Feeding the Tannoys

[GrahamFP]

Thank you Macca, for the steer towards a Denon PMA 350. I have ordered one off Ebay it arrives tomorrow. (Wednesday 12/10)

I have a somewhat catholic taste in music, Beethoven is probably, overall, my favourite composer but I like sometimes to be fired up by music with a sturdy message. So I am looking for a set-up as financially economic as possible, to cater for that. Where the current set up with my Tannoy Revolution R3's/Technics amplifier is, I feel, falling short, is in the more complex passages involving brass and percussion as in, for example Shostakovich's 10th symphony and the Black Dyke Band's rendition of "The God Particle" (by Ralph Rudin) I hope it's not the CD itself or CD player (oh dear, here we go again) but things seem to get very 'scrambled' in the louder, brassier, more percussive parts. So I have listened critically to that today and if the Denon amp arrives tomorrow I will listen again. That's the extreme of course but it will be interesting to see what 50 Watts/channel achieves, I am not seeking excessive volume just clarity and 'presence'.

[Macca]

Hi Graham

I think you'll find the Denon a step up. It's not the ability to go louder but its ability to control the interaction with the speaker that will make the difference.

if it doesn't you can blame me

[GrahamFP]

If it doesn't, I won't blame you, I'll blame the tuner or the CD player - or the wind-up gramophone even! :-)

Many years ago I was into electronics (Air radio fitter in the RAF) I need a refresher course and will try and catch up on the audio side of things. I am trying to get my head around what happens to the back emf from the speaker coils. When I was very young I worked for a spell in a coil winding shop for Associated Rediffusion, I made and tested many coils for their Q factor, I have forgotten more than I currently know. I think!

[Macca]

You're starting from a better place than I did. I still struggle to understand this stuff but it's worth it since it is important.

The problem is many modern (and by that I mean from mid 1980s on) passive speakers tend to be designed without any regard for how difficult a load they present to the amplifier. They may be efficient and give a lot of volume for 1 watt and that tends to be the only consideration.

Reactive loads draw large amount of current and if the amp can't cope it clips, this can happen at very low volume in some situations. Naturally this has a big effect on sound quality.

This means it's necessary to use a speaker that is a very benign load (rare these days) or an amplifier with a very robust power supply (expensive, always).

regrettably the complex interaction between passive speaker and amplifier is almost always overlooked leading to reviewer comments like 'A fifty watt amplifier will be fine' which is such a gross oversimplification as to be meaningless.

It also at least partly explains the wildly different subjective opinions you see on what is a 'good' amplifier and what is a 'good' loudspeaker.

[GrahamFP]

The Denon Amp arrived yesterday and, between other jobs, I have tried it out on a couple of very testing pieces, "The God Particle" used as a brass band competition piece with wide and sudden dynamic changes and very complex sounds, which caused me to be disappointed with the Tannoys on the 30 Watt/channel Technics amp, proved no problem on the Denon. The next test was a fine rendition of (allegedly) Albinoni's Adagio. This was part of the celebration of a overhauled church organ, so the organ was being auditioned too! This piece demonstrated this combo's ability to reproduce the organ pedal-notes and even my 'not easily impressed' wife said; "That's better." There are other 'tests' I want to try but looking very good so far, a definite improvement in capability. My next question...I understand (well, I am told) that film capacitors are more expensive than electrolytics but give better sound. There's a question of 'voicing', I believe. So is it simply a good idea to upgrade electrolytic caps to film as a matter of 'upgrade' or maybe it isn't as simple as that?? I noticed a difference in an R3 announcers voice but wasn't sure what the difference was, maybe a lowering on the treble control?... Or maybe a cap upgrade? :-) One slight problem with the Denon - The Speaker A, Speaker B control. A speakers always on, B speakers as a press button addition. Where the Technics Amp had A and/or B Which is preferable as the speakers are in different rooms. Is a swicth in the A speakers' speaker cable acceptable?

[sailor]

Hi Graham, yes it's a as simple as that and a good idea to upgrade the electrolytics particularly in the tweeter circuit. Replace them with the exact same value. I looked at a photo of your Tannoys and think I have heard a pair or maybe it was a similar model. Was a long time ago but if I remember I found the highs a little soft but it could have been some other reason.

If you find the same lack of sparkle then I recommend you consider a Mundorf EVO in oil. It has a slight up-tilt that adds definition to cymbals and brushes and opens up the sound. There are dozens of others to choose from. Generally a cleaner better defined sound is heard.

Available from many outlets, here's one:
https://www.hificollective.co.uk/com...p_evo_oil.html

From your time in the RAF I suspect you are comfortable with soldering in new parts and should you wish to upgrade more of the XO you can message me and I would be happy to offer some advice.

[GrahamFP]

Thank you, very interesting about the Mundford capacitors, I have never heard of them but the write up is interesting indeed and I will definitely get a couple. Fortunately I have slightly more recent experience than the RAF, working in the water industry. (Only about 25 years ago)!
I represented a Norwegian company selling a special type of water level measuring system. Funny enough it was a system built around capacitance. The capacitor consisted of a length of self heating cable, using the earth shield as one side of the capacitor, the teflon covering as the dielectric and the water, rising and falling, as the other side of the capaicor. The varying capicitance was converted to 'level; and displayed or fed to a controller. Handy for deploying in remote areas where the 'element' could be dry for months but immediately in action (withing a suitable tube) when levels rose (rivers and reservoirs) not suited to dirty or salty water. I don't think I will try one in my speaker though!!

Thanks for this interesting steer. PS Had an interesting stereo PM yesterday, Celia's requests: Larry Adler CD, one track "Caravan" being quite amazing, followed by Elgar's Cello Concerto with Jacqueline Dupré.(Vinyl) I can imagine no finer performance, followed by a Peggy Lee CD Her 'Let's Fall in Love is just so charming and funny and finally for a bit of light hearted fun some Fats Waller, a wonderful Stride pianist and very funny. All sounding pretty good - but good can always get better! But I think the law of diminishing returns would apply before long in this field.

[Macca]

Glad that's all worked out for you there Graham.

[sailor]

Interesting gauge you described. Perhaps it can be re-calibrated for beer which triggers a vibrator in the wallet when the level is low ��

Once you have installed the new caps please report back with your findings. I think you will be pleased.

[sailor]

I forgot to supply this link to a rather exhaustive capacitor review.

http://www.humblehomemadehifi.com/Cap.html

He marks all his personal favourites with an asterisk. The one I recommend is one of them. Have fun.