steve
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Posts: 206
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Post by steve on May 4, 2018 8:25:18 GMT
During the inquest following the speaker debacle, I learned that semi-omnis, as Stu above says, simply don't work in large rooms, so what did I then do? You guessed it! I took them to another big room in Huddersfield viz-viz Dave Brooks' shop dem room for a speaker bake-off. Bad move! You'd have thought I would have learned by then, but no. The result of course was all too predictable. One kind soul whispered in my ear "at least Steve, they are good for background music. They give a nice wash of sound and they are inoffensive."
During my dem, most of the audience lost the will to live and just talked all the way through. I left a broken man, unable to handle the fact that these speakers worked at home but nowhere else. I didn't care if they brought the heavenly choir of angels into MY living room. If they didn't work anywhere else........then as the Swinton advert says "theeeers nagging doubt" I's always going to be there.
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Post by MartinT on May 4, 2018 8:28:58 GMT
If they didn't work anywhere else........then as the Swinton advert says "theeeers nagging doubt" Hmmm, I really wouldn't care if my speakers didn't work in any other room in the world. They work in mine!
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steve
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Post by steve on May 4, 2018 8:32:46 GMT
To cut a long story short. I tweaked up the crossover and finally managed to get the omnis working in different rooms. A mate in Hull with a large room hosted the speakers, which finally worked properly. I had, despite all the problems, produced a semi-omni that not only worked in big rooms, but also played music beautifully.
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steve
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Posts: 206
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Post by steve on May 4, 2018 8:36:37 GMT
So by now, the speakers were sorted, I had two excellent amps in the form of my pink SET and the NVA A20 combo, depending on my mood. Everything was going swimmingly, music filled the room...
........then an email from Richard Dunn, pinged into my inbox......
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steve
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Post by steve on May 4, 2018 11:10:35 GMT
"Diy transistor amps are not as hard as you think as long as you have the design and circuit already done. Recently I have been getting great pleasure out of reading Stu's adventures so I offered him two working boards for £**** and he jumped at the chance....." The upshot is that Richard offered to sell me two boards as well, so I too jumped at the chance and within a few days a couple of NVA amp boards plus four output transistors arrived: Having never even soldered a transistor in anger I thought "now WTF do I do?"
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steve
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Posts: 206
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Post by steve on May 4, 2018 11:18:36 GMT
I set about reading up on bi-polar power supplies and ordered a case, some 25A bridge rectifiers, a mains transformer and some power supply caps and started drawing up a power supply.
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steve
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Posts: 206
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Post by steve on May 4, 2018 11:28:48 GMT
After a false start with an overly complicated power supply, some extremely crap semiconductor soldering hamfistedness and a mild bollocking from Richard, I finally started to listen to advice and simplify the PSU right down to the absolute minimum required to make it work and ended up with one whopping 300VA mains toroidal transformer, one bridge rectifier, two 10000uF caps and two bleed resistors. That was it, as simple a power supply as it was possible to get:
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steve
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Posts: 206
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Post by steve on May 4, 2018 11:45:41 GMT
When I introduced this mutant NVA amplifier into the system and played the first record through it, my jaw hit the floor. I had never in nearly 40 years of owning, using and building my own sound equipment, heard anything quite like it Below is a review I wrote: "The simple power supplied amp, has a lower noise floor than the twin rectifier supplied amp I had before, but there's more to it than that and before you think I'm about to start on that "instruments emerging from an inky black silence" audiophile bullshit, you can rest easy. There's no such thing as inky black silence unless you live in the vacuum of space; no, what the ultra-low noise floor allows, is for you to better hear the silence behind whatever is going on in the recording. Reverb tails or repeat echo effects decay naturally into the studio or venue space and can be heard to do so, even with louder instruments playing at the same time. Now when that happens, you get a far better sense of a human musical event happening between the speakers, which in turn, leads to greater involvement with the performance on the part of the listener, because the aural clues to the space, real or artificial are preserved intact. This may sound somewhat abstract, but the ability of a piece of equipment to pull off this feat is paramount, if the sense of music happening in front of you is not to be compromised. I'm not talking about "detail" or any of that hi-fi nonsense; this is something else and once you are tuned into it, the absence of it becomes obvious. Now I've heard it, it has become a basic requirement for music reproduction. This NVA DIY build has that requirement nailed and not many amps I've heard have it down anywhere near as well. So having had the basics laid down by the DIY NVA so convincingly, we can move on to the more concrete ablities of this piece of equipment. For example, solo piano is notoriously difficult for a piece of equipment to get to grips with due to the complexity of the overtones and harmonics the thing produces and the percussive nature of hammers on strings. The NVA preserves the harmonic structures of the instrument and the attack, sustain and decay, like nothing I've heard short of a top end SET amplifier. Hell, it makes my speakers sing like I've never heard them sing before. You get piano, player, and hall, all interacting with each other to an extent that for all intents and purposes, the performer might as well be playing just for you. If, like me, you are trying to practice mindfulness and are only having limited success, the ability of this amp to take you into the centre of the performance will bring you right into "the Now" and keep you there with a disarming ease that is brilliant. With groups of musicians, whether jazz ensembles, string quartets, full orchestras, choirs, rock groups or anything in between, you get the full picture of what is going on, and where. You can follow all of the instruments, all the time, hear the interactions on single take studio recordings and live performances and what's more, even to a non-musician like me, those interactions and harmonic relationships make sense, you hear not only the individual bits, but also how it fits together as a whole. Those old Blue Note jazz records from the 50s and 60s seem to be lit from inside by some primal force.Lou Donaldson's Hammond driven sax workouts such as "Everything I do Gonna be Funky From Now On" are a case in point and hit the monkey bone right on. On the soul front The Temptations' "Papa Was a Rolling Stone" and "Law of the Land" ooze atmosphere and menace. Stevie Wonder's "I Wish" is complex and layered with bubbling bass synths, insistent hi-hats and funky brass stabs melding together into a funked up festival of sheer infectious joyfulness. OK..now the superlatives are out of the way, you should be getting the general idea that I like this amp.....a lot. The Doc's philosophy that all components get in the way of the music is an interesting one. Having heard for myself the effect of removing unnecessary components from the PSU, I think you absolutely have to take what he is saying, and has been saying for years, very seriously. The man is damned right and if that brands me as a "Dunn Disciple" Then so be it. I don't give a monkey's, it's their loss. This is the first time I have ever reviewed a system and not mentioned bass, treble, midrange, detail, texture, speed, dynamics or slam; I didn't have to. Now that is quite interesting.
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Post by MartinT on May 4, 2018 11:53:34 GMT
Having never even soldered a transistor in anger I thought "now WTF do I do?" I find working on transistor circuits much easier than messing with valves and high voltages.
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steve
Rank: Trio
Posts: 206
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Post by steve on May 4, 2018 11:56:20 GMT
I was the opposite. HV makes me wary, low voltages and high currents scare me crapless. It is far too easy to make an arc welder with transistors, but I'm getting there
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Post by MartinT on May 4, 2018 12:03:32 GMT
This is the first time I have ever reviewed a system and not mentioned bass, treble, midrange, detail, texture, speed, dynamics or slam; I didn't have to. Now that is quite interesting. Thanks for this, I find it very interesting. Sometimes people do get hung up on the semantics (which I mentioned earlier), which doesn't worry me too much as I know what I mean. I do try hard to impart a sense of what I'm hearing but sometimes it's hard and I almost give up. I do find myself talking about air and space, the sound of the venue and vividness more these days because I have more of those things now. Most importantly, it's down to whether you feel you're listening to a musical event or just a facsimile. It sounds like you are now. Congratulations! So... why are you now running different speakers?
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steve
Rank: Trio
Posts: 206
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Post by steve on May 4, 2018 12:25:40 GMT
Ahhh now that is quite an interesting development in itself.
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steve
Rank: Trio
Posts: 206
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Post by steve on May 4, 2018 14:20:04 GMT
So by now, we all will have grasped the unfortunate fact that small, semi-omni speakers do not work in large rooms. I had made one work in a larger room by tilting the up-firing main driver forwards by about 20 deg, giving the direct to reflected sound ratio, favouring the direct a little more. However with Owston coming up again at the end of June and the memory of what happened last time uppermost in my mind, I decided that there was going to be no chance of it happening again. No omni of mine was going anywhere near that venue. This meant I was without a speaker to take with me. A year or so previously I had bought a Fane 12" full range, triple cone driver that claimed extension to 17KHz. The idea had been, to use it in a retro mono radiogram style cabinet, but the project never got started and the driver remained in its box. I had thought a few times about selling it on, but the lack of a suitable speaker for Owston caused me to re-think that idea, so I bought another one, to make a stereo pair.
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steve
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Posts: 206
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Post by steve on May 4, 2018 14:27:27 GMT
The idea was to knock up a pair of simple sealed boxes in cheap softwood ply and take the speakers to Owston to demonstrate with. I was not expecting a lot, so built the pair of ply boxes, with a single brace just under the driver to reinforce the cabinet and prevent the worst of the vibrations. The boxes were relatively easy to build and in a couple of days I had them finished. WAF was missing in action, but when I fired up the system and cued up a piece of big band music, my jaw hit the floor again.
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steve
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Posts: 206
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Post by steve on May 4, 2018 14:37:58 GMT
WTF? The music quotient was now off the scale as far as I was concerned. Bloody hell this was another huge jump in the music making ability of the system. These drivers are 100dB efficient for 1 Watt and they produced a thoroughly convincing musical performance on just a whiff of throttle. These were not going out of the room now! A plan was hatched to veneer them in walnut and produce a retro 50s vibe with a set of oblique wood tapered legs and a front baffle covered with some maroon coloured Rexine, ie make them acceptable in the room, despite their size. Much veneering, application of Danish oil, Rexine on the front baffle and fitting of walnut tapered legs later, I ended up with these fine pieces of late 1950s/early 60s furniture: hi-fi from another era. The wife loves them as can be seen by the application of ornaments and pictures to the top surfaces of the speakers.
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steve
Rank: Trio
Posts: 206
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Post by steve on May 4, 2018 14:44:59 GMT
The simplicity drive was complete, once my son brought round a passive preamp he had upcycled from an old, late 70s Yamaha cassette deck. The volume control is a dual concentric pot, once used to control independently the recording levels on each channel of the Yammy tape deck. Nice:
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Post by ant on May 4, 2018 14:47:15 GMT
I have heard these speakers, i want to bring them here and see what they are like on the end of my F5.
Imo they are very good indeed
And it was out of a sharp tape deck not a yammy....
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steve
Rank: Trio
Posts: 206
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Post by steve on May 4, 2018 14:55:55 GMT
So now we've come full circle, story told and the system looks like this: Now we can discuss Simplicity is the key.
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Post by MartinT on May 4, 2018 15:03:39 GMT
I must say the speakers look great!
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steve
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Posts: 206
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Post by steve on May 4, 2018 15:52:34 GMT
Cheers Martin, they turned out well.
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