Co-Ax and Soldering

[unbalancedgraham]

Hi all!

New member and have looked about a bit but can't find an answer so I hope you guys can help!

I want to use Belden 1505f cable to go from Switchcraft RCA to Neutrik quarter-inch jacks (domestic hifi into pro balanced system). As this is a solder connection is this combination appropriate and worth making?

Will I melt shield layers? Will the bond be good enough? I trust in Switchcraft and Neutrik as have used them for years with balanced audio cables for studio applications but I am now using my old studio gear for my home 3.1 (girlfriend won't allow 5.1 - YET).

I am using a domestic unbalanced soundcard to patch in to a preamp that converts the signal to balanced pro-level audio so I can run long cables to my Genelec speakers that have their own amps built in.

My instincts say this is reasonable? I don't want to buy pre-made or custom made cables as I want to do my own soldering work and cable lengths.

Hope you can help!

G.

 

[Speedskater]

Soldering coax and for that matter Shielded Twisted Pair can be tricky. I built little jigs that hold the mate connector. Practice first on expendable stuff.

 

[highfigh]

Hi all!

New member and have looked about a bit but can't find an answer so I hope you guys can help!

I want to use Belden 1505f cable to go from Switchcraft RCA to Neutrik quarter-inch jacks (domestic hifi into pro balanced system). As this is a solder connection is this combination appropriate and worth making?

Will I melt shield layers? Will the bond be good enough? I trust in Switchcraft and Neutrik as have used them for years with balanced audio cables for studio applications but I am now using my old studio gear for my home 3.1 (girlfriend won't allow 5.1 - YET).

I am using a domestic unbalanced soundcard to patch in to a preamp that converts the signal to balanced pro-level audio so I can run long cables to my Genelec speakers that have their own amps built in.

My instincts say this is reasonable? I don't want to buy pre-made or custom made cables as I want to do my own soldering work and cable lengths.

Hope you can help!

G.

It's best to read what the manufacturer and seller recommend WRT termination. Most of this kind of cable isn't soldered unless it has copper braid for the shield. If it's tinned, sure, but it's easier to have a good, reliable termination without soldering.

This is from the Blue Jeans site-

"All 1505F cables are terminated using Canare crimp connectors."

http://www.belden.com/resourcecenter/tools/Compression-Connectors-and-Tools.cfm

 

[unbalancedgraham]

Soldering coax and for that matter Shielded Twisted Pair can be tricky. I built little jigs that hold the mate connector. Practice first on expendable stuff.

I'll give it a go with a little bit I have kicking about, thanks!

 

[unbalancedgraham]

It's best to read what the manufacturer and seller recommend WRT termination. Most of this kind of cable isn't soldered unless it has copper braid for the shield. If it's tinned, sure, but it's easier to have a good, reliable termination without soldering.

This is from the Blue Jeans site-

"All 1505F cables are terminated using Canare crimp connectors."

http://www.belden.com/resourcecenter/tools/Compression-Connectors-and-Tools.cfm

Thanks for the reply! So if soldering isn't the best solution perhaps changing my tac on cable choice might be the way to go? I'm looking for the best shielded unbalanced cable to use as I fear my desktop computer could introduce a tonne of noise on if I run any cables longer than 30cm.

Being a hybrid pro-audio/domestic set up there are mains leads and line level cables all over the place and thats why i want to convert them to balanced as best and as soon as I can from the source!

What would you suggest?

Thank you again for your thoughts so far!

 

[WaynePflughaupt]

According to Belden’s tech sheet the 1505 has a tinned copper shield, so you should be able to solder it. If you decide to go with a different cable, I’d recommend Canare L-2T2S or L-2E5.

Regards,
Wayne A. Pflughaupt

 

[unbalancedgraham]

According to Belden’s tech sheet the 1505 has a tinned copper shield, so you should be able to solder it. If you decide to go with a different cable, I’d recommend Canare L-2T2S or L-2E5.

Regards,
Wayne A. Pflughaupt

Wayne you legend, thank you so much for your suggestion.

Just another query, aside from co-ax are there any superior unbalanced line cables that offer very high shielding?

Again, so good to have yous guys thoughts and opinions on this! My GF has a pavlovian reaction to reach for a knife if i mention my cable woes.

G.

 

[WaynePflughaupt]

A balanced cable will work just fine for an unbalanced connection; that’s why I recommended the two cables that I did.

But if you’re dead-set on an unbalanced cable, I’m sure anything from Canare, Belden or Mogami will work fine.

Basically what makes or breaks a cable for unbalanced applications is the shield. The 1505f should be better than any so-called unbalanced cable, since it has double-shielding.

Practically speaking, however, I doubt you’ll be able to tell any difference, unless perhaps you happen to live next door to high-powered broadcasting towers.

Regards,
Wayne A. Pflughaupt

 

[TLS Guy]

Hi all!

New member and have looked about a bit but can't find an answer so I hope you guys can help!

I want to use Belden 1505f cable to go from Switchcraft RCA to Neutrik quarter-inch jacks (domestic hifi into pro balanced system). As this is a solder connection is this combination appropriate and worth making?

Will I melt shield layers? Will the bond be good enough? I trust in Switchcraft and Neutrik as have used them for years with balanced audio cables for studio applications but I am now using my old studio gear for my home 3.1 (girlfriend won't allow 5.1 - YET).

I am using a domestic unbalanced soundcard to patch in to a preamp that converts the signal to balanced pro-level audio so I can run long cables to my Genelec speakers that have their own amps built in.

My instincts say this is reasonable? I don't want to buy pre-made or custom made cables as I want to do my own soldering work and cable lengths.

Hope you can help!

G.

As I understand it you are going from unbalanced to balanced. Is this correct? If so your instincts are likely to prove unreasonable.

It is usually straightforward to go form balanced to unbalanced by constructing a floating line. This works because you are going from a low impedance output to a high impedance load..

Generally this does not work going the other way round, as you go from a higher impedance output than the load impedance. So you must know the output and load impedances, or you will get very bad results.

In general the way you are going requires the use of a transformer or an IC opamp interface to convert the unbalanced output to a balanced signal.

This is a common error and can even damage equipment.

 

[WaynePflughaupt]

As I understand it you are going from unbalanced to balanced. Is this correct.

I may be wrong, but I think he’s only interested in the unbalanced connection between his sound card and the pre-amp. The pre amp converts to balanced for the runs to his active speakers.

Regards,
Wayne A. Pflughaupt

 

[unbalancedgraham]

As I understand it you are going from unbalanced to balanced. Is this correct? If so your instincts are likely to prove unreasonable.

It is usually straightforward to go form balanced to unbalanced by constructing a floating line. This works because you are going from a low impedance output to a high impedance load..

Generally this does not work going the other way round, as you go from a higher impedance output than the load impedance. So you must know the output and load impedances, or you will get very bad results.

In general the way you are going requires the use of a transformer or an IC opamp interface to convert the unbalanced output to a balanced signal.

This is a common error and can even damage equipment.

Hi, thanks for your input.

I am running line level unbalanced signals from a USB soundcard to a multi channel preamp that does not have a common control for all channels. This way I can fine tune my speaker balance to my tastest. Are you suggesting that it would be better or easier to run unbalanced cables straight to my Genelecs if I use the correct cable?

G.

 

[unbalancedgraham]

I may be wrong, but I think he’s only interested in the unbalanced connection between his sound card and the pre-amp. The pre amp converts to balanced for the runs to his active speakers.

Regards,
Wayne A. Pflughaupt

Spot on, thank you for clarifying!

 

[highfigh]

Thanks for the reply! So if soldering isn't the best solution perhaps changing my tac on cable choice might be the way to go? I'm looking for the best shielded unbalanced cable to use as I fear my desktop computer could introduce a tonne of noise on if I run any cables longer than 30cm.

Being a hybrid pro-audio/domestic set up there are mains leads and line level cables all over the place and thats why i want to convert them to balanced as best and as soon as I can from the source!

What would you suggest?

Thank you again for your thoughts so far!

You can buy Neutrik RCA plugs, too. Just make sure to immobilize both ends as it cools.

Running AV cables parallel to power cords is a bad idea but the main reason to keep things organized has more to do with ease of install/removal than the utmost in noise rejection. Real world, use the same ends Blue Jeans uses and more importantly, use the correct crimper. This isn't the hexagonal crimper that was used in the past, this puts even pressure all around the barrel.

 

[unbalancedgraham]

The cable is fine, but it's easy to make bad solder joints if you haven't done it often and even then, it may look good and not be. Compression ends are used in the AV industry ALL THE TIME. "...longer than 30cm"? That's a foot- it's not an important length. Go to see a band and if you think you have cables all over the place, you'll see it's not as important as it seems.

Running AV cables parallel to power cords is a bad idea but the main reason to keep things organized has more to do with ease of install/removal than the utmost in noise rejection. Real world, use the same ends Blue Jeans uses and more importantly, use the correct crimper. This isn't the hexagonal crimper that was used in the past, this puts even pressure all around the barrel.

I have used BNC crimp type cables before but have only ever assisted in making them. Therefore, I'd l like not to invest in an expensive tool to do something I could do with the tools and skills I have already - so long as they are correct and safe

 

[TLS Guy]

I may be wrong, but I think he’s only interested in the unbalanced connection between his sound card and the pre-amp. The pre amp converts to balanced for the runs to his active speakers.

Regards,
Wayne A. Pflughaupt

I take it that the preamp has only balanced inputs. If so he almost certainly needs an interface between the sound card and the balanced input of the preamp. If the preamp only has balanced inputs he is in trouble. If the preamp has unbalanced input but has balanced output he is fine. What you can't do is just go from an unbalanced output to a balanced input, but you can the other way round.

 

[unbalancedgraham]

I take it that the preamp has only balanced inputs. If so he almost certainly needs an interface between the sound card and the balanced input of the preamp. If the preamp only has balanced inputs he is in trouble. If the preamp has unbalanced input but has balanced output he is fine. What you can't do is just go from an unbalanced output to a balanced input, but you can the other way round.

The preamp has DI / servo balanced inputs and outputs therefore, one of its functions is to convert unbalanced to balanced. I'm just concerned about noise between the computer and the preamp.

 

[unbalancedgraham]

According to Belden’s tech sheet the 1505 has a tinned copper shield, so you should be able to solder it. If you decide to go with a different cable, I’d recommend Canare L-2T2S or L-2E5.

Regards,
Wayne A. Pflughaupt

Having looked at the two Canare cables you suggested I wonder if you would be able to advise the conflagration of soldering a balanced cable with a 3 wire cable, please?

 

[highfigh]

I have used BNC crimp type cables before but have only ever assisted in making them. Therefore, I'd l like not to invest in an expensive tool to do something I could do with the tools and skills I have already - so long as they are correct and safe

IF you can solder well, do that- a decent compression tool will cost more than you might be able to justify.

You should be able to go on the Parts Express, Sweetwater, Full Compass or other website to buy the cables you need- they sell many different lengths and Mogami has these, too. Even a retailer like Guitar Center has them and I think Hosa may be part of Belden.

Ideally, you would use an adapter that converts from high to low impedance and deals with the unbalanced to balanced issue.

What brand and model is the preamp? That will have as much to do with this working well/not as anything. Consumer audio often operates in the -10dBu signal range and pro is often in the +4dBu range. You could very well end up with issues with signal level by mixing consumer with pro. The Genelec 8050 has an input sensitivity control that goes to +6dBu, but this can introduce noise if the right conditions exist between them and the preamp.

 

[unbalancedgraham]

A balanced cable will work just fine for an unbalanced connection; that’s why I recommended the two cables that I did.

But if you’re dead-set on an unbalanced cable, I’m sure anything from Canare, Belden or Mogami will work fine.

Basically what makes or breaks a cable for unbalanced applications is the shield. The 1505f should be better than any so-called unbalanced cable, since it has double-shielding.

Practically speaking, however, I doubt you’ll be able to tell any difference, unless perhaps you happen to live next door to high-powered broadcasting towers.

Regards,
Wayne A. Pflughaupt

Oh, also, how would I solder together an unbalanced cable using the 1505F? Would I just connect both shields to ground?

 

[TLS Guy]

Oh, also, how would I solder together an unbalanced cable using the 1505F? Would I just connect both shields to ground?

That is the wrong cable. You need a balanced cable. First though you need to know the input impedance of your preamp. If it is lower than the output impedance of the sound card, you are in trouble without an interface.

You need a two conductor cable and a shield.

On the RCA plug you connect black 3 and 1 which is the shield to the ground of the RCA plug. And pin two positive phase to the hot pin of the RCA plug. Now you wire the balanced connector normally,1 ground which is shield, pin 3 black, and pin 2 which is positive phase. You must do this to optimize signal to noise, and also have the signal correctly phased. Doing this wrong will lead to an out of phase condition.

But still you must pay attention to impedance first when attempting to float a line, which is what you have to do to do what you want. What I described above is a floating line.