Tannoys and Cross-overs

[GrahamFP]

Graham from Lincolnshire here, Hello!

This is my seconmd attempt at introducing myself and to ask for advice. The last I tried I was told to register first (I had) and my post was vapourised!

Here's the deal: About 53 years ago I had been 'located' by my employers to a remote part of Saudi Arabia. It was an airbase and was to become, I believe, the highest Lightning Station ever at 6,000 ft. Whilst there I bought an Akai reel to reel tape machine from a colleague. It came with a whole shelf full of 8(?) inch tape reels with recordings that included the sound track of “West Side Srory” I was bowled over, I had never heard such reproduction, it was if the performers were in the room with us” I should say the room was of pre-fab construction, no bricks and mortar. The political situation changed and whilst on UK leave the military contract was ended and I lost my Akai! (I last saw one in the flesh in the Science museum)! In my desire to retrieve a similar audi0 effect I recently went on a long drive to buy a pair of Tannoy Revolution R3's, floor standing, very heavy, speakers.

In some ways I am pleased with them but I find the orchestral bass parts seem distant and quiet, they are certainly not in the room! I am on limited budget but I feel I can get more out of these speakers. Investigations inside indicate that the drivers seem fine mechanically. The speakers cases proclaim they are made in Hungary. Interesting. So looking at the crossover circuit. It is labelled: Elytone 1999 L46.. It looks, to me anyway, that there are a couple of dielectric capacitors and one larger film rype. There is only one choke and that has a ferrite core (thought that wasn't a good idea)? The whole circuit is fitted to the back of the terminal 'block, As there is a tweeter and two further drivers I would expect to see three chokes? Can a way ahead for me be advised please? I can change components myself. Also I was hoping to see a concentric driver but not so.

Thanks for any help on this.

[walpurgis]

Hello Graham. Welcome to AOS.

Take a look around the site, you'll find sections covering every aspect of Hi-Fi and there's music interest too.

If you want to discuss speakers, you may like to start your own thread in our Blank Canvas area.


Enjoy the forum,
Geoff.

[Macca]

Hi Graham

Tannoy Revolution series were Tannoys mid-range offering from around the turn of the century. R3 was a two and a half way design so one driver runs from the low end up to the tweeter and the other just covers the low end. Hence only one inductor.

They are a competent speaker and should be pretty good for orchestral so what you are hearing may be an issue with source or amp rather than the speakers. Hard to say without more info.

You could replace components on the crossover like- for like. Use good quality brands from established known suppliers, there are a lot of fake components for sale these days. That may not solve your issue though.

[GrahamFP]

Thank you I am looking for and ordering replacement capacitors and will compare the modified first speaker with the original other one to see what difference that makes. Listening close up to the drivers I hear very little clear sound from either the tweeter or the bass (lowest position) driver. The middle one seems to be doing all the work, it must be a good driver! I see an upgrade of the Technics amplifier might be on the horizon. Going back to the Akai and it's abilIty to place the sound sources so well may be because with the higher tape speed maybe it's upper frequency (thinking of harmonics) capabilities were superior to 'ordinary' amplifiers/CD players etc.?

[Macca]

Looks like I was wrong about the R3, it does seem to be a proper 3 way design.

I suspect your memories of the Akai tape deck might be a bit rosy though. What speakers and amplifier did you use with it when out in Saudi?

A CD is an exact copy of the production master so should in theory be better than a pre-recorded reel to reel tape of such. With an analogue recording on CD you're effectively listening to the tape machine they used to make the digital transfer, which will be way beyond a domestic Akai machine in quality terms and there will not be any of the associated losses inherent in copying tape to tape.

You might want to look at improving the amplifier, most (not all) Technics amps are not that great with a demanding speaker load, which could be the case here from what you describe. Essentially the amp could be clipping all the time even at low volumes, hence the lack of presence and deep bass that you report.

[struth]

recommended amp power 20 watts up to 170. 8 ohm 3 way.

[Macca]

yes - but nominal impedance value doesn't tell you anything and I can't find any detailed measurements for them. I doubt that they are giving the amp an easy time of it.

[struth]

well if a 20 watt amp is enough then they are unlikely to be too tough a load, although as you say they could be. i'd expect to use at least 70 watt amp for comfort.

[Macca]

It's not about watts though, it's about maintaining power into low impedance swings and sudden phase shifts, and speed of recovery. A lot of amplifiers can't do that no matter how many watts they are rated for and a lot of Technics amps are especially gutless in that regard.

[struth]

agreed... i'd be wanting something a bit beefier. someone was happy with them on end of a brio so will give you an idea.

[walpurgis]

Quad 303 might be OK.

[GrahamFP]

Thanks for the comments on the Technics Amplifier, It states 30 Watts per channel and has speaker A and/or B outlets. I will post back results of the capacitor experiments/changes. I hope to see a bargain Amp one day to upgrade the Technics if needed.

[Alex_UK]

Erm, no idea, but welcome to AoS!

[Lawrence001]

Something doesn't sound right about your description of the crossovers. A 2.5 or 3 way speaker can't have a single inductor as it needs multiple low pass filters.

[EDIT Sorry I should have considered the low to mid range driver could naturally roll off at the top and not need an inductor so take this bit with a pinch of salt]

It's possible there's another crossover or inductor elsewhere in the cabinet so that might explain it

However, I did a search for your crossover and found the photo attached. It claims to come from a Mercury MX2 2 way speaker, which makes more sense.

So I'm wondering if you bought these second hand and someone had a go at repairing them with the wrong crossover. This could also explain the "distant" sound you can hear.

I suppose the low pass could go to both bass drivers with an additional inductor to filter out the mid range from the .5 woofer although this is an odd arrangement.

I think the best thing you can do is post some photos here for us to help.https://uploads.tapatalk-cdn.com/20211001/5ea2600a1e9b92840d450ed0cab4feb0.jpg

[Macca]

Good theory that Lawrence.

[Lawrence001]

If we can get a copy of the proper crossover circuit a new one can be built with good components and they'll sound better than the originals [emoji16]

[GrahamFP]

Here's a photo of the crossover. the blue caps values are 10uF ans 8.2uF the large one is 5.6uF I thought the big blue component was a capacitor but I think it is an inductance coil?

[GrahamFP]

Armed with a solder sucker and my old but still working L/C meter, I have just checked out a couple of capacitors and both well withing spec, so maybe the next step is to look at an upgrade of the Technics amplifier. I am looking at several Arcams on Ebay. Would an Arcam Alpha be a move in the right direction, I have a feeling it's a trifle tpp retro? Seller majors on 'comfort and for a small space. I want to be reduced to emotional wreckage - Shostakovich !0th for instance. Comments welcome

[Macca]

This

https://www.emporiumhifi.com/kent-branch/krell-ks300i-integrated-amp/

if that's too pricey look for a Denon PMA350, ideally a mark one version, should be around a ton.

[GrahamFP]

I will start a new thread/continue this in a more 'proper' part of the forum. Thanks for your help(s). I am looking for Denon PMA350.