DAC90A Celestion speaker - performance of smooth vs. ribbed cone - UK Vintage Radio Repair and Restoration Discussion Forum

Helder Crespo · 18th May 2021, 8:43 am

After a couple of posts aimed at finding a replacement speaker for my 1957 DAC90A, I managed to find a replacement (of sorts) on eBay.
The model I got is a S6JQ (shown in the first two photos). The magnet looks the same as that of the S6KQ on my DAC90A, but the cone is smooth as does not have the 2 concentric ribs found on both the S6KQ and on earlier speakers with the larger magnet (see, e.g., picture #3). The main specs are the same: 6.5 inch diameter and 3 ohm impedance.
To my knowledge, based on posts, ads and google searches, all DAC90As have been originally equipped with ribbed cone speakers. Should the performance of the radio be substantially different with the smooth cone speaker? Once the speaker arrives I will try it out, but I'm curious as to what expect from it vs. the original double-ribbed one. Any thoughts?
Thanks
Helder

18th May 2021, 2:00 pm

No difference at all.

Edward Huggins · 18th May 2021, 2:12 pm

The 3rd photo shows a cone that may have slightly more "give" - but on that output stage and in that cabinet, you'll be unlikely to hear any difference at all.

DonaldStott · 18th May 2021, 2:52 pm

I tend to use the old Mantra "Just Listen" - if it sounds better then for you it is better and at the end of the day that's all that matters.

The ribs on the speaker are probably reinforcing the cone but I don't see how that would impact on 'performance'? Perhaps others will disagree but not sure how one would assess or measure any differences?

By the way, what was wrong with the original speaker?

Helder Crespo · 18th May 2021, 6:28 pm

Thanks everyone. By performance I meant frequency response as well as low distortion. I have performed kalee20's mods in my radio:-

https://www.vintage-radio.net/forum/...ad.php?t=35784)

which have resulted in a broader frequency response - very noticeable as the radio is also equipped with a Bluetooth module Colin Boggis' mod:-

https://www.vintage-radio.net/forum/....php?p=1199800).

DonaldStott, the original speaker was in a poor state (I give a brief summary of its condition and of my attempt at repairing it here:-

https://www.vintage-radio.net/forum/...dac90a+speaker

and in spite of my efforts, its performance (based on my hearing alone, as I didn't do any spectral analysis or anything) is significantly worse than that of my second DAC90A (namely in terms of resonance/distortion). So my reference is basically my second DAC90A.

18th May 2021, 8:43 am	#1
Helder Crespo Hexode Join Date: Sep 2019 Location: Crystal Palace, Bromley, London, UK. Posts: 417	DAC90A Celestion speaker - performance of smooth vs. ribbed cone After a couple of posts aimed at finding a replacement speaker for my 1957 DAC90A, I managed to find a replacement (of sorts) on eBay. The model I got is a S6JQ (shown in the first two photos). The magnet looks the same as that of the S6KQ on my DAC90A, but the cone is smooth as does not have the 2 concentric ribs found on both the S6KQ and on earlier speakers with the larger magnet (see, e.g., picture #3). The main specs are the same: 6.5 inch diameter and 3 ohm impedance. To my knowledge, based on posts, ads and google searches, all DAC90As have been originally equipped with ribbed cone speakers. Should the performance of the radio be substantially different with the smooth cone speaker? Once the speaker arrives I will try it out, but I'm curious as to what expect from it vs. the original double-ribbed one. Any thoughts? Thanks Helder Attached Thumbnails

18th May 2021, 2:00 pm	#2
Guest Guest Posts: n/a	Re: DAC90A Celestion speaker - performance of smooth vs. ribbed cone No difference at all.

18th May 2021, 2:52 pm	#4
DonaldStott Octode Join Date: Aug 2015 Location: Glasgow, UK. Posts: 1,850	Re: DAC90A Celestion speaker - performance of smooth vs. ribbed cone I tend to use the old Mantra "Just Listen" - if it sounds better then for you it is better and at the end of the day that's all that matters. The ribs on the speaker are probably reinforcing the cone but I don't see how that would impact on 'performance'? Perhaps others will disagree but not sure how one would assess or measure any differences? By the way, what was wrong with the original speaker? __________________ BVWS Member

18th May 2021, 6:28 pm	#5
Helder Crespo Hexode Join Date: Sep 2019 Location: Crystal Palace, Bromley, London, UK. Posts: 417	Re: DAC90A Celestion speaker - performance of smooth vs. ribbed cone Thanks everyone. By performance I meant frequency response as well as low distortion. I have performed kalee20's mods in my radio:- https://www.vintage-radio.net/forum/...ad.php?t=35784) which have resulted in a broader frequency response - very noticeable as the radio is also equipped with a Bluetooth module Colin Boggis' mod:- https://www.vintage-radio.net/forum/....php?p=1199800). DonaldStott, the original speaker was in a poor state (I give a brief summary of its condition and of my attempt at repairing it here:- https://www.vintage-radio.net/forum/...dac90a+speaker and in spite of my efforts, its performance (based on my hearing alone, as I didn't do any spectral analysis or anything) is significantly worse than that of my second DAC90A (namely in terms of resonance/distortion). So my reference is basically my second DAC90A.

18th May 2021, 2:12 pm	#3
Edward Huggins Dekatron Join Date: Sep 2015 Location: Southwold, Suffolk, UK. Posts: 8,338	Re: DAC90A Celestion speaker - performance of smooth vs. ribbed cone The 3rd photo shows a cone that may have slightly more "give" - but on that output stage and in that cabinet, you'll be unlikely to hear any difference at all. __________________ Edward.