KEL84 Complete

[Timbo in Oz]

I was still wedded - at the time - to the SS way of measuring and expecting things but from tube amps and wanted all the power I could get.

but we still snubbed each diode anyway.

It is entirely possible that we will return the mid-bass duty amp to UL, and do the NFB experiments.

I am much persuaded that circuits need to be as simple as possible, and complex enough to work - especially power amps,

SO in playing with the NFB and thus bass damping, I'm not adding extra components and three solder joints, just a single contact, and it will be a good switch! I'm just playing with the values of two components that form the NFB around the OPT stage already.

and that the ear gets to rule in audio -> as did Harry Ohlson - who only identified 1 strength of spherical enclosures - ;-)!

their 'very early reflection' behaviour - aka diffraction, which is audible JBTW and this stuff happens a lot earlier than the room reflections and does help with hearing the original hall - and directly affects the wave shape launched at us, not what left the drivers.

As it should, if you think about how the 'hall/-sound' can futz with the acoustic sound on the night!

Have a think about what I might think of Bose 901's !!!!!!!!!!

Even if you made them out of aluminium as in the original and multi Gallos, they are still inherently strong and resist the audibly worst kind of resonance - bending modes.

They are - in 'single enclosure spkr' designs - potentially aimable to an extent unimginable to you. I call it focussing them ;-)! azimuth and elevation and yaw, and, so in roll!

One surprise is how musical/direct/clear they stay way off axis! The imaging doesn't collapse it just gets weirder and weirder. ;-)!

John Dunlavy respected these efforts here in Canberra - when he was running his business in our industry area called Fyshwick.

A clear person is John!!

[Phil Y]

And finally some pictures.

[Phil Y]

And two more.

[Cobblers]

Originally Posted by Phil Y

And finally some pictures.

Neat work Phil.

Note to WD:
It's a shame that all those cables are the same pink, It would be easier with different colour cables for fault finding I would have thought. Easy enough I suppose, petty I know.

[I love my records]

Hi all,

I'm considering the KEL84 as its price is nearer to what I can afford at the moment. Would it be loud enough in a room 3.5m by 4.5m, driving 25As and backed up by a small subwoofer?

Would the fact that the WD25 has well damped bass, mean the signal reaching the sub would be 'tighter'? I'm currently using an Exposure XX integrated which I love as the bass is tight, articulate and seems to have good 'pitch' if you get what I mean.... It sounds great at mid to high levels, but for quiet stuff, there's a little hiss/hum from the speakers and the sound seems a touch mushy or dirty.

Will the KEL84 outperform the exposure at lower levels? Will it be very different in character to the Exposure?

I'm thinking it would go well with my WD25As, but they are a 6 ohm load. Are the transformer taps in the KEL84 8ohm, 4ohm, or both.

Would it really make much difference, if a 6ohm speaker is run from an 8ohm tap?

I was told once that you should run off the tap that is 'higher' than your speaker impedance. Is this true?

So many questions!

Thanks in advance. Dave.

[petercom]

First of all the 'new' WDKEL84 uses the same colour coded cables as the WD88VA to aid both assembly and fault finding. The 'pink' cables from the phono sockets to the input switch are all the same cable of course. There is the option with WDKEL84 to use the relay switching board that we developed for WD88VA instead.

I would imagine the WDKEL84 will sound quite different in the way it plays music compared to the Exposure but the tonal character should be similar, though the bass may be slightly 'warmer' due to the lower level of speaker damping. If your subwoofer is active then the amp won't make an iota of difference as the character of the subwoofer is in its own amp and driver. You might just find that, with the WDKEL84, you can dispense with the subwoofer for stereo listening!

It should certainly sound better at all listening levels. In my experience valves are exceedingly good at expressing musical dynamics, compared to SS amps which sound more compressed.

Run it with the WD25As on the 8 Ohm tap. The usual reason for suggesting a higher tap than the specified impedance is that the 'nominal' impedance is taken at through the low point of a speaker's impedance curve (not the absolute minimum, but near it) and the impedance usually rises through the midrange and treble.

As for loudness in your room this is always difficult to quantify as it depends on how loud you like to listen and how far you sit from the speakers. As a guide you can expect a valve amp to equate to about 4 times the power of an SS amp due to the way it handles musical dynamics. We had no problem at the Heathrow show driving WD25Ts to demonstration levels with the KEL84.

[buddam]

At the last WithamFest my KEL84 (WAD not WD but I guess few differences) drove 2 or 3 pairs of speakers of various types with no difficulties. My own floorstanders are 88-9dB in a room that's up to 14ft high inplaces, 12 foot wide, and 35ft long (although the speakers fire across the room at one end). Not ideal (!), but the neighbour will testify that there are no problems driving those speakers in that room. (Bear in mind, however, that he is a neurotic wimp).

If it helps you decide on the KEL84 purchase you might also like to know that many of the chaps on this BB remarked on what an excellent little amp it is at the WithamFest. I'm certainly still very happy after 3 years

Best

Adrian

[I love my records]

Thanks for all the detailed help guys!

I'll be going to the next Manchester Hi-fi show, in Feb I think...just wondering if WD will be present with all their latest gear as it would be an ideal opportunity to take a few 'classic' LPs along to listen to the amp, although it seems to fit my bill right now.

Maybe one day the wife will let me pop along to an Eggfest? Who knows? She'd probably think I was having an affair!

Thanks again, Dave.

[steve s]

I would come to eggfest 1st... you'll learn so much more...

one of my lads had a party the other night.. his audiolab 8000s and B&something cdm1's sounded particually dreadfull..
... its hard sometimes to remember how good some of this valve gear can be until you compare it to (relatively) good shop bought kit

steve

[petercom]

Originally Posted by I love my records

Thanks for all the detailed help guys!

I'll be going to the next Manchester Hi-fi show, in Feb I think...just wondering if WD will be present with all their latest gear as it would be an ideal opportunity to take a few 'classic' LPs along to listen to the amp, although it seems to fit my bill right now.

Maybe one day the wife will let me pop along to an Eggfest? Who knows? She'd probably think I was having an affair!

Thanks again, Dave.

At present we are planning to be there. Will keep you posted on this.