Hello all,

I've just (finally!) acquired a very nice pair of MC120.2.

I've had Arcam Ones for 15 years so I was used to their brightish (British?) presentation.

After some tests, I find them on the dull side of neutral (think ESL), lacking a bit in treble level and extension. I use a Beomaster 6000, a CDX and a Beogram 8000.

Bass is very, very light too.

The tweeter cap being mylar, I see no reason why it should age to the point of attenuating highs, so it stayed in place...

I also find the cabinet to be resonant compared to my Arcams (just tap one side to feel this) but then Klipsches are VERY resonant and sound amazing in their own way.

Will the speakers grow on me or will I continue to get bored?

Jacques

Have you fiddled w/ the protection circuit reset buttons? They can oxidize.

They have a tendency to cause issues not unlike what you describe.

No, I haven't touched them at all. What should I do then?

chartz:

No, I haven't touched them at all. What should I do then?

Reset them... see what happens.

I can't recall if you can "work" them in and out, but I can in a few days!

How do I reset them? They are already pushed!

Jacques

chartz:

How do I reset them? They are already pushed!

Jacques

Play louder so they pop out!

No really, I don't think you can work or clean them without opening the speaker (which isn't actually that big a job).

I suspect the muddy treble would benefit greatly from a recap.

tournedos:

No really, I don't think you can work or clean them without opening the speaker (which isn't actually that big a job).

Thanks Mika! I couldn't for the life of me recall if they could be worked in and out! I wouldn't be near them for a few days to even try.

The thought actually crossed my mind of playing loud too!

At any rate, I'd bet if you get in there and worked that switch -you'd probably be surpised. Short of that, look into the caps as mentioned. Also, these are prone to foam rot. If they are not obvious yet, they may be in a bad state anyway -leading to bass issues.

They are excellent speakers and well worth the time to get them right.

How would you characterize their "normal" sound then?

How would you clean the protection switch? There is absolutely no oxydation in there, it looks like new.

Thanks,

Jacques

chartz:

How would you clean the protection switch? There is absolutely no oxydation in there, it looks like new.

I wish I was near mine to help... As you have already got to them, I would assume that they are serviceable switches. If they are clean and functional, then it is time to move on, I suppose. Caps?

burantek:

 it is time to move on, I suppose. Caps?

Yes, I guess so... unless somebody has another idea...

By the way, I don't use tone controls. Never. Ever.

I just bypassed the switches on mine - by no means a long term solution though.

Regards the sound I am not terribly happy with my s120's after a recap. They were unloved and have been refoamed, actually quite happy with the bass - I had to restick the mid coils as they had worked loose but this was evident with mid distortion. Anyway to me upper end and mid sounds sort of lifeless and I am missing lots of detail in music. I have used an equaliser to sort things out and I think it has given me a taste of what these speakers really are capable of, but until I can access a decent amp (I have a beomaster 1500 which might be better but needs looking at) I cannot really be sure if it is the speakers, source or ME?!

At the moment I am driving them off a Yamaha amp (DSPA5) which I have never overly been keen on but my s-45's sounded much better in the top end, although seriously lacked the bass for obvious reasons. Can't compare as they have been leant to somone else for now!

My S120s were very well balanced - if being critical I would say the bass could be more extended but that is what the MS150 was for! Very clear top end with very few vices except the tweeter shriek at high volumes which seems to be a characteristic of this - and later - range of speakers. I suggest some fettling is required. The Beomaster 1500 by the way is a little gem - much nicer that the 1700 that replaced it in sound quality.

Do you consider the 1500 to be better sounding than the Beomaster 2400 Peter? Not sure which one to attack first to be honest!!! At the moment the beomaster sounds similar to my yamaha as it needs a full recap. Apart from that it is aok..

Right then.

i have shorted the two protection switches and the highs reappeared—a little...The problem is they are sealed with rivets

Anyway the sound is still lacking here. And the mids are now too prominent!

Bass is still light.

All compared to my Arcams.

However they do image better than the Arcams...

Does anyone here have the crossover diagram please?

Jacques

A few more tests later...

The speakers are (both) very shouty and aggressive. Very unpleasant. All the shouting seems to come from the mid dome driver which was almost silent before shorting the protection switch...

I'll go out on a limb...

1.) I can't advise on bypassing the protection circuit (which sounds like what you may have done) but if the sound has changed, there must be an issue w/ the switches even if they looked OK. I would get them back in line and functional.

2.) I would then look at the caps.

3.) Remember, they are prone to rot even if they look OK. That may resolve the bass.

burantek:

I'll go out on a limb...

So will I... Have you got the diagram?

How come the big dome sounds so awful at higher volume? A bad cap again?

How did you clean your switches?

I'm "listening" to Hotel California right now and it just sounds appalling. No bass, shouty voices and little treble. Back to better speakers... Ah, that's more like it! How can new caps transform this mess into a great speaker I wonder.

Jacques

Yes, hotel california sounded similar on mine without an EQ. I wonder if there are folk here running these speakers on amps other than B&O who perhaps could share their experience?

Caps did make a difference and I was very happy with the grade and quality that Martin (dillen) supplied.

Step1:

Caps did make a difference and I was very happy with the grade and quality that Martin (dillen) supplied.

How would you translate this in subjective terms?

It did not make the difference I was hoping for which is why I came to the conclusion my problems were either in the drivers themselves or downstream from the speakers e.g. amplifier. However the highs were definately lifted with more clarity.

I did wonder if the material used on the early mids could change charactoristics over the years (maybe more so under certain environmental conditions) to lead to a change in sound... Might account for the harsh sound you are experiencing? Could this be the reason why they changed to a doped cloth material in later speakers?

Anyway there are a lot of very knowledgable folk here who I am sure will give you (us) some ideas of where we are going wrong :)

Step1:

 Could this be the reason why they changed to a doped cloth material in later speakers?

Mine are  cloth domes!

Jacques

Ah yes MC120 I forgot for a minute

Hello,

I have now ordered the cap kit, so I shall keep you informed of the results.

As far as bass is concerned, I placed them right against the back wall and this restored some bass. Maybe that is what B&O intended their customers to do, I don't know. Every other speaker I've owned would produced too much upper bass in a situation like this.

How do you place yours?

Jacques

chartz:

Hello,

I have now ordered the cap kit, so I shall keep you informed of the results.

As far as bass is concerned, I placed them right against the back wall and this restored some bass. Maybe that is what B&O intended their customers to do, I don't know. Every other speaker I've owned would produced too much upper bass in a situation like this.

How do you place yours?

 

Jacques

That's because B&O never compensated for the baffle step transition in response with the Beovox series speakers.

I think you should reconsider your position on avoiding the use of tone controls.

I've found that new caps make only a very small difference in sound, unless the old ones are just completely toasted.

First thing I'd check is to see if all your drivers are wired in phase with each other. Remember, with these speakers, they are a transient perfect, filler-driver design, and hence, will all be wired in phase electrically with each other. I've accidentally had mid domes wired out of phase before that cause a funky, shouty sound quality as you describe.

Jon

Hey Jon,

Well a strange phenomenon occured...

After a few hours listening to this dreadful sound from the MC120.2, the sound seems to have improved a bit somehow. I think the dielectric in those electrolytic capacitors is the problem. The caps seem to "reform" somehow while electricity passes through them... is that possible?

I still refuse to use tone controls because I feel they largely deteriorate the balance of speakers and they are too crude anyway.

The speaker units are phased correctly.

Jacques

My MC120.2