Which Tannoys, folks?

[PaulStewart]

I got a bit lost on this thread Who is the one talking bollocks about it not being possible for p/p amps to be class A? I have an Art Audio Quintet playing very sweetly in triode mode class A P/P as I type this. Also getting back to the question about which Tannoys.

The link to my article about the Lockwoods on Musicosis says it all. Again I have read criticism of the Majors based on the fact that their porting was devised, as with all the old Lockwood designs, before the Thiel/Small parameters and without their benefit. Quite right and that's why Lockwoods don't suffer from one note bass the way a lot of modern reflex designs do

I would always stick to my MGs for choice but, the new Majors with the HPDs did sound good

regards to all

BTW see the first of our reader comps on musicosis.co.uk

[chris@panteg]

I'm with you there Simon as with my previous Horning Agathons, they responded far better with a muscular SS feeding them than with any valve amp. It takes a special valve amp to cleanly exploit deep bass with the proper speed, damping and transience. Cheaper route by far IMHO is to bolt on a big power amp. I am tempted to keep the Croft pre (it's a stunner) and I will try the power with the Tannoys, but would also like to try a few SS power amps with it including the 909 which I rate very highly.

Hi Paul , may I ask what amps you heard with the agathons ? A friend who lives in Northampton also called Paul , used agathons for many years , I heard them with AN conquest monos and later a pair of Diavolo's each with border patrol psu's , he's since moved up the range , not sure of the name but the next one up anyway , they sounded fabulous with acoustic and classical music .

[Reffc]

Hi Paul , may I ask what amps you heard with the agathons ? A friend who lives in Northampton also called Paul , used agathons for many years , I heard them with AN conquest monos and later a pair of Diavolo's each with border patrol psu's , he's since moved up the range , not sure of the name but the next one up anyway , they sounded fabulous with acoustic and classical music .

Hi Chris

mine were the later Agathon Ultimates with twin 12 inch bass drivers around back I used a Lumley PP40/ST40 combo to great effect (40 watts push pull 6L6GC valve amp). The next model up is the Eufrodites and mighty fine too although it does occupy a lot of space!

[Marco]

Who is the one talking bollocks about it not being possible for p/p amps to be class A? I have an Art Audio Quintet playing very sweetly in triode mode class A P/P as I type this.

Hi Paul,

That would be Richard Dunn of Nene Valley Audio: a bollocks-talker, par excellence, who's dug himself into a very deep hole - and is still digging!

The link to my article about the Lockwoods on Musicosis says it all. Again I have read criticism of the Majors based on the fact that their porting was devised, as with all the old Lockwood designs, before the Thiel/Small parameters and without their benefit. Quite right and that's why Lockwoods don't suffer from one note bass the way a lot of modern reflex designs do

I would always stick to my MGs for choice but, the new Majors with the HPDs did sound good

Nice one, mate. Extensive experience of listening to the above allows me to concur with your observations

Marco.

[Reid Malenfant]

The link to my article about the Lockwoods on Musicosis says it all. Again I have read criticism of the Majors based on the fact that their porting was devised, as with all the old Lockwood designs, before the Thiel/Small parameters and without their benefit. Quite right and that's why Lockwoods don't suffer from one note bass the way a lot of modern reflex designs do

The reason they don't suffer from "one note bass" as you call it is simply down to the very low driver Qts, this lets any power amp including low feedback valve amps control them very easily. The drivers have huge electro magnetic damping & as a result will sound clean.

Thiele/small parameters used in the right way & with drivers of a suitable Qts will also result in clean bass in a reflex enclosure. Just a shame that Dynaudio & many others tend to stuff high Qts drivers in reflex enclosures, for which they were patently not designed


You may well do a lot of listening, but if you don't understand the technical side of things you'll not see a correlation between driver parameters & bass performance.

[Marco]

Hi Mark,

The reason they don't suffer from "one note bass" as you call it is simply down to the very low driver Qts, this lets any power amp including low feedback valve amps control them very easily. The drivers have huge electro magnetic damping & as a result will sound clean.

Indeed! Any views on the claimed impossibility of push-pull valve amps to be pure Class A? We're looking to educate Mr Dunn, as clearly his technical understanding in this area is lacking

Marco.

[Reid Malenfant]

Hi Mark,

Indeed! Any views on the impossibility of push-pull valve amps to be pure Class A? We're looking to educate Mr Dunn, as clearly his technical understanding in this area is lacking

Marco.

I saw the locked thread earlier, so obviously I cannot comment

But yes, the man is a fool & totally wrong. While any single ended class A amp can be in theory 25% efficient (not allowing for any component losses), a push pull class A amp can in theory be 50% efficient, again not taking into account of component losses.

Where did this guy come from, the Jurassic? If so I guess he stayed there


Fool...

This guy is mean't to be an audio expert

Ok, so I know we didn't get along due to differences of opinion on certain aspects of amplifier protection, but this takes the biscuit.


I'm actually wondering if he gained his amplifier knowledge from a book sold by Tandy by a certain chap called (R A?) Penfold His stuff is honestly about the same level at the end of the day.

[Marco]

Thank you Anthony, and yes, the chap who rebuilt my (last) valve amp said pretty much exactly the same thing to me a few years back which is what my understanding is based on. The thread has wandered slightly off course (as they do) so in the spirit of getting it back on course............................................ .................................................. ................................................T-minus 4 weeks before the Turnberrys arrive. I'd offer a bakeoff, but the thought of cramming in some lockwood majors and other suitably large Tannoys into my listening room might not be too practical

Oooh, nice one, dude. I can sense your excitement! Can I come for a listen when the Turns arrive? If you want, I'll even bring my 'kid-on' Class A P/P valve amp along for a giggle

Marco.

[Marco]

I'm actually wondering if he gained his amplifier knowledge from a book sold by Tandy by a certain chap called (R A?) Penfold His stuff is honestly about the same level at the end of the day.

Lol... As an aside, Anthony's got an original GEC technical manual, from the 1950s, which clearly states the position in relation to KT88s, Class A and push-pull valve amplifiers, details of which he's going to post later

Marco.

[Reid Malenfant]

Lol... As an aside, Anthony's got an original GEC technical manual, from the 1950s, which clearly states the position in relation to KT88s, Class A and push-pull valve amplifiers, details of which he's going to post later

Marco.

It's the same with solid state, bias to half the quiescent current needed & as one device gradually reduces in current, the opposite device increases.

At some point cutoff will occur, though if the output stage is biased to full class A this will only occur if there is a drop in impedance.

Assuming the output stage is biased high enough, it'll operate in full class A.


Admittedly the sonic signature of push pull & single ended are different, but so is the dissipation

While a single ended output stage will output mainly even order harmonics (which are musical), a push pull stage will tend to odd order harmonics. Though these aren't so musical, they'll be at a stupidly low level due to it being biased into class A...

Which is what it is all about


One big advantage of push pull is if it requires more current for the load it can be supplied, though it'll go into class B. A single ended stage will simply crap out (clip), as it can only supply the current it is set at on whichever side the current source is on.