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New Yorks, Tannoy project

good work, I don't know what method you used to clean the gap, but we always used a length of masking tape folded sticky side out then folded lengthwise, it is then worked deep into the gap and moved round, this is repeated with new tape until it comes out the gap completely clean with no debris or dirt.
 
Emporiumhifi said:
good work, I don't know what method you used to clean the gap, but we always used a length of masking tape folded sticky side out then folded lengthwise, it is then worked deep into the gap and moved round, this is repeated with new tape until it comes out the gap completely clean with no debris or dirt.
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Yeah reverse side masking tape, pretty much standard practice, you just have to be patient till its spotless, then I gave it a few blasts of compressed air too, coil and former got cleaned before reassembly.
 
Tannoy DMT15 Mk1 crossover, component values within 1%, 0.5dB HF lift.

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I'm also building some DMT Mk1/2 hybrids that are used in the GRF TW and the new Ardens.

Existing CPA 15 Xovers do sound nice but are a bit hot around 1-2khz so will be interesting to audition what may be fairly subtle differences, though the benefits of much better and tightly spec'd components may prove illuminating.
 
London Lad said:
Just been playing with something very similar for my GRF Memories.

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Cool, I thought you'd sorted these?
So 36.8uF, 3.9uF, 2mH, I've tried 1.7 and 5 ohm so far-one a touch bright the other a tad dark,what value resistor are you using?
What happened to the rather tasty looking Mundorf coil?
I'm trying this circuit at the mo, though the DC side of the 215 used a 4.5uF cap on the HF so may revert to that out of curiosity.
 
The coil measures 2.5mH and is the original Tannoy item.

The resister is 6.8 ohm which again is the same as the original crossover in the 'flat' position.

I was never quite satisfied with the last version with the Mundorf E core coil as although it had a lower measured DC resistance it seemed to result in the midrange being a little recessed.

This reason I started this was to try to get rid of a harshness in female vocals at around the crossover frequency. The last version improved this, and other things quite a lot and this latest version with physically bigger (600 volt) caps has noticeably improved things again with the harshness now gone completely.

I do have a pair of Jensen foil coils which I will try once these caps have settled down but I feel I'm pretty much where I want to be with these speakers now. I would certainly recommend anyone with GRF memories to move the coil away from the driver magnet if nothing else and this made an audible and measurable difference.
 
And the winning crossover is.... between CPA15, DMT Mk1, Mk1/Mk2 hybrid, System 15DMT Mk2........................
The 15DMT Mk2, clearer, smoother, most coherent of the bunch-excellent.
If theTannoy Legacy Ardens sound anything like these they are on to a winner.
 
With the crossover circuit decided and sounding lush, next job is to clean and recharge the tulip waveguide(s) hf with ferrofluid-not some generic FF either, the correct spec/viscosity stuff from Ferrotec.

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We can see the old ferrofluid has gone a bit thick as the esters have evaporated over time and it takes a long time to carefully remove from the voicecoil and former.

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Wicking the ferrofluid out of the gap.
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Lots of buds, masking tape and blotting paper later.

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Recharging is easy as the magnet just draws the fluid into the gap

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Job done, cleaned, recharged, reassembled and good as new.

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Only 6 more to go.
 
2nd set of crossovers built, final tulip HF cleaned and recharged. 3833 basket mid service and awaiting replacement cone.
One of 2 HPD 385's freshly re-coned making guest appearance.

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Interesting observation(well to me at least) is the crossover circuit settled upon-that from the System15 DMT Mk2 is also that chosen by Tannoy for the Legacy Ardens(though in my case sans tone controls).

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They sound smooth, mellow almost but they can rip your head off with just a couple of watts.
I recruited my lad and his 20 year old ears to corroborate my subjective findings and after an alternative control sound as provided by my big JBL's he described them as very civilised, like the BBC!!!-the JBL's were described as 'everything sounded like it was live...'which is pretty much how I'd describe things.
 
After completing the servicing on 4 of these 3836/33 drivers I measured their T&S Parameters using a Dayton Audio DATS V2, the Vas was measured by the added mass method.
They were pretty close tbh with the averaged T&S being;
Re; 5.5
Fs; 30hz
Qts; 0.458
BL; 13.1
Vas; 302L

I'll post the T&S of recently reconed 385 HPD's soon as I've measured the 2nd driver.
 
As promised; These drivers only have a few hundred hours on them.
385 HPD'a'
Re 5.72
Fs 28.7hz
Qts 0.3376
BL 11.7
Vas 508L

385 HPD'b'
Re 5.93
Fs 28.26hz
Qts 0.3475
BL 11.94
Vas 540L
 
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