My visit to the Bermuda triangle (aka Milton Keynes)

[Richard Dunn]

Bloody place

Who ever designed it should be hung drawn and quartered, and even that is tooo light a sentence.

I have been there four times in my life and each time I have got completely lost. Even the AA map got me lost. I got a map from them before setting out, postcode to postcode, AND they sent me the wrong way.

Well I survived the experience with a lot of help from an extremely nice guy - known to you as Bottleneck (aka Chris). I got in and out of the Bermuda triangle with only getting lost four times going in and once coming out, next time I am taking a compass - I wouldn't even trust sat nav with it. Perhaps the streets move when you are not looking - it all a conspiracy - Milton Keynes was put there by aliens and populated by them - they are watching us and waiting to take over

Well the "aliens" I went to see and try are two brown and black monster coffins of *large* proportions, wieghing about a ton and a half, with fiddly little spring clips And a large lump of metal with some strange glass bottles sticking out the top known as a SET.

So how do these Aliens fare musically. Well to be honest I though the contest was going to be easy, antiquated technology pinned (sometimes literally) together with odd bits of wire. BUT this was far from the case, this system sings. It performs in all the right areas but mostly in its sense of scale, which is very close to reality compared with the small scale presentation of most British box offerings. The Yanks love scale, but mostly they cock it up, big panels that give you 10 foot long violins hanging in space. Not these speaker - scale - clarity - and minimal colouration (very surprising). Then those glass bottles - a sense of ease - more clarity than expected. A rightness that only a homogenous and sympathetic symbiosis of a system can provide.

For me, now doubts - can I fit nva into a system that obviously works so much in harmony.

Initial results yes and no. A classic connumdrum - the compromise has shifted. The process for me was very much a design exercise, so I am looking at and for things differently to a normal bake off situation. So to try to explain what I was looking for and how I found it may be a little confusing, so I will leave much of the analysis of that to Chris. But for those looking for a gross explanation - too forward and dominating in the presence region compared with the SET - leading edge and transient information clearly better - trailing edge (valve strong point) as good (very much pleased me as part of my design criteria to compete with a SET). These are gross, many minutia I wont go into here. So "Curates Egg", more work to do. BUT I forgot about those wirewound rheostats (pots) at the back of these beast. One notch down and that presence region come back into perspective.

So for me a lucky win in extra time on penalties not the one nil and cruise home so as not to embarrass the old and aflicted They may be old technology, and in the case of the Altecs old in reality. BUT the music is undeniable and I can understand how Chris has fallen in love with them (the ugly wife who is great in bed ).

For me - well I am happy - it has given me the things I need in my mind to progress the project. I am still not sure if I can be bothered to put it into production, but Chris was nice enough to encourage and nag me to do it, so I will progress to the next stage of production prototyping it. And as it was very much the thread on the Nottingham horns at zerogain that started this, I will make the process open and communicated with you all, and other participants in the next round of listening will be much appreciated.

Much thanks to Chris for his hospitality.

Richard

 

[bottleneck]

Thanks to Richard for coming over, and the generous gift of some of his soundpipe interconnects. Very kind - thankyou!.

I'd like to make a quick plug here for these interconnects. As regular forum people will know, I'm someone who doesn't believe interconnects should be expensive (they are all just a lead with some plugs on the end after all).

In the past I've made interconnects by buying some decent plugs for about a fiver, perhaps another tenner for cable, heatshrink, tubing, outer casing etc. About £15 in all, and burnt fingers and crappy finish to boot.

NVA sell the 'soundpipe' interconnect for £25-£30 on e-bay. If I was starting from scratch I'd just buy some of these. I especially like the way they bend into shape, so you can prevent hums by literally steering round power cables!.

http://cgi.ebay.co.uk/NVA-40cm-1ft-...QQihZ018QQcategoryZ116850QQrdZ1QQcmdZViewItem

I'll write about the amps later, I've run out of time..

 

[bottleneck]

ok..

a few minutes spare to talk about amp comparisons.

As I understand it, the new NVA design is there to provide a solid state competition to SET amplifiers.

We took my sub out of the chain - I normally use a pre-power and the NVA is an integrated, so that wouldn't have worked.

We compared my Glasshouse 300B SET amp (9w SET) with it's pre - a Consonance Basie to the NVA.

Different cables were used with the NVA - the NVA own speaker cables and interconnects. As I understand it that is something that is best done with the amplifier.. certain protection circuitary is left out for sonic reasons, so cables representing odd loads shouldn't be used.

There were many differences between the 2 amplifiers.

Only a day earlier I'd been playing with alternative pre-amps - and used a transformer based passive pre with the glasshouse (a new glasshouse kit is about to be launched with transformer based passives).. so this was fresh in my mind.

To make a long and complicated story brief (for time's sake!!)...

I would say..

NVA - had more detail (in the way that solid state typically does), it was quieter (in terms of background noise), had more treble emphasis and less bounce in the bottom end.

Glasshouse - more rounded at the edges, more bass, less treble. Noisier - but when I used the transformer pre I had more treble, more detail and no background noise.

The NVA I think will make a really great solid state amplifier when it is launched. It didn't sound like a SET amp to me - more like a very good solid state amplifier.. doing all the things well that a good solid state amplifier should do, somethings exceptionally well (like clarity and speed).. you could criticise the power output - but that was never part of the design goal - or critical in this application.

I know Richard will make some adjustments before it goes on the market, perhaps to reduce output in the treble a little..? - I'm not sure.

Essentially what I'm trying to say is that this is an excellent solid state amp. It will especially appeal I think to people who appreciate detail, speed, and purity of signal.

Looking at the very low price of NVA amps on e-bay, you certainly seem to get a hell of a lot of sound for not much.

In my own application I've picked an amp that goes very well with my speakers, so really asking the NVA to step right in and fill it's boots is irrelevant.. it's a very set of requirements that my speakers need. We achieved a great sound at the end of the day however, and people looking for a solid state amp should look this way if they don't need gob loads of power.

I'm waffling here, and perhaps going in circles!!...

I think Richard intends to put the amp in (extremely gorgeous looking) chrome finish... check out the pics below!....as monoblocks I understand with a bigger power supply.

He may put it in a more standard black acrylic 2 case aswell for less money.

I hope he does both - it's a great amp.

some pics of the chrome boxes and acrylic black (much nicer in the flesh)

these pics taken from the following site which has a lot of info about NVA:

http://nva.sclnz.com/

 

[Richard Dunn]

No wont be chrome. Just showing the concept of using a chassis instead of a box the way we did it in the Statement Range back in the early 90's. It will be entirely black acrylic but a chassis type design as in these, if I go ahead.

If you could still say definitely it is solid state then that goes against the aim. I would like eventually when finalised to do this blind. The main difference in SS amps in this type system is they will sound relatively "dirty", this didn't happen, that is what I was looking for. The treble is sharper and more extended as it (the amp) doesn't have to cope with an output transformer. This is why McIntosh used output transformers in SS amps in the 80's to mimic this. This is wrong, all that is needed is to attenuate the super tweeter a little. A transformer whether you like it or not is a big filter and you are compensating for its effect. Frequency anomalies are not the problem, because unless you measure in situ you haven't a clue what is "flat" in the first place and what is compensating for what. It goes beyond that level.

Building systems is what it is all about and that system works and elements compensate for and compliment for each other. I was happy because those compensations are easily catered for in the units, as with the rheostat, and also remember why you needed the super tweeter in the first place. In that system with the nva amp I would virtually turn them off, then the rheostat could come up a little.

Richard

 

[bottleneck]

No wont be chrome. Just showing the concept of using a chassis instead of a box the way we did it in the Statement Range back in the early 90's. It will be entirely black acrylic but a chassis type design as in these, if I go ahead.

Shame! the picture of the chrome amps look gorgeous. Still, if it doubles the price, I'd go for an acrylic one if I was buying too!

If you could still say definitely it is solid state then that goes against the aim. I would like eventually when finalised to do this blind.

I think that I could, but of course the test was not blind, nor dbt. Just because it didn't sound like my SET amp doesn't mean it isn't a valid alternative of course.

The main difference in SS amps in this type system is they will sound relatively "dirty", this didn't happen, that is what I was looking for. The treble is sharper and more extended as it (the amp) doesn't have to cope with an output transformer.

This may definately be part of the reason. I would emphasize that when used with a passive pre-amp, my 300B amp exhibits more treble detail. I think the pre-amp of the nva is passive (?), so of course there was a difference here.

Building systems is what it is all about and that system works and elements compensate for and compliment for each other. I was happy because those compensations are easily catered for in the units, as with the rheostat, and also remember why you needed the super tweeter in the first place. In that system with the nva amp I would virtually turn them off, then the rheostat could come up a little.

The tweeter (can't really call it a super tweeter, it only extends to 22khz!) was added because the compression horn in the Altecs begins to cut off about 14khz, and dies altogether about 16khz. It's losing output well in human hearing. Turning them off (or nearly) would definately reduce the frequency range of the speaker.. I had them like this when I first had the speaker, and the difference with the tweeter added is definately marked, with a variety of different amps.


All the best,
Chris

NB - you have email

 

[Richard Dunn]

Turning down not off.

It will look similar in shape (not a box), just the chrome is too bling, and I don't want to get involved in alluminium work now, in the old days we had a full metal and wood workshop for cases and speakers, lathes - presses etc.

Treble detail and treble extension / prominence *should * be two different things, and should be clearly heard as different as in your pre amp experiment. What I heard last night was initially presence prominence and when the rheostat was turned down then treble prominence. Only at that point did I start to *hear* the tweeter (sorry to refer to it as super tweeter, but it sits on the box like one).

Yup passive pre.

Yup the Altec needs some reinforcement up there, but my point is you are also compensating for the 300B or more to the point its output tranny. Now your experiments with the passive may make me wrong in this, but consider that the type of passive you tried was a transformer one, designed by the same guy who designed your 300B. If I were in his shoes I would put some treble boost in at this stage either by accident or design to compensate again for the output tranny roll off. So we may have another synergy in that case. An active pre would have to be pretty badly designed to roll off that much to make that much difference. Detail I would accept, extension not. Two different things that some people confuse.

This discussion is positive in nature not negative. It is a similar process that would be gone through if you were a member of the company and part of the design process. This for me is part of putting the process in *the public eye* as I promised. I thank you for you input.

Richard

 

[bottleneck]

Hi Richard!

Yes, all good natured friendly discussion

I'm sure you're right in regard of passive's showing detail rather than extension. I think the lower noise floor really helps too. My pre does have hum.. but then I like what it does... a double edged sword

Tried a few passives over time, and I know they are not for me. I experience a cleaner more detailed sound with lower noise floor and they sound better at low volumes. Those I've tried just don't seem to ''push'' the sound into the room - which I especially notice on reggae, dub and dance music. I tend to prefer them for acoustic, classical and some other forms. I'm just living with my favourite compromise I guess!


I really like the acrylic boxes by the way, the photo's just don't do them justice. You really make some superb amps!. Given the price of some of the one's already on e-bay, a lot of a bargain I would say.

 

[Richard Dunn]

I fully understand where you are coming from and admire and respect your system. But I have to pull the lines down certain directions to dig out what I need to know. If I stick to the status quo nothing is ever progressed. Progress always comes from lateral thought. Many (most) lateral lines achieve nothing or parity, but occassionaly "ding" the light bulb goes off. It is a lovely feeling when it happens, but you must push your perception boundaries to create the potential for this. My work with you and this amp is one of these pushes, but also I wont be a slave to your status quo, I will push on your boundaries as well.

That is why I wanted to leave you the amp for a while being selfish and wanting your feedback.

Richard

 

[Richard Dunn]

Oh also in that picture taken of the black box and statement ranges, that was about 91 or 92 and then the black box range weren't acrylic / perspex which is why they look duller. The back front top and bottom were anodised alluminium, the sides were black MDF. We switched to perspex front in 95 and the rest of the case slowly went across. The last thing to change were the end cheeks, they have only changed to acrylic in this latest incarnation.

Richard

 

[Dik Dolan]

Interesting stuff. I dont think there is a lack of high frequency inherant in the Glasshouse..certainly non that I can hear...but I am 48 now, and probably deaf=) Just for clarity, the quoted specs for the amp are : Bandwidth +/- 1dB 16Hz - 20kHz
Another thing to take note of, "SET" isnt a fixed target, different SET amps will sound as different from each other as different transistor amps do, also just changing to different makes of valve will give a different presentation.

 

[julian2002]

nor wishing to be confrontational but isn;t this discussion about, for want of a better word, effects processing or possibly equalisation? the music industry has been using fx pedals and boxes to alter the sounds their instruments make to suit their tastes for years. this has always been anathema to hi-fi enthusiasts, or at least we say it is, yet we still prefer different speakers, cables, amps, etc. isn;t it about time for some of those boxes to cross over from the professional to the enthusiast arena? to a certain extent this is already happening with the bheringer deq 2496 however a quick look at behringers website reveals a whole slew of potentially interesting stuff - including tube simulators etc. anyone have any of these boxes (e.g. a MODULIZER PRO DSP1224P, TUBE COMPOSER T1952 or COMPOSER PRO-XL MDX2600) if so i'd love to hear how close they come to emulating a set setup using a ss amp.

 

[Richard Dunn]

Interesting stuff. I dont think there is a lack of high frequency inherant in the Glasshouse..certainly non that I can hear...but I am 48 now, and probably deaf=) Just for clarity, the quoted specs for the amp are : Bandwidth +/- 1dB 16Hz - 20kHz
Another thing to take note of, "SET" isnt a fixed target, different SET amps will sound as different from each other as different transistor amps do, also just changing to different makes of valve will give a different presentation.

There is character and there is nuance. I put it to you that it is character that attracts you to SET and nuance that gives you final decision as to the make and to part tuning.

It is the character that I am looking for. As I said in a back post, normally into something as easy and efficient as the Altecs transistor amps sound "dirty" because they hide nothing in gross terms and shove it right infront of your face. Sublty and other musical characteristics are another kettle of fish.

It is as though you are dealing with another genre. This is the 1950's. Low power requires high efficiency, requires compromise to give the SPL. Late 60's onwards, power available in bundles so those "percieved" compromises can be traded off against lower efficiency, and acoustic suspension means smaller more domestically orientated case. BUT what comes around goes around, just human nature. In all compromises you miss something, so we now have a throw back movement to get what is lost in terms of scale and dynamic considerations. I am trying for the best of both worlds, I will probably fail miserably, but the fun is in the challenge.

That is the process we are in.

Richard

 

[Richard Dunn]

nor wishing to be confrontational but isn;t this discussion about, for want of a better word, effects processing or possibly equalisation? the music industry has been using fx pedals and boxes to alter the sounds their instruments make to suit their tastes for years. this has always been anathema to hi-fi enthusiasts, or at least we say it is, yet we still prefer different speakers, cables, amps, etc. isn;t it about time for some of those boxes to cross over from the professional to the enthusiast arena? to a certain extent this is already happening with the bheringer deq 2496 however a quick look at behringers website reveals a whole slew of potentially interesting stuff - including tube simulators etc. anyone have any of these boxes (e.g. a MODULIZER PRO DSP1224P, TUBE COMPOSER T1952 or COMPOSER PRO-XL MDX2600) if so i'd love to hear how close they come to emulating a set setup using a ss amp.

That is another route and is well worth looking down. Digital is not my expertise, I am an analogue man, others will have to pursue that path. I am also a great believer in solving problems as opposed to curing them, there is a subtle difference. Solving is benign, every cure has side effects.

Richard