RCA to Banana Plug

S

Sparg93

Active Member
I'm just finishing up my restoration of an amp/tuner/speakers, all from the 1960's.

I'm still a newb, so please correct me if I'm headed in the wrong direction.

The wires and RCA connectors are really poor and an AK member recommended I upgrade to binding posts and speaker wire.

With that in mind, I've been looking at 16ga Speaker Wire & Banana clips. To start, is this the right approach? Also, is there a preferred solder for speaker wires? I currently use 60/40 for all my caps & resistors.

When I look at the wires currently in use, there is a wire soldered to the outside of the RCA clip...is this a ground? If so, is there a recommended approach to grounding the speaker properly when I upgrade all the wiring?
(my amp has one output terminal per speaker)

 
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Sounds as though you have RCA jacks on your amp, with the center pin going to one speaker terminal, and the outside, or ground, going to the other. This is sort of Mickey Mouse.

Banana plugs and the appropriate sockets are much better. In your case, you might want to put the banana plug sockets on the speakers, and solder lamp cord, one side to the center pin on an RCA plug, and the other to the outside. Make sure you pay attention to the polarity. I'd put the copper coloured wire to the center pin on both speaker plugs.

At the other end, attach a red Banana plug to the wire that goes to the center pin, and the other wire to the black Banana plug.

This should work fine, but it would be better to put proper speaker terminals on the back of the amp. Any solder will work, 60/40 is fine.
 
Tinnkindling said:
Sounds as though you have RCA jacks on your amp, with the center pin going to one speaker terminal, and the outside, or ground, going to the other. This is sort of Mickey Mouse.
Click to expand...

"Mickey Mouse" or not, one can still buy decent quality speaker wires pre-terminated with RCA jacks at Radio Shack.
 
I was just reading up on the difference between a banana setup and RCA...and a common point that kept coming up were that the "line" levels would be different. So swapping RCA for Banana may not be the best idea?

If it isn't, I can always upgrade the male & female RCA's, plus add new wires. Thoughts? If this is the best idea, I'd like to custom fit my own...any recommendations on wires without plugs on them?
 
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Could you post a shot of the back of the receiver? I think it would be very helpful.
As for making your own RCA speaker cables, that's a great idea but finding RCA plugs that are easy to work with is no easy task.
 
valvenator said:
Could you post a shot of the back of the receiver? I think it would be very helpful.
As for making your own RCA speaker cables, that's a great idea but finding RCA plugs that are easy to work with is no easy task.
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I agree a pic or two of the unit showing the connections would help.

Mouser, Digikey, RF Parts and a host of others out there all sell various RCA jacks and many other varieties of plugs. They sell banana jacks, even MFJ sells Banana Jacks and other plugs,chassis mount connectors.

Easy to solder with some (not recommended) are even compression fit. You can simply slip the wire through the outside cover and twist to fit. Rat Shack used to carry these things but they aren't a solid connection so word got around and the stuff just hung on the wall till they sold it at a loss to rid the stores of it.

I think Part Express has a Chassis mount 5 way binding post that would work for your unit and then you could choose between wire, Banana jack possibly pin connectors if you so desired.

The fact you stereo unit has RCA plugs for speakers make me wonder about it as many very low cost and consumer priced inexpensive units used RCA plugs, which were very low in power output and severely lacked good reproduction were sold in the thousands over the years.

That being said I have seen RF in excess of 300 watts out-putted through an RCA jack on Heath Kit and other radios, with some purists still running those today almost 60 years after they were first built. The point being audio power out of an RCA will work but there are many different style connectors in use with the top products being Banana/Binding post the most common.

Some still use spring compression methods but those are not as solid not as secure a connection as the Banana/Binding post method. Short of a direct solid mechanical and electrical connection my choice would be for the Banana Jack/Binding Post. There are other methods and connectors but the BJ/BP method is what quality builders and manufacturers use.

If you can mod the unit to use the BJ/BP it would serve you as a reliable connection for many years and is a lot easier use.
Hermit
 
Hermit418 said:
If you can mod the unit to use the BJ/BP it would serve you as a reliable connection for many years and is a lot easier use.
Hermit
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...and that's the reason a pic would be helpful. I'm afraid with it using RCA connectors there might be no room for banana connectors which would require twice the area.
 
Space is tight on this setup, particularly in the amp. Also, this is a unique setup, so I won't make any permanent mods...especially on the amp chassis. Soldering and changing things up I don't mind if it improves the sonic performance, but I have to be able to bring it back to original if needed. The are three independent speakers on each side of the console, the largest is only 25w...but the amp uses x6 Bugle Boy / Amperex tubes plus another x10 tubes in the tuner. I'm really hoping to improve the sound quality with the update...but clearly the wires and ends do not need to handle a lot of power.

Amp = x8 RCA's
Phono = x2 RCA's
Tuner = x2 RCA's

Don't mind the dust, I'm still cleaning everything up and restoring the electronics.

Plate on the left, two outputs



Another set:



Connection to tuner



Top view of a portion of the amp:
 
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Is this a console? Hard to tell from the pictures, but the picture of the bundle of wires behind the drivers makes me think it is. In that case, I'd just recommend replacing the current cables with more contemporary RCA plugs (you can find some inexpensively on eBay if you don't mind waiting for the shipping from China) and decent wire (I wouldn't go crazy because the runs are likely to be fairly short - even 18 gaauge would be OK). Speakers don't have grounds, but amps do, and convention would be to connect the shield to the common (usually marked with a '-' or black binding post on contemporary equipment) connection on the amp, and the pin would be the "hot" ('+' or red) connection. However, since you appear to have RCA connectors on both ends, just make sure you wire pin to pin and shield to shield.

Edit: just noticed how close the RCA jacks are to each other on the amp. In that case, modern plugs may be too large, so you might be better off just trying to clean up the existing plugs as best you can (try fine steel wool - you can get it at Home Depot) and resolder with new wire.
 
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Banana plug is for 1 wire only, RCA is (usually) 2.
I guess changes are dependent on space here.

Edit: the RCA in the picture looks like the solder is a little messy, and there is flux residue.
That could all be cleaned up.
Nothing really wrong with RCA's for speaker connections.
 
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swechsler said:
Is this a console? Hard to tell from the pictures, but the picture of the bundle of wires behind the drivers makes me think it is. In that case, I'd just recommend replacing the current cables with more contemporary RCA plugs (you can find some inexpensively on eBay if you don't mind waiting for the shipping from China) and decent wire (I wouldn't go crazy because the runs are likely to be fairly short - even 18 gaauge would be OK). Speakers don't have grounds, but amps do, and convention would be to connect the shield to the common (usually marked with a '-' or black binding post on contemporary equipment) connection on the amp, and the pin would be the "hot" ('+' or red) connection. However, since you appear to have RCA connectors on both ends, just make sure you wire pin to pin and shield to shield.

Edit: just noticed how close the RCA jacks are to each other on the amp. In that case, modern plugs may be too large, so you might be better off just trying to clean up the existing plugs as best you can (try fine steel wool - you can get it at Home Depot) and resolder with new wire.
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Thank you Swechsler for your insight! Yes, you are spot on, this is a console stereo.

Is there a good quality cable you can recommend?

In terms of space, for the RCA's that are physically next to one another, I'm only using one RCA jack in each of those instances. When I plugged in a modern RCA plug, I can safely fit it in there.

I thought with RCA's we are supposed to keep steel wool away from them b/c it could rub off some of the metals they are coated with? ...or are you thinking steel wool on everything but the mail (+) pin?

For new RCA's, this is what I was considering..recommendations?
http://www.parts-express.com/parts-...-way-binding-post-set-2-red-2-black--320-3375
http://www.parts-express.com/parts-express-chassis-mount-rca-jack-pair--091-1120
http://www.parts-express.com/rca-connector-solder-type-2-pair--091-1265

EDIT:
I took this picture b/c my assumption was that one side of the speaker is being grounded to the amp. Both grey wires come from the speaker, one is wired into the pin (+), the other is soldered onto the shield which I'm assuming is ground
 
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Sparg93 said:
Thank you Swechsler for your insight! Yes, you are spot on, this is a console stereo.

Is there a good quality cable you can recommend?
Click to expand...
Again, since distances are short, I wouldn't go crazy. If there's still a Radio Shack in your area, you can try to see if they have any short rolls of speaker wire. Otherwise, you can use something as simple as lamp cord, available at Home Depot.

In terms of space, for the RCA's that are physically next to one another, I'm only using one RCA jack in each of those instances. When I plugged in a modern RCA plug, I can safely fit it in there.

Sparg93 said:
I thought with RCA's we are supposed to keep steel wool away from them b/c it could rub off some of the metals they are coated with? ...or are you thinking steel wool on everything but the mail (+) pin?
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This would apply to modern gold-plated plugs, but older ones would have probably just a tin coating, which can be cleaned up by lightly rubbing with 00 or 000 steel wool. Use an air compressor or canned air afterwards to ensure you get rid of all the detritus.

Sparg93 said:
For new RCA's, this is what I was considering..recommendations?
http://www.parts-express.com/parts-...-way-binding-post-set-2-red-2-black--320-3375
http://www.parts-express.com/parts-express-chassis-mount-rca-jack-pair--091-1120
http://www.parts-express.com/rca-connector-solder-type-2-pair--091-1265
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Those would certainly work, but way more than you need. Actually, something like this would probably make life much easier on you. We're not talking high-end equipment, so IMO trying make high-end cables is probably a waste of time.
 
BTW, if you are worrird about the plugs touching each other, get a piece of heat shrink tube large enough to slide over the plug and shrink.
 
woodj said:
BTW, if you are worrird about the plugs touching each other, get a piece of heat shrink tube large enough to slide over the plug and shrink.
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Good idea, thanks!

Swechsler, good idea on the pre-made cables...I ordered a set for the record player to tuner. For the other cables that come off the tuner and speakers and run to the amp, I'll have to build those b/c one set of ends are soldered direct.

When I install new RCA ends, should I clean them up with isopropyl alcohol? I read that even new RCA's may have a light layer of film from the factory due to the manufacturing process.
 
Sparg93 said:
Good idea, thanks!

Swechsler, good idea on the pre-made cables...I ordered a set for the record player to tuner.
Click to expand...

I hope not the ones I linked to - those are strictly for amp to speaker. Any use between components would give you a lot of hum due to lack of shielding.
 
Under most circumstances unshielded RCA cables work just fine. Check Kimber cable. They've been selling unshielded cables for years. They currently sell Tonik, Timbre, PBJ and others that are unshielded. I used their Silver Streak cables for a few years. If my wallet had been fatter I'd have used their KCAG cables.
 
^^^
Yup. Not entirely too long ago I would have said unshielded interconnects were a recipe for hum and noise.

However, after making a couple pair of unshielded interconnects from conductors stripped out of Cat5 cable, it became evident that no shielding isn't automatically a problem. For long runs I think the likelyhood of a problem increases, but have not had a problem with 1m length in my systems.
 
JoeESP9 said:
Under most circumstances unshielded RCA cables work just fine. Check Kimber cable.
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Yes, but if I'm not mistaken, Kimber cables braid the ground and signal wire together, which would still give some semblance of shielding. However, it's been years since I've tried something like this, so i'm hardly an expert. He did, however, mention that he was using the cables (confirmed shielded in a later post) for the phono interconnect. Would you use zip cord in that scenario?

Edit: this reminds me of a discussion many years ago on (I think it was) AVSforum regarding substituting Cat5 for VGA cables for long runs to a ceiling mounted projector.
 
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