Jump to content

B&C 120 HF drivers swap


Hasty

Recommended Posts

I've got a pair of ct-125 tweeters with Crites 4500 crossovers  I installed around 6-7 years ago.  Is the B&C 120 driver going to be an improvement?  I like the ct-125, but as others have mentioned it's a little mellow compared to the stock HF driver/ horn although it's been a long time since I swapped the parts, so that comparison is based on memory.  FWIW the midrange has A55G drivers.  Is the HF driver swap going to be a watershed improvement, a sideways move, or a matter of taste only?

Link to comment
Share on other sites

On ‎8‎/‎28‎/‎2019 at 9:31 PM, Hasty said:

  Is the HF driver swap going to be a watershed improvement, a sideways move, or a matter of taste only?

I've never had the chance to hear the CT-125's but the CT- 120's were pretty much a jaw-dropping experience for me compared to the stock k-77's I replaced, nice tweeters for sure best I've ever owned / heard and cannot recommend them enough.

Link to comment
Share on other sites

I have the CT-125s, and I believe they roll off at the upper end. That could be fixed with eq (horrors!), or perhaps a little mod to the crossover to pull that up. To me they are great sounding, but I will still be getting some CT-120s to try myself, as I also have some higher output 2 inch mid drivers.

 

Bruce

Link to comment
Share on other sites

Yeah, the CT-125 seems a little more mellow than the stock tweeter, but it's been a long time since I swapped them out.   When using a Marantz PM-5004 the tweeter was almost too relaxed.  I recently switched amps to the IOTAvx SA3/PA3 stack.  It's a flatter sounding amp and the high frequencies are more resolved, forward, and holographic than the Marantz.

 

Most people using the CT-125 are using it because it can handle operating down to 4500hz, but what I don't know is whether it's "good enough" or if the CT-120 is a clear improvement. 

 

 

Link to comment
Share on other sites

58 minutes ago, Hasty said:

Most people using the CT-125 are using it because it can handle operating down to 4500hz, but what I don't know is whether it's "good enough" or if the CT-120 is a clear improvement. 

 

Yes, it's an improvement. And it would be a no brainer if you had a K77, especially the older K77. They are a little ragged sounding.

Link to comment
Share on other sites

These are 1990 models.  When I got them they were all stock and sounded incredibly bright with some 70's era "silver face" pioneer receivers I had.  To be fair I think La Scala's benefit from a subwoofer, although in some rooms they seem fine without a sub.  I've used these in different locations at times, they've been in two different homes and an office before.  

 

Marvel, do you know if you can still get the wooden tweeter horn for the 120 driver?  I think maybe ALK engineering used to sell them, but I'm not sure of that.

Link to comment
Share on other sites

39 minutes ago, Marvel said:

 

1 hour ago, Hasty said:

Marvel, do you know if you can still get the wooden tweeter horn for the 120 driver?  I think maybe ALK engineering used to sell them, but I'm not sure of that.

 

39 minutes ago, Marvel said:

I believe  @Dave A  Dave was able to make wood horns for those, Don't know if he still will. 😉

 

Bruce

 

 

Click this : http://www.ebaystores.com/ROCKMAN836-LAPIDARY

~

  • Thanks 1
Link to comment
Share on other sites

To be honest I have never sat down and run these back to back to try and determine that. I doubt my hearing is acute enough to be able to tell and they both get mounted in wood motorboards. The section of the horn lenses is pretty thick all things considered so I regard them as cosmetic differences only. I think the Walnut when stained is prettiest and the Aluminum far stronger and for strength reasons my personal preference is aluminum all things considered.

 

  I have some spalted Walnut I have thought about cutting for some time because it is darned pretty. I have some next to where a big branch came out and I think they call that a Herring Bone pattern and it looks cool. How they sound relative to each other has never been anything I have considered or worried about.

Link to comment
Share on other sites

Primary differences are the MAHL's are flush with the motor board front with no alterations so you gain improvement there on sound quality and I have a clamp plate that allows for more than one type of driver to be used on the same horn lens if you wish too. I have no idea if there is potential for resonance problems with thin wall horn lenses but the thicker sectional area of the machined lenses would tend to be better at suppressing that. Claude tested these two types of setups and loose in the air with the DE120's they were almost dead on similar which I figure is a testament to the superb B&C DE120 drivers. And of course if you go to the larger K-76,79 type of horn lens I am the only one making anything for it and it is much better than just replacing a diaphragm. Plus with the larger MAHL there are probably dozens of different drivers you can use on the existing clamp plate which currently comes drilled for four different common screw sizes and patterns. In addition the two sizes also come with 1 3/8 18tpi internally threaded clamp plates so you can use externally threaded drivers where possible.

 

  The idea behind the MAHL's was two fold and it was to be a direct dropin where the lens mouth would be flush with the motor board front to eliminate having to alter the cutout to fit zee brackets in most cases. Some of the later models of La Scalas for instance have large enough cutouts to fit those zee brackets as is but all older ones don't. Klipsch has gone to this design also which I think is evidence they found an improvement worthy of doing. The other one was to make a modular clamping system which would allow for the use of a variety of drivers  and not be limited to just one.

 

  Technology changes and I can simply machine clamp plates to adapt to those and you don't have to change it all just to migrate to a new driver. I have also for instance adapted the size of the small K-77 Mahl replacement to fill the larger cutout in later model La Scalas with a larger horn lens than the standard size one and this is the flexibility of being able to design and then step out to the mill and machine a part. You don't change anything on a molded part without all kinds of trouble but a mill does not care and will cut whatever you need. I can easily accommodate changes from new drivers to new motor boards at any time.

  • Like 1
  • Thanks 1
Link to comment
Share on other sites

  • 2 weeks later...
On 8/28/2019 at 10:31 PM, Hasty said:

I've got a pair of ct-125 tweeters with Crites 4500 crossovers  I installed around 6-7 years ago.  Is the B&C 120 driver going to be an improvement?  I like the ct-125, but as others have mentioned it's a little mellow compared to the stock HF driver/ horn although it's been a long time since I swapped the parts, so that comparison is based on memory.  FWIW the midrange has A55G drivers.  Is the HF driver swap going to be a watershed improvement, a sideways move, or a matter of taste only?

 

I have the same B&C 120 and A-55-G  Drivers on my (correction) 1982 Belles. Will the Dave A adapters and B&C Drivers fit w/o modification(s)?

 

Wb

Edited by Wolfbane
sp
Link to comment
Share on other sites

57 minutes ago, Wolfbane said:

 

I have the same B&C 120 and A55G  Drivers on my 1981 Belles. Will the Dave A adapters and B&C Drivers fit w/o modification(s)?

 

Wb

Yes they will fit. To date the only problems have been with earlier KHorns where the holes were hand routed and there is also an answer for that. PM me please. Question on the  A55G drivers. Do you think they are noticeably better that stock Atlas drivers?

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...