are a pain to use in the old Neutrik speakons and way over specified for bass rigs. 

5. Although Neutrik are the industry standard, both Cliff and Amphenol make fine Speakon compatible connectors. Switchcraft may also but they are not common in the UK.

6. As a general rule I use 20 amperes as the maximum current (amperage is NOT a word) that 2.5mm cable can carry and 16 amperes as the max a 1.5mm flex can carry. Although commercial flex may be rated higher, that does not account for the  losses in the cables. For bass rigs this may be negligible when using a 50cm to 1m cable but PA cables are much longer and the losses add up. 
 

7. So a 2.5mm copper cable, In my opinion, is good for in excess of 3000 watts continuous at 8 ohms. For 4 ohm use you must halve that rating to 15-1600 watts. For 1.5 mm cable, the figures are 1800 watts at 8 ohms and about 900 into 4 ohms. For longer runs I would debate those figures.

 

Conclusion, 4mm cable is overkill for a bass rig. 2.5 and 1.5 are more than enough but buy a reputable make. Some cheap cables are CCAW or copper covered aluminium wire. It is rubbish.

 

A good guide, but point 2 is not quite right. A neutrik/speakon NL4FX 4-pole plug will physically fit a neutri/speakon 2-pole combi jack/speakon socket. Presumably +1 & -1, but I can't check that.

David

[Chienmortbb]

7 hours ago, Mottlefeeder said:

A good guide, but point 2 is not quite right. A neutrik/speakon NL4FX 4-pole plug will physically fit a neutrik/speakon 2-pole combi jack/speakon socket. Presumably +1 & -1, but I can't check that.

David

I think you are correct, it seems that the combo is built to the same spec as the 4 ways, despite only having two speakON poles.