hello all,
ive have just recapped my celestion 66s and had a supposedly good matched spare pair of HF2000 measuring both at 4.5 ohms.
after recapping i thought id bung them in,too my surprise they sounded good but where lacking in hf,they just weren't as loud as the original tweeters.
it turns out they were from a pair of B&O 5700's which use the same hf2000's and mid driver MD500.
I removed those hf2000's and put the original ones back in and everything returned to normal!
the only downside to this is one measures fine,the other measures 9.6 ohms.
id like to replace them with something more modern and it seems from hours reading that the Seas 19TFF is a good drop in replacement.
there are lots of threads on hear with conflicting advice regarding what to change the hf cap values too and they are all very old threads.
i wonder if anyone recently has done this mod and what they used cap wise?
here's a pic of the newly rebuilt crossovers,caps were changed like for like.
the B&O hf2000's
ive have just recapped my celestion 66s and had a supposedly good matched spare pair of HF2000 measuring both at 4.5 ohms.
after recapping i thought id bung them in,too my surprise they sounded good but where lacking in hf,they just weren't as loud as the original tweeters.
it turns out they were from a pair of B&O 5700's which use the same hf2000's and mid driver MD500.
I removed those hf2000's and put the original ones back in and everything returned to normal!
the only downside to this is one measures fine,the other measures 9.6 ohms.
id like to replace them with something more modern and it seems from hours reading that the Seas 19TFF is a good drop in replacement.
there are lots of threads on hear with conflicting advice regarding what to change the hf cap values too and they are all very old threads.
i wonder if anyone recently has done this mod and what they used cap wise?
here's a pic of the newly rebuilt crossovers,caps were changed like for like.
An externally hosted image should be here but it was not working when we last tested it.
[/URL]the B&O hf2000's
An externally hosted image should be here but it was not working when we last tested it.
[/URL]
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Hi again, Jamie. 🙂
I just did some measuring on my old Celestion Ditton 44.
HF2000 is 100mm (4") in a 104mm rebate. Cutout is a mere 62mm, aka 2.5".
Tweeter filter is 4uF/0.14mH/6uF. DCR of the tweeters is 4R and 4.4R.
So a little filing down of the cutout needed for the 87dB soft dome 94mm SEAS 19TFF which has a DCR around 6.2 ohms. But doable. You'll just have to take your chances on any tonal changes. TBH, I'd fit the metal 19TAF/G with a 8.2R/0.68uF Zobel across it.
You could probably make a case for changing the 6uF to 12uF IMO.
I just did some measuring on my old Celestion Ditton 44.
HF2000 is 100mm (4") in a 104mm rebate. Cutout is a mere 62mm, aka 2.5".
Tweeter filter is 4uF/0.14mH/6uF. DCR of the tweeters is 4R and 4.4R.
So a little filing down of the cutout needed for the 87dB soft dome 94mm SEAS 19TFF which has a DCR around 6.2 ohms. But doable. You'll just have to take your chances on any tonal changes. TBH, I'd fit the metal 19TAF/G with a 8.2R/0.68uF Zobel across it.
You could probably make a case for changing the 6uF to 12uF IMO.
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Some info here - Celestion Ditton 44 - HF 2000 tweeter replacement? - UK Vintage Radio Repair and Restoration Discussion Forum which you might be aware of.
Andy.
Andy.
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Well, the bottom line from all the agonising in that thread, is that Kat Manton used a 1R/10R attenuator at the SEAS 87dB tweeter. That's about 2dB reduction.
I think the below is a better way to do things. Better impedance, and flatter response.
Probably a 3W for the 1R, and a 7W for the 8.2R. Small Loudspeaker tags available at maplin along with everything else.
I think the below is a better way to do things. Better impedance, and flatter response.
Probably a 3W for the 1R, and a 7W for the 8.2R. Small Loudspeaker tags available at maplin along with everything else.
Attachments
if you think that threads bad you wanna try reading the other ditton thread,it makes you eyes bleed! lol.
steve,could you explain in layman's terms what adding the resistors do and also the cap increase please?
steve,could you explain in layman's terms what adding the resistors do and also the cap increase please?
The issue here, is that the Celestion filter is for a near DCR= 4 ohms driver. Impedance of a filter tends to be root L/C. Here it's 140uH/4uF=35. Which gives about 6 ohms.
Whatever. If we use a DCR 6.2R tweeter, it's slightly underdamped, which takes impedance low. And makes it a bit peaky. IDK if you'll hear it.
Anyway, 1:3 is your regular 3rd order butterworth filter. It works well, hence my suggestion of 4uF/0.14mH/12uF. But you can keep the 6uF if you want. I like a RC Zobel on a tweeter, particularly with metal ones, because it gives an easy load to the amp and sounds nice.
We then might have to adjust level a couple of dB. Many ways to do that. Below is another way. Whatever you do, nothing is going to blow up. Every ohm in front of a filter takes level down 1dB.
TBH, it seems to me that people have made this far harder than it really is. You can probably fit any tweeter you like. Just adjust the levels. Harbeth use 91dB 104mm SEAS metal domes in this situation. I like them.
H1212-06 27TBFC/G
Whatever. If we use a DCR 6.2R tweeter, it's slightly underdamped, which takes impedance low. And makes it a bit peaky. IDK if you'll hear it.
Anyway, 1:3 is your regular 3rd order butterworth filter. It works well, hence my suggestion of 4uF/0.14mH/12uF. But you can keep the 6uF if you want. I like a RC Zobel on a tweeter, particularly with metal ones, because it gives an easy load to the amp and sounds nice.
We then might have to adjust level a couple of dB. Many ways to do that. Below is another way. Whatever you do, nothing is going to blow up. Every ohm in front of a filter takes level down 1dB.
TBH, it seems to me that people have made this far harder than it really is. You can probably fit any tweeter you like. Just adjust the levels. Harbeth use 91dB 104mm SEAS metal domes in this situation. I like them.
H1212-06 27TBFC/G
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ditton 66 replace tweeter with Founteck neocd1.0
I am very happy for my test , i replaced the original fault hf2000 with the Founteck neocd1.0 . . 6ohm tweeter. The fx range from 2k to 40khz horizontal front very large, mouch more the originally tw. To don t modifying the original f0 at 5khz @ 4,5 ohm i put across the tweeter (parallel) a 20ohm 10watt resistor, so total impedences is 4.6. The sound is nice, light and very near the original, ciao a tutti ik2ugg 73
I am very happy for my test , i replaced the original fault hf2000 with the Founteck neocd1.0 . . 6ohm tweeter. The fx range from 2k to 40khz horizontal front very large, mouch more the originally tw. To don t modifying the original f0 at 5khz @ 4,5 ohm i put across the tweeter (parallel) a 20ohm 10watt resistor, so total impedences is 4.6. The sound is nice, light and very near the original, ciao a tutti ik2ugg 73
Replace the HF2000 with Founteck neocd1.0: I change the resistor for good 8ohm impedence to don't change the f0 of crossover. Is necessary put in SERIES 1,2ohm Now the sound is like my old Hf2000 and the emission is good equalized.
Hi Jamie, I know this is a super old thread, but do you still have the photos of the B&O hf2000's? The link is dead. How do you know they were from that speaker and do you know if it was a 5700 or 5702, early or late model? Thank you!
hi,
no sorry i dont, the tweeters were called red labelled hf2000's because they had a large red celestion sticker on the back. gerry at falcon acoustics confirmed to me they were for the B&O speakers and not dittons.
no sorry i dont, the tweeters were called red labelled hf2000's because they had a large red celestion sticker on the back. gerry at falcon acoustics confirmed to me they were for the B&O speakers and not dittons.
Thanks Jamie. Any chance you kept one of the red labelled hf2000s after all these years?
I'm probably getting old and impatient with all the agonising that goes on about replacing a tweeter. I swap them a lot, just to hear the difference between different dome materials.
The usual internet advice is to replace the plastic HF2000 with a soft dome SEAS 19TFF. Makes no sense to me at all.
Plastic domes in 3/4" or 19mm are all going to sound similar.
The Monacor will need a -3dB attenuator or approx 3.3R resistor in front. SU stands for Suprapronyl, a plastic laminate.
Mylar or Plastic domes tend to be bright at the top, but the grille and dispersion evens that out.
The usual internet advice is to replace the plastic HF2000 with a soft dome SEAS 19TFF. Makes no sense to me at all.
Plastic domes in 3/4" or 19mm are all going to sound similar.
D19TD-05 3/4" Poly Dome Tweeter with 94mm faceplate at 87dB:
https://www.parts-express.com/Peerless-D19TD05-08-3-4-Poly-Dome-Tweeter-264-500Monacor DT-19SU with 100mm faceplate at 91dB:
https://monacor.co.uk/dt-19su.htmlThe Monacor will need a -3dB attenuator or approx 3.3R resistor in front. SU stands for Suprapronyl, a plastic laminate.
Mylar or Plastic domes tend to be bright at the top, but the grille and dispersion evens that out.
Thanks so much for the Monacor recommendation, super helpful. I'm looking for a 4 ohm HF2000 for a Beovox 5700 (opposite of most everyone on the internet who raid 5700s for their Dittons), and I'd prefer not to have to mess with the crossover by replacing with an 8 ohm.
According to the B&O specs, the speaker is supposed to have a sensitivity of 91.2db, so that Monacor is a much better match than the other drivers folks usually recommend.
Bump to Jamie if you still held on to any of the red label HF2000 and would sell.
@system7 Hi, I'm very in late here, just found this discussion.
I'm working hard on those pair of Ditton I got few months ago.
I fixed some cabinet issues, then reccaped everything and now I found out that the two HF2000 tweeter are not matched.
They mid range sound so much better after the recap, but still I feel a big lack in high frequencies, and this is probably because one tweeter measure 6.3 OHM and the other one 8 Ohm.
I am looking for a "no cut" replacement.
Which one between the two you suggested above fit with no problem in the Ditton 44 tweeter hole?
Which one you would go to open the sound in the HF range ?
Thanks for any possible answer or suggestion.
I'm working hard on those pair of Ditton I got few months ago.
I fixed some cabinet issues, then reccaped everything and now I found out that the two HF2000 tweeter are not matched.
They mid range sound so much better after the recap, but still I feel a big lack in high frequencies, and this is probably because one tweeter measure 6.3 OHM and the other one 8 Ohm.
I am looking for a "no cut" replacement.
Which one between the two you suggested above fit with no problem in the Ditton 44 tweeter hole?
Which one you would go to open the sound in the HF range ?
Thanks for any possible answer or suggestion.
The DC resistance of a driver is different to it's AC impedance. The HF2000's can replaced by Seas tweeters, see - https://www.vintage-radio.net/forum/showthread.php?t=55474
Andy.
Andy.