Morel tweeter in Ditton 33's

[Roydee]

I recently acquired a pair Celestion Ditton 33 speakers and the tweeters have been replaced with Morel (cat 298) tweeters. Upon listening to them I was immediately aware of a very bright (thought detailed) sound which soon became very fatiguing.

I would like to ask if any one here can offer any advise/help on how to cure this problem. I have done a bit of searching around but can find no info on the dittons (eg crossover circuit etc) or the morel's.

Would modifying the existing crossover to suit the morel be the best way forward? that would be my prefered option, if so where can I find the information to do this, or could you guys help?

The rest of the speakers (eg bass, mid, cabinets) are in exceptionally good condition so I would really like to sort out this excessive treble problem
Thanks in anticipation

Regards
Roydee

[Inductor]

1. Your tweeter might be HD1000 Dome Tweeter, (xover ~5KHz, used also on the 44's). Xover T 3.order C1=8uF, C2=12uF, L=0,14mH.
2. Here 5,2 Ohm, 89dB Morel Morel (cat 298) tweeter
3. Using Lpad calculator

If old one (assuming that) HD1000 was 84/85dB, 5/6Ohm (?)
Ex #1 for ~5dB Atten.: 7 Ohm@5K (Morel CAT298).
R1=3 Ohm
R2=9 Ohm
Ex #2 for ~4dB Atten.: 7 Ohm@5k (Morel CAT298).
R1=2,5 Ohm
R2=12 Ohm

[Roydee]

Hi Inductor,
Thanks for your reply, sorry for the delay getting back to you (had my eyes laser ed on Monday - still struggling a bit).
I think the tweeters on the 44 may be different than the 33, on an old brochure that i have the tweeters look different and it says the frequency range goes up to 40 khz on the 44, while on the 33 they go to 28khz.
Will this make a difference? or am I still ok to use the values you previously gave?

Regards
Roydee.

[Inductor]

Originally Posted by Roydee

...the frequency range goes up to 40 khz on the 44, while on the 33 they go to 28khz.
Will this make a difference? or am I still ok to use the values you previously gave?

Regards
Roydee.

Roydee, I would not bother with that, if the tweeters are not too annoying on the HF they would be OK, this is if they are well balanced on the mid/highs frequencies. If you don't like the idea of testing with high quality resistors then buy one or two variable L-pad (15, 50 or 100W/8Ohm) and test for the right amount of tweeter output. Leave the pads or change for the same value resistors. Regards.

L-PADS
L-PADS from Parts Express

[royville]

Hi Inductor,

Thanks for the info (eyes just about getting back to normal now)

I think I'll go the way of trying a variable l-pad to get the optimum level and take it from there.
Just out of interest - do you have a circuit diagram for the ditton 33 crossover? I attempted to trace it out myself, but unfortunately I have no way of knowing what the values of the inductors are.

Cheers Roydee

[alan-1-b]

Roydee,
search for the Thread started by Mr_White which has the Title:-
celestion 66 needs Mid-range

On page 25 in Post #246 is the Celestion 33 crossover circuit.
and the Celestion 44 crossover is in #247.

On page 17 in #162 are Celestion 66 crossover circuits.

If you have anything interesting in your 33 that is different to that circuit, then please do post about it here.

I think it is best to try the Morel tweeter with the L-pad,
but measure the DC resistances of your Morel tweeters.
They may be higher resistance than the old Celestion tweeters,
and if so the crossover filter will not be correctly matched,
but a suitably chosen parallel connected resistor can get the matching close if the Morel is higher impedance,
though it will still need series resistance attenuation, and that will cause another impedance change.

You may be lucky to find a setting with an L-pad that gives you close enough to a sound you want,
and then you won't have to spend a lot of time trying series and parallel resistors around your tweeters.

[Roydee]

Hi Alan,
Cheers fort that. I will indeed measure the resistance of the morel tweeters but I don't have the original tweeters to compare with.

Could someone provide me with the DC resistance of the original Ditton 33 tweeter please?

It seems this could be more complex than I first thought!

Regards All
Roydee.

[WayneSwann]

I have a pair of Celestion Studio 66 Monitors. The original HF2000 tweeters were replaced by previous owner by some cheap 'Realistic' horn type tweeters which sound excessively bright and tiring to listen to. I want to replace them and have been given various conflicting advice. I have gone ahead and purchased a pair of MOREL CAT298 Soft Dome tweeters. I am a bit concerned that the frequency response only reaches 20Khz, but I have been told by the supplier that they are the best fit as a replacement without spending too much money. Does anyone have any positive information regarding a replacement for the original HF2000's and any possible required changes to the crossovers?