TANNOY 3128 speaker 1012 and HPD315A crossover. What's the difference?

[cooky]

It would seem safe to assume that there were minimal differences between the 1012 X/O used in the Mk2 end-of-run Cheviots (themselves using the 3128) and the 1020 time compensated X/O used in later Balmoral/Bradly and Chertsey lines.

The whole thing needed refinement, but as previously mentioned, the TC circuit was dropped in later Prestige lines, which bizarrely used the superior Tulip Waveguide only in the entry level models and the pepperpot in the more expensive ones (a nod to the fact that Tannoy were targeting the nostalgia buyer or tannoyista fetishist for sales rather than pushing what was technically superior!). I had this conversation with their Technical Director a few years ago, and he admitted that the main market (Far East) were less inclined to run with technical advances in DC design, such as the Tulip Waveguide and more efficient motors, and more inclined to buy a newer nostalgia model in the belief that it was superior, hence the DC was never really finally developed the way it should have been. The irony here is that the very fans that want it, only want the older designs in the belief that they're all superior, which is not the case. They exhibit higher HF distortion as the HF pepperpot designs break up resonance occurs lower down whilst the TWG can extend cleanly to 30KHz and is smoother within the audible band. Sadly, marketing drives what is developed, not common sense or best technical solution.

Agree 100%, it's heresy to say so but the tulip is a far better unit-particularly when taken to its ultimate refinement in the Super Dual.
It's always of interest to watch developments in the Kingdoms and in that DC mid top Tannoy have abandoned the pepperpot and moved to a slotted phase plug(a la TAD/JBL/Radian) and a 3" diaphragm which allows them the drop the crossover freq to 700hz.

[tonymorris]

[QUOTE=Reffc;849639]It would seem safe to assume that there were minimal differences between the 1012 X/O used in the Mk2 end-of-run Cheviots (themselves using the 3128) and the 1020 time compensated X/O used in later Balmoral/Bradley and Chertsey lines.

The question now seems to be ; Does anyone know what was/is the different between the 1012 and the HPD315A crossover? I guess a shift in frequency from the 'alleged' 1kHz to 1.2kHz was needed? So a relatively easy choice of different smaller HF capacitor and a smaller substituted LF coil perhaps? Who knows, anyone?

[Reffc]

Yes, as previously mentioned Tony, there's a lot of difference...the two are just not interchangeable. The 315 has different T&S parameters, a different motor, different chassis, different voice coil, different cone and a different horn. If you base your design on the 315, the crossover point will be wrong and the driver matching wrong. Leave it with me and I'll see whether I can dig up the 1012 schematic for you. It could be a day or two unless someone here has that crossover and swould be willing to post the schematic.

[tonymorris]

The guy I am trying to help is very eager indeed to get his 3128 Bradleys up and running. I have trawled all over the place trying to uproot the schematic for the Bradley X/O. It 'seems' he has no separate TC circuit present / available. If you could come up with a diagram Paul, both me and my desperate Bradley owner would be very happy.

Hold everything!
I have just managed to unearth the following. http://www.hilberink.nl/tannoy/jpvanson/speakers.pdf
It states crossover was a 1056 first order at 1.2kHz. This is getting VERY confusing now!
"
SL65 Bradley
Surrey Series 1983 1985
34.6"x16.2"x15" 60 65 Walnut Brown Floor Standing
Bass Reflex
38Hz‐20kHz +/‐3dB
90dB/W/M 8 6 50‐180 2 1 First Order, Passive, Time Compensated
1056 1200 3128E (x1)"

You are a star for even offering to look Paul. Cheers.

[cooky]

The guy I am trying to help is very eager indeed to get his 3128 Bradleys up and running. I have trawled all over the place trying to uproot the schematic for the Bradley X/O. It 'seems' he has no separate TC circuit present / available. If you could come up with a diagram Paul, both me and my desperate Bradley owner would be very happy.

Hold everything!
I have just managed to unearth the following. http://www.hilberink.nl/tannoy/jpvanson/speakers.pdf
It states crossover was a 1056 first order at 1.2kHz. This is getting VERY confusing now!
"
SL65 Bradley
Surrey Series 1983 1985
34.6"x16.2"x15" 60 65 Walnut Brown Floor Standing
Bass Reflex
38Hz‐20kHz +/‐3dB
90dB/W/M 8 6 50‐180 2 1 First Order, Passive, Time Compensated
1056 1200 3128E (x1)"

You are a star for even offering to look Paul. Cheers.

FWIW, The 315a and 3128 drivers use the same lf/hf cone/dia/voice coil assemblies and share the same T&S parameters.
The shorter horn probably means you need to shift the required notch position.
From Tannoy; http://www.hilberink.nl/codehans/tannoy39.htm

[Reffc]

FWIW, The 315a and 3128 drivers use the same lf/hf cone/dia/voice coil assemblies and share the same T&S parameters.
The shorter horn probably means you need to shift the required notch position.
From Tannoy; http://www.hilberink.nl/codehans/tannoy39.htm

The magnet/motor assembly was different. The horn length is different. The Force factor (BL) is different, and the Le was slightly different (measured). The horn notch values will be different because of the phasing differences. That's just the way the horn works. The crossover was also higher at 1200 Hz.

The phase response will therefore be different and because the motor Force factor and efficiency were different, the T&S parameters cannot be identical, despite what is found on that site. Indeed, Tannoy didn't actually publish T&S parameters when first manufacturing HPDs because they didn't exist and were only later attributed to them.

You have to be very careful with what you take as gospel from web sources when it comes to Tannoy. I wish that I had kept my measurements for that driver, but the crossovers are simply not interchangeable between the two. It isn't safe to second guess these things, it is only by actually measuring them that you can draw any conclusions really.

[cooky]

FWIW, The 315a and 3128 drivers use the same lf/hf cone/dia/voice coil assemblies and share the same T&S parameters.
The shorter horn probably means you need to shift the required notch position.
From Tannoy; http://www.hilberink.nl/codehans/tannoy39.htm

The magnet/motor assembly was different. The horn length is different. The Force factor (BL) is different, and the Le was slightly different (measured). The horn notch values will be different because of the phasing differences. That's just the way the horn works.

The phase response will therefore be different and because the motor Force factor and efficiency were different, the T&S parameters cannot be identical, despite what is found on that site. Indeed, Tannoy didn't actually publish T&S parameters when first manufacturing HPDs becausethey didn't exist and were only later attributed to them.

You have to be very careful with what you take as gospel from web sources when it comes to Tannoy. I wish that I had kept my measurements for that driver, but the crossovers are simply not interchangeable between the two. It isn't safe to second guess these things, it is only by actually measuring them that you can draw any conclusions really.

The information posted comes from Tannoy. The letter is reproduced on Han's site.

Usual caveats in place of course but here's Phil Shorts investigations into tweaking the short horn DC's..http://www.hilberink.nl/codehans/tannoy53.htm

[Marco]

Hi Frank,

How's it going?

Just a quick one, off-topic I know, but just to say that you made a fab job of renewing the surrounds on Ian's Canterburys - sonically, it's made quite a difference!

Also, Ian was showing me some of the fabulous artwork you do of 'music legends'. They're superb, mate, but you're not charging anything like enough for them!!

Anyway, if you'd like any frames (for nowt), I've got loads of off-cut lengths lying in the workshop I was going to chuck out, so if you do your own framing, or they're of any use to you, then you're welcome to them

Marco.

[cooky]

Hi Frank,

How's it going?

Just a quick one, off-topic I know, but just to say that you made a fab job of renewing the surrounds on Ian's Canterburys - sonically, it's made quite a difference!

Also, Ian was showing me some of the fabulous artwork you do of 'music legends'. They're superb, mate, but you're not charging anything like enough for them!!

Anyway, if you'd like any frames (for nowt), I've got loads of off-cut lengths lying in the workshop I was going to chuck out, so if you do your own framing, or they're of any use to you, then you're welcome to them

Marco.

Hiya mate, I'm fine thanks hope you are well.
Thanks for the kind words re the 'icons'. Oddly enough I was thinking of branching out a bit regards the canvas/boards and indeed after Ian had mentioned your framing work you were front of mind for some future work if I move away from the box canvas route.

Ian's like a pig in shhh, since I did his Canterburys

[Marco]

Yeah, they're significantly improved: faster, tighter, seemingly more extended in the bass, more detailed/less coloured elsewhere, I guess because the drivers are now behaving as they were designed.

Anyway, if I can help at all with framing, you know where I am. Also, if you'd like to link to your Facebook page, in your signature here, feel free to do so. Might help generate some more interest in your artwork

Marco.