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montesquieu
31-12-2011, 18:17
I've been on a bit of a journey with the Tannoys lately which I think might be worth sharing ...

I'm running 15in Monitor Golds, in GRF cabinets, and have been looking at a number of options to improve the sound. The usual Tannoy sound is big, bold and round, capable of great emotion and huge dynamic swings, but sometimes can be a little grainy or coarse - I've always wondered whether this was mainly down to the electronics, or to some other part of the design.

First off, I had some improved crossovers done, made from high-quality bits, especially the inductors and the larger-vale caps. This made a big difference in clarity and I can recommend this course of action to any Tannoy owner. However, they still left a little grainyness and coarseness.

An accident with my drivers - a Krell KSA50 went DC on one channel, causing the coil to over heat and the paper to burn away like the map at the start of Bonanza (showing my age here!) - meant a trip to Lockwood Audio and a recone for both sides (thankfully there was no coil damage done).

Next step was the cabinets. My GRFs were a fairly poor DIY job - was almost embarrassed to show them to Speedysteve when he came round, as they were well short of the quality of his GRF builds. Ply tops and sides but chipboard rear, wobbly horn bits and poor damping made for a speaker far more boomy than they were supposed to be. However a trip up to Russ Collinson in Barnsley (that's a 200 mile schlep from here) was well worth it, in addition to refinishing, he bonded ply onto chipboard panels where they had been used instead of ply, and added a whole loads of struts and supports to stop internal resonances. The result has been almost like a totally new speaker (aurally and visually) - the whole thing is far tighter, images more solid, and generally more coherent over the whole range.

The next step has been to bi-amp - the new crossovers together with Russ's putting them in external boxes, made it easier to achieve separate amping of the channels. I'm currently using a 30w push-pull triode KT88 valve amp to power the 15in bass unit, and a 2.5w 2A3 to power the treble unit. This has made far more difference than I anticipated, got rid of much of the grainyness in the treble and also cleaned up the upper midrange and put in a ton of extra detail and dynamics which I'm sure is magic woven by the 2A3 on that upper treble. (I've found that the 15in cone needs a push-pull amp just to manage all that back EMF - even really good, high-power SET amps like the Unison S8 845 I used to have go squishy handling 15in Tannoy bass - but the 2in driver simply blooms with a low-power SET).

So I'm pretty happy now with what I'm hearing, with all those Tannoy virtues added to a much cleaner, more dynamic presentation than ever before, though short of (say) the absolute transparency of a pair of ESL 57s. I could list lots of hifi words and attributes, but the overall sense is one of effortless detail, and musicality that just commands sympathetic rhythm in the listener's body. String quartets really boogie - what more can you say?

But the next step is going fully active - this in two steps. I've borrowed a Behringer DCX 2496, which digitises and manipulates the incoming signal from the preamp and acts as a crossover outputting appropriate frequencies for the 15in and 2in drivers - I plan to figure this out over the coming week or so and have a play. This should enable me to properly test out the 'active' concept, though I don't see that as a long-term solution as it seems hardly worthwhile paying a premium for really good tube phono stage, DAC and preamp, only to digitise the output before the power section of the amp.

The Tannoy crossover curve is well-documented, and Nick 'Lurcher' is currently building me a fully discrete, stand-alone electronic crossover which will allow me to go properly active through my respective amps for 15 and 2in, and gain-match from there. Anticipated gains from that are are simply to maximise detail retrieval including room ambiance, along with the best possible dynamics, while not compromising the musical feel. If this isn't achieved - then anything I've done is reversible.

Beyond that who knows ... stereo tapped horns to take the first few octaves up to 100hz perhaps? (that very bottom octave below 20-40hz is obviously a target to improve overall realism).

What I do know is that my experience already suggests that whatever fancy cabinets the Tannoys are put in, the electronics feeding the drivers may be compromising the sound, a lesson any Tannoy owner should take note of.

Anyway musings over, would appreciate others' experiences on alternative approaches to getting the best out of Tannoys.

Reid Malenfant
31-12-2011, 18:43
You might ask Nick to build in an all pass delay network onto the low frequency side of the crossover he's designing (if possible) to time align the woofer & tweeter voice coils. That's easily implemented on the DCX2496 & something that is simply overlooked in passive designs.

I have a feeling you'll be pretty surprised at what the DCX will do with a pair of 15" Tannoys driven actively & I'd really love to hear the result :D

Good on you for trying it!


E2A:- Why is this in private exhibitions? Someone please move to a more relevant position as I can't :(

Jonboy
31-12-2011, 18:55
Really interesting Tom, i know what you mean about the push pull over SE amps what you win with one you lose to the other, looks like a very good compromise running them biamped, i have a pair of 15 inch HPDS sitting here waiting for cabinets, crossovers and some time to get it all together :doh:


Any pics of your set up would be good :D

The Black Adder
31-12-2011, 19:06
I'm currently getting some external Crossovers made by Nick too for my 12" MG's/Lancasters.

Nick said something about this job your having done (unless it was someone else) and interested me greatly but the proof will be in the pudding so please keep me updated on this.

I too am running KT88 amps.

Cheers

montesquieu
31-12-2011, 20:38
Any pics of your set up would be good :D

My pleasure

The setup - currently running the Voyd 3-motor TT and the Lenco 88 side by side, Ortofon Rohmann on the Voyd and Audio Note Io on the Lenco. Preamp is an SJS Arcadia Model 2 (the copper chassis one) breathed on by Kevin at Definitive; phono stage by Nick Gorham (all valve incl valve PSU section); Audio Note Kit 2.1x upgraded to 3.1x Balanced and beyond (not by me I hasten to add); Wadia WT3200 transport; VAC PA60C KT88 PP monoblocks/separate PSU 30w triode 70w pentode; TM400 chifi 2A3 integrated.

And a before and after of the Tannoys.

BTW point of detail but I was just informed that what looked to me like an L-Pad is actually a notch filter so scratch that idea!



http://i1181.photobucket.com/albums/x440/montesquieu61/rigbig.jpg
http://i1181.photobucket.com/albums/x440/montesquieu61/rigclose.jpg
http://i1181.photobucket.com/albums/x440/montesquieu61/before.jpg
http://i1181.photobucket.com/albums/x440/montesquieu61/after.jpg

jandl100
01-01-2012, 08:39
Tannoy Dual Concentrics without grainy upper mids and occasionally spikey treble? :scratch:

Nah, don't be daft - I reckon it's the horn tweeter that does it - it's part of their charm! :D

Shame really, as they do so much else wonderfully well. :thumbsup:

Classical Bake-Off sometime, Tom? I'd lurv to hear them, actually, and to find out what improvements are to be had by intense tweakery! :)

___

Jerry (life-long Tannoy hater :mental:)

It's OK, I'll go now. :wave:

HAPPY NOO YEAR to all! :mex:

montesquieu
01-01-2012, 12:38
Tannoy Dual Concentrics without grainy upper mids and occasionally spikey treble? :scratch:

Nah, don't be daft - I reckon it's the horn tweeter that does it - it's part of their charm! :D

Shame really, as they do so much else wonderfully well. :thumbsup:

Classical Bake-Off sometime, Tom? I'd lurv to hear them, actually, and to find out what improvements are to be had by intense tweakery! :)



Hmm, well be prepared to be surprised! Classical music day is in the planning. Will be after it's all active though so dependent on timing of that.

Keen to hear that ten audio of yours so hope you wait for a bit before flogging it !

All the best for2012.

cheers

Tom

DSJR
01-01-2012, 14:51
Tannoy Dual Concentrics without grainy upper mids and occasionally spikey treble? :scratch:

HAPPY NOO YEAR to all! :mex:

Not sure the current prestige range is like that Jerry, but I've only heard a couple of them. Tannoy did loads of detailed work on the crossovers back in the 80's, but the fruits of that research are too new for many Tannoy owners around these parts :D

Jonboy
01-01-2012, 16:18
My pleasure

The setup - currently running the Voyd 3-motor TT and the Lenco 88 side by side, Ortofon Rohmann on the Voyd and Audio Note Io on the Lenco. Preamp is an SJS Arcadia Model 2 (the copper chassis one) breathed on by Kevin at Definitive; phono stage by Nick Gorham (all valve incl valve PSU section); Audio Note Kit 2.1x upgraded to 3.1x Balanced and beyond (not by me I hasten to add); Wadia WT3200 transport; VAC PA60C KT88 PP monoblocks/separate PSU 30w triode 70w pentode; TM400 chifi 2A3 integrated.



Very nice Tom :)

lurcher
01-01-2012, 17:18
You might ask Nick to build in an all pass delay network onto the low frequency side of the crossover he's designing (if possible) to time align the woofer & tweeter voice coils. That's easily implemented on the DCX2496 & something that is simply overlooked in passive designs.

Any idea of the sort of offset that is required?

If not sure, I could lend Tom a measuring mic, and he could use the DCX and a impulse signal to see what the optimum delay was.

Reid Malenfant
01-01-2012, 17:36
Hi Nick, all you need to do is measure the distance between the woofer & tweeter pole pieces on the Tannoy drivers in question. I'm guessing that the older Alnico magnets will give a bigger offset.

What's unusual about the Tannoys is the the tweeter voice coil is futher from the listener than the woofer. With normal two or three way speakers the dome tweeter would effectively be on the front baffle so it'd be the tweeter that would need to be delayed to align it with the woofer.

In this case it's the opposite way round.


The DCX can be set up to align things to 1mm or possibly less. It's more than accurate enough at any rate :)

jandl100
01-01-2012, 19:13
Not sure the current prestige range is like that Jerry, but I've only heard a couple of them. Tannoy did loads of detailed work on the crossovers back in the 80's, but the fruits of that research are too new for many Tannoy owners around these parts :D

I heard a current pair of Westimnster Royals (I think) at the LHR show a couple of years back ... magnificent beasts with (mostly) sq to match, but occasionally spikey treble was still in evidence ... I don't know about the mid/treble grain as I often take a half hour or (sometimes much) more to "tune in" to it, and I only stayed in the dem room for 10 minutes or so.

chelsea
01-01-2012, 21:56
Interesting read.
I have york cabs but using arden ones as i prefer the 70's look.
Hoping to get new xovers and may make some big cabs later in the year.