Audio question .. gofre?

Watch
FrancisPM
Badges: 9
Rep:
?
#1
Report Thread starter 2 years ago
#1
Hi
I have a quick audio question ..
I have the option of getting some Music fidelity MF200b for about 35 quid.
The MF200b model differs from MF200 model in that they are balanced headphones with a 4 pole XLR connector. I do not want to buy the related amp, in fact what I want to do is simply change the plug to a standard jack plug .. I am quite competent in doing so.
However, I am unsure whether balanced headphones can be converted to unbalanced in this way and also whether they need/ draw additional power from the headphone amp.

these are the headphones I would like: http://www.musicalfidelity.com/suppo...phones/mf-200b

If anyone has any view/ experience then appreciated.
I mention Gofre in the title in that I have read his advice on other audio matters and has a wide knowledge on audio tech.
cheers
Francis.
0
reply
username3006294
Badges: 14
Rep:
?
#2
Report 2 years ago
#2
(Original post by FrancisPM)
Hi
I have a quick audio question ..
I have the option of getting some Music fidelity MF200b for about 35 quid.
The MF200b model differs from MF200 model in that they are balanced headphones with a 4 pole XLR connector. I do not want to buy the related amp, in fact what I want to do is simply change the plug to a standard jack plug .. I am quite competent in doing so.
However, I am unsure whether balanced headphones can be converted to unbalanced in this way and also whether they need/ draw additional power from the headphone amp.

these are the headphones I would like: http://www.musicalfidelity.com/suppo...phones/mf-200b

If anyone has any view/ experience then appreciated.
I mention Gofre in the title in that I have read his advice on other audio matters and has a wide knowledge on audio tech.
cheers
Francis.
I have no idea about tech but I'll tag Gofre to help and also RoyalSheepy might be able to help
2
reply
FrancisPM
Badges: 9
Rep:
?
#3
Report Thread starter 2 years ago
#3
(Original post by em_lj)
I have no idea about tech but I'll tag Gofre to help and also RoyalSheepy might be able to help
that is very kind of you.
Francis
0
reply
uberteknik
  • Study Helper
Badges: 21
Rep:
?
#4
Report 2 years ago
#4
(Original post by FrancisPM)
Hi
I have a quick audio question ..
I have the option of getting some Music fidelity MF200b for about 35 quid.
The MF200b model differs from MF200 model in that they are balanced headphones with a 4 pole XLR connector. I do not want to buy the related amp, in fact what I want to do is simply change the plug to a standard jack plug .. I am quite competent in doing so.
However, I am unsure whether balanced headphones can be converted to unbalanced in this way and also whether they need/ draw additional power from the headphone amp.

these are the headphones I would like: http://www.musicalfidelity.com/suppo...phones/mf-200b

If anyone has any view/ experience then appreciated.
I mention Gofre in the title in that I have read his advice on other audio matters and has a wide knowledge on audio tech.
cheers
Francis.
(Original post by em_lj)
I have no idea about tech but I'll tag Gofre to help and also RoyalSheepy might be able to help
Hello.

In short, yes you can convert them without any problem. But your best approach is simply to buy an adaptor cable:

If you let me know the size of the jack you require, I will point you to the correct adapter.

As far as amplification is concerned, again, there is no difference. The same transducers are used in both types.

Balanced is a bit of buzzword hijacked by the marketing people from the professional electronics world. For low level signals working in a high electrical noise environment, balanced offers advantages to cancel out noise with the use of differential amplifiers and high common-mode noise rejection.

Most people will be lost on the technical stuff and so applied to headphone amplifiers, it sounds impressive and technically plausible. In reality. from a headphone perspective, it's pretty much worthless as you won't hear the slightest difference in normal use.

On to the practicalities:

In a normal headphone jack, there are three conductors, one each for the left and right channel signals, and one is a common return for both channels.
In the four pin XLR connector, each channel has a separate return.

To convert, the two (-ve) return XLR conductors need to be joined (soldered) together and attached to the jack plug (3 pin) common tag. The left and right signal conductors go to their respective jack pins.

This website gives the pin allocation for the most common types of connector. Simply scroll down to find the ones applicable:


http://www.diyaudioblog.com/2016/02/...nouts-for.html
2
reply
RoyalSheepy
Badges: 20
Rep:
?
#5
Report 2 years ago
#5
(Original post by em_lj)
I have no idea about tech but I'll tag Gofre to help and also RoyalSheepy might be able to help
Thank you for the tag! Although, I'm going to be honest, I have no idea about any audio tech :lol:
0
reply
dpm
Badges: 13
Rep:
?
#6
Report 2 years ago
#6
(Original post by uberteknik)
Hello.

In short, yes you can convert them without any problem. But your best approach is simply to buy an adaptor cable:

If you let me know the size of the jack you require, I will point you to the correct adapter.

As far as amplification is concerned, again, there is no difference. The same transducers are used in both types.

Balanced is a bit of buzzword hijacked by the marketing people from the professional electronics world. For low level signals working in a high electrical noise environment, balanced offers advantages to cancel out noise with the use of differential amplifiers and high common-mode noise rejection.

Most people will be lost on the technical stuff and so applied to headphone amplifiers, it sounds impressive and technically plausible. In reality. from a headphone perspective, it's pretty much worthless as you won't hear the slightest difference in normal use.

On to the practicalities:

In a normal headphone jack, there are three conductors, one each for the left and right channel signals, and one is a common return for both channels.
In the four pin XLR connector, each channel has a separate return.

To convert, the two (-ve) return XLR conductors need to be joined (soldered) together and attached to the jack plug (3 pin) common tag. The left and right signal conductors go to their respective jack pins.

This website gives the pin allocation for the most common types of connector. Simply scroll down to find the ones applicable:


http://www.diyaudioblog.com/2016/02/...nouts-for.html
Many thanks for your detailed explanation!
I have just bought them and will see how it go's!
the actual socket on the headphone looks like this..
(and I would like to connect them to a a/4"jack to use with my fiio player )
cheers
francis
(ps .. I know this is a different user account and I don''t like multiple accounts, but this is my work pc and I keep all accounts separate!)
Image
0
reply
uberteknik
  • Study Helper
Badges: 21
Rep:
?
#7
Report 2 years ago
#7
(Original post by dpm)
Many thanks for your detailed explanation!
I have just bought them and will see how it go's!
the actual socket on the headphone looks like this..
(and I would like to connect them to a a/4"jack to use with my fiio player )
cheers
francis
(ps .. I know this is a different user account and I don''t like multiple accounts, but this is my work pc and I keep all accounts separate!)
OK. It's a 4 pin mini XLR type which is unfortunately not widespread in professional use. But that needn't be a problem. You will need to cut the cable, bare the conductors and then make a few resistance measurements.

You will need to work out the pin assignment, which will be much easier if you have access to a small digital ohmmeter. Pick one up for around £8 from Halfords will do the trick.

http://www.halfords.com/workshop-tools/tools/hand-tools/rolson-digital-multimeter?cm_mmc=Google+PLA-_-Tools-_-Hand+Tools-_-710273&istCompanyId=b8708c57-7a02-4cf6-b2c0-dc36b54a327e&istItemId=wxmtpaxpq &istBid=tztx&_$ja=tsid:94971|cid :865695754|ag id:42483195983|tidla-331463656798|crid:203186066553|n w:g|rnd:14282286024233346863|dvc :c|adp:1o9|mt:|loc:9046019&gclid =EAIaIQobChMI0fHHj-v41gIVdTPTCh1EPQygEAkYCSABEgJC3f D_BwE

Then it's a case of measuring the dc resistance across the bared wires. There will be two pairs measuring around 64 ohms across each.

Make a note of the pin allocation. It should be something like:

Image

The next bit is a little more tricky because we want to know which is the left channel and which is the right. So wire up one pair to the jack. One cable to the tip and one to the sleeve. You will most likely find the red or black cable is the +ve of one channel. This needs to be wired to the tip of the 1/4".

Image

Then try it out with some music and see which ear the headphone works on your head.

If all is good, wire up the ring and sleeve for the other channel and try it put again. This time both channels should now work.

The final test is for correct phasing. (+ve to +ve and -ve to -ve on both channels). It helps if you have access to a proper stereo test tone. There are a few on youtube.



Play some monophonic music. If the phase is correct, the sound will be dead centre and will sound correct. If the phase is not correct, the sound will be diffuse and not appear dead centre.

In which case, one pair of wires needs to be reversed. i.e. sleeve with tip swapped over.

Try again. Everything should now be OK. Make a note of the cable colours and pin locations, finish any soldering/tidying and put the connector back together.

Voila. Job done.
0
reply
dpm
Badges: 13
Rep:
?
#8
Report 2 years ago
#8
(Original post by uberteknik)
OK. It's a 4 pin mini XLR type which is unfortunately not widespread in professional use. But that needn't be a problem. You will need to cut the cable, bare the conductors and then make a few resistance measurements.

You will need to work out the pin assignment, which will be much easier if you have access to a small digital ohmmeter. Pick one up for around £8 from Halfords will do the trick.

http://www.halfords.com/workshop-tools/tools/hand-tools/rolson-digital-multimeter?cm_mmc=Google+PLA-_-Tools-_-Hand+Tools-_-710273&istCompanyId=b8708c57-7a02-4cf6-b2c0-dc36b54a327e&istItemId=wxmtpaxpq &istBid=tztx&_$ja=tsid:94971|cid :865695754|ag id:42483195983|tidla-331463656798|crid:203186066553|n w:g|rnd:14282286024233346863|dvc :c|adp:1o9|mt:|loc:9046019&gclid =EAIaIQobChMI0fHHj-v41gIVdTPTCh1EPQygEAkYCSABEgJC3f D_BwE

Then it's a case of measuring the dc resistance across the bared wires. There will be two pairs measuring around 64 ohms across each.

Make a note of the pin allocation. It should be something like:

Image

The next bit is a little more tricky because we want to know which is the left channel and which is the right. So wire up one pair to the jack. One cable to the tip and one to the sleeve. You will most likely find the red or black cable is the +ve of one channel. This needs to be wired to the tip of the 1/4".

Image

Then try it out with some music and see which ear the headphone works on your head.

If all is good, wire up the ring and sleeve for the other channel and try it put again. This time both channels should now work.

The final test is for correct phasing. (+ve to +ve and -ve to -ve on both channels). It helps if you have access to a proper stereo test tone. There are a few on youtube.



Play some monophonic music. If the phase is correct, the sound will be dead centre and will sound correct. If the phase is not correct, the sound will be diffuse and not appear dead centre.

In which case, one pair of wires needs to be reversed. i.e. sleeve with tip swapped over.

Try again. Everything should now be OK. Make a note of the cable colours and pin locations, finish any soldering/tidying and put the connector back together.

Voila. Job done.
wow ! what a detailed post .. truly, many thanks! this all makes sense and i am looking forwards to giving it a go!
all the best
Francis
1
reply
Gofre
Badges: 21
Rep:
?
#9
Report 2 years ago
#9
(Original post by FrancisPM)
that is very kind of you.
Francis
Uberteknik's response is pretty much what I'd have said but with far more detail than I could have provided : yep:
1
reply
uberteknik
  • Study Helper
Badges: 21
Rep:
?
#10
Report 2 years ago
#10
(Original post by dpm)
wow ! what a detailed post .. truly, many thanks! this all makes sense and i am looking forwards to giving it a go!
all the best
Francis
Did you eventually buy the headphones and change the connector?

How did you get on?
0
reply
dpm
Badges: 13
Rep:
?
#11
Report 2 years ago
#11
(Original post by uberteknik)
Did you eventually buy the headphones and change the connector?

How did you get on?
Hi

I bought a couple of adapters on amazon and when the headphones arrive .. low and behold there was an adapter to 3.5mm jack in the box..

I also ordered this on amazon (for 99 pounds) ... V 90 BHA .. but it never arrived !! and have been told it is probably lost in the post an hence a refund is imminent ..

I must say, that I am really happy with the headphones as is, but will keep an eye out for said amplifier.

many thanks for the help again (I am planning to make an additional adapter this weekend to keep at work!)

cheers
D.
0
reply
X

Quick Reply

Attached files
Write a reply...
Reply
new posts
Back
to top
Latest
My Feed

See more of what you like on
The Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

Personalise

Are you confident you could find support for your mental health if you needed it in COVID-19?

Yes (25)
20.33%
No (98)
79.67%

Watched Threads

View All